"Jim Alexander" wrote in message
...

"PeterCB" no.mail@please wrote in message
...
Good for youI hear you say!

Don't want to spend to much £80.
What do you recommend?
Needs 2 x batteries - Hammer not important.

Assuming its your first drill or you might not be asking, if you pick one
you like the balance of with a 2 to 3 year replacement policy you probably
won't go wrong if its DIY you are doing. My first drill was a B&D 8.4V
(RIP). OK I've got a cheap 18V Parkside now which is fine. Even has an
automatic locking chuck normally found only on more expensive brands. OK
its batteries are not brilliant but with 2 and fast charge I always have
power. Its high speed is a fast as a Metabo. I'd really hate it if I
still had an expensive 8.4V Makita or Metabo just because it was still
possible to get spares and service. Who wants to service a 3 year or
older drill when the service costs would exceed the residual value.

Jim A

Thanks Jim - It's not my first drill - I've been coping with a ferm drill
for a while - It worked well at first but has only lasted a year.
It's ready for binning now. I want one for daily use for light to medium
weight drilling (very occasional hammer - when I can't be bothered to
get my sds hammer drill out!)

If I was to opt for the ryobi drill at twice the price of my old drill,
I'd expect it to last at least twice as long.

Thanks for your reply.

Pete

On Thu, 21 Oct 2004 19:15:00 GMT, "PeterCB" no.mail@please wrote:

Don't want to spend to much £80.
What do you recommend?
Needs 2 x batteries - Hammer not important.

Any online sites that you care to mention.

Bought one in Homebase today. 18v. 2 1.7Ah batteries. 1 hr charger.
Carrying case. £79.99 - but being Homebase 10% off day it cost just a
shade over £70. It's this one:

http://www.argos.co.uk/webapp/wcs/st...ckfrom=imag e

*** DO NOT BUY THIS FROM ARGOS! ***

Instead, buy it from Homebase. They've got a special offer on at the
moment (at least, Homebase in Bracknell have), buy a Worx tool costing
more than £50 and they throw in a completely free workbench. They
reckon the workbench is worth £50 but that's possibly debatable - I
reckon £30-ish if you were to shop around (however, Homebase are
selling the workbench as a separate item for £49.99 so maybe it is a
valid price).

The workbench is similar to a traditional B&D Workmate in design, but
the top platform can be angled - could be very handy for some jobs.
The top platform can also be raised and lowered to different heights
off the ground. The workbench is pretty sturdy and took me minutes to
put together this afternoon. Even if you weren't looking for a
workbench it would make someone a really nice Xmas pressie - or you
could donate it to a charity for use as a tombola prize or something.
It's not crap IMHO.

And I used the drill this afternoon for a short time. Not a bad piece
of kit, feels fairly sturdy. I think it came with a 3 yr guarantee
(need to check that....).

Andrew

"IMM" wrote in message ...
"Mark Begbie" wrote in message
om...

I'm in the same boat - 4.8V electric screwdriver just gives up when
pushing bigger screws.

Anyone know if Worx tools (Homebase and Argos) are any good? I've
seen a 14.4V drill/driver with 2 x 1.5Ah bats and 3 yr warranty for
£45 which looks like a REALLY good deal.

Probably is, but only if they are 1 hour charge time.

They are 1 hour IIRC, which B&D aren't.

In article ,
Mark Begbie wrote:
Anyone know if Worx tools (Homebase and Argos) are any good? I've
seen a 14.4V drill/driver with 2 x 1.5Ah bats and 3 yr warranty for
£45 which looks like a REALLY good deal.

Probably is, but only if they are 1 hour charge time.

They are 1 hour IIRC, which B&D aren't.

Why this fetish for buying a cheap drill good enough for limited DIY use,
but insisting on a fast charger?

Like for like, the faster you charge the batteries, the less time they
will last. And more so with poor cells - which is one of the main problems
with cheap power tools.

--
*How come you never hear about gruntled employees? *

Dave Plowman London SW
To e-mail, change noise into sound.

On Fri, 22 Oct 2004 20:01:55 GMT, "PeterCB" no.mail@please wrote:



Thanks Jim - It's not my first drill - I've been coping with a ferm drill
for a while - It worked well at first but has only lasted a year.
It's ready for binning now. I want one for daily use for light to medium
weight drilling (very occasional hammer - when I can't be bothered to
get my sds hammer drill out!)

If I was to opt for the ryobi drill at twice the price of my old drill,
I'd expect it to last at least twice as long.


You might expect it, and that is the rub.

If you buy a proper branded product at a decent price from a
manufacturer with spares and service backup you can expect and get a
good quality product with the ability to get it fixed if and when it
fails. Also, in the context of consumer legislation, if you have
bought a good quality product then you can reasonably and effectively
squeeze the retailer to replace it in case of early failure.

The low end and OEM manufacturers operate to a different principle
because their products are sold through volume distribution outlets
such as B&Q. The retailers do not want to implement any form of
customer service, spares or repair but only to shift boxes - it
doesn't fit their business model and would cost them money.
They also know that because the products are low end, a significant
proportion of would-be customers won't buy them because they are
unknown, there is little or no backup and that a customer would likely
not do well if trying to invoke consumer legislation.
To get around this, they offer a three year warranty, serviced by
exchange and push the returns back to the supplier. The implication
is that after the warranty has expired, there is no further backup, so
in effect, the tool should be considered as written off and living on
borrowed time after that.

Interestingly, the branded manufacturers are now also starting to
offer three year warranties, partly to compete with this but also on
the basis of continued spares availabilitiy, service and quality.
The higher reliability means that they can do this at little cost and
also have an opportunity to gain visibility into the customer base
through returned warranty registration cards. In effect this is
removing any perceived advantage offered by the low end suppliers with
the advantages of better products and better service.

It really becomes a question of which factors are most important to
you

They can be

- quality and performance of the product
- ease and comfort of use
- total cost of ownership over the anticipated product lifetime
- initial purchase price
- availability of spares and service (usually inherent from first
three)

Personally, I set my criteria in the order above.
I can understand if people want to set initial purchase price as their
most important purchase criterion, but it is naive to do so without at
least considering most or all of the others.



..andy

To email, substitute .nospam with .gl

On Sat, 23 Oct 2004 10:48:18 +0100, "Dave Plowman (News)"
wrote:

In article ,
Mark Begbie wrote:
Anyone know if Worx tools (Homebase and Argos) are any good? I've
seen a 14.4V drill/driver with 2 x 1.5Ah bats and 3 yr warranty for
£45 which looks like a REALLY good deal.

Probably is, but only if they are 1 hour charge time.

They are 1 hour IIRC, which B&D aren't.

Why this fetish for buying a cheap drill good enough for limited DIY use,
but insisting on a fast charger?

This is one of the OEM manufacturer's ploys - the same as having
higher voltages. I think it was Screwfix who was recently offering
a 32v drill at £32 with a slogan of £1 per volt. Of course, that is
all that it is - a slogan.

Battery quality is one of the main factors in cordless tools and one
of the main cost factors also. Hence the Panasonic 15.6v products
bening able to easily outperform other manufacturer's 18v offerings.

Considering the low end, the batteries are so poor and have such
limited capacity, that the only way to achieve any degree of
acceptability is to fast charge them. it also adds an additional
marketing ploy that they can claim a fast charger. Is the charger
designed with all of the electronics necessary to correctly charge the
batteries and preserve their lifetime? Of course not.

Fortunately for them, there are enough gullible people around to buy
these offerings along with their National Lottery tickets.


Like for like, the faster you charge the batteries, the less time they
will last. And more so with poor cells - which is one of the main problems
with cheap power tools.

..andy

To email, substitute .nospam with .gl

In article ,
Andy Hall wrote:
Battery quality is one of the main factors in cordless tools and one
of the main cost factors also. Hence the Panasonic 15.6v products
bening able to easily outperform other manufacturer's 18v offerings.

Yup. As well as a decent cordless drill, I've got a PP one. 18 volt. Good
enough to take where it might get stolen. When the first battery died, I
altered the charger to a 14 hour type, and bought a new battery. Then
re-celled the old one with decent (Sanyo) cells.

I doubt many who only use cheap tools would believe the difference in
performance between the two battery types. The starting torque is miles
better and easier controlled.

Retail, the batteries would have cost more than a new drill. But it
doesn't require a genius to figure out why.

--
*Your kid may be an honours student, but you're still an idiot.

Dave Plowman London SW
To e-mail, change noise into sound.

On Sat, 23 Oct 2004 10:48:18 +0100, "Dave Plowman (News)"
wrote:

Like for like, the faster you charge the batteries, the less time they
will last. And more so with poor cells - which is one of the main problems
with cheap power tools.

Do you have any reliable information to support that claim?

I'm not saying you are wrong, and indeed it's entirely possible that
you are right. But it would carry a lot more conviction if there were
supporting evidence that the jury could convict on.

Andrew

On Sat, 23 Oct 2004 16:10:57 +0100, Andrew McKay
wrote:

On Sat, 23 Oct 2004 10:48:18 +0100, "Dave Plowman (News)"
wrote:

Like for like, the faster you charge the batteries, the less time they
will last. And more so with poor cells - which is one of the main problems
with cheap power tools.

Do you have any reliable information to support that claim?

I'm not saying you are wrong, and indeed it's entirely possible that
you are right. But it would carry a lot more conviction if there were
supporting evidence that the jury could convict on.

Andrew

Have a look at these....

http://www.national.com/appinfo/power/files/f19.pdf

http://www.national.com/appinfo/power/files/f7.pdf



Regarding batteries - it is possible to get batteries that are
designed to tolerate fast charging without damage or degradation.
Unsurprisingly, these cost more.

Fast charging implies (or should imply) implementing good quality
chargers to look at battery voltage and or temperature.

NiCd and NiMH batteries can both be charged using the Delta V method
which involves monitoring the battery voltage very accurately to
detect the small voltage drop that occurs just after peak charge and
to stop the charging. With NiMH, the drop is about 2mV per cell, so
implementing chargers is not easy.

The other approach is to use detection of cell temperature as well and
to stop when the temperature starts to rise, which it will
significantly at the end of charge.

Another interesting approach is that by Rayovac who have cells with
charge control circuits built into the cells.

http://www.rayovac.com/products/rech...nutes/qa.shtml




..andy

To email, substitute .nospam with .gl

Andy Hall wrote:

Considering the low end, the batteries are so poor and have such
limited capacity, that the only way to achieve any degree of
acceptability is to fast charge them. it also adds an additional
marketing ploy that they can claim a fast charger. Is the charger
designed with all of the electronics necessary to correctly charge the
batteries and preserve their lifetime? Of course not.

How do you know that?

I suspect that with the advent of cheap, single chip, fast charger ICs
it's just as cheap, if not cheaper to provide a proper, 'intelligent'
fast charger as it is to supply a 'unintelligent' one.

I'm almost tempted to take apart the charger from my cheapo, generic,
cordless lopper to see if it does have an intelligent charger. It
certainly acts like it has one.

--
Chris Green

Andy Hall wrote:

NiCd and NiMH batteries can both be charged using the Delta V method
which involves monitoring the battery voltage very accurately to
detect the small voltage drop that occurs just after peak charge and
to stop the charging. With NiMH, the drop is about 2mV per cell, so
implementing chargers is not easy.

It's trivially easy with a ready made chip that does all the hard work
for you. They can be bought 'off the shelf' now. One off price is
only a dollar or two and I'm pretty sure they'd be a lot cheaper in
quantity. The most well known manufacturer is Dallas/Maxim.

--
Chris Green

In article ,
Andrew McKay wrote:
Like for like, the faster you charge the batteries, the less time they
will last. And more so with poor cells - which is one of the main
problems with cheap power tools.

Do you have any reliable information to support that claim?

Only my own experience based on using re-chargeables every day in
connection with work. Even with a decent intelligent charger, both Ni-Cad
and NiMH have a longer life if charged at the 14 hour rate. This is with
good quality cells.

--
*Procrastination is the art of keeping up with yesterday.

Dave Plowman London SW
To e-mail, change noise into sound.

On 23 Oct 2004 17:34:26 GMT, wrote:

Andy Hall wrote:

Considering the low end, the batteries are so poor and have such
limited capacity, that the only way to achieve any degree of
acceptability is to fast charge them. it also adds an additional
marketing ploy that they can claim a fast charger. Is the charger
designed with all of the electronics necessary to correctly charge the
batteries and preserve their lifetime? Of course not.

How do you know that?

I'll give you an example.

I looked at the instruction manual for a $25 drill during a recent
trip to the U.S. It came with a claimed one hour charger.
The instructions told the user to make sure that the battery was
discharged before recharging and then to charge for no more than an
hour to avoid overheating the batteries and damaging them.
Presumably they had a safety vent to at least avoid their exploding if
the user forgot.



I suspect that with the advent of cheap, single chip, fast charger ICs
it's just as cheap, if not cheaper to provide a proper, 'intelligent'
fast charger as it is to supply a 'unintelligent' one.

I'm almost tempted to take apart the charger from my cheapo, generic,
cordless lopper to see if it does have an intelligent charger. It
certainly acts like it has one.

Some products may and some may not. The main point is that if
fast charging is going to be done, then battery life is substantially
shortened if the batteries are not designed for fast charge behaviour.


..andy

To email, substitute .nospam with .gl

On 23 Oct 2004 17:43:21 GMT, wrote:

Andy Hall wrote:

NiCd and NiMH batteries can both be charged using the Delta V method
which involves monitoring the battery voltage very accurately to
detect the small voltage drop that occurs just after peak charge and
to stop the charging. With NiMH, the drop is about 2mV per cell, so
implementing chargers is not easy.

It's trivially easy with a ready made chip that does all the hard work
for you. They can be bought 'off the shelf' now. One off price is
only a dollar or two and I'm pretty sure they'd be a lot cheaper in
quantity. The most well known manufacturer is Dallas/Maxim.

Yes I know.

However, consider the impact of a dollar or two on the costs and
margins for a Chinese factory making a power tool that will end up in
B&Q for a few tens of pounds. The ex-works price is probably around
£10-15 tops so anything that does not need to be there is likely to be
left out. Every cent counts.

The game is not quality, it is of meeting a minimal price and a
minimal spec. and having an acceptably low return rate within the
intended warranty period.

If usage is low enough, then with cheap batteries and a crappy charger
circuit, these parameters can be met simply because the battery will
not be subjected to that many recharges during the warranty period.
After that the retailer doesn't care. They would rather have the
marketing ploy of fast charge because that sells product.

The retailers are taking a reasonable gamble that a large proportion
of the customers will not be discerning, will have low usage rates,
sling the tool when it breaks and probably have lost the receipt
anyway.



..andy

To email, substitute .nospam with .gl

In article ,
Andy Hall wrote:
If usage is low enough, then with cheap batteries and a crappy charger
circuit, these parameters can be met simply because the battery will
not be subjected to that many recharges during the warranty period.
After that the retailer doesn't care. They would rather have the
marketing ploy of fast charge because that sells product.

Yes; I've seen at least one one hour charger which was simply an
unregulated DC supply with a series resistor between it and the battery.

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.

Andy Hall wrote:
I'm almost tempted to take apart the charger from my cheapo, generic,
cordless lopper to see if it does have an intelligent charger. It
certainly acts like it has one.

Some products may and some may not. The main point is that if
fast charging is going to be done, then battery life is substantially
shortened if the batteries are not designed for fast charge behaviour.

I'm not at all convinced that's true. A proper delta/V fast charger
will do what's required with any NiCd or NiMh bttery.

Of course better batteries will always be better batteries. But does
"designing for fast charging" necessarily cost more? In the
(distantly related) case of car batteries the ones designed for fast
charging are actually a lot cheaper.

--
Chris Green

"Andrew McKay" wrote in message
...
On Sat, 23 Oct 2004 10:48:18 +0100, "Dave Plowman (News)"
wrote:

Like for like, the faster you charge the batteries, the less time they
will last. And more so with poor cells - which is one of the main
problems
with cheap power tools.

Do you have any reliable information to support that claim?

I'm not saying you are wrong, and indeed it's entirely possible that
you are right. But it would carry a lot more conviction if there were
supporting evidence that the jury could convict on.

He makes things up a lot.

Andy Hall wrote:
On 23 Oct 2004 17:43:21 GMT, wrote:

Andy Hall wrote:

NiCd and NiMH batteries can both be charged using the Delta V method
which involves monitoring the battery voltage very accurately to
detect the small voltage drop that occurs just after peak charge and
to stop the charging. With NiMH, the drop is about 2mV per cell, so
implementing chargers is not easy.

It's trivially easy with a ready made chip that does all the hard work
for you. They can be bought 'off the shelf' now. One off price is
only a dollar or two and I'm pretty sure they'd be a lot cheaper in
quantity. The most well known manufacturer is Dallas/Maxim.

Yes I know.

However, consider the impact of a dollar or two on the costs and
margins for a Chinese factory making a power tool that will end up in
B&Q for a few tens of pounds. The ex-works price is probably around
£10-15 tops so anything that does not need to be there is likely to be
left out. Every cent counts.

I knew you were going to say that which is why I added the bit about
"they'd be a lot cheaper in quantity".

The game is not quality, it is of meeting a minimal price and a
minimal spec. and having an acceptably low return rate within the
intended warranty period.

Yes, and what I was saying is that the chips are now so cheap that
it'll be no more expensive to produce tools with 'intelligent' fast
chargers and you'd get a gain in reduced returns etc.

--
Chris Green

"Dave Plowman (News)" wrote in message
...
In article ,
Andrew McKay wrote:
Like for like, the faster you charge the batteries, the less time they
will last. And more so with poor cells - which is one of the main
problems with cheap power tools.

Do you have any reliable information to support that claim?

Only my own experience based on using re-chargeables every day in
connection with work. Even with a decent intelligent charger, both Ni-Cad
and NiMH have a longer life if charged at the 14 hour rate. This is with
good quality cells.

See. He makes things up a lot.

wrote:
Andy Hall wrote:

Considering the low end, the batteries are so poor and have such
limited capacity, that the only way to achieve any degree of
acceptability is to fast charge them. it also adds an additional
marketing ploy that they can claim a fast charger. Is the charger
designed with all of the electronics necessary to correctly charge the
batteries and preserve their lifetime? Of course not.

How do you know that?

I suspect that with the advent of cheap, single chip, fast charger ICs
it's just as cheap, if not cheaper to provide a proper, 'intelligent'
fast charger as it is to supply a 'unintelligent' one.

I'm almost tempted to take apart the charger from my cheapo, generic,
cordless lopper to see if it does have an intelligent charger. It
certainly acts like it has one.

I've just done exactly that with my 18v NiCd battery and charger from
B&Q. It's one of their Performance Power range and is common to a
whole lot of their cordless garden tools (I have the mini chainsaw
lopper).

It turns out that, to my mind at least, they've done it the most
expensive way possible, so much for shaving off the last few cents.

It has a fairly solid looking transformer rectifier power supply,
full wave rectification by the way, no corner cutting there. There are
then various indicator LEDs, a microswitch (with an external button to
press it) and a latching relay. There are *three* connections to the
battery, one of which is a temperature sensing one, when the
temperature rise indicating full charge is detected the relay is
latched off.

As I said, this surprised me, because it makes the charger relatively
complex. A crude rectifier and series resistor would be cheaper and
so would a delta/V detecting IC. As it is they have to have a
latching relay in the charger, three connections to the battery and a
temperature sensor in every battery. Certainly not corner cutting to
my mind.

--
Chris Green

On Fri, 22 Oct 2004 18:15:37 +0100, "IMM" wrote:

The Makita for £96 with 3 batts and a 30 min charger looks excellent
value at ony £16 over the OP's budget.

He obviously wants a substantial drill. The combi type Ryobi is beefier
than the 12v drill/driver Makita's.

Yes, you want the highest possible battery voltage and biggest
possible cells. It doesn't matter that they have the same torque and
the Ryobi is 50% heavier...

cheers,
Pete.

On Sat, 23 Oct 2004 10:48:18 +0100, "Dave Plowman (News)"
wrote:

In article ,
Mark Begbie wrote:
Anyone know if Worx tools (Homebase and Argos) are any good? I've
seen a 14.4V drill/driver with 2 x 1.5Ah bats and 3 yr warranty for
£45 which looks like a REALLY good deal.

Probably is, but only if they are 1 hour charge time.

They are 1 hour IIRC, which B&D aren't.

Why this fetish for buying a cheap drill good enough for limited DIY use,
but insisting on a fast charger?

Hi,

If there are two or more battery packs, they can be used in rotation.

cheers,
Pete.

On 23 Oct 2004 20:23:44 GMT, wrote:

wrote:
Andy Hall wrote:

Considering the low end, the batteries are so poor and have such
limited capacity, that the only way to achieve any degree of
acceptability is to fast charge them. it also adds an additional
marketing ploy that they can claim a fast charger. Is the charger
designed with all of the electronics necessary to correctly charge the
batteries and preserve their lifetime? Of course not.

How do you know that?

I suspect that with the advent of cheap, single chip, fast charger ICs
it's just as cheap, if not cheaper to provide a proper, 'intelligent'
fast charger as it is to supply a 'unintelligent' one.

I'm almost tempted to take apart the charger from my cheapo, generic,
cordless lopper to see if it does have an intelligent charger. It
certainly acts like it has one.

I've just done exactly that with my 18v NiCd battery and charger from
B&Q. It's one of their Performance Power range and is common to a
whole lot of their cordless garden tools (I have the mini chainsaw
lopper).

It turns out that, to my mind at least, they've done it the most
expensive way possible, so much for shaving off the last few cents.

It has a fairly solid looking transformer rectifier power supply,
full wave rectification by the way, no corner cutting there. There are
then various indicator LEDs, a microswitch (with an external button to
press it) and a latching relay. There are *three* connections to the
battery, one of which is a temperature sensing one, when the
temperature rise indicating full charge is detected the relay is
latched off.

As I said, this surprised me, because it makes the charger relatively
complex. A crude rectifier and series resistor would be cheaper and
so would a delta/V detecting IC. As it is they have to have a
latching relay in the charger, three connections to the battery and a
temperature sensor in every battery. Certainly not corner cutting to
my mind.

This would all be a point if you were considering western component
costs and labour rates. The electromechanical components are very
cheap indeed and the labour rates to assemble them a tiny fraction of
western levels.

The charger you describe could be put together by virtually unskilled
labour whereas as soon as ICs and PCBs are used, the game changes.






..andy

To email, substitute .nospam with .gl

On 23 Oct 2004 19:51:40 GMT, wrote:

Andy Hall wrote:
On 23 Oct 2004 17:43:21 GMT, wrote:

Andy Hall wrote:

NiCd and NiMH batteries can both be charged using the Delta V method
which involves monitoring the battery voltage very accurately to
detect the small voltage drop that occurs just after peak charge and
to stop the charging. With NiMH, the drop is about 2mV per cell, so
implementing chargers is not easy.

It's trivially easy with a ready made chip that does all the hard work
for you. They can be bought 'off the shelf' now. One off price is
only a dollar or two and I'm pretty sure they'd be a lot cheaper in
quantity. The most well known manufacturer is Dallas/Maxim.

Yes I know.

However, consider the impact of a dollar or two on the costs and
margins for a Chinese factory making a power tool that will end up in
B&Q for a few tens of pounds. The ex-works price is probably around
£10-15 tops so anything that does not need to be there is likely to be
left out. Every cent counts.

I knew you were going to say that which is why I added the bit about
"they'd be a lot cheaper in quantity".

Of course they would, but the other factor is the skill level in
assembly.



The game is not quality, it is of meeting a minimal price and a
minimal spec. and having an acceptably low return rate within the
intended warranty period.

Yes, and what I was saying is that the chips are now so cheap that
it'll be no more expensive to produce tools with 'intelligent' fast
chargers and you'd get a gain in reduced returns etc.

They would be if you ignore the skill and labour factors.

..andy

To email, substitute .nospam with .gl

In article ,
wrote:
In the (distantly related) case of car batteries the ones designed for
fast charging are actually a lot cheaper.

Care to clarify? As far as I'm aware, all standard car batteries can be
charged at the same rate pro rata with size. You have to take more care
with similar size SLA batteries and they're more expensive, but that's
probably just economies of scale.

--
*I'm not your type. I'm not inflatable.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
wrote:
As I said, this surprised me, because it makes the charger relatively
complex. A crude rectifier and series resistor would be cheaper and
so would a delta/V detecting IC. As it is they have to have a
latching relay in the charger, three connections to the battery and a
temperature sensor in every battery. Certainly not corner cutting to
my mind.

Still not a brilliant way of doing it, though, as it's unlikely all cells
heat at the same pace, and the sensor will only be on one.

--
*Starfishes have no brains *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
IMM wrote:
Only my own experience based on using re-chargeables every day in
connection with work. Even with a decent intelligent charger, both
Ni-Cad and NiMH have a longer life if charged at the 14 hour rate.
This is with good quality cells.

See. He makes things up a lot.

Perhaps you'd then give us the benefit of your personal experience
charging good quality batteries?

Oh - I forgot. You only buy ****e tools. Except for the hacksaw you use
for most things...

--
*The only difference between a rut and a grave is the depth.

Dave Plowman London SW
To e-mail, change noise into sound.

On Sun, 24 Oct 2004 00:09:25 +0100, "Dave Plowman (News)"
wrote:

In article ,
IMM wrote:
Only my own experience based on using re-chargeables every day in
connection with work. Even with a decent intelligent charger, both
Ni-Cad and NiMH have a longer life if charged at the 14 hour rate.
This is with good quality cells.

See. He makes things up a lot.

Perhaps you'd then give us the benefit of your personal experience
charging good quality batteries?

Oh - I forgot. You only buy ****e tools. Except for the hacksaw you use
for most things...

I guess that there's a difference between buying and being.....


..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Sun, 24 Oct 2004 00:09:25 +0100, "Dave Plowman (News)"
wrote:

In article ,
IMM wrote:
Only my own experience based on using re-chargeables every day in
connection with work. Even with a decent intelligent charger, both
Ni-Cad and NiMH have a longer life if charged at the 14 hour rate.
This is with good quality cells.

See. He makes things up a lot.

Perhaps you'd then give us the benefit of your personal experience
charging good quality batteries?

Oh - I forgot. You only buy ****e tools. Except for the hacksaw you use
for most things...

I guess that there's a difference between buying and being.....

...yes "being" a lot better off in the pocket.

On Thu, 21 Oct 2004 19:15:00 +0000, PeterCB wrote:

Good for youI hear you say!

Don't want to spend to much £80.
What do you recommend?
Needs 2 x batteries - Hammer not important.

Any online sites that you care to mention.

Well you could do much worse than the £75 DeWalt from Screwfix.
I have one it works well. It is not the same as the £200+ Makita or DeWalt
units. But it is well made comes with a 1 hour chargers, 2 batts and some
bits. The torque control is quite stiff but I expect it to loosen up over
a few years hard use, if it is not stolen prior.

You'll likely be about to drill masonry with _sharp_ masonry bits and firm
pressure. The higher torque settings are quite capable of snapping the
head of a 4mm screw.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Dave Plowman (News) wrote:
In article ,
wrote:

As I said, this surprised me, because it makes the charger relatively
complex. A crude rectifier and series resistor would be cheaper and
so would a delta/V detecting IC. As it is they have to have a
latching relay in the charger, three connections to the battery and a
temperature sensor in every battery. Certainly not corner cutting to
my mind.


Still not a brilliant way of doing it, though, as it's unlikely all cells
heat at the same pace, and the sensor will only be on one.

Ironically its a technique that would work better on a more expensive
battery pack where someone has taken the time to more closely match the
cells.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Ironically its a technique that would work better on a more expensive
battery pack where someone has taken the time to more closely match the
cells.

How would you match the cells? Just intrigued. Economic?

IME, cell life is a pot luck exercise. I find that batch A last x years
and batch B from the same manufacturer don't, in the same application
and charged in the same way. It does seem to depend on the manufacturer
to some extent, but nor reliably IME.

Regards
Capitol

Capitol wrote:


John Rumm wrote:

Ironically its a technique that would work better on a more expensive
battery pack where someone has taken the time to more closely match
the cells.


How would you match the cells? Just intrigued. Economic?

The way it is often done is with a A to D converter on a computer and a
resistor bank for a load. You charge up each cell until "full" and then
connect up to your discharge rig. This then records the discharge over
time, and allows you to plot a discharge graph. Then having done it with
a bunch of cells you can cherry pick ones with closely matching curves
for making into a battery pack.

You can buy cells that are already matched (at a price premium), or you
can match them yourself. The "fast electric" RC model guys who are
serious will typically do the matching themselves.

(I met a truly fanatical fast electric boat anorak once, who delighted
in talking me through the details of his particular boat - kevlar /
carbon fibre hull, 12 pole motor, 36 computer matched sub C cells - a
couple of grands worth all in. This boat was designed to race for 500m
round a triangular circuit - apparently it is a layout that is typically
used for record attempts. To be considered "good" you should be able to
do the three sides, a 180 turn at the end of the last, and then another
2 sides to the finish in under 20 seconds (at the time the record was
something like 14). The battery pack would typically be expected to dump
most of it charge in that time - developing a power output over 2kW!.
After each run he would then hook the whole pack up to a discharger for
a little bit before using a shunt with an a old galvo wired up to
individually discharge each cell to 1V before he would fast charge the
whole pack again.)

IME, cell life is a pot luck exercise. I find that batch A last x years
and batch B from the same manufacturer don't, in the same application
and charged in the same way. It does seem to depend on the manufacturer
to some extent, but nor reliably IME.

Hence the need for matching. Some brands do seem consistently better
than others (e.g. sanyo, panasonic) - but as you say there can be quite
dramatic differences between apparently similar cells.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Fri, 22 Oct 2004 18:15:37 +0100, "IMM" wrote:


"Pete C" wrote in message
.. .
On Fri, 22 Oct 2004 13:23:01 +0100, "IMM" wrote:



http://www.lawson-his.co.uk/scripts/...%20Drill%20/%2
0
Drivers%2012V

only 12 v. The Ryobi has 3 batteries and a 2 yr guarantee to.

Hi,

Best to compare torque, quality of speed control and and weight rather
than battery voltage alone.

The Makita for £96 with 3 batts and a 30 min charger looks excellent
value at ony £16 over the OP's budget.

He obviously wants a substantial drill. The combi type Ryobi is beefier
than the 12v drill/driver Makita's.

Because of the "he-man" handle?


..andy

To email, substitute .nospam with .gl

On Fri, 22 Oct 2004 21:57:00 +0100, Andrew McKay
wrote:

On Thu, 21 Oct 2004 19:15:00 GMT, "PeterCB" no.mail@please wrote:

Don't want to spend to much £80.
What do you recommend?
Needs 2 x batteries - Hammer not important.

Any online sites that you care to mention.

Bought one in Homebase today. 18v. 2 1.7Ah batteries. 1 hr charger.
Carrying case. £79.99 - but being Homebase 10% off day it cost just a
shade over £70. It's this one:

This sounded like the one I got there for £50 at the same time but it
turns out mine is a PBX model. 2 yr warranty. Just like the last
cordless drill I bought, I'm expecting the drill to outlast the
batteries.

The earlier comments requesting proof that fast charging shortens the
life of nicads - this is common knowledge in the modelling world
(cars, planes etc) and has been for years. Likewise prolonged storage
without use leavng the battery to self-discharge below its minimum
level (1.1v per cell IIRC).

MJ

"Dave Plowman (News)" wrote:
In article ,
wrote:
In the (distantly related) case of car batteries the ones designed for
fast charging are actually a lot cheaper.

Care to clarify? As far as I'm aware, all standard car batteries can be
charged at the same rate pro rata with size. You have to take more care
with similar size SLA batteries and they're more expensive, but that's
probably just economies of scale.

What I meant was that car batteries are *much* cheaper than the
equivalent capacity lead acid batteries designed for long term trickle
charge and deep discharge applications (i.e. traction batteries and
alarm backup batteries). A car battery is designed to cope with high
discharge rates (starting) and high charge rates (the alternator will
pump in tens of amps at times). A traction battery of similar
capacity won't cope with use in a car at all well, but on the other
hand will cope with repeated deep discharges OK. Since car batteries
are produced in much larger quantities they tend to be a lot cheaper,
I think that's probaly the only reason, I don't think there's an
inherent technical reason for the difference in price.

--
Chris Green

Andy Hall wrote:
It turns out that, to my mind at least, they've done it the most
expensive way possible, so much for shaving off the last few cents.

It has a fairly solid looking transformer rectifier power supply,
full wave rectification by the way, no corner cutting there. There are
then various indicator LEDs, a microswitch (with an external button to
press it) and a latching relay. There are *three* connections to the
battery, one of which is a temperature sensing one, when the
temperature rise indicating full charge is detected the relay is
latched off.

As I said, this surprised me, because it makes the charger relatively
complex. A crude rectifier and series resistor would be cheaper and
so would a delta/V detecting IC. As it is they have to have a
latching relay in the charger, three connections to the battery and a
temperature sensor in every battery. Certainly not corner cutting to
my mind.

This would all be a point if you were considering western component
costs and labour rates. The electromechanical components are very
cheap indeed and the labour rates to assemble them a tiny fraction of
western levels.

It *is* on a PCB, the latching relay is of the 'looks like an IC'
variety. The assembly costs of a charger with a delta/V chip instead
would be near enough identical, if not a little cheaper because there
wouldn't be the additional complication of the temperature sensor in
the batery.

The charger you describe could be put together by virtually unskilled
labour whereas as soon as ICs and PCBs are used, the game changes.

You're not seriously trying to persuade me that the PCBs, chips, etc.
used in 'expensive' tools aren't assembled in the Far East are you?

--
Chris Green

"Dave Plowman (News)" wrote:
In article ,
wrote:
As I said, this surprised me, because it makes the charger relatively
complex. A crude rectifier and series resistor would be cheaper and
so would a delta/V detecting IC. As it is they have to have a
latching relay in the charger, three connections to the battery and a
temperature sensor in every battery. Certainly not corner cutting to
my mind.

Still not a brilliant way of doing it, though, as it's unlikely all cells
heat at the same pace, and the sensor will only be on one.

Yes, delta/V would be better and, probably cheaper.

I was just trying to show that a 'cheap' tool doesn't necessarily have
corners cut in the electronics.

--
Chris Green

Andy Hall wrote:
On 23 Oct 2004 19:51:40 GMT, wrote:

It's trivially easy with a ready made chip that does all the hard work
for you. They can be bought 'off the shelf' now. One off price is
only a dollar or two and I'm pretty sure they'd be a lot cheaper in
quantity. The most well known manufacturer is Dallas/Maxim.

Yes I know.

However, consider the impact of a dollar or two on the costs and
margins for a Chinese factory making a power tool that will end up in
B&Q for a few tens of pounds. The ex-works price is probably around
£10-15 tops so anything that does not need to be there is likely to be
left out. Every cent counts.

I knew you were going to say that which is why I added the bit about
"they'd be a lot cheaper in quantity".

Of course they would, but the other factor is the skill level in
assembly.

One of the major advantages of an IC base solution is that very little
skill is required to assemble and test. Stick the components on a
PCB, slap it all together and it just works, no set up or anything is
required.

--
Chris Green

Ed Sirett wrote:

You'll likely be about to drill masonry with _sharp_ masonry bits and firm
pressure. The higher torque settings are quite capable of snapping the
head of a 4mm screw.

My ancient Skil 12v and my modern (cheap, green) Bosch 9.6v will both
snap 4mm TurboGold screws occasionally if I forget to turn the torque
down.

I am thinking of getting something beefier for driving 6 x 100 screws
though.

--
Chris Green