Is charging battery tools through an inverter - bad?

Someone said using an inverter to charge up battery tools
destroys the batteries in them:
is this true?

Is it possible to charge batttery tools from a caar battery, solar panel
etc?

[g]

george (dicegeorge) wrote:
Is charging battery tools through an inverter - bad?

Someone said using an inverter to charge up battery tools
destroys the batteries in them:
is this true?

no. Nothing bad about it in terms of he effect on the battieries.
However stoppeing voltage up then back down is energy inefficient &
cost inefficient.


Is it possible to charge batttery tools from a caar battery, solar panel
etc?

[g]

course. Providing the source voltage is higher than the charging
battery voltage, plus a small margin fo the charging circuitry. The
simpole way is to just use a resistor to lmiit charge current. The
better way is to feed an intelligent charger with the low votage
power, that way it delivers the right amount of charge every time,
charges fast, and shuts off once full.


NT

wrote:
george (dicegeorge) wrote:
Is charging battery tools through an inverter - bad?

Someone said using an inverter to charge up battery tools
destroys the batteries in them:
is this true?

no. Nothing bad about it in terms of he effect on the battieries.
However stoppeing voltage up then back down is energy inefficient &
cost inefficient.

I tried using a 300w inverter to charge Makita batteries with a Makita
charger & the red light warning of overheating came on all the time - so I
stopped doing it.

Daft I know using a 12v car system boosted up to 230v, then stepped back
down to 12v, but it would be handy sometimes.


Is it possible to charge batttery tools from a caar battery, solar
panel etc?

[g]

course. Providing the source voltage is higher than the charging
battery voltage, plus a small margin fo the charging circuitry. The
simpole way is to just use a resistor to lmiit charge current. The
better way is to feed an intelligent charger with the low votage
power, that way it delivers the right amount of charge every time,
charges fast, and shuts off once full.


NT

On Thu, 29 Jan 2009 18:55:12 +0000, george (dicegeorge) wrote:

Someone said using an inverter to charge up battery tools destroys the
batteries in them: is this true?

Not likely, always assuming the charger is happy on an invertor supply. My
phone charger is but I have a "universal" AAA/AA charger that does two
batteries per side and only one side works when on the invertor supply,
it's fine on mains.

Is it possible to charge batttery tools from a caar battery, solar panel
etc?

With the relvant charge controller yes but don't expect raopid results
froma small solar panel... Also you'd be limited to power tools with
batteries of less than 10v or so allowing for ineffciencies in the chareg
controller. Of course you may be able to find a charge controller that
lives on 12v but can up the output voltage.

Probably a lot easier to get an invertor and use the normal mains charger
if it's happy.

--
Cheers
Dave.

If you can justify 40 quid, this is the best way:

http://cgi.ebay.co.uk/Makita-Automotive-charger-DC1822-Ni-MH-Ni-Cd-7-2-18V_W0QQitemZ370120304043QQcmdZViewItemQQptZUK_Hom e_Garden_PowerTools_SM?hash=item370120304043&_trks id=p3286.c0.m14&_trkparms=72%3A1683|66%3A2|65%3A12 |39%3A1|240%3A1318

wrote:

If you can justify 40 quid, this is the best way:

http://cgi.ebay.co.uk/Makita-Automotive-charger-DC1822-Ni-MH-Ni-Cd-7-2-18V_W0QQitemZ370120304043QQcmdZViewItemQQptZUK_Hom e_Garden_PowerTools_SM?hash=item370120304043&_trks id=p3286.c0.m14&_trkparms=72%3A1683|66%3A2|65%3A12 |39%3A1|240%3A1318

But my only Makita has an LiIon battery!

(I know buying one of those would be silly for just one device.)

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

"george (dicegeorge)" wrote in message
...
Is charging battery tools through an inverter - bad?

Someone said using an inverter to charge up battery tools
destroys the batteries in them:
is this true?

Is it possible to charge batttery tools from a caar battery, solar panel
etc?

I charged a Li-ion camera battery a few times using an inverter on holiday
and it never seemed to hold its charge as well afterwards.

I don't know whether the inverter produces a dodgy 240V AC profile and that
mucks up the stepped down output from the charger, but I wouldn't try it
again.

I'm happy to be told I'm worrying unnecessarily, but I'd want a very strong
reassurance.

"OG" wrote in message
...

"george (dicegeorge)" wrote in message
...
Is charging battery tools through an inverter - bad?

Someone said using an inverter to charge up battery tools
destroys the batteries in them:
is this true?

Think only one person said it could be a problem.... i can only imagine
those who said it wasnt have never tired it,

the kinds of inverters you get to from catalouges, supermarkets, makro, b&q
etc are modified square wave inverters,
that is they make up the sine wave of the AC output with a few steps,
cheaper the inverter the less steps there are, which results in a rough
power output,

for most items thats not a problem, lights couldent care less, motors will
buzz but still work, owt with a transformer in it will buzz, run a little
hotter but usually be fine,

But anything that uses a switched mode psu in it, which most drill chargers
do nowadays, will not like the non pure sine wave, and anything which uses
tyristors for speed controll will let the magic smoke out pretty quick.

Some smpsu's will not even power up, others will but make bad whining
noises, some will apparantly be working fine but will overheat in a short
time, depending on the protection circuits this could be a one time only
event, i.e. the gharger/psu is dead afterwards, or it could work again once
it's cooled down.

I used to have a 1600 watt modified sine wave inverter in my motorhome,
powered the items i needed at the time (the centeral vacuum which was a
simple universal motor, GF's hair drier... universal motor and heater
element, microwave, which ran a little noisier than on mains) everything
else i ran from 12 volts directly (which is provided by a 460 AH battery
bank, 350 watt solar array, dedicated alternator on the engine and a 12 volt
generator)

However when i fitted a washing machine, the modified sine wave inverter had
to be changed for a pure sine wave model, about £350 quid with the part ex
from my existing inverter, but we are talking a 1500 watt inverter here that
can power the whole motorhome.

you'd prolly only want a 100 watt inverter to run a charger, but even that
will be over 100 quid,

and as others have mentioned, it's a bit daft to go from 12 volts DC, upto
240 AC, then back down to 12 volts DC to charge the battery,
i used to charge ni-cad drill packs using a radio controll models charger,
there are tons of them available, 90% run on 12 volts DC, you just need to
be able to connect the battery to the charger, an old mains charger can be
canibalized for the contact plate, or croc slips used if the batt pack has
pins.

I've now got li-ion batteried drills, i do have a li-ion/li-po 12 volt input
charger for my RC planes flight packs, but i havent had the need to use it
to charge the drill packs yet,

In article ,
The Medway Handyman wrote:
no. Nothing bad about it in terms of he effect on the battieries.
However stoppeing voltage up then back down is energy inefficient &
cost inefficient.

I tried using a 300w inverter to charge Makita batteries with a Makita
charger & the red light warning of overheating came on all the time - so
I stopped doing it.

Daft I know using a 12v car system boosted up to 230v, then stepped back
down to 12v, but it would be handy sometimes.

Assuming the tool is less than 12v, it might be possible to modify the
charger to also accept an input direct from the car battery - ie after the
mains SMPS in the charger.

Or try another inverter. Some produce a better waveform than others.


--
*If a turtle doesn't have a shell, is he homeless or naked?

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

The Medway Handyman used his keyboard to write :
I tried using a 300w inverter to charge Makita batteries with a Makita
charger & the red light warning of overheating came on all the time - so I
stopped doing it.

Were you perhaps charging the batteries in the passenger footwell, with
the heater going full blast?


Daft I know using a 12v car system boosted up to 230v, then stepped back down
to 12v, but it would be handy sometimes.


A typical modern tool battery charger is a switch mode type power
supply. The convert the mains input to DC, then chop that back to high
frequency AC to feed through the internal high frequency transformer
before converting back to DC. So basically running it off a 12 to 240v
inverter should not make any difference at all.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

gazz wrote:
"OG" wrote in message
...
"george (dicegeorge)" wrote in message
...

Is charging battery tools through an inverter - bad?

Someone said using an inverter to charge up battery tools
destroys the batteries in them:
is this true?

Think only one person said it could be a problem.... i can only imagine
those who said it wasnt have never tired it,

Since the charger smpsu will have a rectifier & reservoir cap input,
what possible difference does it make? Assuming of course that the
output voltage has correct peak value.


However when i fitted a washing machine, the modified sine wave inverter had
to be changed for a pure sine wave model, about �350 quid with the part ex
from my existing inverter, but we are talking a 1500 watt inverter here that
can power the whole motorhome.

That's understandable, the WM controller operates on different
principles and assumptions to a battery charger.


NT

In article ,
Harry Bloomfield wrote:
A typical modern tool battery charger is a switch mode type power
supply. The convert the mains input to DC, then chop that back to high
frequency AC to feed through the internal high frequency transformer
before converting back to DC. So basically running it off a 12 to 240v
inverter should not make any difference at all.

Snag is some inverters produce what could be described as a very dirty
sine wave and some SMPS won't work correctly from it.

--
*A 'jiffy' is an actual unit of time for 1/100th of a second.

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