Hello,

I posted this on he camping group but I've had no replies. perhaps
they are all on holiday?

I was advised (on uk diy) that a leisure battery might discharge if
left unused for some time and I was told that a solar charger would
top-up the charge and prevent this. What size solar panel would I
need? Does the output of the panel have to be a certain ration of the
capacity of the battery? If so, what's the magic formula?

BTW can you recommend a good make of leisure battery and any good
suppliers?

Thanks,
Stephen.

Stephen wrote:

I posted this on he camping group but I've had no replies. perhaps
they are all on holiday?

I was advised (on uk diy) that a leisure battery might discharge if
left unused for some time and I was told that a solar charger would
top-up the charge and prevent this. What size solar panel would I
need? Does the output of the panel have to be a certain ration of the
capacity of the battery? If so, what's the magic formula?

BTW can you recommend a good make of leisure battery and any good
suppliers?

You would probably get a few opinions on uk.rec.caravanning

Chris
--
Chris J Dixon Nottingham UK


Have dancing shoes, will ceilidh.

BTW can you recommend a good make of leisure battery and any good
suppliers?

You would probably get a few opinions on uk.rec.caravanning

Any chandlers should have a good range of solar chargers too. Not aware of
any specific newsgroups though. GIYF.

Al.

In article ,
Stephen wrote:
I was advised (on uk diy) that a leisure battery might discharge if
left unused for some time and I was told that a solar charger would
top-up the charge and prevent this. What size solar panel would I
need? Does the output of the panel have to be a certain ration of the
capacity of the battery? If so, what's the magic formula?

The rate of self discharge of a lead acid battery is very low - I've
expect it still to be healthy after the seasonal break in use. And a
charge with an ordinary charger before use will be fine. Solar units are
very expensive for what they are - and not reliable in the UK climate. Get
a Lidl charger when they come up again - about 12 quid and small enough to
fit in the pocket.

--
*Why isn't 11 pronounced onety one? *

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

Stephen presented the following explanation :
I was advised (on uk diy) that a leisure battery might discharge if
left unused for some time and I was told that a solar charger would
top-up the charge and prevent this. What size solar panel would I
need? Does the output of the panel have to be a certain ration of the
capacity of the battery? If so, what's the magic formula?

There is no magic formula. It needs to be large enough to more than
cover the self discharge, plus any loads such as alarms multiplied by 2
or maybe even 3 during the shorter and darker days of winter.

Likely a 5w or better unit would take care of the self discharge of a
110amp/hour leisure battery, but don't expect it to recharge the
battery from flat.

Cheaper and arguably better would be the use of an intelligent charger'
at least every month or two, assuming the battery has no loads to
support between charges. Aldi/Lidl have had these chargers on special
offer several times for around £10 and they really are well worth
buying and highly recommended. With one of these you can either top the
charge up regularly, or simply leave it connected to the charger for
the entire winter.

Getting back to the solar charger...

www.maplin.co.uk sell a variety of these, but if you get one make sure
it is a controlled output type rather than one which simply keeps on
charging irrespective of need. Over charging is as damaging as under
charging, or leaving a battery to go flat.

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

"Harry Bloomfield" wrote in message
k...

Getting back to the solar charger...

www.maplin.co.uk sell a variety of these, but if you get one make sure it
is a controlled output type rather than one which simply keeps on charging
irrespective of need. Over charging is as damaging as under charging, or
leaving a battery to go flat.

They have a 12W panel for £50 ATM.

In message , "dennis@home"
writes


"Harry Bloomfield" wrote in message
. uk...

Getting back to the solar charger...

www.maplin.co.uk sell a variety of these, but if you get one make
sure it is a controlled output type rather than one which simply
keeps on charging irrespective of need. Over charging is as damaging
as under charging, or leaving a battery to go flat.

They have a 12W panel for £50 ATM.


You only want to blow the bloody doors off den you dick


http://www.maplin.co.uk/Module.aspx?ModuleNo=98358

at £12 should suffice

--
geoff

On Mon, 23 Feb 2009 22:10:27 +0000, geoff wrote:

http://www.maplin.co.uk/Module.aspx?ModuleNo=98358

at £12 should suffice

I have one of those on the genset battery. Last time I started the genny
(a month or so ago) there was no problem. Panel sits behind a north facing
window so doesn't generate an awful lot of juice and would put 50% more
into the battery if it didn't have 50% duty cycle flashing LED...

Lead Acid batteries have very low self discharge rates. 40%/year according
to: http://www.batteryuniversity.com/partone-6.htm.

So an 80A/hr battery 40% is 32A/hr over a year (8760hrs) = 3mA = 0.04W. So
even a 1.5W panel is more than capable (even taking into account dark and
cloud) of maintaining quite a decent sized battery.

--
Cheers
Dave.

In article et,
Dave Liquorice wrote:
Lead Acid batteries have very low self discharge rates. 40%/year
according to: http://www.batteryuniversity.com/partone-6.htm.

So an 80A/hr battery 40% is 32A/hr over a year (8760hrs) = 3mA = 0.04W.
So even a 1.5W panel is more than capable (even taking into account dark
and cloud) of maintaining quite a decent sized battery.

Wonder how much current such a device *draws* from the battery in low
light conditions when not charging? It must be something.

--
*Rehab is for quitters.

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

"Dave Liquorice" wrote in message

Lead Acid batteries have very low self discharge rates. 40%/year according
to: http://www.batteryuniversity.com/partone-6.htm.

40% is considered very low... bloody hell,

The li-po batteries i use to fly my model planes have a 2% self discharge
per year, and they are working on getting that better!!!

In message , Stephen
writes
Hello,

I posted this on he camping group but I've had no replies. perhaps
they are all on holiday?

or out to lunch ...


I was advised (on uk diy) that a leisure battery might discharge if
left unused for some time and I was told that a solar charger would
top-up the charge and prevent this. What size solar panel would I
need? Does the output of the panel have to be a certain ration of the
capacity of the battery? If so, what's the magic formula?

BTW can you recommend a good make of leisure battery and any good
suppliers?

Just go and buy the one Maplins have on offer at the moment

Solar chargers depend on light falling on the cells - otherwise more or
less known as sunshine

we live in the UK - go figure

--
geoff

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Stephen
saying something like:

Hello,

I posted this on he camping group but I've had no replies. perhaps
they are all on holiday?

I was advised (on uk diy) that a leisure battery might discharge if
left unused for some time and I was told that a solar charger would
top-up the charge and prevent this. What size solar panel would I
need? Does the output of the panel have to be a certain ration of the
capacity of the battery? If so, what's the magic formula?

BTW can you recommend a good make of leisure battery and any good
suppliers?

I've been using a cheapy 5W panel I got off ebay two years ago and it's
been topping up an 80Ah battery quite happily for most of that time.
Peak current from it is around 300mA during sunny days and dips to
almost buggerall on really horrible overcast winter days - 17mA or so.
Overall it works rather well and I'd buy another one as the need arose.

On Tue, 24 Feb 2009 03:03:33 +0000, Grimly Curmudgeon
wrote:


I've been using a cheapy 5W panel I got off ebay two years ago and it's
been topping up an 80Ah battery quite happily for most of that time.
Peak current from it is around 300mA during sunny days and dips to
almost buggerall on really horrible overcast winter days - 17mA or so.
Overall it works rather well and I'd buy another one as the need arose.

I have 2 x 5w panels in the South facing workshop windows connected
via a charge controller / switch to the backup workshop lights.

Seems to be working ok on a 10Ah gel motorcycle type battery (that I
had spare).

The charge controller is only there as a light switch and to protect
against over-discharging the battery. As an aside it also has a couple
of multi state LED's to indicate charge and battery status.

It's surprising how 'dull' a day can be yet the charge indicator can
still shows green.

Cheers, T i m

p.s. I had one of the 1.5W panels permanently connected on the dash of
my old Sierra Estate and that helped keep the battery up (at least
against any self discharge).