Solar Panels

[kitchenman]

Maplin do a wind charger
http://www.maplin.co.uk/50w-telescop...turbine-396269

[laurieash]

Originally Posted by solarman216

there is no such thing as a leisure battery, they are start batteries and call themselves something different, a start battery, you can only take to 50% discharge without damage, a full traction battery can go 80% and will do this 350 times a year for more than 15 years, but cost a lot more, a start battery will only survive a few tens of full discharges before failing, so it really depends on usage, for a caravan used only occasionally, and not taken below 50% then you may well get two or more years from it, but simply get the cheapest battery you can find, wet flooded with caps, if you go for sealed, and they tend to be dearer, then you can only charge it at a slow rate 5 amps or so or you will loose electrolyte and will not be able to top, gell batteries are another matter altogether, hope that helps, Rick

Rick i have a wagon battery dont Know what the AH is as stickers are off it, so would that be better than a 110 leisure. it wont fit in battery box but not bothered about that. Laurie.

[solarman216]

Originally Posted by laurieash

Rick i have a wagon battery dont Know what the AH is as stickers are off it, so would that be better than a 110 leisure. it wont fit in battery box but not bothered about that. Laurie.

only way to tell is fully charge it, that is to 15.2 volts (it should be gassing well after around 14 v) this makes sure the electrolyte is well mixed, then apply a load say 10 amps (check with meter) and see how long it will supply that load till the voltage drops to about 11.5 volts off load, this is not as straight forward as it sounds as when the load is on it is giving a false reading of actual battery voltage, so you have to guess a bit and say with 10 amp load on take the voltage to say 11.0 volts then remove the load and check the battery after half an hour, if it is above 11.5 then there is still some amps left to use, the total hours drawing 10 amps will give yo an accurate number of Ah this battery can supply, Rick

[rustic]

Originally Posted by solarman216

The total hours drawing 10 amps will give you an accurate number of Ah this battery can supply, Rick

Just to clarify Rick's great post,
So if it supplies 10 amps for 11 hours it's capacity is 10 x 11 = 110Ah


This may not be the batteries original Ah rate, as the battery may have deteriorated.

I have used 2 old head light bulbs as the load, but you need to check the current as the current will be lower as the battery voltage drops.
This test you can do on old leisure batteries, but for an 85Ah battery I would use only one headlight bulb.



Do a table. Measure the voltage and current say every half hour at first.
Time..........Current.......... Voltage


You'll be amazed at how poor a 2 year old leisure battery actually is.


Battery tests are normally done on a 20 hour rate, so an 85Ah battery will supply 85 divided by 20 = 4.25 amps, so it should supply 4.25 amps for 20 hours. On a good day, fully charged battery at the right temperature etc.

It doesn't mean it will supply 42.5 amps for 2 hours though.

Safety issue.Just to add, be aware that the headlight bulb gets very hot, so ensure it is in a safe place.

[Hilltop]

Originally Posted by rustic

The Sturmey Archer "in wheel dynamo" from the old bikes are often used as wind generators, plenty of info on the web, so they sell at quite a premium when sold on ebay.

The output of these is only 6 volts AC and would have to be transfomed UP and then rectified to DC to charge batterys




.