can anyone tell me have they tried the small solar panels on e bay just to keep the battery topped up while the van is in storage and if they have can you just clip to the battery and leave or do you have to put them on the roof. I know its sound a bit silly but i was just wondering how you use them just for topping up , and would it be worth getting one. I know someone will be able to give me someadvice
They use to do ones for cars that u would plug into cigy lighter,so as long as they are about 12v should just be plug and play, try asking a seller on eBay.
------------- Mark
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We bought it to keep the battery topped up when in storage (and to help when away on rallies). Within a few days our low battery was up to full charge again and I think there is only the alarm that draws on it whilst in storage. My husband rested it on the roof and ran the cable down through the skylight and plugged it into the 12v socket in the caravan. He has since rigged something up on the roof so that the panel is secure, but easily removable for when towing..... although there are instructions on Wizard's website on how to fix them permanently to the roof, but we were happy with the 'easy' option! Haven't tried it on a rally yet (may do this weekend, weather depending) but I see no reason why it won't extend the time the battery stays charged for.
Anyway, it's served its purpose for when in storage and for that we are happy as it otherwise meant buying a new battery and then swapping them over periodically.
If you mean this from my experience they are a waste of money. A maximum charge of an eighth of an amp is pitiful. I bought a couple from my local supermarket, because they were reduced to £4.99 - I soon found out why they were reduced
Personally I would look at one of at least 10W as the losses in the cables etc will mean that virtually nothing would get to the battery. However if you go above about 20W you will need to fit a regulator to control the charging. A quick rule of thumb is if you multiply the output of the panel in W by 3.5 then that is about the number of Whr you will get per day on average, assuming the panel is facing south at an optimal angle. In the wintertime it will be less and in the summer more. As Francophile says the very small panels are not much more than toys although they are good for teaching people about PV and its pros and cons.
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I use the ones from ebay have done for years as long as it is just to compensate for battery loss during storage they are fine, how ever if you have a permanent alarm fitted depending on type they won't help a lot solar panels in this country are a real rip off try sontasun panels selling over here for nearly £300 (80 watt) can be bought for as little as £60 if you do what I did and bought a batch you can actually make some money and get your panel free
I use a small one for storage. Keeps Jack Frosts fingers off me cells. I've made the cables a bit longer and passed them through the grommet in the battery box. When in storage the panel sits on top of the partially closed rooflight blind. Keeps my battery in good order all through Winter - enough charge in it after a 5 month layup to drive the mover. Wouldn't recommend it for keeping a battery charged on-site though.