vehicle trickle charging

[openspaceman]

I'm not sure if this should rather be under the transport sub forum .

My niece parks her horsebox at the stables she rents, no electricity, and as it is seldom used the battery needs occasional topping up. I have used the little A4 sized ones which plug into the cigar lighter and not been impressed so am now looking at a 90 or120W panel which should just fit inside the screen.

Control is the issue as it more than doubles the price to add a PWM controller, could a voltage controlled relay safely do the job as they only cost 16 quid, set them to cut the panel at 13V and cut back in at 12.5V? It could then also run her electric fence.

[AGT]

https://www.windandsun.co.uk/products/sunguard

These would do nicely and made by Morningstar you know it’s decent.

[Stinsy]

Those A4 panels couldn’t possibly work! You’ll get 5W at best, and then only if the sun is shining. A “100W” panel with PWM controller will cover the self-discharge and standing loads even in winter.

[openspaceman]

Thanks but limited to 4.5A so maybe with a smaller panel.

[AGT]

https://www.windandsun.co.uk/products/shs