Cheap and cheerful top-up panel?

[Tomotto]

OK. I read the threads about solar panels and still have a question. I have a van with the vehicle battery and a leisure battery which are linked by gubbins that charge both when driving and when on EHU. Someone gave me a simple solar panel - 20w - which plugs into the cigar lighter socket and trickle charges a 12v battery. I would like to trickle charge the vehicle battery to keep it topped up when I am not taking it out for a while. The base vehicle is a Fiat Ducato and on the dashboard panel there is a cigar lighter and a separate 12v socket. I think the cigar lighter is standard Fiat issue and the separate 12v socket was fitted by the converter. There are another two 12v sockets in the habitation area.

I assume (but am asking anyway), that the standard Fiat cigar lighter is wired to the vehicle battery as opposed to the leisure battery. Is this the one to which I should connect the solar panel? Do I need to check whether it is "live" when the vehicle is not running? Should I assume the other three 12v sockets are wired to the leisure battery?

Any advice gratefully received.

 

[Emmit]

Hi Tom,

All 'vans are different at the Hab area and even though you've got a Fiat doesn't mean that your Fiat will be the same as ours, However,
I can say that neither of the sockets in the Vehicle area of our 'van are connected full time. They only work when the Ignition is on.
The Socket in the Hab area however works 24/7.
I suppose ours is standard. I have been mooting for some time to make one of the vehicle sockets work 24/7. A job for the future.
Easy way to check. Plug a mob. phone via a USB plug. If it 'wakes up' then that socket is live.

 

[Tomotto]

Thanks for the quick response. I have a follow-up question, for you or someone else who joins this thread.

If the vehicle and leisure battery are linked, what would happen if I plugged the solar panel into one of the "live" habitation sockets? Would it trickle charge both, albeit slower?

The panel comes with both clips and a male plug for the sockets. If necessary, I guess I could use the clips directly on the vehicle battery.

 

[68c]

No, the starter and habitation battery are only linked when the engine is running. The D+ terminal on the alternator (which also controls the red light on the dashboard) switches a relay to join the batteries when the alternator is outputting. It is to stop you flattening your starter battery when parked up.

You could connect the solar panel direct to the starter battery with crocodile clips. Make sure you know which lead is positive and connect that to the battery positive and the other to the negative.. With such a small solar panel you will not need a controller.

 

[Jev88]

Check your 12v sockets are live without ignition on, like on older vans.
If so you can simply plug in and keep engine battery going. Don't expect it to charge the battery, only hopefully maintain.

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