How to wire up solar controller - can anyone advise?

[roxburd]

Hi,

I got one of these to keep a motorhome topped-up over winter:

20W 25Watt 12V Solar Panel Kit With Controller Battery Charger Boat Camping RV | eBay UK

1 x 20w Solar Panel Kit. Item model number ‎Solar Panel Kit-20W. Efficiency ‎High Efficiency.

www.ebay.co.uk

The van has a 100W panel on the roof that works brilliant March to November... but over the depth of winter the sun is so low the rays just bounce off the horizontally-mounted panel. Last year I topped up by mains battery charger but this year I'm trying an auxiliary panel propped up on the dash facing south.

Unfortunately, the panel/controller kit came with Chenglish instructions - useless. My question, really, is this: What the heck is the load connection for? The controller has three connections:
- one for the panel (yep, got that)
- one for the battery (yep, makes sense)
- and then one for load... D'Uh?

Can I just leave that disconnected? I just want the controller to take the power from the panel and use it to charge the battery. Or is the load required to dump excess power? Surely not...

Thanks!!

 

[ericmark]

I would say load can be left disconnected.

The problem is with stage charging if it drops to final stage when the output drops to say 1 amp, and you're drawing 1 amp it can't drop into final stage and can overcharge the battery.
1) At that output, unlikely to overcharge a battery.
2) You're not using the battery while being charged.

At 20 watt, if I look at my own panel's 6 kW which today don't even get to 3 kW I would not expect over 10 watts which with a 60 Ah battery could be left charging at that rate 24/7 without a problem.

 

[sparkwright]

The load would typically be a light (for example in a shed), via a switch.

 

[SUNRAY]

And one of the things I hate about those connectors is devices can end up with the wrong polarity.

 

[robinbanks]

The van has a 100W panel on the roof that works brilliant March to November

Can you fashion a bracket to allow you to raise the panel so it is held in place at an angle, and park the van so it catches a reasonable amount of sun?

 

[roxburd]

Can you fashion a bracket to allow you to raise the panel so it is held in place at an angle, and park the van so it catches a reasonable amount of sun?

That would be ideal, huh? Yes, I had wondered about that... It is permanently fixed down flat so I would have to fashion something that could be released to angle the panel up. I would also need to keep a ladder at the storage yard so I could get up there...
All in all, I figured that £15 and another panel in the windscreen would be easier...
But thanks for the suggestion!! I think if I kept it at home I would probably do that...