Solar Panel/Charge Controller question

[Perkster24]

Hi All,

Newbie electrical question guys.

We bought our 2017 plate camper, a Fiat Ducato 2.3ltr , Weinsberg Carabus 541, last June. We had a small solar panel installed when we bought the van but it only charges the leisure batteries. Over the winter period the starter battery has gone flat. There's obviously something pulling some juice from it when it's left for long periods.

Looking at the installation with fresh eyes I’m wondering if I can use the existing system to trickle feed the starter battery. I can see it’s fitted with a 10A twin battery charge controller, a Solar Technology DC STCC10, (see pic). Only one of the battery feeds is currently being used. Am I right in assuming that all I need to do is take a cable from the second battery feed on the charge controller and hook it up to the starter battery in the passenger foot well?

Also, the current solar panel is a 600 x 500mm ish 45w jobbie. Will this be sufficient to keep both sets of batteries charged during the relatively dark winter months? Based on current research I’m thinking it might be under powered for what I’m proposing although It’s worked ok with just the leisure batteries so far.

Any advice gratefully received.

 

[Jimbohorlicks]

You really need to increase your solar panel wattage, the small one you have has just kept the leisure battery charged up whilst not in use. If you had fitted a battery master, £15 of e Bay, then this would also have kept your cab/starter battery charged up also. If you are off grid the solar you have will only be sufficient to keep the leisure battery topped up if you are using internal lights etc. In winter time you may be lucky to keep the batteries just about topped up. But you do need to check what space you have on your roof for a bigger or additional panel. You may also have to increase the capacity of the controller.
Ps yes you can connect the cab battery to the 2nd battery terminals on the controller to charge up the cab battery. If you check the manual for the controller you can set it to 70/30, 80/20,90/10 etc. Leisure/cab battery charging.

 

[RustyRuss]

Do you have a control panel that shows battery status etc? A pic could be useful....

Cheers!

Russ

 

[Jimbohorlicks]

The control panel in the op's original picture shows that the solar is outputting to the controller, the green light top left, and the hab battery is charging, which is the light to the right.. There is no connection to a second battery.

 

[kevenh]

I've a much smaller solar panel trickle charging my CAB & HAB batteries.
It only works to keep both batteries topped up with our recent decent summer.

If you want to stagger your upgrade, with my 2.4W panel results as a guide, you can add wiring to get solar charging to your cab/engine battery.
Then later look at larger solar panels for better results with how long things will have power when there's no hookup.

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[Stealaway]

That controller will be ok up to maybe 150watts of solar. It's a petty the controller was connected your starter battery but it can be pig to feed the cables to the stater battery. Try taking some cable to the the starter battery it will help you in the long term. You will need more solar panels eventually.

 

[PhilandMena]

45 W is about as much use as a chocolate tea pot. You can never have enough solar power and if your planning to be off grid and keeping both your leisure and cab batteries charged and possibly an inverter at some stage you need to plan to do it once and do it right. 300 W and a good quality MPPT regulator will see you right. Consider Gel batteries too if your going to do a lot of wilding.

 

[Perkster24]

Thanks for the replies guys.

Have just checked the charge controller and it's actually a Solar Technology DC STCC20 which, according to the manufactures bumf, is good for max 300w panel. I think my limiting factor if I upgrade the panel will be the space available on top!

 

[Jimbohorlicks]

That controller will be ok up to maybe 150watts of solar. It's a petty the controller was connected your starter battery but it can be pig to feed the cables to the stater battery. Try taking some cable to the the starter battery it will help you in the long term. You will need more solar panels eventually.

It was easier for me to fit a battery master as basically hab battery to cab battery connection with one wire. I followed the wiring harness that connected both and clipped the wire on with ties. To go from the controller was difficult, behind fridge etc down through a sealed outer fridge casing.

 

[Jimbohorlicks]

Thanks for the replies guys.

Have just checked the charge controller and it's actually a Solar Technology DC STCC20 which, according to the manufactures bumf, is good for max 300w panel. I think my limiting factor if I upgrade the panel will be the space available on top!

How about a potable panel?

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[pappajohn]

There is no connection to a second battery.

Which is what the OP asked.... Can I connect the controller to the starter battery.

 

[xsparks]

The cab radio may be the reason for the discharged starter battery.

 

[Perkster24]

The cab radio may be the reason for the discharged starter battery.

Tell me more. It's obviously off when we're not using it. Does it draw a current even when off?

 

[Stealaway]

Modern vehicles all need power. ECU needs constant power and the door lock/alarm.

 

[pappajohn]

Tell me more. It's obviously off when we're not using it. Does it draw a current even when off?

Yep...... Only a few Milliamps to retain channel memory but a few Milliamps soon turn into a few amps then, before you realise, the battery is dead.
ECU, alarm, radio.... All need power when the ignition is off.

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[Perkster24]

So best to trickle charge using my battery charge controller or disconnect the battery over winter. No alarm fitted at present.

 

[Jimbohorlicks]

Which is what the OP asked.... Can I connect the controller to the starter battery.

Yes, aware of that, I was answering RustyRuss comment.

 

[autorouter]

I think some on here may disagree, but I think a 45W panel should be enough to keep leisure and starter batteries charged up in storage, even in winter. But not much use while camping, just about enough to charge your phone.

 

[Perkster24]

What size cable would you say I need to run from the charge controller to the starter battery? Would a twin core PVC 0.65m2 which has a 5.75 amp rating do the trick and I presume I need an inline fuse? 5A?

 

[Jimbohorlicks]

I would say that's OK, as its only a low amps probably less than 2 amps in reality. Evenif you have more solar you won't get much more than that.
With your 45 w panel you would be looking to get less than 0.5 amp to your cab battery even if it was all sent to the cab battery.