Solar systems - regulators?

Submitted: Monday, Nov 22, 2010 at 13:00

ThreadID: 82619 Views:4393 Replies:1 FollowUps:4

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Ki Tech Kitchens

Hi,

Firstly I am brand new at this so please except my appologies now before I start.

I have 2 questions regarding solar on my camper trailer.

When I purchased my camper it come with a solar system built in which is awesome. The way this is set up is the panel removes from the storage area and sits on a stainless pole at the front of the trailer. From there a purpose made leed runs from the panel to a socket on the front of the trailer. This then runs through to the built in solar regulator and then to the batteries.

I have now decided that while this was great, when it comes time to put some charge into my 4WD batteries, I can't due to the fact that the solar regulator is built into the trailer.

What I have done is purchased a 2nd regulator and siliconed it to the back of the panel and conected it to the power which is coming from the back of the panel. From there I have made up my own leed which comes from that to charge my 4WD batteries.

It all seems to be working fine so far.

OK, and now for the questions:

no.1 - While using the original set up, will the 2nd regulator be affected while sitting on the back of the panel with power running to it - keep in mind at this stage it would be just sitting there without charging anything?

no.2 - Is it possible to use both the regulators at once? One regulator would be charging 2 x 100 amp hours in the trailer and the other regulator would be charging 1 x 100 amp hours in the 4WD.

I hope this is clear and doesn't stuff anyone around.

Regards,

Darren.

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Reply By: Member - John and Val - Monday, Nov 22, 2010 at 13:35

Monday, Nov 22, 2010 at 13:35

Hi Darren,

Firstly, re question 1 - It depends on just what sort of regulators you are using. Some manage charging by loading down the panels, others simply interrupt the flow of current to the batteries once they are fully charged, and then there are MPPT (maximum power point tracking) types that actually change the panel voltage to that required by the batteries. So, no simple answer to question 1.

Question 2. - Again it depends on the above. I would suggest that it's better not to run both at once, because of possible interaction, but in any case you will need a lot of panel to make much difference to 300 Ah of batteries.

There is however a simple way of avoiding the concerns altogether! To maximise charging, it is better to have the controller at the battery end of the cable, not at the panel end. That way any resistive losses in the cable are "upstream" of the controller and it can do its regulating job better. Suggest move the controller to the other end of the cable (as it is in the camper) and arrange things so that the output of the panel can be connected to either the camper or the vehicle, but not both at once.

Sounds like you have a good amount of storage. How much panel capacity are you carrying? You might find our blog Electricity for Camping of interest.

Cheers

John

J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein

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AnswerID: 436612

Follow Up By: Ki Tech Kitchens - Monday, Nov 22, 2010 at 13:42

Monday, Nov 22, 2010 at 13:42

Hi John,

Thanks for your quick reply.

Both regulators are Morningstar - the one in the camper is a 15 amp and the one on the back of the panel is a 20 amp.

Panel size is 130 watt.

Hope this helps.

Darren.

FollowupID: 707980

Follow Up By: Member - John and Val - Monday, Nov 22, 2010 at 14:09

Monday, Nov 22, 2010 at 14:09

Darren,

They are good gutsey controllers, and almost certainly you can run with them both connected concurrently to the panel. There is however major advantage in moving the controller from the panel end to the battery end of the cable - depending on the cable size and length you may well double the rate of charge into the vehicle mounted battery.

BTW, your 130W panel could probably do with some help in dealing with 300Ah of storage. Depending on your usage patterns, it might be worth adding another panel in parallel with the present one. The controllers will easily handle another 130W, but just another 60 or 80W would be a good match for your storage.

Sounds a good setup.

Cheers

John

J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein

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FollowupID: 707983

Follow Up By: Battery Value Pty Ltd - Monday, Nov 22, 2010 at 14:12

Monday, Nov 22, 2010 at 14:12

Hello Darren,

Q1: no effect

Q2: your MS solar charge controllers are either series PWM type or MPPT.

In case one or two are MPPT, then the batteries will get less than maximum charging current becaue the two controllers will confuse each other.
The least problems you would encounter if both controllers were series PWM.
Note that the batteries will behave like being wired in parallel, i.e. the ones which are discharged the most will receive more solar current than the others.
The SOC of all batteries will equalise during charging though.
And for this reason, you could just as well wire all batteries in parallel while they receive charge from only one controller.

cheers, Peter

FollowupID: 707984

Follow Up By: Ki Tech Kitchens - Monday, Nov 22, 2010 at 14:25

Monday, Nov 22, 2010 at 14:25

Judging by the response so far, I think it will be easier/safer to just run either the camper regulator or the new regulator at separate times. The original set up works perfectly and the second regulator was only to charge the aux battery in the car. This will only be put into practice if we sit for any more than 2 days without starting the car. It is no problem to disconnect the camper plug and connect the new one so I really think it's the safer way to go.

Thank you so much for your opinions, I feel heaps better now.

Cheers,

Darren.

FollowupID: 707986