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Hoohaa 10-10-2016 20:29

Solar charging question.
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I have about 240 watts of solar charging a house bank and cranking batt. I do have a battery charge controller, by using this I can see when the charge from the solar is coming in.
Currently, only when switched to all do i see the corresponding increase in amps coming in. And a clear reduction of amps coming in when switching to house or start.
Currently the wires from the solar are connected to a bus wich apears to be connected directly to the All switch.
Could someone please tell me were the solar input should be wired to so that it directs its charge to where the switch is indicating?

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newhaul 10-10-2016 21:01

Re: Solar charging question.
Actually the solar output from the controller should go direct to the house bank along with all other charging sources. Not thru the battery switch. ( many charge controllers can be damaged if the panels are hooked up but he batteries are not.)

HankOnthewater 10-10-2016 21:04

Re: Solar charging question.
The photo shows two MPTT chargers. Is that one charger for each panel (of approx. 120 watts)? If so, that is very good. Although I do not recognise these controllers. Your diagram is not really clear to me.

Now to your question. There has been dozens or multiple of dozens of threads on this.
I will try to find one or two of them.

In the meantime, a short version what I believe is best:
- Connect engine cranking battery to ignition and startermotor, and nothing else
- Connect all other loads to house (ship’s) battery
- Connect output of solar controller(s) to house battery
- Connect output alternator (and sensor) to house battery
- Get VSR (voltage Sensitive Relay), some call it an ’ACR’ (automatic charge relay), to charge engine battery from house batteries

That way the use of the “1-2-both-off” switch is relegated to emergencies only. And, here is also a link to improve the use of such switch (however you didn't ask about this switch, so that is just for your consideration).

Maybe I didn't answer your question, as I added a VSR (for you to purchase), to make a good system. The following links provide more details (and opinions).

Basic Battery Wiring Diagrams

1/BOTH/2/OFF Switches Thoughts & Musings | Forums

If after all that, you prefer not to have VSR, and you cannot get a good answer from these links, I am happy to provide a simple solution, but one that requires you to use the '1-2-both-off' switch every time you start and stop the engine.

On edit: And then indeed, as per "Newhaul" post, the output of solar controller(s) to be connected to house battery as would be the essentials like bilgepump, radio memory and the like.

Hoohaa 10-10-2016 21:32

Re: Solar charging question.
Hank. Yes they are separate units for each panel.
NH. So I should connect the solar wiring directly to the positive side of the house bank?
Is this as simple as moving the current wires across to the posative terminal of on of the house batteries?
Does it matter which battery?
What is the C post on the battery? I assume its the posative?
Hank. Thanks for that info. But i am not in a position to start altering my system. But am looking for a simple fix using what I already have. I do appreciate your help .
Its not hard to work out that I am coming from a diy background and electrics are not my strong point.

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HankOnthewater 10-10-2016 23:10

Re: Solar charging question.
Hi Hoohaa

I am not sure what a 'C' post is on a battery, but many '1-2-both-off' switches have a (common) post marked as such. And therefore I will mention that later.

If you check this link:
1/BOTH/2/OFF Switches Thoughts & Musings | Forums
the first diagram is a most common (but not best) electrical layout. The text shows the pitfalls of such configuration (BTW, that post courtesy of “MaineSail”).
Please read it, and if you abide by that (ie remembering when to use the 1-2-both-off’ switch) then all can be good.

The second diagram in that link shows a better setup, but you need to change the connections of the alternator. But no new stuff needs to be purchased.

Now the solar controller. Many or most supply the regulated supply (output) on the positive side. That being the case:

Still using the 1st diagram (not sure if I can ethically copy that from a different user and different forum), one could connect the positive lead from the controllers to the ‘C’ (common) post of that switch. Not a good option in my opinion as it would mean:
- You need to leave the switch in the ‘1’ or 'both' position
- All the DC circuits are live/active while you are not at the boat
- If you were to put the switch in the 'off' or '2' position, then the solar controller is not connected to a battery, and some controllers may die in such condition.

Still using the diagram #1 in that link:
You can connect solar controllers to the ‘1’ post of the switch or to one of the positive terminals of the house batteries:
- You can turn the ‘1-2-both-off’ switch to 'off' when you are not on the boat
- Solar panels will continue to charge the house battery
- You need to connect the essential equipment like bilgepump to the same post '1' (and fuse it)
- all other DC equipment will disconnected while you are away
- If your house battery bank has more than one battery, than all positive terminals will be connected with short thick wires, assuming all batteries are 12 Volt?

In short, as you said, it could be as simple as moving the solar controller output to the positive terminal of the house battery.
If things are not clear, let us know, there a lot of knowledge on this forum.

Hoohaa 12-10-2016 02:28

Re: Solar charging question.
Thanks Hank. Great info and a really good link.

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Stu Jackson 12-10-2016 10:03

Re: Solar charging question.
The C post of the 1-2-B switch is the output of the switch.

You may read a lot more about electrical boating systems in this link, which includes the links provided earlier and many, many more.

Electrical Systems 101 Electrical Systems 101

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