Solar Panel

[Voyager1]

I have one 100 watt solar panels with two batteries. Batteries are connected to selector switch 1/2/both/off. Can I use a controller that can only be connect to one battery. connect the positive lead to battery one and negative lead to battery two. At times one battery will be discharged more than the other. Photo does not have solar cables connected.

 

[rgranger]

If you connec the leads the way you describe, then you have a single two-battery bank in parallel. Yes you can do that but the switch no longer plays a role. You have one bank with double the capacity.

 

[Stu Jackson]

Can I use a controller that can only be connect to one battery. connect the positive lead to battery one and negative lead to battery two.

No.
Why?
Because while the negatives are common to both banks, the positives are not.
Either leave your switch in the B position (most don't like to leave the power on whewn away from the boat) or get a combiner.


What are ACRs, Combiners & Echo Chargers? (by Maine Sail) [scroll to the top]
Battery Switch Question ? and Battery isolator / voltage regulator / batteries

Making Sense of Automatic Charging Relays (2019)
Making Sense of Automatic Charging Relays - Marine How To

 

[dlochner]

The wiring on your batteries is not clear.

The smaller red wire, it looks like it goes from #1 to #2, why?

Are the negatives on #1 and #2 connected? What is the small black wire for? What is the white wire for?

If the small red wire is connected to both the positive terminals, then you both batteries are wired in parallel and it doesn't matter whether the switch is in Position 1, 2, or both. The wire is also too small to carry the current between the batteries.

Before you connect the solar panel, you'll need to straighten out the wiring. This article will help you understand how the 1-2-both switch works.

1/2/BOTH Switch Considerations

1/2/BOTH Battery Switch Considerations - Ever wonder how to make the 1/2/BOTH switch easier to use, let this article explain how to do that.

marinehowto.com

 

[Voyager1]

Stu, that is what I was thinking, just was not sure. Wouldn’t a controller where you can connect two batteries work.

photo turned out bit fuzzy but each of the large red wires goes to switch from each battery positives. Large back is grounded to engine. Both batteries negative are jumper. The thinner back wire goes the dc panel ground. Other small red and white are from old old charger that has been removed.

 

[dlochner]

Other small red and white are from old old charger that has been removed.

Abandoning in place is a time honored technique when old wiring and plumbing is no longer useful. However, it is usually only practiced when removing the item is very difficult or too expensive. It would be best to remove those old wires. And while you're mucking around in the battery compartment put some fuses on the batteries, ABYC says fuses with 7 inches of the battery terminal.

Back to your original question.

Yes you can connect the negative to on negative post on the battery. It would be best installed on #2.

Attaching the positive to one battery will allow that battery to be charged, but not the other battery. The better solution is to use an ACR as Stu mentioned to keep both batteries charged. The articles he and I linked to will provide you with a detailed and understandable explanation.

 

[Richard19068]

Other small red and white are from old old charger that has been removed.

Just to make sure (from my view). The small red wires that are on each of the positive terminals are NOT connected together somewhere else. Both of the other ends are unattached?

The picture makes it look like it may only be one wire connecting the positive terminals together.

 

[Voyager1]

Small red and white wires have been removed. Old photo

 

[Richard19068]

Thanks

 

[Stu Jackson]

Stu, that is what I was thinking, just was not sure. Wouldn’t a controller where you can connect two batteries work.

The articles he and I linked to will provide you with a detailed and understandable explanation.

V1 - That's what we've been trying to tell you. What do you mean by "a controller?"

 

[Voyager1]

V1 - That's what we've been trying to tell you. What do you mean by "a controller?"

I understand a ACR will do the trick. The Article explained it well. Was thinking another option could be a dual battery solar controller where you can connect two batteries. Most only allow connecting to one battery but some you can connect two batteries. Not sure if ACR would be a better option than a dual battery solar controller. Cost seems about the same.

 

[Ron20324]

I put two solar panels on my B323, connected to a 3-output controler. Each output goes to the battery side of 3 on/off switches. Pick and choose which battery to use or charge as needed. Been working great for 12 years.

 

[dlochner]

I understand a ACR will do the trick. The Article explained it well. Was thinking another option could be a dual battery solar controller where you can connect two batteries. Most only allow connecting to one battery but some you can connect two batteries. Not sure if ACR would be a better option than a dual battery solar controller. Cost seems about the same.

An ACR will work with all charging sources, alternator, solar, and battery charger.