Adding solar to 5 batteries, 3 banks. How's my wiring diagram?

[beebopbogo]

I am going to install a couple 180W solar panels on my Cal 39 in preparation for a trip to Tahiti. I spent quite a bit of time tracing my wiring, created a wiring diagram, then added the solar stuff to my diagram.

The Solar Controller, Solar Shunt, and Solar Panels will all be new, everything else is previously existing.

I took a few classes in physics but am not an engineer by any means. If anything looks funky, I'd love to hear about it. The one area I'm most hazy on is the grounds from all the charging sources. There may some errors in the diagram I would like to correct.

So yeah!
1) Any errors?
2) Solar setup look good?


Thanks all,

Adam

[wellin]

Looks like both house banks are wired together before the batt switch with no way to seperate them, making it "one" bank. And it also looks like you will get no solar charging or batt charger unless you leave one of the batt switches on. I think the solar and batt charger should be working without the big switch on. The batt switches should be for things using power , not charging.

Andy

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[djmarchand]

Well, at the very minimum I would combine the two house banks into one. I assume that the solar shunt is an external current measuring shunt for the controller display.

Beyond that I won't give specifics, but here are some objectives to think about:

It is always better to charge your house batteries from the alternator. Your Freedom 20 has a built in Echo Charger. It doesn't matter where the DC source is: internally from the charger or externally from the alternator, it will supply up to 15 amps to a starting battery connected to that output as long as the input voltage is above 13.5, ie charging. The Echo Charger isolates the start from the house bank, so with that trick, all of the battery switching goes away and all you need are on/off safety switches in case of a fire.

If you do the foregoing you can greatly simplify the wiring and make it a set and forget system. I do keep a spare heavy 2/0 cable so I can bolt it up temporarily to start the engine from the house bank in an emergency. Automotive jumper cables work as well.

David

[smac999]

comment for new stuff.

the solar shunt needs to go between the solar contoler and the ground terminal. not between the ground bus and xantrax shunt. otherwise it's trying to measure both solar and charger current which is probably too much for it to handle.

the pos of the solar should go to the house bank direct before the switches. so it charges when the swtichs are off. as mentioned above.


old stuff.

the whole swtich / shunt setup is dumb. they've used the dual shunt but then tied the batteries together into one bank anyways. and also the right hand switch doesn't actually change batteries.

waste of wiring and adds confusing.

also it looks like they ran cables from the alt to the house and start battery. which means you actually don't even have 2 banks. you only have one as they are all paralleled together through the alt cables. you need a diode block in there to do that. and even if you turn the engine battery switch off you are still draining the engine battery into the house...

do you have an AC panel on the boat? or the wires just go directly in and out them the freedom? do you plug into 30a or 15a?

the freedom should have it's own battery switch from the battery not using the house loads swtich.

does the freedom have an echocharger cable? otherwise it's not charging the engine battery. (actually it is through the alt cable LOL....)

this whole thing was wired by someone smart enough to get himself into trouble but not smart enough to do it right.

I just noticed also that if you turn all battery swtiches off you will still have DC boat power comming from the engine battery... maybe you've missed drawn it. or maybe it's just really bad...

[beebopbogo]

Great info. I'm definitely going to have to go back and verify my accuracy in drawing. Hopefully it's a simple line change on paper and not a rewiring job!

The previous owner wanted two banks so he could use one at a time. His reasoning was that if one of the AGMs failed it wouldn't bring down all 4 house batteries.

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[sabray]

The pos solar should go to fuse then the bank. The bank should have fuse before it goes anywhere. The freedom should have a fuse before it goes to batts. There are no fused links in the drawing anywhere. Or I need 3x glasses. Just don't see them. I like house ,engine, combine switches. Against the grain I like stupid voltage register charge combiner. It's easy to top up the start batt and keep it that way. My house banks will die before the start bat.simple with well placed fuses is safe and reliable.


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[beebopbogo]

I've updated the wiring diagram, hopefully fixing quite a few mistakes from the first version.

My Freedom F20 does not have an EchoCharge feature, so I have the Alternator and Solar output tie into the charging circuit from the Freedom F20 before the battery switches. Hopefully that makes sense.

The diodes allow the battery combine switches to work correctly, I hope.

I also moved the solar shunt per smac999's suggestion.

Whew! Working on it, and definitely learning a lot about boat wiring!

[smac999]

your inverter isn't going to work too well.

connect the 2 house batteries together. run the solar and alt straight to house bank. put an acr between house and eng batt.

[mitiempo]

Originally Posted by smac999

your inverter isn't going to work too well.

connect the 2 house batteries together. run the solar and alt straight to house bank. put an acr between house and eng batt.

I agree - there is no good reason to have separate house banks. As one bank they are more efficient, will charge better, and last longer.

The diodes are not needed and are actually a detriment. There is a voltage loss through them. The 14.4 out of the alt will only be about 13.7 volts at the batteries. The same for the solar controller. The only way to avoid that loss is to buy an external regulator for the alternator with battery voltage sensing. For solar a better controller with the same battery voltage sensing. Voltage is pressure and a battery will take a lot longer to charge at 13.7 volts than at 14.4 volts.

Use the other side of the shunt to monitor the start battery.

Simple is better.

[mitiempo]

A question. Are you using the same fuse for both the alternator and solar output? That only makes sense if the wires are the same gauge. I would think the alt output wire would be the larger of the 2. What gauge are they?

The shunt is shown in the wrong location - before the panels.