Battery isolator for 6v bank. Need help please.

[Bussy]

Hey all just wanted to say thank you to all who share their knowledge on this website. It was the Bible for us when we were building this summer. We are finally finished and living fulltime in our e350 shuttle bus!

So here's my problem!

We run a bank consisting of 4 6V golf cart batteries in series parralel charge by solar and isolator.

The problem we are having is the isolator. Before our 6v bank we ran one 12v and the isolator ran flawlessly. Now that we've upgraded to the 6v bank I seem to be getting a fault code for over current. I can't seem to figure it out and I can't get any help from Wirthco. All the wiring stayed out during the swap, I have all my positives coming off the top corner of the bank and all the negatives coming off the opposite side of the bank. Farthest point. Everything is grounded properly, I've troubleshoot as much as I can but my limited knowledge can only get me so far. Is it even possible? Should I be running another wire off the AUX post from the isolator? Is it too much for the alternator I don't know, that's why I'm hoping somebody here can chime in. I've posted a VERY simple drawing to breifly explain what's gng on.

Cheers.

Brent

[john61ct]

If the charge source is your alt and it's wired to the Starter side

maybe the bigger bank just needs a bigger combiner?

[JDOnTheGo]

Hi Brent - when/where are you getting the over-current alert?

[Bussy]

It's coming off the actual isolator itself. I forgot to mention it's 150A Battery doctor isolator. I've checked all the connections everything is good and sound. I've tried hitting ovveride to reset and I always end up with over current/over charge

[Bussy]

Originally Posted by john61ct

If the charge source is your alt and it's wired to the Starter side

maybe the bigger bank just needs a bigger combiner?

What do you mean combine?

[john61ct]

Isolators are generally inferior to combiners, aka VSR/ACRs

They all perform the same basic function, connecy (close) the two circuits when the charge source(s) are active, and

isolate (open) when not.

[john61ct]

your house bank is what 450A?

When well depleted possible but unlikely would draw anywhere near 150A (0.3C) especially if FLA type.

If AGM, then that likely is the problem, higher CAR chemistry.

[JDOnTheGo]

If I understand correctly, the scenario is that you have the engine running and the isolator reports the "charging over-current" condition. This didn't happen previously and the only thing that has changed is the new/larger battery bank. If all that is correct...

What is the state of the battery bank? Does this happen when the bank is fully charged?

I'd put a meter on the isolator and see what it is unhappy about.

[PNW_Steve]

A thought,

If your house battery bank is significantly discharged and you connect it to your starting battery you may exceed the capacity of the isolater.

I had a somewhat similar experience with the "battery" connection on my 5th wheel trailer. It is intended to charge the house battery from the pickup charging system. The Einstein that came up with that idea thought a 12 gauge wire fused at 20amps would be adequate.

I let my house battery discharge significantly while boondocking. I plugged into the truck to recharge and promptly blew the fuse. I could not charge from the truck any time the house battery got below a certain state of charge.

[PNW_Steve]

FWIW: You have a 12v battery bank that is made up of 6v batteries.

[Bussy]

Originally Posted by JDOnTheGo

If I understand correctly, the scenario is that you have the engine running and the isolator reports the "charging over-current" condition. This didn't happen previously and the only thing that has changed is the new/larger battery bank. If all that is correct...

What is the state of the battery bank? Does this happen when the bank is fully charged?

I'd put a meter on the isolator and see what it is unhappy about.

Charged or depleted makes no difference for the fault. I'm wondering if it's not reading it as a 12v system

[Bussy]

If I "split" my bank of 4 6vs into two I was wondering if it would efficient to run 2 6vs to power my 12v power supply and run that off solar then my other two 6vs would run off the alternator and that would power the DC fridge and outlets? How does this sound?

[o1marc]

Originally Posted by Bussy

If I "split" my bank of 4 6vs into two I was wondering if it would efficient to run 2 6vs to power my 12v power supply and run that off solar then my other two 6vs would run off the alternator and that would power the DC fridge and outlets? How does this sound?

That would work, but you would only be able to charge the fridge while the bus is running.

[Bussy]

To everyone that chimed in, I appreciate it very much. The end conclusion after days of scrolling through forums and troubleshooting and reading about isolator I have determined the 150amp battery doctor is not a good match for our setup. I ended up running a manual switch and it works great. Our batteries are charging and holding much more power versus solar alone.

Thank yoh again