Alternator, Combiner, Wiring, Help!

I have a battery issue. Stumped. Last year I was having generator fuel issues. While on the phone with the Generator Rep He mentioned that during cranking it sounded like i had weak batteries. (ain't the live video chat great!) So i replaced the batteries (4 6V golfcart) with new Interstate batteries. One 800 cranking battery and one 700 extended hour battery.


The cranking (start) battery is fine. The combiner always brings it back to 13.8V. The extended (house battery) is always weak. It never gets above 12 V. It dies during use from head use, water pump, or chart plotter use (even while underway, with engine running full speed.)

Today I went down to the boat, installed a identical crank battery in place of the extended hour battery. (thinking dissimilar batteries were an issue) no difference. Then I swapped the combiner leads from one battery to the other. No difference. I'm amazed that the combiner wasn't the problem. The changed leads still charge the start battery to full quickly and the house battery barely gets charged.


So my quandry is: what to look for before I throw in the towel and call a marine electrician and blow a boatbuck or two to fix it?

make sure that the ground connection between the two batteries is good, Might connect the two negative terminals together with a jumper cable to test...

What make/model combiner? There are lots of different kinds.

Ka_sea_ta said:

make sure that the ground connection between the two batteries is good, Might connect the two negative terminals together with a jumper cable to test...

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I agree with checking the grounds. Sounds like the positive side / combiner is working as it should. At least on the start battery. A poor ground connection on the other battery will limit its charging and / or output. Combining grounds with a jumper while charging is a quick and easy way of testing. You could also test the resistance between battery grounds with a simple volt meter.

It may be wired incorrectly for differing size banks. The article below can help shed some light on this.

https://marinehowto.com/automatic-charging-relays/

Cigatoo said:

I agree with checking the grounds. Sounds like the positive side / combiner is working as it should. At least on the start battery. A poor ground connection on the other battery will limit its charging and / or output. Combining grounds with a jumper while charging is a quick and easy way of testing. You could also test the resistance between battery grounds with a simple volt meter.

Click to expand...

I ohmed the common neg cable. It was good. I removed all the cables and cleaned the connections (nothing stood out). It is a west marine ‘battery combiner ll’. Labeled 130-2.

Ka_sea_ta said:

make sure that the ground connection between the two batteries is good, Might connect the two negative terminals together with a jumper cable to test...

Click to expand...

Going to try that today. Nothing else seems to be changing any ability to charge.

That West Marine labeled combiner was probably supplied by Yandina. Call them and ask for help. They are extremely helpful and offer a lifetime warranty for their products, but don't know if that applies to WM branded stuff.

http://yandina.com/

David

cappy208 said:

So i replaced the batteries (4 6V golfcart) with new Interstate batteries. One 800 cranking battery and one 700 extended hour battery.

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I couldn't get beyond the ambiguity of this description of your battery arrangement. Is it four 6V batts and two others, like GP 27s, or two banks of differing sized 6Vs?

If your combiner is properly installed it should be fused at the positive terminal of each battery. Usually a buss fuse. Might want to check those. If it’s a Blueseas ACR you will have flashing green light indicating a poor connection / blown fuse at the battery.

Ok. After further digging:

This is a fairly accurate representation of my current system.



Incorrect use of battery switches instead of cut off switches makes this installation not allow battery combiner to charge batteries.

Any suggestions how to rewire and make proper?

Of course with my limited knowledge of electronic blueprints.....

cappy208 said:

Ok. After further digging:

This is a fairly accurate representation of my current system.

View attachment 104773

Incorrect use of battery switches instead of cut off switches makes this installation not allow battery combiner to charge batteries.

Any suggestions how to rewire and make proper?

Of course with my limited knowledge of electronic blueprints.....

Click to expand...

This is the original installation (as far as I can determine).