Battery charger working?

Tom J · Dec 28, 2018

Sounds like one circuit of the battery charger is not working. Could be a wiring problem. It might be possible to check the outputs at the battery charger, and compare that to the voltages at the batteries.
We can't be sure if the water levels are a problem. It doesn't seem like the charger was overcharging the batteries. Maybe check the levels again in the future.

jssailem · Dec 28, 2018

How about connecting batteries in parallel and then charging the positive on battery one and the negative takeoff on battery two. The way the charge runs through both batteries.
Maine Sail has a good diagram on his site as to your wiring procedure.

SG · Dec 29, 2018

Clyde,
As an extension of the comments above, and in order to make it easier to help you:

Please confirm that both of your batteries are in one-bank? (Not two, with a battery switch between.
Are your two batteries linked "in parallel" -- i.e., are there jumper cables that link the positive and negative terminals to their corresponding "partner" on the each of the two batteries -- so that you two 4D are connected.
What manufacturer and model number of charger do you have? (Some chargers will NOT do anything unless they see a minimum voltage in the battery [say 10.8 Volts], so trying to see if you get some output is not achieved by disconnecting the charger from a battery.)
Was the system working before you installed the new batteries? Did you hook them up the same way?

KZW · Dec 29, 2018

Does your charger wiring go direct to the batteries or through the battery selector switch?

SG · Dec 29, 2018

KZW said:
Does your charger wiring go direct to the batteries or through the battery selector switch?

Installed two new 4 D batteries. When picked up asked if full of fluid. Was assured
topped off. Did not check voltage. Week after installation thought better check
and sure enough need top off with distilled water.
Checked voltage. One at 13.45 other at 12.40. ( 70 % ) One small red wire to
positive on battery and small ground wire to second battery. Best way to check charger
output remove small red wire one leg voltmeter there and second voltmeter wire
leg to negative on same battery? If output ok will remove everything from battery
and attach battery charger for three - four hours see if take charge? Appreciate any
suggestions. Original charger,
Clyde Thorington
C310 # 245
I LEAN TOO
San Jose, CA

Tom J · Dec 29, 2018

SG said:
Installed two new 4 D batteries. When picked up asked if full of fluid. Was assured
topped off. Did not check voltage. Week after installation thought better check
and sure enough need top off with distilled water.
Checked voltage. One at 13.45 other at 12.40. ( 70 % ) One small red wire to
positive on battery and small ground wire to second battery. Best way to check charger
output remove small red wire one leg voltmeter there and second voltmeter wire
leg to negative on same battery? If output ok will remove everything from battery
and attach battery charger for three - four hours see if take charge? Appreciate any
suggestions. Original charger,
Clyde Thorington
C310 # 245
I LEAN TOO
San Jose, CA

This is very confusing, Clyde. Are you saying that there apparently is only one set of charging wires to the batteries? If the one small red wire is going to the pos terminal of batt. 1, and the one small black wire is going to the neg terminal of batt. 2, then only batt. 1 will charge. The voltage will feed to the pos terminal of batt. 1, and return through the common ground, but batt.2 will not see any voltage. This is assuming the batts are not paralleled.
The original setup for the C310 has two battery charging circuits, with a separate set of wires to each battery.
We really need detailed pictures of all the batteries to figure out what is going on.

marchem · Dec 30, 2018

Clyde, having a picture, or even better, a schematic of your wiring would be very helpful.

In the meantime, I would check the voltage at each battery with the charger turned on, and then turned off.

Tom J · Dec 30, 2018

Clydo said:
Yes indeed pictures and/or schematic would be of great help. Didn't know if brief description would get it done.
Boat 100 miles away will get picture and/or schematic soon. Good idea to check voltage with charger on
and off. Thanks all for some great thoughts. Am great with this electric stuff cause only takes couple
other guys and myself to change light bulb.

Clyde Thorington
C310 # 245
ILEAN TOO
San Jose, CA

Sounds like a good plan, Clyde. I'm sure someone on this forum will be able to figure it out. It can be frustrating being away from the boat. I live on my boat in the summer, but am 5,000 miles away for the rest of the year.

SG · Dec 30, 2018

Clyde:

It is possible that your charger i) an ancient thing which is hardly a "smart" charger; and, it has only a single output; iii) someone installed it is very weird way because "whenever we use the charger, the battery switch is set for 'Both'"; and, iv) you should simply buy a new "smart" dual output marine charger. I'd probably get something that matches you charging needs and just wire it properly and quit messing with the old Charles unit.

If the Charles unit is something different, then maybe it's worth messing with...but I personally doubt it.

How do you use your boat? What are your electrical needs? You have two 4D's -- that's probably 300-400 AH of capacity. Do you have an inverter, radar, do you draw down the batteries a bunch, etc., etc. , etc.