trolling motor - battery/charging issue?

[Boater633]

I have charged it with a very long extension cord which it said not to do - red and green light after 24 hours of both being on. I unplugged it, plugged it back in and got a green light. After that use I used a much shorter cord, left it for a couple days pulled the plug without checking the charge, checked the meter on the motor and it was 50%. I have a 24v 80lb trolling motor w/guest charger on my 2012 targa. The dealer is an hour away and don't want it sitting there for a week for them to change a fuse (which were all ok). 50% = 1 battery? Any ideas? Thank you!

 

[Mike Ratko]

First guess is a bad battery or batteries. Has it been like that all season? The best way to check the health of a battery is a hygrometer that measures the density/sulphuric acid levels in the water. Check the water levels in each cell of each battery too.

Chargers can go bad from time to time. Check the voltage of each battery individually and do a load test on each one individually.

 

[Boater633]

I don't normally check the meter. I think recent because of the use of the trolling. Do I disconnect the batteries from each other to check the voltage? I won't bother you with the load test. thanks!

 

[Mike Ratko]

you don't need to disconnect them to read the voltage.

To check the charger, check the voltage on each battery while it is plunged in. The voltage should be around 14V.

Mike

 

[AirForce]

You could (and I would) check each battery, but wait 4 hours after charging. This will give you info on whether or not the battery is maintaining charge. You mentioned 50% on the meter - what meter? TM gauge? Have an ohm meter read voltage of each battery would be more accurate as Mike's method will just show the charger is working (if in charge mode).
Am I understanding this charger is NOT the onboard mounted type? But rather a portable unit? If after 4 hours the batteries are not at 12.65v or higher, then its not fully charged. How OLD are these batteries? What is the amp output of this charger unit? Is it an AGM or wet cell batteries?

 

[cq]

Remember your best battery is only as good as your worst battery. If your batteries are in series or parallel all batteries will migrate to the worst. Here is a site for battery basics.
http://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html

 

[Boater633]

I checked them out and they seem to be charging this time around both were 14.whatever. Minnkota TM meter, on board charger. loose fuse, really low batteries? I was surprised to only see 50% charge when I got to the lake. heading out tomorrow to do some crabbing, meter shows a full charge. I'll pull the batteries this week to check the levels (cant get to the caps on the one). thanks all!