Battery Problem

[SteveM]

I have a 2016 Defender HD10 purchased new.  It is very lightly used…typically only started once a week and run for ten minutes. Recently, after a short ten minute ride and shutting if off for ten minutes it would not restart.  I had to haul it home.
 

Typical voltage before ride 12.55, after ride 12.38.  This morning with engine running it goes up to 14.67 after shutting off 12.93.

I’m hoping someone might have some ideas. I’m thinking maybe I should replace the battery.

[Andystoy19]

A couple of things you can check before you replace the battery are:

Try running the machine for a longer period of time to allow more charge time. Do you have any accessories on when the machine is running? Your charging system seems to be working with the voltage where it should be to charge the battery.

Disconnect one of the terminals on the battery right after you have run the machine and leave it sit for several days or even a week or more checking your voltage to see if the battery drops voltage on its own. A slight drop of .1or .2 volts is okey and it should remain above 12.6 volts to indicate it is fully charged. Worst case you can take it out and have it load tested at a battery shop. You can charge the battery with a small charger set at 2 amps until it indicates full charge and again check the battery to see if it remains at 12.6 volts or higher.

If your battery remains at 12.6 volts disconnected but drops steadily when connected to the cables you may have a parasitic loss slowly draining your battery. Your before ride voltage indicates your battery is not fully charged and the after ride voltage should be higher than the before ride not lower unless you have a large draw when the machine is running that is exceeding your charging currant??? Light bar, winch, stereo? Clean the battery cables if corroded with baking soda.

If you decide to replace the battery remember to buy a 30 amp battery instead of the 20 it will provide you with 50% more reserve and the new ones have been upgraded to the 30 Amp. FYI🤔

[Dragoon]

I haven't had any luck with new batteries lasting longer than 4 years these days. If you're on the original battery it's probably time to replace it.

[SteveM]

Thanks. Do you think a bad battery could cause the symptoms I described?

[Dragoon]

It could be, although, it's odd that it would start run awhile and then die. Seems like if the battery was shot it wouldn't even start. Maybe you have just enough juice to get it running and then it runs on the alternator until the battery can't keep up???

[Mark]

Harbor freight has a pretty good electronic battery tester for about $60.  I use mine a lot.  Also if you go to battery store such as Napa or batteries Plus they have the electronic tester that can test the battery.  12.38 volts is pretty low, somewhere around 50% of capacity.  Sometimes the voltage can be good and they still cannot deliver the amps, only way to know is to test it with a tester.