Weird battery issue

[Ed255fsh]

Strange . seems like my group31 agm start/deep
Battery not charging. Charger is OK. House batt OK. Its been hot but not that hot. First noticed after day on water while cleaning up the connect and dash shut off. Yesterday connect would not turn on , I had to use battery combiner. I have same batt in the garage bought same time on a trickle charge. Guess what . doesn't seem to be holding charge.
Are they just defective ?
1 1/2 years old

 

[Ed255fsh]

Strange . seems like my group31 agm start/deep
Battery not charging. Charger is OK. House batt OK. Its been hot but not that hot. First noticed after day on water while cleaning up the connect and dash shut off. Yesterday connect would not turn on , I had to use battery combiner. I have same batt in the garage bought same time on a trickle charge. Guess what . doesn't seem to be holding charge.
Are they just defective ?
1 1/2 years old

Quick update
Connect powered on this am . volt on dash read 12.9. Then dropped to 12.5 when turning off charger. Then heard a click and connect shut down no power to dash. Turned battery combiner on and connect powered up. Volt read 12.5 on connect. Old analog meter shows over 12 v on batt when not on charger. 13 when charger on.
Can't be more accurate with old analog meter.
With charger on combiner off it took a few min and connect powered up. At this point looking at buying new batt.

 

[Neutron]

Quick update
Connect powered on this am . volt on dash read 12.9. Then dropped to 12.5 when turning off charger. Then heard a click and connect shut down no power to dash. Turned battery combiner on and connect powered up. Volt read 12.5 on connect. Old analog meter shows over 12 v on batt when not on charger. 13 when charger on.
Can't be more accurate with old analog meter.
With charger on combiner off it took a few min and connect powered up. At this point looking at buying new batt.

Could be a dead cell. Batteries are terrible these days. You need to charge the battery then load test it

 

[FSH 210 Sport]

Have you checked all your connections?

 

[Ed255fsh]

The boat seems to know when I have free time and makes a thunderstorm to stop me from looking.

 

[Ed255fsh]

As wrote that it started pouring .....

 

[Ed255fsh]

LoL
"Passing shower"
Still coming down hard

 

[Ed255fsh]

Wiring under dash is good. Checked batt charger.
Its on maintain. Turn key. Volts 12.7 .unplugged charger. Watched volts drop quickly. 12.4 then click conext shut off.
Bass pro shop has sale. Bought 31 start/deep agm for $180 . pick up tomorrow.

 

[Julian]

Not sure if you are familiar with these charts, but many are not:



AGM:

 

[Ed255fsh]

Thanks. So as I thought , batt no good.