Power problems-batteries are charged, but acting dead

[Bonesquatch]

My Lance 850 has been sitting quietly for the past couple of months and when I went to do some work on it today, the batteries acted dead. Strange I thought, since it's solar and had been holding a charge just fine the past year and some. So I pulled the batteries, checked them, and they're fine. The problem seems to be somewhere else. When I push in the battery disconnect, they act like they're charging from solar just fine. I pull the plug (connecting the batteries to the electrical system) and they power up the lights and stereo for a few seconds before quickly acting like they're discharging. The voltage regulator on the solar system clicks off completely and that's that. Disconnect by pushing the plug in, let them sit for a couple of minutes, fire it up and the same thing happens. The camper works fine when plugged in to shore power, so I'm guessing the issue is somewhere else...any ideas? Keep in mind I'm an absolute idiot when it comes to electrical stuff, so you won't offend me by speaking in ridiculously simplistic terms! Thanks!

[bigfootford]

mkirsch wrote:
Lead acid batteries will fool you. They will show full charge and even act like they're taking a charge, but will have zero capacity. That's why a voltage check only shows half the story.

Exactly...

Quick check is to measure the battery (s) with no load and no charging. remove your shore power.... Then while watching the voltage turn on your lights one or two at a time.. If the voltage starts dropping .1 or .2 that might be ok, more than that is deep poo! Then turn on a fan... If your battery voltage drops more than around .4 you have a battery problem or a charging problem... or both.

Jim

[mkirsch]

Lead acid batteries will fool you. They will show full charge and even act like they're taking a charge, but will have zero capacity. That's why a voltage check only shows half the story.

[billtex]

If you are leaving your TC "quiet" for months at a time...I would strongly suggest AGM's. You need to check wet cells monthly at a minimum...

[Bonesquatch]

Thanks for the suggestions. I hooked up each battery to an external charger that reads voltage and they both showed a full charge.

Edited to add:

I took my Innova volt meter out and did a load test and just as you guys predicted. Boom. Both batteries are failing to hold a charge. Just that simple.
Thanks for the suggestion. Seemed to damned obvious, but there it is.

[Big_Rig1]

Best way to check the batteries is with a hydrometer. I found a dead cell that way. Had me going in circles till I did that check.

Big Rig (John)

[ticki2]

Bonesquatch wrote:
So I pulled the batteries, checked them, and they're fine.

How did you check the batteries , voltmeter , hydrometer , or load test . It sounds like one or both batteries are dying . If you test them with a voltmeter right after removing from a charger they will look OK , wait a day or put a load on them and they will go down fast . Have a load test done and that will tell you the next step .

[Bonesquatch]

Roger that. All clean and happy. Connections are good and nothing seems out of the ordinary except that the voltage panel for the solar unit was hot to the touch earlier today. Makes me think something may have burned out.

[Itchey_Feet]

First thing, did you clean all the battery terminals and cable ends when you had the batteries out?