Sunday, October 31, 2021

All good things come to an end

 I knew my eight-year-old Concord Sun-Xtender AGM batteries were approaching the end of their usefulness. They had been taking a lot longer to reach float and they were reading around 12.5V before sunrise instead of their usual 12.7V. The shorter days of winter are approaching, making getting through the days more challenging. Then, when I woke up in the middle of the night a few days ago, the voltmeter read 12.1V, with the fridge cycled on. Not good, even though it returned to 12.5 when the fridge cycled off. Time for new batteries.

I briefly considered LiFePo like all the cool kids but, besides the higher price, there would be the hassle of reprogramming my solar controller. So I'd go the easy way and get AGMs again. Sun-Xtenders like mine are about $340 each. Mmmmmm, seven-hundred bucks would be a tough bullet to bite right now. So I decided to go with a couple of Universal brand at half the price. If I get only half the life out of them, I'll still break even.

All installed and running fine

UPDATE: If one night is an indicator, things are fine with the new batteries. They held at 13.0V most of the night, dropping to 12.9V just before sunrise.


  1. I am several years into my batts like yours. They are working just fine for me. My rig has been modified to run all the 12 v off the batteries and they only get charged by the solar panels. 14 years in that arrangement now with no troubles at all.

  2. I found when I installed this set of batts 7-12-2019. The first set failed in about three years due to an inverter shorting out and draining them to 00.0 volts while boondocking near Del Rio Tx.

  3. First time commentor, long time reader - way back you had a post about Kolob Reservoir and free boondocking. I try to visit family who has as off-grid cabin around the Kolob community. We hit the reservoir daily. They are now charging $50 per night for campsite. All good things come to an end (like free camping at Kolob)!

    1. What I heard was that the residents got tired of campers using their dumpsters. Or something like that.