Fun and games of a dying battery...

Photowhit
Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
I had an interesting couple weeks with my slowly dying, 11+ year old forklift battery.

2 weeks ago, I had a couple cloudy days followed by ice then 12 inches of snow, I did go out and try to clear the snow once,but had a nice 1/2" of ice on the array. Looked like I was getting maybe 200 watts once I cleared them best I could, and we had more snow that evening followed by a single digit overcast day. I got out mid-afternoon and cleared the panels best I could. It was similarly overcast to the previous day.

I also kept the main room very warm, for me, around 70 and that's where the 20-year-old fridge lives. Doubt I received more than a single kWh either day. and that was most of the charging I had over the near 5 day period. I was surprised my battery struggled through it. I did NOT check SG, but know I have a dead cell which hasn't reached any serviceable capacity for 2 years, perhaps more. If I knew the rest of the cells were in as good shape, I might have replaced the dead cell. 

So back to 'normal' I came home after a night in town Tuesday, put my groceries up and taking advantage of the sunny day, ran a small 5-600-watt heater in the bathroom, while clearing the ash from the wood stove, and getting a fire going. I hadn't slept well and mid afternoon after a late lunch I laid down and fell asleep...

About 7 my computer which I had left warned it should be connected to a power supply. It has about an hour of useful battery, So the combination of high loads and the fridge kicking on shut down the system about 6pm. Went out and checked the system and the 24 volt battery was reading about 23.8 volts, which is pretty high since 1 cell isn't really contributing. I had turned off the heater, I turned the inverter back on and had no issues through the night.

Really hard to judge system capacity with the voltage sag of a dead cell. Guess I'll bite the bullet after the rainy season and get a replacement. I feel a whole lot better about my judgement on a forklift battery surviving 15+ years. This battery was poisoned when I worked security in the subdivision/playground for adults where I worked. It was maybe a year old when it happened. 1 cell was dark when I checked it and it remained one of the better performing cells for a couple years, but the electrolyte was always darker. Slowly it died. SG couldn't be brought above 1.23 for a couple years. 

Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
- Assorted other systems, pieces and to many panels in the closet to not do more projects.

Comments