Have extra Gels and D8s. Need another battery string. Which to use?

softdown

Have two extra 109 Ah Alpha Cell gels at 75 lbs/each. Alpha owns Outback. Excellent batteries though may not be ideal for solar. New ones will cost about $250/each with shipping. Expect about 3-4 years of use...that is a wild guess.
Have two extra D8s by Johnson Controls at 125 lbs/each. These are lead acid. Big batteries for big trucks though not ideal for solar. New ones will cost about $200/each with tax. Expect about 2-3 years of use...that is a wild guess.

Seems like a real toss up to me.

softdown

Have not been able to get a quote on Alpha Gels. I think they will be much higher than I expected. 8Ds can be either starting batteries at 1400 CCA or Deep Cycle. Deep Cycle cost about $250/battery...or almost $50 more than the starting 8D.

So 8Ds can be alright if you get the Deep Cycle model I would think. No idea about expected longevity.

softdown

Looks like two 8Ds were butchered by a combination of running down to 10.5 volts for a couple days then overcharging. I did a two week desulfation procedure. Their resting charge is now 10.7 volts and 11.7 volts. Like I said....butchered.

So that took me from eight 8Ds down to six. Think I will get two more and cross my fingers. 8Ds are sub par solar batteries but better than hella expensive gels I would think.