Whats your boost?

[Newenough]

I'm not completely confident on my boost duration time for my lifepo4's.
What I Have
-8 x 8S 60ah 24v giving 280ah usable
-Morning average starting voltage is 26.2 to 26.4
-Upper limit set point is 28v
-Current boost is set at 28v for 120 minutes
-Float is 26.4
-No equalization
- Use 3 Epever Triron 4210's averaging 25-30 amps average charge output
-Batteries are usually show fully charged by noon.

My question is, is 120 min to long? Ive read recently (here) that it should be 30-40 min. As my calculation say I'm charging at .3C is 30-40 min long enough?

Any issues you see (or need me to provide) for flaws in my setup?

Also. To negate possible battery memory, as I learned in the same lifepo4 paper recently shared, how often should we drain/fully charge our batteries. Did not see that mentioned.

 

[gnubie]

If you can, discharge the battery as you normally would but when it comes to charging it, disconnect all the load so you can monitor the battery current without interference (if you use a shunt to monitor battery current that'd do to) and let it charge as it normally would. Once the CC flips into boost/absorption stage watch the total current into the battery. When it falls to a low level, and I'm not sure exactly what that would be but 500mA perhaps, take a note of the time to reach that point and that will be a good point to set the time limit on this stage of charging, unless someone else can come up with something better.

 

[tictag]

Hey, @Newenough, @gnubie's approach seems pretty solid, I do have a quick question, though, if you don't mind ... why 28V? Was this recommended by your battery's manufacturer? I only ask because, from what I've read, 28V should only get you to 90% SoC. Is this by design?

 

[Newenough]

Hey, @Newenough, @gnubie's approach seems pretty solid, I do have a quick question, though, if you don't mind ... why 28V? Was this recommended by your battery's manufacturer? I only ask because, from what I've read, 28V should only get you to 90% SoC. Is this by design?

Its recommended to go 90% SOC to get the most life out of the batteries. Also, going no less the 75% DOD as well. Though I rarely get below 50%.