Lithium battery life span

[basser38]

I am currently running a relion 100ah starting battery that is 8 yrs old and 2 36v lithium pro battery's for the trolling motor.. all seem to be doing fine..Is there a way to test these batteries capacity/ life span..How do I know when it's time to replace them? these batteries did not come with a blue tooth feature..
Thanks for all replies

[goodman_fishing]

You can do a capacity test on them and see how many Watt-hours (or Amp-hours) you get out of them versus their original spec.

LiFePO4 batteries should lose about 1%/year just due to calendar aging. You're likely well within the cycle life. I wouldn't worry much.

[bobcoy]

Good advice! Don’t worry until they don’t do the job as long as before. JMO. Bob no

[DBolton]

Consider adding this to the battery(s) and you'll know how they are doing.

Bluetooth Smart Battery Monitor – Amped Outdoors

[C.Warrix]

On year 9 with my Relion Batteries with no issues!

[CJ1]

I will bet the BMS will die before the cells do. CJ

[basser38]

Been very impressed with the litiums.im past the point I needed to justify the cost when I bought them..I've never killed them in a day of fishing. I just worry they'll die with no warning.i just added an iconic to run my graphs.thatll take some of the load off the relion and give me a spare battery..

[bobcoy]

Basser, age or number of cycles will not suddenly make the battery stop working. In fact when they consider them used up they will still be at 80% capacity. As for the BMS failing all of a sudden, it could. I think the major factor there is how tightly sealed the battery is. All need a bit of venting for expansion from heat, however the ones that can be submerged in 1 meter of water for a time allow much less junk to get in the battery to corrode the BMS. IP67 being that rating. Some have a much lower resistance to that. You are in good shape in that regard with your Relion batteries. You will be saving money on your lithiums a while longer. JMO Bob