Short answer is No.
The cells don’t mind where you keep them, but if you are going to store them for a year or more then it is best to charge them to around 60% before you store them.
There are 3 main things that impact your lithium cells.
They only have a limited amount of use cycles in them, after which they will start to have a reduced capacity.
how fast your charge/discharge the cells and if this is inside their limits.
any overcharge / undercharge of the cells.
If you keep them inside their limits, then the amount of cycles you should get should be as expected.
There is 1 negative when keeping the cells low for long times. And that is that you could see cell imbalances over time which will not be corrected as your balancers on your BMS only start working when the cells reach higher voltages. This again will depend on the health of your cells as older cells could need more balancing.
I think most require once a week. One of the selling points of LiFePO4 is precisely that you can leave them half-discharged for longer periods.
The bigger issue (I think?) is SOC drift. If you run them between 30% and 80% for long periods of time, then SOC drifts occurs (the real state of charge is different to the estimate from the BMS). The BMS needs to hit a “waypoint” to get a better estimate, and for that to happen, you need to push it above 85% (or something like that) periodically.
Increase the SOC on bad weather days with 10% increments to cater for clouds moving over.
Then setting the inverter to draw from batts from 6 pm till the sun takes over, the wattage set to cater for LS in-between.
The only time where this “falls off the horse” so to speak, is on really bad weather days with no spare to recharge the batts. Then the human “AI” has to intervene IF there is LS early morning.
Hence the Weather App is now the most important App for solar systems.
On good sunny days, one does not need these Flows, as Victron takes care of most.
The problem comes in with Cpt winters, or any rough weather days anywhere, to give the batts a wee bit of a headstart, where possible.
The SOC increase ties in with limiting the inverter to the max the panels can do.
This NodeRED flow, seeing what goes into the batts, setting the inverter max wattage accordingly, my case, max 4kw. The 4kw in my case also solved any and all overload warnings I used to get too, when grid-tied.
Thats absolutly brilliant and i didn’t even thought about that case, thanks a lot for sharing.
We are completly new to this topic, and even if i have a lot of IT experience, i have to admit that the possible functions and configurations are a little overhelming.
I’m running Release Candidate, latest update includes a Node Red upgrade, no problem.
Inside the new Node Red Upgrade, there are Palette upgrades.
… and there the wheels went flying!!!
What I know of Linux, picture a 500 pound gorilla set loose, plastered on maroelas left for days in the sun, in a nuclear facility with all the launch keys left in and turned … peeved like hell.
In the end:
Had to wipe the Cerbo by reverting back to Standard.
Then deleting ALL the Node Red folders. (sommer cause the OCD kicked in)
Re-install again Large OS and set everything back again.
… was fun. Wrote it off as “Practicing Disaster Control”.
Next time I can have it done in wot, 20min(?), instead of the entire evening.
And for all those naysayers who say DON"T RUN LATEST stuff … blah blah blah. ?What fun is there in THAT!?
The rule stays fairly solid when it comes to NR , if it isn’t broken don’t bother with it.
Oh and make backup’s
Must say my node red on the Cerbo has been running for over a year now without a hitch.
