What to do with the freshly delivered Space Cell?


#1

Hello everyone!
Short question.
I just got my battery for the raptor but have no board for the upcoming weeks.
Do you think its a good idea to just let it sit around (32% currently) or should I charge it up?
Thanks


#2

40% is about the best state to leave lithium based batteries at for storage. 32% is good too. Keep it in a cool/dry place and it should be ready to go when you have your raptor!


#3

Thanks! Ill charge it up for a bit and then its going to see the inside of a cold dark place in my apartment :wink:


#4

40% of 42v ??


#5

For 18650’s I think the recommendation is 3.7 volts per cell for longterm storage


#6

42v is full charge so yes. Unless I’m misunderstanding your question.


#7

@csn All the new 18650 cells I’ve receive ship at 3.6-3.65V. That would, presumably, be the ideal storage voltage from the factory. That’s for Samsung 25R.


#8

Edited:

You are not accounting for voltage settling after the charger shuts off. Charge to 3.7 and the voltage settles to 3.65v after a bit of time.


#9

Haha guys! Im a total noob when it comes to these electronics.
My space cell (enertion) is currently 32% charged and my question was, whether to charge it or not until the raptor arrives in a few weeks

And id love someone to explain these 3.65 or 3.7V per something :smile:


#10

Your charging-display monitors the voltage over your batteries.

I don’t know the settings of the voltage meter that enertion uses, but normally 4.1V per Cell means full and 3.3V per cell means emtpy.

4.1V(full) - 3.3V(empty) = 0.8 Volts.
0.8V / 100 * 32(your percentage) = 0.256 V left.
3.3V + 0.256V = 3.556

Your cells seem to be around 3.556V wich is slighty below optimum storage voltage.
If you want, you can charge your battery to 40%, this should also balance out all the cells.

If I’m wrong, I’d be glad to be informed :slight_smile:


#11

Alright! Thanks, seems legit!


#12

Thanks @chaka. Does voltage sag occur without an electrical load? I’m testing all of these cells individually with a multimeter. They aren’t connected to anything yet, just fresh out of the box.


#13

I edited my previous post since using the term “sag” was grossly incorrect and should only be used when describing a circuit under load.

I don’t suspect a factory to trickle charge to a storage state so the voltage will settle quite a bit after charging at 1 amp. If you charge at a much lower amperage the cells will settle much less after removing the charge.