how to test your lipos capacity, for dummies.

[istandalone]

i've got an mrc superbrain 977 for a charger. it says to test my battery's capacity that i can discharge fully then recharge to see how much mah i put back in. thing is, you can't fully discharge a lipo safely. wtf? so how can i test my batterys cap without overdischarging?

on a side note, i dropped my thunderpower 1320 down a flight of stairs by mistake and it's fine. that's got to say something about quality.

[DebianDog]

Well on a TP1010 a "Full Discharge" is when all the cells read 3V per cell. The pack is fully discharged.

[istandalone]

but isn't 3v per cell in the danger zone? or are you saying i can discharge safely to 3 volts per cell and then re-charge? in case you haven't noticed i know absolutely shite about lipos.

[DebianDog]

It is the ABSOLUTE LOWEST voltage you would EVER want go to. I never go below v3.3

[Dave M]

You should be able to discharge to a "specific" voltage UNDER a "specific" load, then when load is removed you will still be in a safe voltage to charge. The only problem is I have no clue at what "specific" should be. :dontknow

So in other words....this post was probably worthless to you. :hammer :OK

[WhirlingBladesOfDeath]

Just to add another uneducated response. I think it is probably OK to goto 3V per cell if you go there SLOWLY. It's one thing to be drawing max amperage down to the cutoff compared to having your charger slowly and carefully drop it down to that voltage.

Or I could be completely wrong. :)

[Pinecone]

The difference is, if you are drawing down slowly, the pack will be at 3 volts per cell when you stop. If you are drawing near the max discharge rate, when you remove the load, the resting voltage will be much higher.

[MrMel]

20-25C batteries should NOT go under 3.2v or else they can take damage.
(I know, killed a 10s pack that way)


No, there is no good way to know the capacity if you didnt do a reference discharge when the pack was new.
However, doing a discharge to 3.2v will at least do as an indication.

Then you can perhaps find that or a simular pack (same C rating) on Battery Vault over at rcgroups, then guesstimate how much that type of battery store from 3.2 to 3.0, on newer packs its very little though.

[Pinecone]

Basically I don't do this. I fly by timer and lipo alarm. If a single pack starts to trigger the alarm early, the pack is going bad.

And what are you going to do anyway? I just keep flying it, knowing that eventually it will be shot.

[istandalone]

And what are you going to do anyway? I just keep flying it, knowing that eventually it will be shot.

if i've learned even one thing in this hobby, it's better safe then sorry. i also like to keep my machines and equipment in as tiptop shape as possible. thanks for the replys, guys!