Thank you 
I will do this!
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Good luck!
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It is charging now, it says that the voltage is 18.55 after it has been balance charging for a little while. How much higher will it go during charging? As I understand it will charge the batteries to 4.2/cell so 21 V and then charge with constant voltage?
It will try to charge the pack to whatever voltage you have set. If it is 21.0V then it will charge to 21.0V. You are the only one who know what the charger is set to. 
21.0V is the proper voltage for a 5S standard li-ion/lipo pack.
At some point, depending on how it handles balancing, the charger will start balancing the cells. You need to monitor each cell voltage to make sure none are going veey different from the others as that would indicate a damaged cell. The pack voltage isn’t very important right now as the charger will watch that.
I set the balance charger to 18.5 V and it said 5S and 18.5 V. But it’s going beyond that now. alright. I am not sure if I can go back to monitor the cells while it’s charging. Maybe I can temporarily pause the charger to see the voltage though. aah nvm it was set to charge it 4.2 end voltage. right now it seems fine though. after 20 minutes it has been charged to (per cell: 3.77 3.76 3.77 3.73 3.75) and I was able to monitor per cell while it’s charging.
When would the diff between the cells be considered too much? Are these values fine after 20-25 minutes of charging?
I have no idea what you’re doing as what you described doesn’t make sense for charging a 5S pack…unless you are trying to only charge to a very low voltage.
I strongly urge you to stop until you can get someone to come over and set this up properly for you.
There’s no set number but a few millivolts means very little. 100mV is a lot if the cells have been balanced but means nothing if they are still being balanced. This all assumes nothing is under or over-voltage.
I don’t know.
They’re all very close though and that’s good. I still recommend stopping until someone else can show you everything that’s involved and how to ensure you are doing it properly.
I mean no disrespect but I’m completely confused regarding why you have LiPo packs but don’t understand the basics for their maintenance and charging. They do not tolerate abuse well.
I believe it’s fine, each cell has settled to 3,8 V, the temperature is stable at 33 degrees and it is currently charging with a constant voltage. the amount of energy in the battery is creeping up ever so slowly.
What doesn’t make sense with what I am doing?
It has been charging now for 130 minutes. with about 600-700 mAh added to the battery.
End voltage is set to 21 V (which makes sense for 5 fully charged cells)
We learn as we go. It would be impossible to know and counter-productive to know exactly everything of every single component of the system before starting a project such as this. I have already learned a lot and the maintenance of the batteries seems pretty straight forward after fiddling with it now. My question was more related to batteries that had been sitting for 4 years without ever having been charged (aside from the initial charge it came with). I wanted to know if they were still fine to use. Which they turned out to be And that was also thanks to you.
I will charge the batteries and wait for the final voltage to settle like you suggested to see if they are still good after such a long time.
Would it be unwise to increase the C rate now that they are balanced at 3.8V? I am charging at 1/10C (0.3A)
Setting up TB direct drives with a MakerX DV6 on FW 5.2. My good motor is stuttering backwards when I let go and reapply the throttle.
I swapped the motor to the other ESC side, and the issue followed the motor. Very strange; anyone have ideas? Didn’t use to have this issue with a stormcore, alebeit without sensors. Going to try sensorless on the DV6 I guess…
Edit: Solved! Traction control was the culprit. I guess because that motor doesn’t slow down as fast traction control was trying to equalize the speeds. Disabled it.
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That sounds like an issue that dissolves the moment you step on the board. Just a bench-only issue.
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Am I correct in assuming that as long as each cell across my batteries are within 0.1 - 0.2 V of each other, I should be fine to couple them in parallel once the voltage has settled post charging? and same cell count
I’ve joined plenty together with that delta no dramas. Whether or not it’s good practice, I can’t say, but anecdotally i’ve had no issues.
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I’m revising the design on a baseplate extender I had made a while back. How thick does this plate need to be in your opinion? This 1st design is 10mm, made out of 7075. The wheelbase “extending” is 25mm and the “capture holes” are 3,5mm deep
I feel 10mm is pretty overkill and wanna slim down
Would you say 7mm is overkill as well?.
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Anecdotal evidence: I made some from 5mm plate I had layout around. Ok so far.
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by how far did it extend the wheelbase?
Nice, that gives me a bit more confidence. thanks man
Clever thing that extra hole through the baseplate, I’ll have to see if I can incorporate that in my design somehow
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So just idiot checking myself here, does this wiring diagram for my board look alright? This is the first board I am doing with a second external battery so I just wanted to make sure I wasn’t missing anything.
No. You need to disconnect the internal battery before connecting external battery.
Otherwise, a mismatch can turn into a fireball.
You could only connect them at same voltage, but relying on humans to not make mistakes will eventually leave you disappointed, and here the stakes are high.
Well the point of this build is specifically to ONLY plug in the external range pack when both packs are fully charged. So in that use case then this would be the right wiring if I understand your message correctly. Don’t really think that there is any other way to have an external battery other than doing the connect at same voltage method.
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Looks fine to me. Personally I bought a few of these voltmeter / ampmeters so that I can always double check the voltages before plugging the batteries together.
Also I now fuse all my batteries’ outputs with something like this:
So that in the worst case the fuse blows rather than the pack. Some people on here have tested such fuses, they do actually work, and aren’t an issue under normal operation.
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