How do I get more distance? (or am I dumb?)

Hey everyone! I need some help here maybe just explaining some things to me, so I am looking to the Hive Mind for filling in some gaps of my elementary understanding of electric vehicals.

First I cannot get my battery to charge past the 39.8v Is this the upper limit or is there something wrong with the balancing or are the individual cells unbalanced? I read all of them with a multimeter before I welded it all up and they were the same voltage at assembly. Or is this just normal operation?

My second question: is there any way I can increase my range?

Now I have ridden the board a few times and she works GREAT! I love it! So much response and power and it just accelerates like crazy, but it cuts out right at 9.5 kilometers. Here is my latest test ride. I stayed close because I ended up pushing the last kilometer. (also I stopped and grabbed a drink at Quick Trip on KM 4 and 5 to explain the time change)

and here is the voltage at then end No Throttle

When I hit the throttle

My batteries are Samsung 18650s 25R

My BMS is this one that @Namasaki sold me. (THANK YOU IT’S WORKING AMAZING!)

Thanks to anyone who offers me some insight and maybe explains some things I don’t quite understand about current draw to me because I just made things without fully understanding what I’m doing.

Also as a thanks. Here is my “Boosted Clone” we are talking about.

If it not charging to full, it’s because the cells are too far out of balance. They have to be balanced before you assemble the pack.

What is your battery configuration? 10S4P? 9S4P?

Can you post your esc settings too?

E: If its a 10S3P, then they are out of balance. Are you discharging through your BMS or bypassing it? If you’re bypassing it, then you’ve most likely damaged your pack already

Judging from the voltage sag I’m guessing 10s2p

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I measured them out before I assembled it, and everything read at 4.2v each. I was wondering if I should take it all the way apart and rebalance every cell… That would suck but I guess it might be an option.

Sorry I didn’t put that in, it is in a 10S3P configuration, and I have 2 of the Enertion VESC 4.12

Judging by the screenshot He bought 30 cells so I think 10S3P

Maybe some bad cells?

lol, see that is what makes me thing something is up with my battery pack. because it’s a 10S3P

Are you bypassing bms to discharge?

Even at 3p it’s only 60a max But something else is wrong not charging past 39v

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I have it wired up through the BMS like the diagram above in the specs page shows. I don’t know as much about what I am doing so I just followed the instructions.

Maybe some bad connections in the battery pack

And that’s what I was thinking, I have charged it for hours and then discharged it, (rode around) and charged again for all day thinking the BMS would just take time to balance it or something, but nothing.

When fully charged, read the voltage through the bldc tool or with a meter… could be your lcd that is wonky


Good point @Blasto check it with a good multimeter.

Yeah, Ill try that one out too. I can measure out both to see if there is anything dropping between the battery before the BMS, After the BMS and at the ESC.

Ill try that in the morning when I get it charged.

Weird. Your battery should have never dropped beneath 25V. The BMS should prevent it. You need to adjust your VESC settings too to decrease the potential of damage.

Do you have a voltmeter?? I was about to suggest the same thing about measuring voltages.

E2: @denton Measure the voltage across each cell on the BMS if you can before charging so we know if you’ve damaged the cells

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Patrick has a good point, the BMS should shut down if any cell group drops hits 3v Are you sure the balance leads are properly connected and are you turning the power switch on to charge?

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I do, and I will bust it out in the morning. It drops like that and then the VESC shuts it off. It just shows 36 and sits there, then when you hit the gas it will shut it off because it drops down to like 22. Is that normal or is that part of my issue here that it fluctuates that far?

Do you only have a 39.8v charger? You need a 42v charger for full charge. Only other thing I can think of is that the cells are imbalanced, or the LCD is off.