Can I connect 2 48v Ebike batteries in series for 96v?

A

AlexFerrer

10 µW
Joined
Aug 28, 2018
Messages
5
Any one knows if it will be ok to connect 2 identical e-bike battery units (MXUS 48V 11A) in series for 98V ?
1. I am not sure if the BMS would have a problem with that.
2. Anything else might affect the batteries? (different discharge rates?)

Thanks

Alex.


* My motor and my controller can handle 144V 400A
 
I might be answering myself her.. but I just found:
https://endless-sphere.com/forums/viewtopic.php?t=90476#p1319441
 
I do a similar thing daily with two 36v packs to make 72v

Occasionally when i have forgotten to charge one as much as the other as i remember late in the day to switch one pack for another on the charger they start the journey at different Voltages (or states of charge). My thinking is this makes the lower voltage one work harder and twice now i have blown an smt s3m diode on the bms inside the pack. Luckily i have been able to use my hot air gun and repair this and thus salvage the pack and it only seems to happen when i have imbalance between the two packs.

Anyway i would do as fecther says in the thread you listed i.e. the reverse biased diode. (i think i might look into this too) :D
 
Any idea if it would be a problem if the packs do not have the exact same mAh ?
The one I got now uses 2900mAh cells. The new one I am building will use 2600mAh cells..
 
The big issue is if the BMSs will work in series... sometime they do and sometimes not. I do the 10s (36v) series up to 20s (72v) but I run bare packs with no BMS and manually balance them. Re the amp hour difference, thats not a problem. The packs need to be the same voltage, but the capacities can be different.
Re the getting the packs charged the same... even though my chargers end up at the exact same voltage, they do it at a different rate, so if you stop the charge before its done the batteries dont match. So when I know I dont have time for a full charge, I use one charger and parallel it to both packs... then theyre the same.
 
STILL waiting for the Five Million Volt ebike... (Local building codes establish sub-fifty volts as a "safe" voltage.)

Why 96 volts? ... may I ask? Like, why not drive up the amps (more cells in parallel) if yah "want" more watts?
 
^^ "higher top speed"... where in a 21st-century urban world, "hitting" 20 mph is... "excessive"... (and passing everybody else). :wink:
 
Thankfully out here in the wide open spaces of the American West, there's still enough room that 20 isn't excessive... Or even barely noticeable amidst the hustle and bustle of our car traffic. Now talk about excessive!
 
^^ Hehe... Have been "urban" all my life as a "city kid"... Only used to "bumper-to-bumper" "traffic" on streets they term "PARKlands"... etc. NO problem getting around "faster", using "tiny" vehicles like bicycles. :lol:
 
21st century LockHart 💘. There are some people that you can go 40 50 miles an hour act professional and not get pulled over there are some people that can go 18 miles an hour screw loose screw ball screw this and get cuffed. I always wear a turtleneck sweater that way they don't suspect me oh and argyle socks with penny loafers. Don't ask because my front basket is already full
 
999zip999 said:
21st century LockHart 💘. There are some people that you can go 40 50 miles an hour act professional and not get pulled over there are some people that can go 18 miles an hour screw loose screw ball screw this and get cuffed. I always wear a turtleneck sweater that way they don't suspect me oh and argyle socks with penny loafers. Don't ask because my front basket is already full
Click to expand...
I wonder what is in your diaper/baby bag!? Ahemm 😂
 
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