RUNNING LITH-ION BATTERIES IN SERIES FOR ELECTRIC SCOOTER

[Scooterbuilder]

I have 13 different electric scooters, most custom built some factory design... I have a 40magnet wheel (UKNOWN WHEEL RATING) I am running 36v 15.8ah battery and a 36v/48v 1000w controller... I am running 25 mph at top speed fully charged. I want to find a way to get atleast 10mph more out of it so 35-45mph is what I am looking for. This scooter is very well built and sturdy. 11inch solid wheels. ITS A Electisan ES200.. AKA THE TANK

I have multiple 36v 5.2ah external Es4 batteries OR
I have 2 36v 12ah? I believe
I am going to wire 2 together in SERIES To make 72v , and also get a 72v controller..
Can anyone tell me anything I need to know? Will they both charger normally if I have 2 seperate chargers? Do I need to match the voltages on them before I wire them together??

I have experience in wiring plenty is parrell but I have never acually wired 2 batteries this big in series... also I know for pushing a lot of power it will prolly get hit being on a electric scooter so want to double check...

 

[amberwolf]

lots of threads specifically about this, some are in the lists below, even more with other searches

https://endless-sphere.com/forums/search.php?keywords=pack*+series*&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

https://endless-sphere.com/forums/search.php?keywords=batter*+series*&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

 

[Scooterbuilder]

I’m acually looking for some specific answers as I have a 36v rated hub motor is it okay to run it at 72v

 

[amberwolf]

I’m acually looking for some specific answers as I have a 36v rated hub motor is it okay to run it at 72v

Then you should have asked *that* question, which is not anywhere at all in your original post:

I have 13 different electric scooters, most custom built some factory design... I have a 40magnet wheel (UKNOWN WHEEL RATING) I am running 36v 15.8ah battery and a 36v/48v 1000w controller... I am running 25 mph at top speed fully charged. I want to find a way to get atleast 10mph more out of it so 35-45mph is what I am looking for. This scooter is very well built and sturdy. 11inch solid wheels. ITS A Electisan ES200.. AKA THE TANK

I have multiple 36v 5.2ah external Es4 batteries OR
I have 2 36v 12ah? I believe
I am going to wire 2 together in SERIES To make 72v , and also get a 72v controller..
Can anyone tell me anything I need to know? Will they both charger normally if I have 2 seperate chargers? Do I need to match the voltages on them before I wire them together??

I have experience in wiring plenty is parrell but I have never acually wired 2 batteries this big in series... also I know for pushing a lot of power it will prolly get hit being on a electric scooter so want to double check...

Most brushless motors can be run at at least several times their "rated" voltage. The "rating" is really only to show you what voltage it takes to give the speed it's meant for (or vice-versa).

If it's a geared hub, keep in mind the higher torques this higher voltage (power) will cause have the potential to damage teh clutch or gears, and the higher waste heat buildup inside can damage the motor windings / halls / gears.

If it's a DD hub, it's less likely to damage things, but still possible to overheat stuff.

Either way, the higher torque at the axle may also require better torque arms or torque plates to prevent axle spinout, if all there is now is just the dropouts, etc.

To learn more about some of this, go to http://ebikes.ca/simulator , read teh entire page to get an idea what all the stuff is and does and means, and then play with different systems to compare what theyre like at each voltage you want to use.

 

[John in CR]

Assuming it's a brushless motor, ie 3 phase wires at the controller, then yes the motor itself can work at double the voltage. As AW mentioned, a geared hubbie becomes problematic at double the voltage, and direct drive not so much so. Double the rpm may be a problem though, since you're already spinning above 750rpm at cruise. The only hubmotors I know of that don't run into heat issues from iron losses much above 1000rpm are the high efficiency hubbies I use that became too costly to build so production ceased 7 years ago. For just 10mph more, you're talking about 1100rpm or so, and the only way to know for sure is to spin it at that rpm with the wheel off the ground and see if it gets hot in minutes. It doesn't have to be powered to test this, so if you can figure out a way to spin another wheel at the 35mph you want, you can use it to drive your motor as a friction drive. Do it for a minute or so and check for heat, and if it's okay then do it for 5-10min and check again for heat. Yet another way to test would be to go down a few mile hill at 35mph and see how hot the motor gets (be sure you have good enough brakes for such a test). My guess based on how how cheap those little motors are, is that it doesn't have the efficiency to run rpm that high.

Be sure to let us know your results, and be really careful at those speeds on such small wheels, since a hole in the road could easily ruin your year.

 

[Voltron]

Usually, the volt rating on the motor case is more about it running at normal legal speeds when fed that voltage.. just be ready for how much further it takes to stop!

 

[Scooterbuilder]

Thanks everyone for the replies sorry I’m a newbie to forums as eveything I know is hands on. I have another question

Say I’m running
36v 1000w 10inch wheel diameter = 25mph

What would a estimate be for
72v 1000w 10inch wheel diameter =___mph??
Is this 1900rpm?

I am waiting for my 72v controller to come in 3 days so getting antsy trying to figure out what my new speed will be,,, ive changed feom 350w to 1000w and only saw 4mph difference so hoping this 36v to 72v is gonna to make me gain atleast 10mph

 

[Scooterbuilder]

Tried to do a mock-up and get a idea using a 36/48v 500w controller with the 72v battery...

I checked the controller first, it’s running a 80v capacitor so I figured it would run it,

Connect eveything and get nothing, reading 72v and all, I plug it and I get 1-2 spins out of the wheel like the learning mode(self learn mode) is kicking it but not enough power to do so..done it multiple times and get the spin everytime so I’m not blowing anything that’s for sure.... I’m assuming this is a self shit off or over voltage protection not letting this happen any ideas? Could anyone confirm that’s wat is causing it to not connect with the motor?

 

[Scooterbuilder]

Got a top speed of 37mph