Get a bms!! Saves so much hassle
good luck man! would love to see a parts list of your build! Iāve just ordered the first parts of my build 
1 Like
I have the parts list here.
We are currently planning a battery build using the Samsung 50E 21700 cells.
This is the price difference and cell difference calculations we came up with and itās pretty significant.
Note: prices are for cells only
3 Likes
Oh what. Dudeā¦ 2019 is gonna be rad.
So just to make sure I have my understanding right, a 12S4P has four times the capacity and 12 times the power? Thus if I wanted to build a board with twice said range I would build a battery that was 12S8P? Also (this is off topic somewhat) If I wanted to get the most power possible, could I double the voltage of the battery and use 2 VESCs (ie if I wanted to build a AWD board but wanted each wheel to have as much power as if Iād built it as a 2WD board). In that Scenario could I build a 24S8P, giving me twice the range and power output of the normal 12S4P and simply splitting the power between 2 VESCs? (sorry for the long question, Iām very new and want to learn all I can)
Hey would love some help. I purchased this battery (see link below) and charger with the hope of using it in my own home build only to realise that the charger is only compatible with the balance scooter board the battery is made for. Any advice on how I could incorporate the charger into the home build? I have the resources to solder ect but just donāt know what Iām missing.
Hey I was just wondering If anybody would know what I should do, I want to have a 10s lipo perferably two 5s in series I but i just donāt know what batteries to use and if i should get a high discharge rate, Thanks
Question, I had my cells welded together. When the company I got to do it welded them they did not put any rings around the top of the cells so the nickel is touching the plastic wrapping. Will this be a problem in the future or can I just leave it and not have to get them welded again?
I was wondering. I have a very small penny board setup and cant afford to incorporate a Li-ion pack because it takes up too much space. I am currently using 2 Turnigy 5000mah 20C 3s lipos in series and Iāve already accidentally puffed up 2 of them from excessive discharging. Iām only upset because I get like one ride out of them before theyāre ādischarged beyond returnā. Would upgrading my setup to 4 batteries, 2 series configurations in parallel (2s2p), give me additional Ah that would extend my ride time but provide me with the same voltage and current to have an enjoyable ride?
donĀ“t mix old and new lipos.
If I have 4 new lipos is this possible.
Yes that would work
So I just bought a lipo that is not enlarged at all. I took it on one ride and the other old one puffed up but this one is fine. Do I really need to buy another 4 lipos or will 3 and this one work?
Depends. Is it the same brand of lipo you buy? The thing is, that if you wire up lipos in parallel there internal resistance should be similar. If one is older that might be different from the new ones. As lipos way more sensible to overcharge and over discharge i just wouldnāt take that risk and get 4 new ones from the same brand with same capacity
Damn, ok I understand. Thank you so much, just this little bit of insight is more than I had before.
More info on LiPoās, āWhat the numbers meanā. file:///D:/RC%20stuff/RC%20Powers%20threads/LiPo%20INFO/What%20the%20numbers%20mean%20with%20regards%20to%20LiPo%20cells.pdf
Thatās too simplistic of a way of looking at it. You motor can handle a certain amount of heat. If youāve ever cooked, you know a pot doesnāt lose all of it heat the second you take it off the stove. Metal retains heat, including the stator (made of steel), the motor parts and the copper winding.
The by product of more amps is more heat. So by adding a second motor, your doubling the amount of space that can hold this heat. Thus you can adjust the settings to double the amps and you should expect the motors wonāt run hotter than they did before pulling double the amps.
An example:
setup 1:
- motor 1 with max 40a limit
- battery with 80a limit
output of setup 1:
- 40a amps will go to motor 1
- battery will output 40a
- You will likely move but you will be pushing the single motor very hard, resulting in a lot more heat.
setup 2:
- motor 1 with max 40a limit
- motor 2 with max 40a limit
- battery with 80a limit
output of setup 2:
- 40 amps will go to motor 1
- 40 amps will go to motor 2
- battery will output 80a and split it between the motors
- Motors will run at max power output
setup 3:
- motor 1 with max 40a limit
- motor 2 with max 40a limit
- battery with 60a limit
output of setup 3:
- 30 amps will go to motor 1
- 30 amps will go to motor 2
- battery will output 60a and split it between the motors
- Motors will run at medium power output, staying a bit cooler, but running at a higher power output than 1 motor
setup 4:
- motor 1 with max 20a limit
- motor 2 with max 20a limit
- battery with 80a limit
output of setup 4:
- 20 amps will go to motor 1
- 20 amps will go to motor 2
- battery will output 40a and split it between the motors
- Motors will run at max power output
Thereās many ways to configure it.
In terms of draw. Everything comes down to our evil friend called resistance. And if we brushed up on our physics, we can recall that Amps = Voltage / Resistance. Amps create heat through resistance. The way a battery can have a higher amp rating, without changing the voltage or size of battery, is by lowering the internal resistance of the battery. Which is what higher c rated batteries are doing.
Itās always wise to spend extra on batteries with far higher ratings than you need. Voltage sag with a vesc in current control mode (i.e. controlling the flow of amps), which is the traditional way of running a vesc, doesnāt care about your voltage dropping. Since watts (watts = amps*voltage) describe your overall power, youāll feel power dropping out from under you on hard accelerations since your voltage will drop. For this reason, bigger batteries are always advised as well.
1 Like
Has anyone ever purchased cells from cheap-batteries.com?
Their price for the Samsung 30Qs seem too good to be true. Do you think they are legitimate cells? If so, it would be a good vendor option in the US.
1 Like