What exactly is the Rating saying ?

[akerr95]

I have done electrical before but being that i went university to peruse a Computing degree i havent spent anytime in my electrical and as such i think i have forgotten alot of things such as understanding the battery ratings, so i decided to make my own battery and said i was going to use some li-ion battery 3.7v battery 5800mah, Now it needs to supply 48V and anything below 45 Amps, so I said i would connect the batteries in series then parallel, but in series ( connecting 4 cells ) this gives 14.8v now if i connect 4 of these in series ( basically connecting 4*4 cells in series ) would give me 59.2v Which would be too much and maybe burn out my circuit or so i think, but if i use 4*3 cells in series i get 44.4 which is below the required voltage.

Someone told me that if fully charge it could be >48v but for how long will they stay above 48v ? My other solution is just connect some lower voltage batteries with them to get a figure to 48v. Is this wrong of me to do , if so please tell me i am here to learn and give back if i can.

"Embrace the Change"

Thank you.

 

[wesnewell]

A 12s rc lipo battery pack, 44.4V nominal, that charges to 50.4V when fully charged is perfect for standard 48V controllers that have an LVC of 42V. that will alloe you to use up to 96% of the batteries capacity before lvc cutts the power to the controller off. Going more than 12s will allow the controller to draw more than 100% of the battery capaicity, thus damaging the pack every time you run it to lvc. All 48V controllers are rated for at leat 63V max (15s). And you can run them at that, but unless you change the LVC voltage setting, you will damage the pack even more the higher number cells over 12 you go if you run them down until lvc cuts the power off. 42/12=3.5V per cell. 42/15=2.8V per cell.

 

[Tench]

A 12s pack would have a full charged voltage of 50.4v. Lipo celles rated by their nominal voltage of 3.7v have a full charge voltage of 4.2v. The voltage you would consider a 12s pack to be flat is about 43v, below this there is very little useable capacity remaining. A 13s pack may suit your needs better, 54.6v hot and 46 ish v when ready to recharge.

 

[akerr95]

Thank you guys

 

[dogman dan]

A typical "48v" controller can easily handle 14 cells in series. But 12s is a handy voltage for many for various reasons.