I want to series batteries. I currently have it wired for parallel. Can I make a adapter to reverse the polarity when going from parallel to series?

James340

100 W
Joined
Feb 20, 2024
Messages
127
Location
Aguila Arizona USA
The batteries all have ideal diode's.I have a 12v/3p 13s battery I did for 12v compressor ect.I would like to try it in series with a 48v battery.The controller has 100v caps.This is for a Dapu 36v/350 watt geared hub motor
 
There's....a lot to unpack here.

I have a 12v/3p 13s battery I did for 12v compressor
Do you mean a 3s 13p? Even then, 3s would barely get you 12v @ full charge (4.2 x 3 = 12.6).

I would like to try it in series with a 48v battery
So you want to get higher voltage?

This is for a Dapu 36v/350 watt geared hub motor
To be clear, the motor itself doesn't really care what voltage you feed it (for all intents and purposes here). It'll care how many amps you put through it (because that'll be heat; which too much of will be smokey burnt up motor).

Generally, the controller is what needs to handle the voltage. And, just because it has 100v caps doesn't entirely mean that it can handle that voltage; there may be other components that could fail at too much voltage.

I want to series batteries. I currently have it wired for parallel. Can I make a adapter to reverse the polarity when going from parallel to series?
This sentence...doesn't make sense. What does reversing polarity have to do with anything? And, no, I don't believe there's an "adapter" that can swap around all the series/parallel connections on a battery by, like, flipping a switch.
 
With a four pole double throw switch, you could rig 3 batteries to be in series or in parallel. It has to be a break-before-make type switch. Each battery needs its own BMS, and the BMS has to handle the combined voltage of all three. Sit down with a pencil/paper and you can figure it out,
 
With a four pole double throw switch, you could rig 3 batteries to be in series or in parallel. It has to be a break-before-make type switch. Each battery needs its own BMS, and the BMS has to handle the combined voltage of all three. Sit down with a pencil/paper and you can figure it out,
and second guess yourself while you anticipate a BIG BANG! on first test..

Whats the use case for connecting a 12v? and 48v battery in parallel other than danger?
 
I wouldn't bother with it.
You have a lot of new problems doing this with a battery that has a BMS.
The end solution would be expensive, heavy, and complex.

RC Lipos with series/parallel adapters might be more ideal. You can play with increments of 8-22v. But there is an art to using them safely without burning your house down.
 
I wouldn't bother with it.
You have a lot of new problems doing this with a battery that has a BMS.
The end solution would be expensive, heavy, and complex.

RC Lipos with series/parallel adapters might be more ideal. You can play with increments of 8-22v. But there is an art to using them safely without burning your house down.
I am curious about 60v performance but it's more hassle than I am willing to endure just for curiosity. 48v is pretty impressive with this motor
 
You could probably get a taste of that 60v power if your controller is programmable and supports phase weakening, to achieve higher speed on the same voltage.
 
based on the smippets of incomplete random information from the OP, i am guessing that they have:

two 48v batteries already in paralell on the dapu

a 12v battery built of 3 parallel 12v batteries

want to have 60v on the dapu

if this is true, then there is no reason to change antyhing from series or paralell or at all.

you simply wire the 48v set you already have in series with the 12v set you have, and tehn you have a 60v nominal battery.


however:

the lowest capacity ah between the 12v and 48v is now the actual battery capacity.

and

the lowest current amps between the 12v and 48v is now the actual amps of the entire system.

and

if the 12v packs or the 48v packs have bms, and htose bms are not rated for the full charge voltage of the 60v system, the fets may fail and leave the bms unable to protect the cells, and you probably wont' even know this has occured, until damage occurs to cells that causes sytstem problems that are obvious, and/or a fire starts.

and

the dapu display probably only handles up to around 60v max, maybe not even that, so it may fail as soon as the battery set is connected to it, and never turn on again.
 
Back
Top