Battery charging question for experts

[ktronik]

Hi guys,

I have 2/ 7.4v lipo packs, each with a balance lead & power lead (7.4v out)

I have them wired, via power lead, in series for 14.8v out, with a protection fuse on the serial link of the 2 battery's

I have 2/ 7.4 balanced chargers. I want to charge both battery's @ the same time with the 2 balanced chargers.

Question: Can I charge both packs @ the same time (via balanced leads), when they are still in series?? Or would I have to pull the fuse, making them 2 separate packs again??

Thanks in Advance

Ktronik

 

[smopoim86]

Depends on the balancing setup. If you had a way to connect the balance leads to be 4serial, it would work. I'm not sure if a adapter is available off the shelf to do it though.

~Daniel

 

[ktronik]

If you had a way to connect the balance leads to be 4serial, it would work.

~Daniel

Yes I know that would work, but that's not my question...If I wanted that I would just wire on a 14.8v (4S) balance lead... I guess I will just pull the fuse, making them 2 separate pack with a charger each.

Anyone else, sliverfox???

 

[SilverFox]

Hello Ktronik,

I believe you would have to pull the fuse and treat them like 2 separate packs.

To charge all 4 cells in series, your charger would have to be capable of charging 4 cells.

Tom

 

[Mr Happy]

I believe the question is like this:

   -------    -------          -------    -------
  [+     |---[+     |---[~]---[+     |---[+     |
 | ------- :  ------- |     |  ------- :  -------|
 |         :          |     |          :         |
 |         :          |     |          :         |
 |    ------------    |     |    ------------    |
 +----|Charger #1|----+     +----|Charger #2|----+
      ------------               ------------

Will this work as a charging arrangement, or should the fuse be pulled in the middle, like this:

   -------    -------          -------    -------
  [+     |---[+     |---[ ]---[+     |---[+     |
 | ------- :  ------- |     |  ------- :  -------|
 |         :          |     |          :         |
 |         :          |     |          :         |
 |    ------------    |     |    ------------    |
 +----|Charger #1|----+     +----|Charger #2|----+
      ------------               ------------

To which the answer is, "it depends".

If the two chargers are completely electrically isolated from each other, then it will not be a problem. However, both chargers may be connected to the same mains supply, and although the outputs should be completely isolated from the inputs, there is always a chance they are not.

So in case of doubt, it is much safer to pull the fuse and charge the two halves of the pack while disconnected from each other.

 

[ktronik]

I believe the question is like this:

   -------    -------          -------    -------
  [+     |--:-[+     |---[~]---[+     |---[+     |
 | -------  : ------- |     |  -------    -------|
 |           :        |     |                    |
 |           :        |     |                    |
 |    -------:-----    |     |    ------------    |
 +----|Charger #1|----+     +----|Charger #2|----+
      ------------               ------------

Will this work as a charging arrangement, or should the fuse be pulled in the middle, like this:

   -------    -------          -------    -------
  [+     |---[+     |---[ ]---[+     |---[+     |
 | -------    ------- |     |  -------    -------|
 |                    |     |                    |
 |                    |     |                    |
 |    ------------    |     |    ------------    |
 +----|Charger #1|----+     +----|Charger #2|----+
      ------------               ------------

To which the answer is, "it depends".

If the two chargers are completely electrically isolated from each other, then it will not be a problem. However, both chargers may be connected to the same mains supply, and although the outputs should be completely isolated from the inputs, there is always a chance they are not.

So in case of doubt, it is much safer to pull the fuse and charge the two halves of the pack while disconnected from each other.

Thanks silver fox & Mr happy :bow:

I will pull the fuse as both 7.2v balance chargers are on the same supply...

Thanks for the pic Mr happy, to me you pic looks like it is missing the link from the middle of the 2 cells to charger that a balanced lead normally have, other than that I get what you are saying..

K

 

[Mr Happy]

Thanks for the pic Mr happy, to me you pic looks like it is missing the link from the middle of the 2 cells to charger that a balanced lead normally have, other than that I get what you are saying..

I left out the balance leads for simplicity, since the answer is the same whether or not a balance lead is included in each charging circuit.

 

[smopoim86]

Beautiful ascii art Mr Happy

 

[ktronik]

I left out the balance leads for simplicity, since the answer is the same whether or not a balance lead is included in each charging circuit.

got ya, thank you all :twothumbs

K