Parallel Charging Lipos

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6 years 4 months ago #14996 by AlanF
Parallel Charging Lipos was created by AlanF
Does anybody here do this?

There are a few things to consider obviously and the consequences of getting it wrong are potentially disastrous but it seems a good way of getting multiple lipos charged in reasonable time.

Does anyone have any charger boards that they've used and would recommend? one with replaceable fuses would seem be a good idea.

Do cells maintain their balance when charged multiple times this way?

Apart from lipo charge state and lipo type symmetry requirements and charge current/power calculation, is there anything else to consider?

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6 years 4 months ago #15006 by MikeSeale
Replied by MikeSeale on topic Parallel Charging Lipos
Yes. I charge 4×5000mAh 6s batteries this way. I check that the batteries have reasonably similar voltages...seems to coincide with 15% to 35% on my battery checker. It's not necessarily quicker but you don't have to keep going back and swapping batteries all the time.
It could also be argued that it is kinder to the batteries...if I charge my 5000mAh batteries at 1C that is a 5A charge. But my charger only does 10A max so if I charge four in parallel that's only 2.5A each which is 0.5C and could arguably extend battery life.

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6 years 4 months ago #15008 by John Bannister
Replied by John Bannister on topic Parallel Charging Lipos
Mike how do you physically wire up the batteries? you can't balance charge them can you.
Where do you charge your batteries it's been stated many times that lipo's should be never left unattended while charging. I charge mine in the garage on a metal shelf and on occasions forgotten about them and left them overnight on charge, relying on the charger to stop charging when full, perhaps a accident waiting to happen.

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6 years 4 months ago #15010 by MikeSeale
Replied by MikeSeale on topic Parallel Charging Lipos
Yes, John. They are balanced using something similar to this

HK parallel balance board

I'm using a different one now with fuses but cannot find a link to it...Chris001 might have it.

I charge my batteries in the morning before I go flying, so there is no chance of leaving them overnight
The following user(s) said Thank You: John Bannister

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6 years 4 months ago #15011 by
Replied by on topic Parallel Charging Lipos
With a balance board you can balance charge a number of batteries like Mike says. I only use the ones with fuses on both the main power lines and with polyfuses on the balance lines. Like Mike,I individually check each battery before I connect them.

Unless using XT60 or Deans your probably going to need adaptor leads and It's helpful to have balance extension wires too, depending on how generous they are on the batteries.

I charge 4 x 5000mAh packs on this at 7.4 Amps (my power supply is the limiting factor here) I have done this will all my batteries since day one and they have always been balanced when checked afterwards.

John, I charge mine in an ammo can on its side, with the lid off on the concrete floor of the garage. If the worst happens I'll loose all batteries and the balance board, but the ammo can should direct the flames outside as I leave the garage door slightly open.
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6 years 4 months ago - 6 years 4 months ago #15012 by JRI
Replied by JRI on topic Parallel Charging Lipos
I think you need to be sure that your battery packs are discharged to a very similar level every time and that you don't have any 'low' cells in any of the packs. My own personal experience of using a balance board with a pair of 5K 6S batteries was a huge flash and two of the balance tracks on the balance board evaporated. I know others have had a less dramatic experience!
When you think about it logicaly, all you are doing is paralling each cell with its parter in another battery(s), and the higher potential cell is going to try and dump its contents until the cells are at the same potential - you are relying entirely on the internal resistance of the cell and the tracks and connectors to stop this happening in an instant (i.e hundreds of amps want to flow from one battery to another).
P.s it puzzles me why jump leads don't evaporate when jumping a car, but maybe there is a scientific reason that I don't understand!
Last edit: 6 years 4 months ago by JRI.

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