Lipo

[biker]

hi all
charging 6 x 2s 7.4 v the end voltage 4.2 what would would you set currant at on a parallel board to charge them all at the same time.
roger

[Martind]

Need to know the packs mah size ie 2s 1500mah

[biker]

Hi
200 mha

[Mike Sanders]

For 1 C charge, 200 milliamps X 6 = 1200 = 1.2 amps charge rate .

[biker]

hi
thank you very much
roger

[Shep0479]

This was a post when i asked the same question

Do not to parallel batteries together if they are not very close to the same voltage. You can charge together if the batteries are within 0.2V but more than that you risk damage or even a fire.

All battereis that are parallel charged together must all have the same number of cells.

You CAN charge batteries with differing capacities providing the first two rules are followed.

So, now you have a number of batteries that are all the same number of cells and are all within 0.2V of each other. You CAN charge battereis with differing capacities.

You set the charger to the voltage for one of the batteries (remember, they must all be the same). So for 1S that is 3.7V

You set the capacity to be the total of all capacities of the batteries being charged together... e.g. if you 1 x 150mah and 5 x 190mah that would be a total of 1100mah.

To charge at 1C that would then be charged at 1.1A


The 2 most important rules are:
1) Only charge together if all batteries have same nominal voltages (number of cells)
2) Only charge together if they all have very close actual voltages... say within 0.2V

[biker]

hi all
thanks to all again what a wealth of knowledge on this site ok take care tnks again
roger

[Shep0479]

hi all
thanks to all again what a wealth of knowledge on this site ok take care tnks again
roger

Never break the 0.2v rule. And don't leave your lipos unattended when charging.

[biker]

ok will do
ta roger

[Grumpy]

Never break the 0.2v rule.

It depends on the number of cells. 0.1v per cell is a very conservative safe difference, but that would be 0.3v for a 3s or 0.4v for 4s etc. To be honest you can go a lot higher without issue, even 0.2v per cell wont cause any real problems.

The issues with different voltages when parallel charging are often exaggerated. I did an experiment a couple of years back using two 3s, 2200mAh batteries. One was fully chargers and one at 3.8v per cell (11.4v total), difference between pack was 1.2v. I connected them directly together via a wattmeter. Some would forecast that this would surely result in explosion and fire and my house burning down, but the reality was a lot less exciting. I got a very brief surge of 20A which dropped in seconds to around 10A which was within the 5c max charge of the batteries.
Neither battery showed any sign of distress or even got hot. I left the batteries coupled until their voltage was fully balanced. After charging both batteries worked normally and two years and countless cycles later they are still working normally with no puffing or any other sign of damage.

While I don't recommend connecting fully charged and used batteries together my experiment does at least prove that the consequence is not nearly as bad as some would insist on.

Also FWIW most batteries these days are perfectly good for 2c charge rate or higher, so you probably dont need to limit to 1c charging

[biker]

Well again every post is well received from what I have read They can be very volatile if not charged
correctly. Thank you for all your input
roger