130x - Can you parrallel charge different 130x batteries at the same time

[Paz26181]

Hi guys,

I got 4 stock batteries and a parrallel charge cable for 6 lipos. I'm thinking of getting two new lipos to make better use of the charge cable.

Can i charge the 4 stock and 2 nanotech 450mah lipos at the same time or would you recommend not mixing batteries?

If it is possible to charge different batteries then what would the formula be for setting the charge capacity and C rate. When i charge the 4 stock batteries i set the charger to 1200mah, 7.4v and 2.4C.

[Stanley Speel]

yes you can - just add up the mah

[Paz26181]

Thanks for the response Stanley; that’s good news. I didn’t fancy buying any more stock batteries especially when the nanotech ones are cheaper and on paper out perform the stock batteries.

Just out of curiosity; any ideas on how the charger ensures all the batteries are fully charged and balanced when parallel charging batteries of different capacities?

Is it a good idea to ensure the stock and upgrade batteries contain a similar amount of mah before charging? E.g. would it be a problem if I ran the stock batteries for 3 minutes and the upgrade batteries for 4 minutes or should they all be run for the same amount of time for parallel charging purposes?

Apologies for the novice questions; I’m new to parallel charging!

[Nick B]

As soon as you connect multiple lipos they will balance out with each other.If you connected one with 30% and one with 20% they will both be 25% in seconds.

[Paz26181]

Thanks, that makes perfect sentence.

[cjcj1949]

If they do balance out in seconds there will be a lot of current flowing to do this. Most people try to get the volts as close as possible. The charger doesn't do anything to help with parallel charging it just sees one battery. The current will not flow equally to all batteries during charge and so some may be charged at higher currents. Overall all batteries will get the correct charge. Be careful with connecting up as you can make a mistake that will damage batteries and you. If you can try to discharge your batteries to the same volts offload. Somewhere between 3.70 and 3.80. And try to keep within the 80% rule. Lipo current varies a lot with small changes in volts which is why they are constant current and not constant voltage charged. The end of charge is constant voltage but only after the current limit has been reached. If you want to connect batteries at different voltages you can use long leads that will limit the charge current. It does seem that high charge currents are not that much of a problem, but opinion is divided.

The order you connect the batteries makes a difference as well. If you connect all the high batteries first and then a low battery you will get a much higher peak charge current than if you do it the other way round. As lipos will provide about 10 times more current on discharge than charge, it seems more sensible to do it that way.

Just because two batteries are in parallel doesn't mean they are equal in volts. One will be charging the other and this will be reflected in their net charge current. Internal resistance is very low, and the current from one lipo to the other is the voltage difference divided by the internal resistance of both batteries and their connectors.

[Paz26181]

Thanks for the feedback; it’s been very helpful.

So best practice is to try get all the batteries to a similar voltage level before charging and when connecting batteries to charge the order is important too.

Should the charge cables already be connected to the charger before I connect the batteries to help avoid damage?

[Nick B]

Thanks for the feedback; it’s been very helpful.

So best practice is to try get all the batteries to a similar voltage level before charging and when connecting batteries to charge the order is important too.

Should the charge cables already be connected to the charger before I connect the batteries to help avoid damage?

Yes and yes with the charger turned on.

[Nick B]

My set up

[brin]

i have one of the balance charge leads that treat three single cells as a 3s and balances them out before charging.i also use the six way lead when i have ones that have been used for the same time.

[cjcj1949]

Series charging is safer than parallel provided you make up some connectors that stop you plugging the balance connectors into the wrong slot. It is very easy to do and then you have to rewire the balance connector that has just vapourized. Not dangerous but a nuisance. With 3 1S batteries in series there may be no way of screwing it up. If you can screw it up you usually will I've found.