How to charge my 3 cell?

[lipbr302]

I have a 2-3 cell balancing lipo charger from parkzone. I just got a xr10 and I bought 3, 3cell Tunringy batteries. Ive charged my 2 cell before on this charger and have plugged in the deans plugs and the balancing plug at the same time. The guy at the lhs told me I should plug in the balincing plug for a while. Then charge it with the balancing plug not connected. Is this correct? By the way the 3 cell batteries are for my xr10 and are soft cased, and the 2 cell is hard cased if that matters. I realy need to know! I dont want to burn my house down! Thanks

[SMR 510RR]

Read the directions that came with your charger. Every charger is different but the basics remain the same. You will have to set the charge rate and the number of cells in series (2s,3s,4s,etc.) before you start charging. Most packs can only be charged at 1C (1A for 1000mah do the math for the size of your packs). On my charger I have to select balance rather than charge so make sure that you are balancing or else your cells will end up at different voltages and then when you charge or discharge one or more cells may go outside of the "safe zone" even though the packs total voltage is saying otherwise.

There is no reason not to balance charge every time but there is a reason why you should. IDK what that guy was talking about, the balance plug should be left in the whole time.

[JohnRobHolmes]

Yes, leave the balance plug in! It will keep the cells from getting overcharged and catching fire is something goes wrong with the pack!

[wizner]

Originally Posted by JohnRobHolmes

Yes, leave the balance plug in! It will keep the cells from getting overcharged and catching fire is something goes wrong with the pack!

i realize that if anyone on here knows anything about rc it would probably be u john. but i was under the impression that if you dont use a balance plug in lets say a 3s battery, that the charger will stop charging only to the first cell to be fully charged. so essentially if the other 2 cells discharged a bit more during a run, they will only be charged up the amount the strongest cell has charged in relative time, and not relative to each individual cells required capacity for a full charge. so there would be no worry in overcharging, but a worry that each individual cell is not charged to full capacity. im a newbie, so edjamakat me

[JohnRobHolmes]

Without the balance plug, the charger only knows the bulk total voltage of the pack. It has no way of knowing where each cell sits. So if one cell is under voltage by 1v, the other two cells could be over charged by .5v each. This is a worst case scenario, packs normally stay fairly well balanced depending on quality and age.

[wizner]

ok, that makes sence. so if its not balanced then its just looking for 11.1v for a 3s and it doesnt know how its getting there. it could be 4.2v+4.2v+3.2v in your example and that would be waaay over charged. thanks John

[JohnRobHolmes]

Exactly. The termination for LiPo is 4.2v per cell, so the charger takes it up to 12.6v and waits for the amperage to taper down to 1/10th of the charge rate before shutting off (simple controlled current controlled voltage scheme). Without a data stream that indicates that one cell is going past 4.2v, the charger will just keep chugging away.

[wizner]

ok, so in your example i should have written 4.7+4.7+3.2=12.6 which is when the charger will think its good even though 2 packs are overcharged by .5 volts. thanks again john. so why in the hell does onyx sell an $80 charger that charges lipos but doesnt come with a balancer? now this sounds like a lawsuit if i were to burn my house down from charging with that charger per the instructions? there was no recommendation for an external balancer with lipos in the instructions, and i always read all of the manuals i get for anything.

[JohnRobHolmes]

I don't know really, is it only for two cell packs?

[wizner]

Battery types: 1-8 NiCd or NiMH cells (1.2-9.6V)
1-3 LiPo, Li-Ion, or LiFe cells (3.7-11.1V)

copied from duratrax website. i know im getting off track with all these questions, but im that guy that wants to know how everything works so i can take full advantage of what ever i have. thanks for all your replys.

also, since all you do is play with wire all day i was wondering if you have one of these http://www.series4.co.uk/prodeqpt/section01/ds5.htm i got one off ebay for only $50 and its a life saver. i used to build mil-spec harnesses and this is the best ways to strip wire with out damaging it. if you search under you tube for toh srezeew, i gave a little demo for my step dad cause i bought him a pair.