Seting up Nicads?

[Mouldy]

Hey all,

In Turbulance we currently have 4x12v 3amp battlepacks giving a total of 6amp 24V (2x6amp 12v packs). We have been told by some people that running the packs to give 2 lots of 6amp 12v packs is a bad idea, especialy during charging, However others have told me that theyve done this without any problems. So will it be ok running the packs as i am currently? Any advice is appreciated

Dave + Ed
http://www.teamturbine.comwww.teamturbine.com

[ewan]

It all depends on how the single 12v 3A packs were used before you made them into larger packs.

Basically the cells need to be matched with each other so that they will all be at the same point of charge/discharge at any one point in time. When you first attached the packs in parrallel, were they matched in charge?

If want the packs to last a reasonable life you should seek having them professionally matched/zapped (whatever they call it...) before coupling them in parrallel for charging/discharging.

[kane]

Do NOT charge NiCds in parallel. This WILL result in fire.

Furthermore, do not leave the batteries connected in parallel as this is also dangerous.

Using the batteries in parallel is fine and what many teams do.

[Mouldy]

Ewan- they were brand new so i just stuck them together thinking they would be identicle from the manufacturer. Looking back on it i should of realised.

Kane- Thanks for the advice Ill re-do my wiring asap.

[big_nipper]

Very dangerous to charge them in parrallel, should never be done, as Kane said. We use 6 packs in Big Nipper, 3x24 Cells & 3x6 Cells arranged in 3 sets of 30 Cells in parrallel in the robot. Even packs in parrallel will discharge differently even if matched if just the wire length is different.

I dont see anything wrong with charging them as 2 seperate 24V packs, we would charge ours at 36V if the charges could, and the 24 Cell packs were made up from 3 9.6V packs and have not been seperated since new.

I would recommemnd that you discharge the 12V packs to a set voltage level (Most Pro-peak chargers and other do this) then re-charge them, check the capacities are the same (should be with new packs) then connect them together to get your 2 24V packs. When you connect in parallel unless they happen to be perfectly matched one set will start to slowly discharge the other and if connected for a long time could damage both sets. We simply connect them just before a fight and disconnect them just after.