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[retepsnikrep]

I've been thinking about this a lot recently as I am getting more and more enqs from members in UK about help with battery issues as the vehicle stock ages.

The Triton and Overloader Nimh Chargers are good but take ages, some times weeks and can really only do one or two sticks at a time, they also require a lot of user intervention changing over subpacks and noting results etc.

We need something much more automated that also does not require complete dissasembly of the battery.

We can't do it using the BCM balancing connector due to the low current allowed by the inline 180R resistors. We need access to the ends of the subpacks.

So my proposal is make up two end pieces using some light foam board and the orange connector boards as pattern for the holes to line up with the supack terminal bolts.

To this board fix neodynium magnetic connectors resting on some foam fubber to absorb any slight misalingment. Then we can just put these boards onto each side of the pack and have access to each subpack with a reasonable (5A) current connection and without dissasembling the pack.

So now we have 20 wires from each side of the pack this feeds to a pcb containing 40 x dpdt 5A relays. These relays allow the subpacks to be isolated and connected individualy to a 5A charger or 5A load respectively.

A pic monitors the cell voltages and current and the device can be programmed to discharge one cell whilst charging another. The pic logs the data and starts at subpack one and then advances through the pack with no user intervention simultaneously charging and discharging different subpacks, before finishing off with a quick top up charge of each subpack at the end of the cycle. It only needs a 5A 12v dc supply and can be left unattended with the device also controlling the pack fan so that can be activated if reqd for cooling. It would also be possible to use the bcm plug to access the ptc strip temp sensors and provide a warning of an individual cell overheat scenario.

It sounds complicated but it isnt really and can be left to get on with it, and can be changed to a new battery pack in seconds due to the magnetic connectors. (neodynium gold plated disc magnets about 7mm diameter) which fasten themselves to the subpacks bolt heads.

I'm working on a circuit diagram I'll post details later. I may well get a pcb made up if anyone is interested.

I also though about using a DC-DC converter as the load which would pump the discharging energy back into the charging side of the circuit so we are not wasting so much energy.

I think the circuit needs to be designed so it can be made easily and not use surplus parts that may be unobtainable next week.