Using dewalt DC9000 as dumb charger?

[Malcolm]

I'm using some A123 cells in a "minimalist" 10s1p pack for short trips into town on my ebike, just to give an occasional burst of speed to keep out of the way of traffic and to assist on a couple of hills. I'm using the controller LVC to cut off at 30V. I understand the risks of not having cell level LVC, but I intend to monitor the cells regularly.

So far I've been using a little 10A power supply set to 3.6V to charge the A123 cells, but this means reconfiguring them in parallel every time I need to charge. I'd like instead to charge them mostly as a series string, and use the 3.6V charger to balance them once in a while. I could just buy a cheap charger and tweak it for 36V, but as I already have a dewalt 36V charger, I was hoping to find a way to fool this into thinking it had a dewalt pack in place, so that I can use it as a dumb charger that will cut off at 36V.

I opened up the charger and connected the pack to the positive and negative spade connectors. When I switched it on, nothing happened at all. Four of the wires to the connector block are orange, so I connected them together just to see what would happen. The result was three flashing LEDs, which I think usually means that the cells are too low to take a charge (not true in this case). I've just about reached the final frontier of my electronics knowledge, so I was wondering if anyone else here has done this before or has any suggestions on how to fool this charger? (I've searched the forum but not found anything yet).


The wires to the connector block are as follows:

1 Black - negative
2 Brown - enable?
3 Yellow
4 empty
5 Orange
6 Orange
7 Orange
8 empty
9 Orange
10 Red - positive

 

[Lessss]

Use a timer on the plug in case you forget to shut off your dumb charger. Some power bars come with timers, then again you can alwys use christmas tree timers.

 

[dak664]

I expect the dewalt packs communicate with the charger using some sort of proprietary smart bus http://www.batteryuniversity.com/partone-17.htm which would be integrated into the firmware running the power supply, making it difficult to disable without access to the firmware. Probably you could fool it with the electronics from a salvaged pack.

 

[reagle]

It does not look like they do- everything I've seen so far seems to indicate just a dumb protection circuit with balancing, but not much more. And no SMBus on the connector as far as I can tell. I was trying to talk to the Dewalt packs the way I'd talk to any normal smart battery, and got nowhere

 

[Malcolm]

Thanks for the replies. I probably didn't make it clear – all I'm trying to do is to switch on the charger. It needs some sort of input to the connector block in addition to the positive and negative supply from the battery in order to start charging. I've tried using a resistor to bridge between the supply terminal and each of the smaller terminals to see if I could wake it up, but not got any response yet. I suspect that the required input is fairly simple, although I've got no real grounds for that suspicion.