Dewalt DC9000 Charger/DC9360 & DC9280 Batteries Hacked?

[LI-ghtcycle]

I'm looking to see if any of you who are electronics wizards have confirmed what exactly a Dewalt DC9000 charger (the one that is for charging the 36v and 28v A123 batteries, DC9360 & DC9280 respectively) does or does not do.

I have read where a lot of people have speculated what these charges do, and I have seen where at least two people have successfully charged their Dewalt batteries using nothing more than a "smart" SLA type charger.

I guess what I am really asking is, does the charger do the balancing or is that simply something done by the internal BMS of each individual battery, because I am wanting to wire up to the charging circuit of my batteries and find a good "smart" 48v SLA or similar type charger that will just supply constant voltage (if I understand that is what could be used) until it senses a similar value being put out by the battery, thus lowering the Amperage.

I also understand that one of the phenomenal properties of A123 cells is their ability to take a charge at high amperage allowing for very quick charging. The charging circuit has a 15A fuse, so I'm wondering what would be a safe amperage? Would a maximum 10A SLA "smart" charger that senses the state of charge of the battery and adjusts amperage accordingly, be a good choice? I am hoping to get the quickest safe charge for 2s 4p 28v Dewalt batteris (total 8 batteries) with a nominal voltage of 52.8 - 54.8, and 8- 9.2 AH.

Thoughts?

 

[bzhwindtalker]

hello,
I'm currently testing 28v dewalt with a s350 set for 29v output, I tried charging through the + and - sides of the bms, it charges but I don't think it does his balancing job, as I ended with a cell at 3.3v when the others were at 3.7 mostly...
I need to figure how make it kick in.


adam

 

[LI-ghtcycle]

hello,
I'm currently testing 28v dewalt with a s350 set for 29v output, I tried charging through the + and - sides of the bms, it charges but I don't think it does his balancing job, as I ended with a cell at 3.3v when the others were at 3.7 mostly...
I need to figure how make it kick in.


adam

Hmmm not familiar with that charger ... I'm still new to the who Li-Ion stuff, but I am guessing you mean you charged through the positive and the most outward negative (furthest left) as that is the charging circuit as I understand. Now that I think about it, if you discharge from this side, you by-pass the BMS, so maybe their really isn't much balancing done when charging, or maybe that feature is in just the charger it's self?

I wouldn't be unhappy about a cell at 3.3, long as it's a solid 3.3, since that is nominal voltage for these cells, but it it's only a surface charge and the working charge is lower than 3.3 that could be a problem.

 

[bzhwindtalker]

finally, I cut the bms and wired balancing plugs directly to the cells tabs, as the bms is heavy, and I don't know how to activate it.
I have a 6s lipo/ life balancer, It will do the job for now until I build a simple balancer/ lvc board.
It will be a zener, a led, a 5w resistor and a wire to go to the main contactor to cut power when a cell hit lvc.
Or maybe going the simple way and buy gary's boards

 

[Doctorbass]

This question about the dewalt charger or BMS hack have been posted few times in the past... Please search in the forum history.. :wink:

Doc

 

[LI-ghtcycle]

This question about the dewalt charger or BMS hack have been posted few times in the past... Please search in the forum history.. :wink:

Doc

Please give me a hint?

I have tried several search terms, and still haven't found anything specific about getting inside the Dewalt charger it's self and modifying.