Easy way to connect Dewalt Batteries?

[pizark]

Hi Everyone,

First time poster, first time e-biker. I just bought a Crystalyte 408 kit with a 48V 25A controller, and had a question about Dewalt batteries.

Is there any way for me to connect parallel connect 4 to 6, 36V Dewalt (A123) batteries without having to take apart each battery?
Doing this would make a 36V (9-12Ah) battery, right?

I was thinking of buying 2 chargers to actually charge,.. and 4 to 6 chargers to take disassemble to use as parts to make some sort of system that would allow me to just slot the stock batteries into and have them run in parallel. I think I just like the idea of making the system look really clean, and I thought that not disassembling the batteries and connecting the cells to create a custom battery would help me to avoid the A123 cells from imbalanced charging. Am I correct with the latter assumption?

I heard it takes 12-20 minutes to 80% charge a dewalt battery using their charger. How long it take to charge the remaining 20%?
I know jack nothing about battery management systems and I'm pretty new to all things ebike related. I would appreciate any bits of wisdom/advice/etc.

Thanks,

Paul

 

[pwbset]

I'm a total noob myself, but if I might voice my .02. I think most people are harvesting a123 cells from DeWalt packs anyway because the battery management systems in those packs aren't very good... or so I've read. Even just 4 DeWalt packs will cost you like $600+ these days - not to mention chargers. You should give serious thought to using Milwaukee tool packs. You can get 6 of them with free business shipping for $480 from toolup.com. You can get 3 chargers for about $60 shipped from Amazon.com. You could very easily wire 2 in series and 3 in parallel to get 56v and about 8-9ah. Your 48v controller likely has 60v fets in it so you could probably run at 56v - best to check that first of course. Anyway... do a member search for posts by lazarus, jondoh, maytag, mlrosier and others to see what's being done with Milwaukee packs. They are awesome and probably the best bang for the buck out there right now and second only to a123s, lifebatts, kinions etc. in terms of power/max amp draw etc.

I use them to climb a mountain to work each morning.

http://endless-sphere.com/forums/viewtopic.php?f=3&t=4775

 

[docnjoj]

Milwaukee also sells the snap in connectors at a reasonable price so U can do the series // thing. U dont have to cut up power tools to connect them!!!!
otherdoc

 

[pwbset]

Milwaukee also sells the snap in connectors at a reasonable price so U can do the series // thing.

Oops. Right! Forgot that part sorry.

Milwaukee Direct: 1-800-729-3878
Assembly Block Part #: 22561729

They were like $12ea when I ordered I think.

 

[pizark]

dayamn... it's amazing how helpful all of you are. I spent the last 2-3 days racking my head trying to find a workable solution, and then I get this amazing bit of advice.

Thanks!

Paul

 

[Jay64]

yeah, those milwaukee assembly blocks are awesome. I wish someone would make some for dewalts. I thought I got mine for about $4 ea though. That was about 8 months ago or so, so maybe they increased the price now that they see people are buying them to modify stuff with. Two members on here made their own 'assembly blocks' for the dewalts. I was pretty impressed with both. I forget the thread that they were on though so i can't source it for you. I'm going to attempt to make some here real soon. But then again, maybe if the dewalt charger is such crap, you could get a used one for even cheaper then a new one on ebay. I think I got mine new on ebay for about $20.

 

[Jay64]

Even just 4 DeWalt packs will cost you like $600+ these days - not to mention chargers. ]

Just FYI, I just picked up 4 DeWalt packs on Ebay for $560 with free shipping. Still a lot more expensive then the first two I bought for a little over $100 ea. There are some idiot bidders out there, out bidding themselves etc.

 

[TylerDurden]

Just FYI, I just picked up 4 DeWalt packs on Ebay for $560 with free shipping. Still a lot more expensive then the first two I bought for a little over $100 ea. There are some idiot bidders out there, out bidding themselves etc.

That doesn't read as well as it sounds, Jay. :lol:

 

[TylerDurden]

FWIW, I found connectors for my Ridgid Batts by using the parts-sheet for the flashlight. DeWalt may have similar.

 

[EMF]

You can make a connector for your dewalts as simply as cutting a piece of plywood into a shape that fits inside the raised guides on the battery, with a bit of play. Then you could put some copper strips one on each side of the wood piece, and they will then slide up into the outside terminals of your battery. Make the block just slightly longer than the battery, to help hold it steady from the bottom. Then just use screws that screw into the copper strip and into the wood to hold your wiring. Better yet, use T-nuts and bolts.

I saw a guy with a recumbent do his Dewalts this way, can't remember the website. This bypasses the BMS of course, and you still have the fuse to worry about. Having enough Dewalts paralleled to keep the amps under 15 when factoring your highest amp draw will protect you from that scenario. You could even add a fuse or circuit breaker to your leads that go to the controller, that would trip prior to the fuse blowing in each Dewalt.

 

[Jay64]

Just FYI, I just picked up 4 DeWalt packs on Ebay for $560 with free shipping. Still a lot more expensive then the first two I bought for a little over $100 ea. There are some idiot bidders out there, out bidding themselves etc.

That doesn't read as well as it sounds, Jay. :lol:

Huh?

 

[Link]

Just FYI, I just picked up 4 DeWalt packs on Ebay for $560 with free shipping. Still a lot more expensive then the first two I bought for a little over $100 ea. There are some idiot bidders out there, out bidding themselves etc.

That doesn't read as well as it sounds, Jay. :lol:

Huh?

LOL

 

[Jonathan]

Unless you get yourself quite a few in parallel, you're bound to get the infamous blinky.
The advantage of these cell are for ... sprinter ebikes not long distance marathon.
Looking at your spec of achieving +10 Ah, you're probably better off with the Makita or Milwaukee LiMn.

My 10S4P Dewalt pack have nominal loaded voltage of 30-33V & 8Ah with a high LVC cutoff @ 29.0V.
With a Mastec 5020 PS, I can charge this at 20A, I get ~80% capacity in first 20 minutes in CC mode.
It then takes another 10 minutes or so to top it off with CV mode.

Regarding balancing, Dewalt BMS does a horrible job. If you want to keep these well balance I recommend you use FMA CellPro 10S or iCharger 1010B. Each of which have their own strength / weakness. Also keep in mind they will cost you +$200

Conclusion: The advantage of keeping the pack is THE WARRANTY! The disadvantage is the BMS &| Fuse & Size.