Dewalt Batteries In Parallel?

[PeteCress]

I've read quite a few threads/blog entries by people who use the Dewalt 9360 36-volt batteries to power their eBike.

But they have all had a seriously (to me...) technical bent to them.

Accordingly, I thought I'd start this thread - whose purpose is to create a dumbed-down discussion of the ins and outs of using Dewalt 9360 batteries

What I'm thinking is:

1) Using Dewalt 9360's to power an eBike has certain advantages:

• Modularity: If something goes south, it's limited to one battery
• Quality Control: Dewalt is a beeeeg outfit and their nich is top-quality tools
• Fungibility: These batteries are widely available, Dewalt isn't going out of business anytime soon, and if one dies another is as close as the nearest Home Depot or Lowes
• Adjustability: Long trip, many batteries; Short trip, only one or two batteries

2) Seems like there are two ways to use these batteries:

• Wire them in parallel, using a chopped-up Dewalt flashlight for each as in http://tinyurl.com/yzh7ca9
• Use a single flashlight part and cycle them during a ride as each wears down. i.e. carry as many as warrented, but only use one at a time.

3) Since I don't even know the diff between BMS, Charger, and Controller,
charge them on the native Dewalt charger and feed the output into my existing controller.

Could those who know comment?

Just dumb it down for somebody who knows *nothing*, nada, zero, bupkis, zilch about electric stuff.

 

[dogman dan]

When you want it dumb, I'm your man. But I have little experience with tool packs. At one point, I was waiting for my ping, I took some 24v B&D nicad drill packs, paralelled two and rode on 24v. Even two of those paralelled was way too small, they ran down in 1 mile, and got really hot. 4 was better, but then these were only nicads.

The batts you are talking about are lithium, presumably good cells, a123 or something close in discharge rate. I seem to recall several riders using two in paralell, usually with a low watt motor like a bafang running 300 watts or so. Mid power motors like yours seem to require 4 in paralell to have any distance, and to prevent cell damage.

If you are looking for range extension, all kinds of stuff can be paralelled with your current battery. Even some lame sla's would work well once paralelled with your lifepo4, since they would be getting discharged slower. Using a diode will prevent a meltdown if you accidently connect a charged battery paralell with a discharged one. See the tech section for a diodes discussion.

The best bet might be to just buy a second battery from Jason for more range, or get one from pingbattery. If you need the power tools anyway, or can score a great deal on em, it's a different story.

 

[Lyen]

I've read quite a few threads/blog entries by people who use the Dewalt 9360 36-volt batteries to power their eBike.

But they have all had a seriously (to me...) technical bent to them.

Accordingly, I thought I'd start this thread - whose purpose is to create a dumbed-down discussion of the ins and outs of using Dewalt 9360 batteries

What I'm thinking is:

1) Using Dewalt 9360's to power an eBike has certain advantages:

• Modularity: If something goes south, it's limited to one battery
• Quality Control: Dewalt is a beeeeg outfit and their nich is top-quality tools
• Fungibility: These batteries are widely available, Dewalt isn't going out of business anytime soon, and if one dies another is as close as the nearest Home Depot or Lowes
• Adjustability: Long trip, many batteries; Short trip, only one or two batteries

2) Seems like there are two ways to use these batteries:

• Wire them in parallel, using a chopped-up Dewalt flashlight for each as in http://tinyurl.com/yzh7ca9
• Use a single flashlight part and cycle them during a ride as each wears down. i.e. carry as many as warrented, but only use one at a time.

3) Since I don't even know the diff between BMS, Charger, and Controller,
charge them on the native Dewalt charger and feed the output into my existing controller.

Could those who know comment?

Just dumb it down for somebody who knows *nothing*, nada, zero, bupkis, zilch about electric stuff.

Don't worry, we were all noobs when we were born. I too have spend countless hours of research prior I decided to use the Dewalt battery. Below are my reasons:
1. Buy American product to support America
2. America products have better quality control & management over some other countries
3. America product are mostly honest
4. Topeak seatpost rack & slide out DXP bike bag both can be easily be attach & use that battery on my other ebikes to save money. Most of us here in this forums usually have more than one ebike due to upgrades and the need for more power later. Also Topeak is another America product.
5. Dewalt battery is the only one that you can fully charge in an hour. I sometimes lock my bike up outside a nearby Starbucks, take my battery with me to a coffee shop; buy a cup of coffee & read my Kindle there while charging the battery in an hour there and leave. It was the most enjoyable experience.
6. Modular capacity > you can carry more or less battery as need to reduce the unnecessary weight on the ebike.
7. The battery has durable plastic to protect it from getting damage
8. They are yellow. Yes, it looks cool on my black Dahon Cadenza. People always compliment my add-on when I commute with it.
9. The internal BMS inside the battery is voltage adjustable
10. You can actually use the flashlight from the flashlight holder while in the dark by simply "snake" it onto the handlebar

 

[PeteCress]

I too have spend countless hours of research prior I decided to use the Dewalt battery.

How many do you have connected at one time?

Is there danger of cooking the battery if just one is used (as in very short trips) or does the battery's built-in BMS protect it 100%?

Are the batteries just plugged into the flashlight adapter(s) which are connected to the controller? Or is there something else going on?

 

[Lyen]

I too have spend countless hours of research prior I decided to use the Dewalt battery.

How many do you have connected at one time?

Is there danger of cooking the battery if just one is used (as in very short trips) or does the battery's built-in BMS protect it 100%?

Are the batteries just plugged into the flashlight adapter(s) which are connected to the controller? Or is there something else going on?

You can parallel them as many as you like by using the Schottky diodes. The diodes & built-in BMS both do protects the battery so it is kind of like a full coverage insurance.

I currently have 4 connected in parallel but I used to have only two in parellel and support my 35A BMC motor fine. The reason I connected 4 is because I am tired of swapping batteries when they ran out of juice at the 7th mile. Technically, I was able to have the motor runs on one battery without tripping the BMS by applying only 1/3 throttle at 8mph.

There is a circuit board inside the flashlight that I took out and simply wire a few resistors in place with an external switch, diodes and a fuse. It is a very simply modification. :wink:

 

[morph999]

I agree. A lot of the discussions on here are way too technical for me. I like pictures and slow, step-by-step instructions.

 

[biohazardman]

http://endless-sphere.com/forums/viewtopic.php?f=14&t=2498 Just read it all a few times and you will understand. They need paralleled for longest life. I run 2P 14s pack at the time and like Lyen, same motor same range, will soon be connecting two packs for 4P for more range and longer battery life.

 

[PeteCress]

http://endless-sphere.com/forums/viewtopic.php?f=14&t=2498 Just read it all a few times and you will understand.

I'm guessing that "balancing plugs" are plugs connected to wires that somehow connect individual cells to "balancing" devices.

Also guessing that "a 10s4p, 33V/9.2Ah, subpack" means 4 bundles of 10 cells in series with the 4 bundles connected in parallel.

Am I even close?

 

[biohazardman]

I believe that is the way it is. One can use the Dewalt balance plugs, as shown in Gary's post, or solder on your own wires to make things a bit more compact. Then there are the others who prefer to use the battery packs as they come from Dewalt. Many ways to do things and lots to read to learn. Knowledge is power. I may do the next one a bit different to make it look nice but looks aside this rats nest werqs just fine and fits in the space I had too. I decided not to use the BMS I built for on board Low Voltage Protection as the controller has done fine with the LVC on it's own. I do run the charger through the BMS when I charge to ballance the packs. Although they stay well balanced for several charges without it.

 

[LI-ghtcycle]

I strongly suggest you read Kin Fong's post here:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=10986
I knew nothing at all about using these batts or E-Bikes at all when I armed only with basic soldiering experience 20 years ago in high-school, and now I am able to make these packs work for me with no problems.

Make sure that if your going inside the packs that your willing to do a lot of soldiering/spot welding the tabs. I really prefer Kin's method since I can keep the integrity of the pack, and if un-altered, I'm sure that you could address any failures of the batts with Dewalt as long as the batts are still with-in their 2 year warranty. (tools have 3 years, but batts only 2 years)

The only difficulty I found with the BMS of batteries was when the 15 amp charging circuit fuse blew and wouldn't allow one of the packs to charge (the dewalt charge just suddenly showed all blinking lights indicating a bad battery) and after looking on ES, I found the info to do my own fix here:
http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=14219

One thing that I initially over-looked was the need for a ferride torrid (fancy word for an Iron loop often resembling a donut that can be bought for $5 from most places, or just use some 3/4" + fender washers, we used 3 stacked together) which is then wrapped with wire, no real specific amounts of turns, just check the pics in Kin's write-up, and that will keep the BMS on the batts from turning off when you connect your battery to the controller.

There really isn't much to worry about hurting these batts as long as you aren't hitting them with a sledge-O-matic :lol:

The BMS is touchy, but that's a good thing. They protect themselves very well and they reset very quickly if you trip the "circuit breaker" in the BMS.

I have literally dropped one of my 28volt packs with my custom mounts glued to the bottom 3 feet onto a rough concrete patio to make sure the ABS pipe glue I used was strong enough, and not only was the battery not hurt, the glue held with out a hint of it coming apart.

Check out the last page of Kin's post for pics the simple design he came up with for his battery mounts, very easy and not too hard to do with just basic tools and a little time.

But if your a maverick like me, and want to do something more difficult, check my post out for the progress of my dewalt battery mounts here:
http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=14912&p=224318#p224318

Something else I wanted to pass on, for those who are using Kin's circuit boards, when soldiering the the male connectors to the boards, just plug the board (with provided plastic spacer) into your battery at the same with with the male connectors. Now you have the perfect jig to hold them still while you soldier them into place. 8)

I want to make sure I take the time and give credit where it is due, I have been standing on the shoulders of giants here at ES, if not for all the helpful people here, I doubt I would have felt comfortable doing this at all. :bow: