Dewalt 36v Packs, are they worth using?

[everest]

Hi.

Surfing around the net i see a few people using dewalt 36volt packs, is it worth the hassle of using them, or am i better
off buying a ping battery.

I need a 36volts system than can deliver 15-20amps. What do you recommend. There's so many options!!!

The dewalts look good, but i take it you can't discharge them in series or parallel due the bms, the charger only charge 1 pack at a time.

Okay, i may be wrong about *all* of this, however there's so much information out there, it's hard to know what's current. I'd thought i'd ask here and get the latest information..

if dewalts are out of the picture, then what's the best batteries/charger i can use. not an easy question i know.

thanks for the help.

 

[DerekG]

If you only need 15-20 amps continuous I would go with a 15 amp ping battery... cheaper and much easier to work with. The DeWalts I believe use A123 batteries which most people pull out and use to build custom packs. The ping batteries are rated at 2C so even a 15aH battery would not be taxed at 20 amps.

A123's are in another league entirely vs anything except high-rate Li-Poly cells. A 15aH A123 battery at 36volts would be able to sustain 450 amps continuous Then again, an A123 or Li-Poly pack is just a little overkill for a 15-20 amp controller Plus a Ping will charge easily and will probably be more reliable in the long run.

 

[everest]

thanks for the excellent reply. Look like I'll go down the ping route.

Is it possible to charge these strange battery chemistries with solar or wind or any other kind of renewable power.
I know sla it's fairly easy, however is it possible to do this with any other kind of battery?

is it possible to be distcharging into a motor, and be charging them up via solar for instance or is that a problem with anything but sla?

 

[DerekG]

It wouldn't be a problem , however, just know it is going to take a while unless you have a decent sized array of panels. I don't know a lot about solar as I live in a fairly cloudy valley however I will try to help

There are a few ways of charging off of a solar array... or so I believe.

I would think the most reliable way would be to use the solar cells to charge a large SLA deep cycle which would act as a buffer for an inverter which you would plug your charger into.

The alternative would be to build an array which output at the full charge voltage of the pack, (around 44 volts in your case), however, then you would have to worry about putting in a diode inline to prevent backfeeding into the array as the sun changes positions. Not sure how much time you would have to put in... hopefully someone else can help me out

I would say it's possible but it would probably be expensive and thus not very viable. My uncle is going to put up a wind turbine on his property, however, even then quite a bit of control circuitry goes into it as the turbine will only output the correct voltage after a certain RPM speed is reached.

 

[dogman dan]

A very important factor in deciding ping vs toolpacks is how far you ride. For me, it's all about long range. Work is 15 miles away, and coming home it's up hill. On the weekend I like a nice long ride, say 60 miles or so. So for me a ping, or even two is the only way to fly. My motor has a 22 amp controller. If you like 36v, the 20 ah is a handy size to carry and in 48v the 15 ah one is easy to fit in bags or boxes on a rear rack.

But if all I ever needed was 5 mile range, the decision would be much different. Then high discharge rate batteries and much lighter weight would make a lot of sense. So toolpacks or lipo, a123's etc would be great. Why buy more battery than you need.

I do find though, that I'll ride till the battery is gone, no matter how big of one I have. I just like the ride that much.

As for the charging, a larger battery like a ping would take a long time with a good size panel. No way can you carry enough unless you ride just once a week.

You really need to charge lifeop4 through an apropriate charger. I don't know of 36 or 48v charge controllers for solar panels. If you have 24v batteries I believe the charge controllers are common for that voltage. So for a 36v pack it may be more best to use a bank of lead acid, and draw on that with an inverter to run a charger. Lots of losses, and two sets of batteries wearing out.

It's really cool to say your EV runs on solar. But really, I bet there are lots of ways you can save 1kwh a day in you household cheaper than charging solar. Some compact florescent bulbs may save enough power to run the bike. Replacing one leaky window, or fixing the weatherstrip on the door. If you rent, just turn the thermostat down 1/2 degree in winter. If you can afford a larger solar panel instalation, mabye just tie it to the house power instead of trying to charge the bike with solar. That way all the potential power is gathered.

The real eco impact of the electric bike is when you go a lot further than you would on a pedaling only bike. All those trips you don't take in a car have a huge eco impact. Personally I cut my car use by about 30%. I cut my car use to get to work by 70%.

 

[Lyen]

I am one of the long term Dewalt DC9360 commuter in San Francisco. I have chosen the 36V tool packs to attack the hilly area due to higher torque with higher discharge rate plus less weight and less stretch on the batteries on my 10 miles one-way or 20 miles round trip commute. I have tried other Lifepo4 batteries before and the BMS from them tend to tripped when going uphill.

The second advantage is you can add capacity on demand which is very nice if you have different places to go to and only need to carry enough capacity & weight to your destination. This way, you can carry more things and/or go further.

Third, I usually charge my batteries in less than an hour with four chargers at home.

Lastly, Dewalt is an American product and I appreciate if you can support us. You may also get an honorable warranty with no question ask. :lol:

 

[The Mighty Volt]

I have to be honest here.....after paying a Mafia-esque, extortionate fee to have my Cammy units shipped from China vis UPS........they have worked fine for me.

I dragged 16AH out of my 36v 20AH unit with no difficulties...........I only decided to sell when I got to reading about the super-batteries that other members have been building to feed their X5's and their BMC's. I never had any cutouts, or serious sagging. The battery flagged after a 12 mile ride at full tilt when I asked it to go up another hill with 15Ah used. That was it. When I say full tilt I mean, I had that throttle down. Plastic to the Plastic, so to speak.

I got to be honest...the battery worked and they showed up, from China to Ireland, in 4 days.

It's big, heavy, awkward..but they worked, for me.

 

[everest]

thanks for all the replies, some really good info there!

 

[PeteCress]

... long term Dewalt DC9360 commuter...

I'm dabbling in DeWalt right now - two 36v packs.

They work for my application, but I notice that my top speed on battery-only is about 13-14 mph on my 400w eZee rig.
OTOH, I get about 18 mph on my 9C rig using a regular 36v LiFePO4 battery.

Is this tb expected bco the lower voltage?

Or might I be doing something wrong?

 

[Lyen]

... long term Dewalt DC9360 commuter...

I'm dabbling in DeWalt right now - two 36v packs.

They work for my application, but I notice that my top speed on battery-only is about 13-14 mph on my 400w eZee rig.
OTOH, I get about 18 mph on my 9C rig using a regular 36v LiFePO4 battery.

Is this tb expected bco the lower voltage?

Or might I be doing something wrong?

Your running 33V with your 400W eZee motor. I assume your wheel size is 26". So 13-14 mph is to be expected due to the gearing and power output from your eZee motor.

Your 9C runns faster because it is a 500W motor. Also, a typical 36V Lifepo4 battery is actually outputting 38-42v depending on whom you purchased from.

I was able to get 26-27mph with the 33V DC9360 by tuning the gearing, tire size, current output to a 600W motor, as well as aerodynamic.

 

[PeteCress]

Your running 33V with your 400W eZee motor. I assume your wheel size is 26". So 13-14 mph is to be expected due to the gearing and power output from your eZee motor.

Thanks. Actually the speed in question is a-ok for my application. I was just thinking maybe I was doing something wrong.

 

[PeteCress]

I've come a cross a number of posts where it was said that running just a single 36v DeWalt pack was abusing it and at least two, preferably 4, should be paralleled.

For me there's a convenience issue around running just a single pack sometimes.

I'm guessing that the abuse comes from pulling a lot of watts relative the battery's capacity.

Would I be correct in thinking that setting my CA's limit to 13 amps (about 400w) would mitigate or eliminate the abuse factor when running a single pack?

 

[Russell]

... long term Dewalt DC9360 commuter...

I'm dabbling in DeWalt right now - two 36v packs.

They work for my application, but I notice that my top speed on battery-only is about 13-14 mph on my 400w eZee rig.
OTOH, I get about 18 mph on my 9C rig using a regular 36v LiFePO4 battery.

Is this tb expected bco the lower voltage?

Or might I be doing something wrong?

Your speeds, both of them, appear too low, are you sure your speedo is calibrated correctly?

-R

 

[pwbset]

said that running just a single 36v DeWalt pack was abusing it

Abusing the BMS maybe.. the cells could care less if you sucked them dry in a few minutes. There are people that bypass the BMS and slurp gobs of power from these packs. Otherwise buy a single 36v Bosch fatpack... no BMS issues and can sustain 1kw+ easy. Did it all last summer for 2mi round trip blasts to town and back.

 

[PeteCress]

Your speeds, both of them, appear too low, are you sure your speedo is calibrated correctly?

Pretty sure - especially on the 14 mph rig bc it also has a conventional speedo that agrees with the CA.

I would attribute slightly lower speeds to my 220# of lard.

FWIW, on the 14 mph rig, I changed tires last nite - from a Schwalbe Marathon on the front and a WTB Mutano Raptor 55/55 on the rear to a 1.5" cyclocross on the front and a 1.5" slick on the rear and non-pedaling speed increased to 15-16 mph. That increase is consistant with my non-ebike speeds with a similar tire comparison.

 

[Russell]

Your speeds, both of them, appear too low, are you sure your speedo is calibrated correctly?

Pretty sure - especially on the 14 mph rig bc it also has a conventional speedo that agrees with the CA.

I would attribute slightly lower speeds to my 220# of lard.

FWIW, on the 14 mph rig, I changed tires last nite - from a Schwalbe Marathon on the front and a WTB Mutano Raptor 55/55 on the rear to a 1.5" cyclocross on the front and a 1.5" slick on the rear and non-pedaling speed increased to 15-16 mph. That increase is consistant with my non-ebike speeds with a similar tire comparison.

I haven't heard of anyone with a 9x7 9C only top out at 18 mph on a 36V LiFePO4 pack. My top speed was if I remember correctly right around 23 mph on Bosch Fatpacks (41.3V max) running 700C x 35mm tires and most folks with 26" tires get 21+mph. Both your CA and cycling computer should agree if you input the same tire circumference however if that measurement is off they will both be off. Of course when you switch tires you need to enter the circumference of the new tires otherwise the indicated speed will be meaningless (measure inflated tire with string, string w/tape measure then subtract 1%(max) for deflection).

Your weight (220 isn't that much) won't make all that much difference in the top speed on level ground with no wind, the kicker is finding flat ground and no wind :wink: Of course if you are artificially limiting the current to the motor the top speed may suffer though I ran my 9C for a time on 36V/15A and it made no difference, to the top speed anyway, just the acceleration.

-R

 

[PeteCress]

Both your CA and cycling computer should agree if you input the same tire circumference however if that measurement is off they will both be off.

The tire measurements seem tb on the money - I rolled the wheel across the garage floor and measured the distance for one rotation.

Only thing left to do, then, is to put a GPS next to the speedos and see how they stack up. The trick is going to be keeping a steady speed long enough that the different latencies in the devices have time to cancel out.

 

[Russell]

16mph sounds about right with the (2) DeWalts and eZee motor, at least from what I see from the ebikes.ca simululator. With the 9C if your battery sucks, and from your other posts I think it just may, then that could explain your low 18 mph top speed if the speedo calibration is correct..

-R

 

[PeteCress]

Otherwise buy a single 36v Bosch fatpack... no BMS issues and can sustain 1kw+ easy. Did it all last summer for 2mi round trip blasts to town and back.

Did you just hook the FatPack directly into the controller?
EDIT: I withdraw the question, having found the thread "Bosch 36V fatpacks opened up"

The DeWalts, AFIK, need an interface board (either Kin Fong's or one cannabilized from a DeWalt floodlight).

I'm doing pretty well with my two DeWalts so far... but if I decide I want more capacity it's sounding like the third battery being a FatPack might be more cost-effective.

 

[Lyen]

I've come a cross a number of posts where it was said that running just a single 36v DeWalt pack was abusing it and at least two, preferably 4, should be paralleled.

For me there's a convenience issue around running just a single pack sometimes.

I'm guessing that the abuse comes from pulling a lot of watts relative the battery's capacity.

Would I be correct in thinking that setting my CA's limit to 13 amps (about 400w) would mitigate or eliminate the abuse factor when running a single pack?

Yes, running a (I meant only one) Dewalt DC9360 is doable. I actually ran my ebike with only one pack multiple times due to connection/wiring issues (human error). However, you need to understand the characteristic when running one pack or the BMS inside the pack will tripped the protection circuitry. The way and the trick is to ride at less than 6-7mph or pedal along when attack hills. The key to to prevent power draw of more than 15A. You should only do this in case of an emergency like me.

 

[PeteCress]

Yes, running a (I meant only one) Dewalt DC9360 is doable. I actually ran my ebike with only one pack multiple times due to connection/wiring issues (human error). However, you need to understand the characteristic when running one pack or the BMS inside the pack will tripped the protection circuitry. The way and the trick is to ride at less than 6-7mph or pedal along when attack hills. The key to to prevent power draw of more than 15A. You should only do this in case of an emergency like me.

I've been running just one all week. My needs are so low that capacity-wise it's 100% acceptable to me.

But my real question is whether or not I'm going to cause the battery to degrade prematurely by doing this - with the stipulation that the CA limit is set to 13 amps.

 

[pwbset]

But my real question is whether or not I'm going to cause the battery to degrade prematurely by doing this - with the stipulation that the CA limit is set to 13 amps.

You can't possibly lower the battery's cycle life by running it within it's puny 15A BMS limit. You should get 1,000s of cycles being that tame with it.

 

[Lyen]

Yes, running a (I meant only one) Dewalt DC9360 is doable. I actually ran my ebike with only one pack multiple times due to connection/wiring issues (human error). However, you need to understand the characteristic when running one pack or the BMS inside the pack will tripped the protection circuitry. The way and the trick is to ride at less than 6-7mph or pedal along when attack hills. The key to to prevent power draw of more than 15A. You should only do this in case of an emergency like me.

I've been running just one all week. My needs are so low that capacity-wise it's 100% acceptable to me.

But my real question is whether or not I'm going to cause the battery to degrade prematurely by doing this - with the stipulation that the CA limit is set to 13 amps.

If you considered your ebike motor as a DeWalt drill, than your worrying should be gone by now since a motor in the drill draws more than 15 amp in some occasions and also do tripped the battery BMS when drilling hard stuff.

 

[PeteCress]

You can't possibly lower the battery's cycle life by running it within it's puny 15A BMS limit. You should get 1,000s of cycles being that tame with it.

That's what I was hoping to hear. Thanks!