Cordless Tool Packs (DeWalt 60V in Particular)

BatJ

10 µW
Joined
Nov 5, 2017
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6
Looking back through the forum, cordless tool packs has been discussed and aren’t particularly cost effective but I can’t find an answer to my question.

There’s a user on Pedelecs who uses a 6s1p, 2.5ah pack for his 10 mile commute and that would suit me fine although I’d like to use a DeWalt pack off the shelf as they’re compatible with my tools, safety, warranty, solid BMS, solid charging, chargers at my destination, can carry a second or third pack if I’m going further. I also only need a very light pedel assist.

It looks like the 60v DeWalt packs need a FlexVolt tool to switch to 60v mode. Someone even managed to brick a pack trying to activate it. That rules out a 54v 3ah Setup.

An 18v nominal controller doesn’t appear to exist, am I right? That rules out an 18v 9ah Setup.

If I went for two 18v packs in series with diodes across them, would I need to be certain they were both at the same voltage before putting them back on the bike? That rules out partial charges at my destination.

I think I’m asking for the impossible?
 
If they're not the same state of charge, then the less-charged of the packs will limit the range.

It wouldn't actually matter if they were the same voltage if in series (only in parallel).


They sound like a PITA to use for anything other than the tools they were made for, though. You might end up having to take a tool apart and use the tool to provide the power to the bike. Seems expensive. :/
 
Spinningmagnets wrote an article here:
Blair’s E-Cruiser, using DeWalt cordless tool battery packs
https://www.electricbike.com/dewalt-cordless-battery-cruiser/
No mention of any diodes used.

Another one:
DIY: Home Made Electric bike battery box with cordless tool Dewalt/Milwaukee battery by vuaeco (length: 19m39s)
Skip past intro to ~4:08. No diodes here either.
At ~10:58 he shows using 1 Milwaukee + 1 Dewalt in his battery box.
https://www.youtube.com/watch?v=izBDbKbOj9w
[youtube]izBDbKbOj9w[/youtube]
 
First where do you live ? And what motor do you want to run. Also very important what controller do you want to use. It is called a controller for a very important reason after we know this we can decide the strength and the power of a battery you need pause how much you weigh and is going to be flat or Hills if it's Haley well you need a bigger battery then if it's flat Terrain.
If you're always going downhill it would take very little battery but if you're always going uphill you will need two to three times as much battery
 
Thanks for all the reply’s
I only have access to my phone for some time, so it’s hard to reply to each

Amberwolf, the dewalt packs (at least the 18/20v ones) don’t have LVCs. The LVC in the controller wouldn’t sense the voltage of the lower pack would it? It’s not often I wouldn’t have the packs equally charged but it would be something that could go wrong.

Mark5, Blair build is certainly beautiful and it’s been a while since I watched it, but I’m pretty sure he has to monitor the voltage of all six packs. Part of the reason I’d like to use them is due to the plus and play nature.
I haven’t seen the second video, I’ll watch that later.

999zip999. In the south of the UK. Most of my journeys will be less than 10 miles round. I’m not looking to go any faster than 20mph, 15 would be fine. There’s one hill on one of my regular journies but to town and the supermarket is flat. I’m 70kg, 20kg at most for the bike and racks, then add EBike components and my shopping.
I want to use the DeWalt packs, if it can be down safely, so my first thought was a 52v, low amp (PAS levels affect the current draw correct?) controller but as I said above, it looks impractical to use them in the 52v mode. Second option is 18v/9ah but there’s no such thing as an 18v ebike right? So final option, can a series 36v be done safely/Easily
 
BatJ said:
Amberwolf, the dewalt packs (at least the 18/20v ones) don’t have LVCs. The LVC in the controller wouldn’t sense the voltage of the lower pack would it? It’s not often I wouldn’t have the packs equally charged but it would be something that could go wrong.
The controller LVC is for the whole stack of batteries attached to it--it doesn't "talk" to any individual pack in there, so can't know anything other than total voltage.

So yeah, it could go wrong, if the packs themselves have no LVC to protect themselves from overdischarge.

FWIW, it seems quite odd to me for them not to have an LVC, but to obviously have a BMS of some sort (the only way a pack could be "bricked" is if it has electronics inside that get damaged or otherwise shutdown output).

(I used to have some DeWalt NiMH/NiCd packs that had no BMS or other cutoff, but the ones with A123 cells and the generation right after that did have a BMS; not sure if they still use one or not. They might just let teh tools (and chargers) take care of pack management, to reduce costs of the packs. )



Regarding using 18v packs to run a bike--you could, but you'd need to alter the LVC of the controllers, if using ones that have one above an 18v's lowest safe level.


Alternately, you can use controllers that don't have an LVC; there's at least a few really cheap types out there for scooters and such. Some brushed, some brushless. But some of those also dont' have current limiting either, which might cause you some issues. I don't recall ATM which specific ones, but some of the places that sell cheap scooter stuff probably have them.
 
Excerpts of Syonyk's Dewalt 20V Max teardown & analysis from here:
https://syonyk.blogspot.com/2016/09/dewalt-20v-max-30ah-battery-pack.html

Syonyk said:
In the middle are some other terminals of interest. From left to right, top to bottom: TH, ID, C1, C2, C3, C4.

A tiny bit of experimentation with packs demonstrates that C1-C4 are actually the individual cell bank voltages, conveniently brought out for my use!
...
One thing of note here: The battery is always connected to the terminals. There is no way that the BMS can cut off current if the pack voltage is low. It's up to the tool to determine the cutoff point and refuse to work below that.

This also means that if you stick something in the terminals, you can get power out. Don't leave it running and drain the pack, but this would be a really easy pack to repurpose should you care to do so. There's literally nothing to do but jam metal blades into the B- and B+ terminals.
 
That’s what I suspected regarding the controllers LVC.
I guess I could fit stand-alone LVC boards between the packs and the series wiring if I went with 36v.

The 18v (not flexvolt) 6ah packs have no LVC and no real BMS, the tool and the charger handle those respectively. I haven’t been able to find out if the Flexvolt packs have them.

If I did find a controller with a 15v LVC and used a 250w motor. 250w/18v=13.9A, much less than the 60A the cells in the 6Ah pack are rated for (30A*2p), let alone the 9Ah pack. But would that even provide any benefit over peddling at a low speed?

Sorry for going off into so many tangents here.
 
The DeWalt "Flexvolt" 60V packs are definitely 15S. They have a clever internal arrangement that is automatically configured as 5S / 3P, or 15S / 1P, depending on which tool they are plugged into. If you charge to 4.2V per cell, the top voltage when fully charged is 63.0V...

That being said, I really like the 14S / 56V EGO packs very much. I can verify that they are 14S. The individual cells are sleeved with a type of "phase change material" (PCM) where it can absorb a significant amount of heat from the cell during peak draws (it converts from a solid to a soft rubber), and then it sheds that heat over time. The packs spread the cells out just enough so air can be fan-circulated through the pack during charging and also discharge.

They definitely use high-amp cells to reduce the amount of heat that is generated in the first place. You can get them in 5.0-Ah and 7.5-Ah sizes. I have the mower and the weed-wacker, and I'm very pleased with both.

https://www.electricbike.com/cordless-tool-batteries-for-ebike/
 
spinningmagnets said:
The DeWalt "Flexvolt" 60V packs are definitely 15S. They have a clever internal arrangement that is automatically configured as 5S / 3P, or 15S / 1P, depending on which tool they are plugged into. If you charge to 4.2V per cell, the top voltage when fully charged is 63.0V...

That being said, I really like the 14S / 56V EGO packs very much. I can verify that they are 14S. The individual cells are sleeved with a type of "phase change material" (PCM) where it can absorb a significant amount of heat from the cell during peak draws (it converts from a solid to a soft rubber), and then it sheds that heat over time. The packs spread the cells out just enough so air can be fan-circulated through the pack during charging and also discharge.

They definitely use high-amp cells to reduce the amount of heat that is generated in the first place. You can get them in 5.0-Ah and 7.5-Ah sizes. I have the mower and the weed-wacker, and I'm very pleased with both.

https://www.electricbike.com/cordless-tool-batteries-for-ebike/


Just a shame you can’t easily access that 15S mode.
Also I believe the DeWalt charger defaults to 4.1V a cell.

The Ego packs do look good but I’m not already invested in those unfortunately.
 
It is difficult to standardize on one battery tool line. I gave up, and keep it to a few, but the one-does-it-all just doesn't work out.

Ego has some really excellent yard tools. They are superior in the high power segment needed for these type tools. It is clear from their battery design that they really understand how to work with Lithium power. The leaf blower is quite excellent, and the chainsaw and string trimmer are quite good. The DeWalt I used before doesn't compare at all.

DeWalt has a history of jerking their designs (and quality) around periodically and so I've moved on. The multi voltage battery gimmick is a recent example of this. They had some nice A123 packs but they messed that up years ago. More consistent vendors like Ryobi have more of the tools that I need and more consistent long product life cycles. Ryobi seems to have the only small drill-style compressor and it is really excellent for small tires and compressed air needs that I have. Most of my DeWalt tools end up having a problem of some kind and none of them seem to work anymore. I bought a DeWalt 18V contractor grade drill and the motor controller whined so loudly that my family complained, and the bearings were poor. The Makita was far superior, so that Dewalt went back for refund. Between Makita, Ryobi and EGO I think I don't need the DeWalts.

In the 60V class, EGO is a really good choice.
 
I'd have to find the reference but...the reason Greenworks went to 80V is so they could use lower-current cells, which cost less. The cells are not bad cells, but...they are not high current.
 
It's easier to have one pack of the same voltage and more than enough amperage hour that you need then multiple packs that must be all of the same voltage all the time. Last chance for trouble. 36v or above battery. Do you want a battery hobby or a ez running ebike.
 
999zip999 said:
It's easier to have one pack of the same voltage and more than enough amperage hour that you need then multiple packs that must be all of the same voltage all the time. Last chance for trouble. 36v or above battery. Do you want a battery hobby or a ez running ebike.

Yup, that's why I was hoping to get by with one of these Greenworks 80v packs. But I need something that can handle 40Amp peaks and based on Spinningmagnets response, it sounds like I would wreck these things.
 
Let's start from the beginning. What do you want the bike for how many miles ? is it for hills is it 4 Flats how much do you weigh ? You can get away with a 36 volt maybe 8 Amp Hour battery at the smallest. With a 15 to 20 amp controller. A 750watt bike ? Maybe this is something more like you need. Maybe looking at it from a different angle we might get a better answer for you .
 
amberwolf said:
Alternately, you can use controllers that don't have an LVC; there's at least a few really cheap types out there for scooters and such. Some brushed, some brushless. But some of those also dont' have current limiting either, which might cause you some issues. I don't recall ATM which specific ones, but some of the places that sell cheap scooter stuff probably have them.

Or you could the 18v nominal input into a DC boost converter while using a regular controller. I think mine will accept input voltages from 10V to 60V and output up to 90V. The boost converter I'm using also has a configurable LVC. I think most do. Some even make it easy to set via an integral digital display.
 
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