Using cordless drill batterys

Batteries, Chargers, and Battery Management Systems.
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Bmckelvie   1 µW

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Using cordless drill batterys

Post by Bmckelvie » May 02 2017 7:53pm

I am looking into building a 36v 500w trike.
I am already heavily invested in Milwaukee m18 cordless tools, so if possible I would like to keep the same battery format and be able to use the charger that came with then. My idea it is to use 2 m18 9ah Milwaukee packs in series to get me to 36v.

My questions are:
Is this a good I idea? Has anyone had any experience doing this? Will it damage the batteries?

Thanks

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Sunder   1 GW

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Re: Using cordless drill batterys

Post by Sunder » May 02 2017 8:31pm

If I could find blanks for the tool side of Ryobi One+, I probably would have done the same thing. Instead, I've gone the other way - My Ryobi lawnmower is driven by my bike battery.

I haven't seen inside a Milwaukee pack, but most of the known brands are made using high quality 18650s, so should meet the requirements well. I would lower my expectations for pack longevity though. Power tools generally aren't used continuously for long periods, so these packs are usually not well ventilated and cooled.
eBike: Q100H on 16S with Phaserunner FOC Controller
eMotorscooter: Vectrix VX-1 Died... Electrified Ninja in Progress!
eCar: Mitsubishi Outlander PHEV... Warramty expired. Still not game!
eHouse: 6.2kw On-grid solar with battery backup coming soon!

After 5 builds, the best advice I can give, is start with high quality products. I prefer http://www.ebikes.ca

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Icewrench   10 kW

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Re: Using cordless drill batterys

Post by Icewrench » May 02 2017 9:27pm

viewtopic.php?f=14&t=69889&p=1054967#p1054967

Using tool packs can be done. As mentioned e bikes pull more amps than most hand tools so 2 or 3 in parallel would be a good approach.

Bmckelvie   1 µW

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Re: Using cordless drill batterys

Post by Bmckelvie » May 03 2017 9:40am

Thanks for the replies.

My quick math for figuring out the amps required gives me 500w / 36v = 13.9 a.

Does that mean that I should try to get to over that value in amp hour ratings on battery pack (in parallel)?

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spinningmagnets   100 GW

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Re: Using cordless drill batterys

Post by spinningmagnets » May 03 2017 10:19am

You can Google DeWalt electric bike, he used three 5S /20V packs to make a 15S / 60-ish volt pack. He has several videos detailing the process with very useful tips.

If someone was determined to use a cordless tool pack, I would urge them to seriously consider the EGO "56V" 7.5-Ah lawnmower packs. They are 14S, which various ebike vendors have called 50V or 52V. The cells inside are each covered with a heat absorption sleeve to prevent heat spikes during peak loads, and the cells are configured for good air circulation, along with the PCB being fully potted and water-proof.

I don't know anything about the cordless tool 36V batteries, but I recall Worx, DeWalt, and Black Decker, etc make a 36V pack (Worx calls it 40V, but...).

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Icewrench   10 kW

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Re: Using cordless drill batterys

Post by Icewrench » May 06 2017 5:17pm

Bmckelvie wrote:
Does that mean that I should try to get to over that value in amp hour ratings on battery pack (in parallel)?
The DeWalt 36 volt tool packs have an internal potted fuse that will blow if too big of a load is applied. Maybe that fuse was 10 or 15 amps? I do not remember the exact rating.
Using a single pack to supply a 20 amp controller would pop the fuse.

Try to find the max amps the packs you want to use will supply.
If the controller is rated for 22 amps it will likely draw 30 to 40 amps for a split second on start ups. So a pack that can supply a steady 30 amps might be a build target.
If your tool pack can supply 10 amps then 3 parallel and 2 series could work.

Amp hours of capacity is like how big is the tank of electricity.
The old DeWalt 36 volt packs were 2.3 amp hour capacity so 4 parallel was not quite 10 amp hours.

Hillhater   100 GW

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Re: Using cordless drill batterys

Post by Hillhater » May 06 2017 6:04pm

Using tool packs can be / has been done but as described above, you will likely need 4, 6, or more to safely meet your power and range (run time/distance) requirements,
You will need to find multiple battery connector "sockets" from somewhere to retain the pack attachment facility.
This forum owes its existence to Justin of ebikes.ca

Firedog   10 W

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Re: Using cordless drill batterys

Post by Firedog » May 27 2017 1:41am

IMG_2025r.jpg
Mountain bike conversion
IMG_2025r.jpg (149.18 KiB) Viewed 1504 times
IMG_2026r.jpg
1984 Univega road bike conversion
IMG_2026r.jpg (136.48 KiB) Viewed 1504 times
Tool batteries are great for ebike power. My experience is with Genuine Makita 18V and much cheaper Chinese clones sold "for Makita". But, I think you can expect the similar result from DeWalt's and other quality tool makers.
I've converted 3 tandem using 36V 800W front hub kits and a bunch of single bikes using 36V 500W front kits. The tandems have six battery slots (2s3p), the singles 4 (2s2p). The batteries load and lock just like putting a battery on you drill.

The advantage of using tool batteries.
1. Cost
2. Rugged construction and designed to be abused, dropped.
3. Very high amps with very little voltage drop.
4. Fast recharge: typically 30 to 45 minutes in a Makita charger(battery is fan cooled during charging). Newer Makita batteries balance charge each cell.
5. Flexibility. Just carry the # of batteries you need. If your trip is less than 10 miles, two 5ah batteries will get you there. If you need to go 40-50 miles, mount 4 and carry 4 in a bike bag. Why carry the weight of a big battery if the trip is short?
6. You can use also use the batteries in your tools.
7. Tool batteries have long warranties. Makita; 3 years. I haven't had one fail, but I understand it's a full replacement.

Genuine Makita 18V Li Ion batteries use ten, 2.1ah/cell Sony SE US18650vt4 in the 4.0ah battery; ten, 2.6ah/cell SE US18650vt5 in the 5.0ah battery. These Lithium nickel manganese cobalt 18650 cells are rated at 30amps continuous; 60amps peak/cell. Since these batteries are 5s2p, 60amps continuous is available. When I ride with only 2 battery, the range is cut, but the performance is not. On the 500W single bikes, I see 800 to 900 watts (22-25amps) accelerating from a stop and on hills, even with only 2 batteries.

Don't expect the full AH rating of printed on the battery. The Sony cells do deliver the 2.1ah and 2.6ah promised, but only under the following conditions. Charged to 4.2v/ cell then discharged at .5A/cell to 2.5 volts. Makita's chargers don't charge cell to 4.2v , but 4.05 to 4.1v. This knocks off some capacity, but increases the number of recharge cycles significantly. (remember, they promise 3 years!) Bikes and tools use a lot more than current than .5A/cell and most controllers cut off at 20v (3.0v/cell). You should expect about 85% of the rated capacity of a new battery in actual use. That will decrease over time. Ebike battery builders do the same thing. They rate the battery using the specs of cells used.

The Chinese copies are less than half the price of genuine Makita batteries. There are 2 kinds.

The first uses chinese made 18650 cells that are built to have low capacity and discharge rate and very are cheap. They may work in your drill if recharged often, but would be terrible on an e bike. If you ask the seller what cells are inside, they usually won't answer.

The second kind is worth considering. Billions of 18650 cells are produced each year by Sony, Samsung, LG, and few others. Millions do not pass the QC test; low capacity, voltage too low at high rate. They are graded (#2 #3 etc). #2's don't miss specs by much. Most Chinese battery companies don't actually make cells, but put a new wrap and label on "fails" from Samsung, etc. Samsung won't allow a re-label to say "Samsung", so it's gets no label, a private label, or its made to look like another major brand. 99% of the time "these new cells" are sold with greatly inflated specs. The ones I tested were Samsung cells 2.1ah 25amp cells wrapped and labeled to look like 2.5ah 25amp LG cells. To avoid counterfeit laws, 1 character of LG's label is changed. When you ask the seller of the Makita clone batteries, he say they use genuine Samsung or LG cells. Ya, sort of.

Pictures are of a 1984 Univega Superstrada conversion, and a 90's mountain bike.

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minnemike   1 mW

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Re: Using cordless drill batterys

Post by minnemike » Apr 19 2019 10:41am

Firedog wrote:
May 27 2017 1:41am
Tool batteries are great for ebike power. My experience is with Genuine Makita 18V and much cheaper Chinese clones sold "for Makita". But, I think you can expect the similar result from DeWalt's and other quality tool makers.
I've converted 3 tandem using 36V 800W front hub kits and a bunch of single bikes using 36V 500W front kits. The tandems have six battery slots (2s3p), the singles 4 (2s2p). The batteries load and lock just like putting a battery on you drill.

Sorry for the response to an old thread but I ran across this and had to jump in.

I have a few makita LXT batteries and want to do exactly this! Awesome.

Where did you find connection boards for the batteries to mount the bike? I cant think of anything apart from tearing apart old broken tools if I could ever find them or maybe taking apart chargers (expensive). Seems like the only other option is to wire something up that really wouldnt be very user friendly. Thanks.


SwampDonkey   100 W

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Re: Using cordless drill batterys

Post by SwampDonkey » Apr 20 2019 12:41am

Sunder wrote:
May 02 2017 8:31pm
If I could find blanks for the tool side of Ryobi One+, I probably would have done the same thing. Instead, I've gone the other way - My Ryobi lawnmower is driven by my bike battery.

I haven't seen inside a Milwaukee pack, but most of the known brands are made using high quality 18650s, so should meet the requirements well. I would lower my expectations for pack longevity though. Power tools generally aren't used continuously for long periods, so these packs are usually not well ventilated and cooled.
I have an old 18V Ryobi Lithium pack from 2010. Its by far the most powerful battery Ive ever used of any brand. Both in output and capacity. I also have some brand new Craftsman batteries of equal size, not even close to the old ryobi.

Firedog   10 W

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Re: Using cordless drill batterys

Post by Firedog » May 20 2019 9:55am

Where did you find connection boards for the batteries
PM me for DIY instructions or a quote for me to build one.

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