Batteries - a better approach?

Firedog

10 W
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May 26, 2017
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I find quality ebikes being dumped for a few dollars on Craigslist. Reason? Battery failure and owner's not willing spend $700 for another proprietary battery that will likely fail much sooner than advertised.

I bought a 2014 Izip E3 Dash last weekend. Nice bike, bad battery, very cheap price. Rather than replacing the 48v8.7ah (really 46.8v) battery, I built a simple tool mount for 3 Makita mount batteries. The mount fits nicely in the Izip's battery slot. Since Makitas are actually 18v (5*3.6v), 3 in series is 54V. The Izip and all 48v bikes I've tested work fine (better) at the higher voltage. I'd hoped for increased top speed using throttle mode. It doesn't, but the current is reduced 15% at the 20 mph top speed so the range using 3, 10.5 ah batteries is nearly double the OEM battery. As with any aftermarket battery, the BMS will not report the battery charge state to the display, but voltage based capacity displays are not acceptable to me anyway. I use a Watt meter which displays volts,amps,watts and keeps a true record of ah and wh consumed. Since 3 are in wired in series, it is important that all 3 be in the same state of charge. The LED voltmeter on each battery gives a quick check to help prevent that error.

I use high quality batteries built with 15 LG MJ1 cells (10.5ah), but the genuine Makita or very inexpensive clones will work as well. 3 batteries 10.5ah batteries is 25% smaller, 15% lighter, 39% more watt hours than the OEM Izip battery. The batteries charge off the bike in an hour or so on inexpensive Makita chargers. Long trip? Pack 3 extra. I've used used this system for the last 3 years; thousand of miles on singles and tandems with only one battery failure. That was a ebay, chinese clone. I've previously posted pictures of custom builds using these batteries and buses and usually get flamed. It seem most think tool batteries are not for serious ebikers.

I can make a few extra mounts and I have some 10.5ah batteries, I anyone is interested, pm.
 

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So each battery pack is 5S3P? And they have their own internal BMS? Seems pretty good, depending on the price. But I don't see how this is any better than a purpose-built 15S e-bike battery, since these cordless powertool batteries are often sold at a premium..

How many battery amps are you running them at and how much voltage sag are you seeing? And what is the make/model of those battery packs?
 
Yes, each has a internal BMS. The BMS in true Makita's balances the cells, but the largest capacity available only 10 cells and 6ah. The BMS in the batteries I have built don't balance the individual cells. They use 15 genuine LG MJ1 cells (3.5ah-10a continuous). I've added a 6 pin header to allow monitoring the individual cell sets for my personal use and to allow manual balancing if ever needed. Over a year of hard use and they've stayed balanced, so I don't install the headers my customers builds.

The Izip controller max is 17amps and 3 MJ1 cells are rated 30amps continuous. Not much sag at all. On tandems and higher amp controllers, I like to run 36v...2s2p.

cordless powertool batteries are often sold at a premium

Actually, the genuine Makita batteries and chargers are dumped by dealer buying tool/battery/charger discount combos. The dealers break the package and sell the tools alone, since most users already have plenty of batteries and chargers. Their 10 cell 5.0ah batteries use Sony VT6 cell, balance BMS, and sell for about $55 and continue to drop. The 15 cell batteries I have built cost a few dollars more, and I like to make a profit.
 
Hello

Very nice setup!
I'm considering going the same route, would you care to share how you have constructed your assemble on the frame? Are the battery holders 3D-printed and how is it wired?

Thanks
Terje
 
Just to clarify,...
Are you actually using OEM Makita 10.5 Ah packs ?
I cannot find any reference to them at tool stores. Milwalkee have 9Ah , and Bocsh have a new 12Ah 18v pack, but the costs is ludicrous..$250 ? If you can find them.
 
Hillhater said:
Just to clarify,...
Are you actually using OEM Makita 10.5 Ah packs ?
I cannot find any reference to them at tool stores. Milwalkee have 9Ah , and Bocsh have a new 12Ah 18v pack, but the costs is ludicrous..$250 ? If you can find them.
Sorry for the long delay in answering. I've spent the the summer with wife, RV, and ebikes touring. Fun!

Makita doesn't make 10.5ah batteries.

I use a supplier in China that builds quality batteries to fit Makita and other brand tools. In addition to standard cases for 10 cells(5s2p) they build a taller case that holds 15(5s3p). The 15 cell case allows them to use lower rate, cheaper, Chinese cells since the current is shared by 3 cells not 2. The results in a inexpensive decent performing tool battery, sightly bigger.

If those 15 cell cases are filled with with a top quality cells instead, you get a high rate, high capacity battery perfect for ebikes. I tried several, and the LG MJ1 cell is a great choice. 2, 15 cell batteries give 10.5ah at 36V and can support 30A continuous discharge with very little voltage sag. The cost per wh is much less than half what most pay for a "traditional" ebike battery. Charging is off the bike and very fast. The flexibility of moving one set of batteries between several bikes (tandem, road, trail) and a host of great tools is invaluable. Carrying a couple small spare batteries also a nice option.

I build 36V and 54V bikes. The 54V use three 18v batteries in series. The 36V have slots for 4 batteries (2p2s), but most owners buy and use only 2, 10.5ah batteries. Some buyers prefer Genuine Makita batteries. They usually buy 4, 5.0ah to get decent range.

Construction of battery mounting bus is pretty simple although tolerances must be tight. A sheet of Plexiglas is the base. "T" shaped Plexiglas rails are glued then riveted to the base so the batteries can slide snugly into place. Two "L" shaped rails of copper or stainless steel are riveted and bolted to the Plexiglas to make electrical contact when the battery is in place. A slit is cut in the Plexiglas base that catches the batteries spring loaded locking tab. Done right, there is no vibration or danger of the batteries coming off even during a spill.

Mounting the battery buss varies. On the down tube, use the water bottle lugs and zip ties. On front drive bikes, I use an inexpensive front aluminum rack that attaches to the brake bosses and bottom the head tube (fender mount). The controller mounts to on the underside of the rack and the battery buss on top. It's very compact and efficient to build. I expected the added weight on the front wheel would cause handling issues. So far all builds have handled very well. I will post some pictures when I get a chance.
 

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I love your front rack mounted to brake shoe . I'm a believer in tool packs. Will be getting a makita charger as I find them locally.
 
This is actually a genius idea.

I'd contact makita or dewalt and pitch the idea.

As a way to encourage trades to cycle, etc. You could design a bolt on adapter kit or something.

They could charge batteries on site.

Kudos for outside box thinking

Sent from my CLT-L09 using Tapatalk

 
I've seen several examples of 3D-printing a mount and using several cordless tool packs, works well. For simplicity, I like the EGO 14S packs, which are labeled 56V but we call them 52V. They have 7.5-Ah packs, and are coming out with 11-Ah packs soon for their chainsaws and other large equipment.
 
spinningmagnets said:
I've seen several examples of 3D-printing a mount and using several cordless tool packs, works well. For simplicity, I like the EGO 14S packs, which are labeled 56V but we call them 52V. They have 7.5-Ah packs, and are coming out with 11-Ah packs soon for their chainsaws and other large equipment.

terrafirma is where I got my 3d printed mounts and they are working great. If EGO would have existed (or I knew about them) I probably would have bought the trimmer and mower long ago. But, I chose the greenworks 40v line and now have a trimmer, mower, chainsaw and leaf blower in that lineup. I recently purchased several knock off replacement batteries now available in 6ah format. The other tool format I use is ryobi 18v as I am not a contractor, but I love all the gadgets that Ryobi 18v lineup has. Right now I need a new drill and I am considering Makita, Dewalt and/or milwaukee tools as they also sell 3d printed adaptors to use in Ryobi tools. It's really nice getting dual use out of my batteries. :D
 
Like the idea of this. I have an Izip E3 Dash with a mid-drive transx gta16 motor. Was wondering the reason for the 4 connectors in the battery hookup on the bike. Thinking the one labeled 48 is pos next one over 48 neg. Would the other two be for a different bike model. Would be great to know what they all are for.
TIA
 

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Hillhikerz said:
Was wondering the reason for the 4 connectors in the battery hookup on the bike. Thinking the one labeled 48 is pos next one over 48 neg.

Many battery ports have four blades, just to increase the conductive path through the connector. The ones I've seen in Hailong "shark" packs are labeled + + - -

If you open the battery and look at the connector on that side, you can figure out whether all the terminals even connect to anything.
 
Guess I should have mentioned, the battery and charger were stolen out of my car along with a few other things.
So looking into the tool battery thing or a rack mount battery.

Am trying to not take anything apart. Not able to find a schematic. Hopefully someone with this bike model can chime in with the answer.
 
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