Searching for small capacity 36V battery packs

[pascal.desmet@telenet.be]

Hello,

Can anyone tell me why it is so difficult to find "off the shelve" 36V battery packs with small capacity? Like between 4 and 7 Ah?
Most water bottle and other types have 10s4P heavy battery packs starting from 9Ah that I'm not interested in. (I only need like 15 km range, light assistance).
Has it got something to do with the C-rate of the 18650 cells used for most of these battery packs?
Can anyone suggest me alternative solutions? I'm not really into welding cells or balance charging RC lipo's...

Pascal

 

[Russell]

Most E-bike batteries are made from low C-rate cells so to get current delivery in the 10-20A range they generally need to be 10Ah+. Most folks also want a range of at least 20 miles so once again 10Ah or more is needed.

For a time I have used a couple of 5Ah 6S hobby LiPo batteries in series (50Vp) as my main battery. I bulk charged them and used two battery medics to balance them. Not the most convenient but also not a big deal either. Otherwise the smallest ready-made battery packs I have seen are these from Batteryspace.com;

http://www.batteryspace.com/high-power-li-ion-battery-37v-6-4ah-236-wh-30a-drain-rate-a-fire-retardant-bag-19-2-----un38-3-passed-dgr.aspx

http://www.batteryspace.com/LiFePO4-Battery-38.4V-6.6Ah-253-Wh-30A-rate-with-PCM.aspx

I don't know of anyone who has used these however.

-R

 

[motomech]

Paul at EM3ev will build you any pack you want.
BMS Battery has a large selection of Batteries. The new models offer Panasonic cells and intergrated controller.
If I were not using Lipo, I would buy one of those.

http://www.bmsbattery.com/123-li-ion

 

[dogman dan]

Go to the home depot or whatever, and look at the latest lawnmower batteries. 36v 4 ah. Pricy though.

Just one won't do for a 20 amps controller, but if you have a 250w bike, ok.

 

[Matt Gruber]

http://www.homedepot.com/p/DEWALT-20-Volt-Max-4-0-AH-Premium-XR-Lithium-Ion-2-Pack-DCB204-2/204311278?cm_mmc=shopping-_-WhereToBuy-_-D25-_-204311278?srccode=cii_15053889&cpncode=33-38037094
20 amps work fine, 2 packs in series, tested by me.

 

[pascal.desmet@telenet.be]

Anyone experience with this Bosch 36V 4Ah Coolpack (1300 gram)?

https://www.buyaparcel.com/p/batteries-and-chargers/bosch-36v-4-0ah-battery-pack-lithium-ion-cool-pack-li-ion-1600z0003c/

not the cheapest if you look at price per Wh, but I suppose reliable plenty charging cycles?

But how about max C-rate for this type? At wich amp would they be limited combined with the tools they are meant for?
Could this work, combined with 250W motor and BMSbattery S06S controller?

 

[bionx 1954]

Hi I have been using the Bosch Batt 620 18V @4A. These are the new Bosch Cool Pack batteries. I use them in series to get 36V. If you can get the 36V 4 A Bosch for 112 pounds that a good price. These cells are really powerful and can do 10C easy. If you are running a 250 Watt motor then you will have no problems. Plus all you need is any Bosch 36 v charger to charge them .Also these are very SAFE batteries, just plug in to the charger , there is no "bms" to worry about, and charger shuts down at around 40.7V insuring long life cycles.

 

[pascal.desmet@telenet.be]

HKM akkutechnik sells Li 36 Volt Rotak battery (used housings, new cells)
also with Samsung cells, good for 5Ah pack for 159,99 €.
HKM akkutechnik claims continuous discharge 40 ah

seems perfect solution for me, except for the expensive 36V Bosch charger maybe.
Any idea what to do with the BMS system (middle 2 contacts)? Do I need to shunt them in order to get the battery working?

 

[bionx 1954]

REAL Bosch batteries DO NOT have a BMS. If you open the case just cut the PC out and wire the plus/minus to the output. You can use a 36v 10S to charge. or a Bosch charger but you need the slide in plate on the battery to charge.

 

[wineboyrider]

Greenworks 40v Gmax battery go for about $125.00 and a nice small 4ah battery I might add and you can mow your lawn with it too. :?

 

[pascal.desmet@telenet.be]

It seems as if Horcura is the European version of greenworks. Looks completely the same, except for the colors.
At this moment there is a nice price deal on the official Horcura website: 69.9€ for the 4Ah battery

http://www.horcura.com/Gartengeraete/Akkus/Horcura-Li-Ion-Akku-A2--4AH-aid56939335.php?id_campaign=6&position=9