Silly battery question:

[chas58]

Would it be possible/practical to wire 3 of these in series to create a 36v 9ah (or 4 packs for 48v) small light short range battery pack for a small hub motor (Q100)? BMS battery seems to have something similar in a 36V9ah battery, but of course they charge about $80 in shipping on top of the battery cost.

http://dx.com/p/9800mah-12-6v-rechargeable-emergency-power-li-ion-battery-for-cctv-devices-100098

Deal Extreme battery:
9800mAh 12.6V Rechargeable Emergency Power Li-ion Battery for CCTV Devices
- Input: DC 12.6V
- Output: DC 10.8~12.6 V 9800mAh
- Comes with AC 100~240V power adapter (2-flat-pin plug)
- Plug: 2.1 x 5.5
- Cost $42 including shipping (cost for 36v: $126 shipped)

BMS's $140 (+$80 shipping) solution (cost $220 shipped)
36V 8AH LITHIUM ION ELECTRIC BICYCLE BATTERY PACK
http://www.bmsbattery.com/36v/514-36v-10ah-lithium-ion-electric-bicycle-battery-pack.html

 

[el_walto]

I would not trust the dealextreme one at all. BMSbattery option is much better, comes with real charger also.

 

[friendly1uk]

I thought you had made a bmsbattery order? It might not effect postage much at all, and as it is only a week since your order, It's unlikely they have sent it yet.

That battery would annoy you. It is not 4s it is 3s, perhaps 3s2p. A 10v battery, not 12v as they claim. El-Walto is right to not trust them.

Your local hobby king no good to you? I know some countries bump the price to cover later disposal costs. Here (in the uk) they would cost about 15% more, but are the right batteries. So pretty much even

Edit: HK in the USA are asking $60 for 10ah 3s (well.. $30 for a 5Ah hardcase) So about 30% more unfortunatly. In the uk you get a 4th cell and it's $22 but I don't think I can help you. It's a heavy parcel.

My 10v estimate is low. It's 11.1v. My bad

 

[SamTexas]

Would it be possible/practical to wire 3 of these in series to create a 36v 9ah (or 4 packs for 48v) small light short range battery pack for a small hub motor (Q100)?

Look at the connector of that battery. It's a 5.5 x 2.1mm power jack. The wiring is most likely 22awg. So the maximum current it can support is about 3A. 3x36
is 108W. So yes, it's possible and no, it's not practical.

 

[chas58]

Thanks for the feedback! Nogo on that.
I’m interested in a light weight 36v battery for commuting. If I charge at work, it probably doesn’t even need much Ah. BMS bat has a small lightweight 36V8ah battery for $130, but the $80 shipping is a killer for me.
Friendlyone, I’ll be in Europe in May, but not sure I’ll be battery shopping. The kit from GreenBikeKit came yesterday – less than a week after I ordered it.

 

[friendly1uk]

A week!? That's extremely quick. I'm looking forward to hearing how well it goes

How far would you get on 3.3Ah? $60 in a US warehouse. 850g http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=21410
Of course, using cells means getting more involved than you really want to. However I suspect your controller will have an appropriate LVC . The battery is already taped together with a balance plug hanging out, waiting for an RC charger of some sort. All consumer kit, and a common approach. There is the complication of a $20 watt meter with built in balance checker if you really want to get involved, but still it's consumer kit.
They might sell a bms, but I think a simple lvc while in use, with balancing only being checked during charging, is pretty normal. It seems quite a few people here follow the same path, with the addition of a watt meter to monitor capacity

You can connect them in parallel to sum them up. 6.6Ah could be the ticket.

It seems a large number of cells arrive DOA. There are threads about it. 5-10% over many purchases for some. The more cells in your pack, the higher your chances of a dud. This is a real issue if they need returning, and the odds are not favorable. Besides which, you need them now

 

[wesnewell]

Buy 3 of these when they get back in stock for 5ah 12s (44.4V nominal, 50.4V charged). Also need a small 6s charger. Total should be under $100.
http://www.hobbyking.com/hobbyking/store/__18631__Turnigy_5000mAh_4S1P_14_8v_20C_hardcase_pack_USA_Warehouse_.html

 

[chas58]

Lipo is looking like an alternative as the 36v battery pack isn't giving much speed and is fairly heavy (may be good for slower long range trips)

 

[d8veh]

Would it be possible/practical to wire 3 of these in series to create a 36v 9ah (or 4 packs for 48v) small light short range battery pack for a small hub motor (Q100)? BMS battery seems to have something similar in a 36V9ah battery, but of course they charge about $80 in shipping on top of the battery cost.

http://dx.com/p/9800mah-12-6v-rechargeable-emergency-power-li-ion-battery-for-cctv-devices-100098

Deal Extreme battery:
9800mAh 12.6V Rechargeable Emergency Power Li-ion Battery for CCTV Devices
- Input: DC 12.6V
- Output: DC 10.8~12.6 V 9800mAh
- Comes with AC 100~240V power adapter (2-flat-pin plug)
- Plug: 2.1 x 5.5
- Cost $42 including shipping (cost for 36v: $126 shipped)

BMS's $140 (+$80 shipping) solution (cost $220 shipped)
36V 8AH LITHIUM ION ELECTRIC BICYCLE BATTERY PACK
http://www.bmsbattery.com/36v/514-36v-10ah-lithium-ion-electric-bicycle-battery-pack.html

What they've done is add up the mAH from each 3.7v cell to get 9800mAH, so that's actually 3300maH at 12v (3s2p guess), so you'd need nine of them to make a 36v 10aH battery. You can buy the individual cells welded up into any configuration from Ebay, but it doesn't work out any cheaper than buying a ready-made battery.