Help needed with Lipo battery selection

[gavztheouch]

Hi I am looking for a new battery for my ebike. I would like to try Lipo batteries from hobby king I have picked out a couple of batteries and a charger from hobby king and was wondering if someone who knows about lipo could look over my selection and tell me where im may be going wrong.


Batteries?
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=32216
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=34830

These batteries are 5 cell 18.5v so I would need 2 packs to give me 37v for the bike. Each pack is 8000mah so 2 packs together at 37v should hopefully still give me a 8AH 37v battery for 100-120 pounds. Just two packs should mean easy charging, wire managment and battery changes

Charger?

http://www.hobbyking.com/hobbyking/store/__20613__Turnigy_MEGA_400Wx2_Battery_Charger_Discharger_800W_.html


Many thanks
Gavin

 

[Deleted member 4366]

That stuff is OK. I've never used that charger. I started on the cheapo Imax chargers, which work. Then I got the BC168 charger that charges through the balance leads, which makes it very convenient. It's effectively six single cell chargers in one box.It's very quick to balance the cells that way.
http://www.ebay.co.uk/itm/BC168-RC-Model-Super-Speed-Li-ion-Li-Polymer-Li-Fe-Hobby-Balance-Charger-BC016-/261247122104?pt=UK_ToysGames_RadioControlled_JN&hash=item3cd38abab8

It comes with a balance board, which you'll need to charge two packs at the same time.

You'll need a monitoring system on your bike to avoid over-charging. A wattmeter is useful for predicting how much range you have left, and a couple of lipo alarms until you can trust your packs and what you're doing with them:
http://www.ebay.co.uk/itm/8S-Lipo-Battery-Tester-Checker-Low-Voltage-Buzzer-Alarm-/290955696228?pt=UK_ToysGames_RadioControlled_JN&hash=item43be4f9864

 

[KirstinS]

For my tuppence it's worth the extra couple of quid and get hard case lipo alarms like this. I keep breaking pins on the other types there is no surround to hold the balance plug in position

They are very loud indeed mind !

http://www.primrose.co.uk/warmawear-deluxe-heated-sports-gloves-for-touchscreen-devices-p-18330.html?cPath=6597_6619&src=list_img

 

[peerjay56]

For my tuppence it's worth the extra couple of quid and get hard case lipo alarms like this. I keep breaking pins on the other types there is no surround to hold the balance plug in position

They are very loud indeed mind !

http://www.primrose.co.uk/warmawear-deluxe-heated-sports-gloves-for-touchscreen-devices-p-18330.html?cPath=6597_6619&src=list_img

That link has taken me to a very nice pair of heated gloves, Kirstin
Touch screen friendly though!

 

[gavztheouch]

Just scared myself by typing "lipo fire" into youtube. Its like having a bomb between your legs. Are lipos really only likely to explode when on charge?

 

[Deleted member 4366]

They only explode when you over-charge them, but they catch fire when you drop them,. Any short in the wiring can also make them burn nicely.

Lipos are a good solution if you want a battery pack less than 8aH for light weight, or if you want to go with a voltage other than 36v or 38v, or if you need high power from a small pack, otherwise they're not worth the hassle. They don''t work out cheaper in the long run because their life is shorter, and you'll probably brick them before that anyway.

LiMnNiCo batteries are still available from China at reasonable prices with a charger, which are plug-and-play - much better for a normal 36v application. I just paid £180 for a bottle battery with includes sine-wave controller and LCD. and charger.

 

[KirstinS]

I just paid £180 for a bottle battery with includes sine-wave controller and LCD. and charger.

Really ? Care to share the link for that - that's amazing price

Thanks

 

[Deleted member 4366]

http://www.bmsbattery.com/36v/567-bottle-ebike-battery-controller.html

 

[pdarnett]

Looks good does that Dave, will you do a review when you get it? Even with shipping its around £190

 

[Deleted member 4366]

I ordered it with some other stuff so the cost went right down to about £160, which is really cheap considering that a sine-wave controller's included with LCD. You then you have to factor in a proportion of the duty as well. On its own, the duty will be about £30.

 

[pdarnett]

Damn you duty! Have you got it then and tried it out?

 

[Deleted member 4366]

Yes, it's fine, but there's always a but.

The O-ring seals between the case and plastic ends were missing, so I used silicone sealant, and the LED window was wrongly installed, so the windows was totally loose and dropped back about 37V. I think the switch that operates the LEDS was too long, which they bodged. I filed it a bit and installed the windows and the LED pcb properly. Now everything is OK. None of this would affect the working of the battery, but in the rain, water would pour in. BMS said that it was not supposed to be waterproof.

 

[KirstinS]

Thanks ! Does the controller support an independent throttle please ? I could not tell

 

[Deleted member 4366]

Thanks ! Does the controller support an independent throttle please ? I could not tell

Yes.

 

[KirstinS]

Final question for you please d8veh - do you is it feasible to wire in a booster battery or is the proximity of the controller/battery coupling preventative ?

Thanks again

 

[pdarnett]

What cells were in there Dave, could you see?

 

[Deleted member 4366]

I didn't take out the cell-pack, but I wouldn't think that the cells are anything special.

Yoy can detatch the controller, so a booster battery should still be possible. I haven't tested that S06S with higher voltage, but, as you know, most are OK with it but not all. The controller is potted, so you can't see or change anything.