LiFePO4 batteries with a case

[Arbol]

Hello, I am looking around to build my e-bike.

So far, I have been suggested a BPM CST 500W 36V motor is a good one for me.

Since it is a 36V motor, I am looking at 36V batteries. One possibility would go with lipos, but LiFePO4 have good characteristics, too. One issue is very few LiFePO4 have cases. And in most cases, they are with polymer cells, with 15A of max continuous discharge current. Since the CST is provided with the KU123 as the kit, and I believe the KU123 accepts up to 30A in a continuous fashion (please correct me if I am wrong), it seems to make sense to get either Headways with a good BMS, or ping / cell_man.

But then, very few of these have cases. The only one I have been able to find is the "36V 10AH Headway 38120 LiFePO4 Battery Pack", in two webpages:

http://www.bmsbattery.com/packs/114-36v10ah-lifepo4-battery-38120-ebike-battery-pack-with-carrier.html
http://www.elifebike.com/peng/iview.asp?KeyID=dtpic-2011-1J-AMQH.1E8NH

But the description is very scarce. In particular:

- BMSbattery does not seem to provide the option to improve the BMS to 30A / 60A, unlike the equivalent battery without a case (which has 30A / 60A and even 50A / 100A as options). Also, one of the pictures in elifebike shows the inside of the case, with the blue Headways, but I cannot see the BMS inside. Could I order this product, but with an improved 30A / 60A BMS, sitting inside the case?
- How is safety designed on this package? There seems to be a key lock, and also the rack seems to be perfectly suited to the battery case. But is the key lock only to open the battery case? Or is the key also fixing the case to the rack, such that a burglar could not steal the battery case (and the battery inside it) without "breaking" the key lock?

 

[dogman dan]

Back up a step, then find out what your controller amps specification is. Then you can start discussing what battery to buy. For typical bike battery stuff rated at least 2c, 1 ah per 1.5 ah of controller wattage can be ok.

Grin cyclery has some good batteries in a case. Not lifepo4, but a safe chemistry compared to lico (rc lipo).

It's VERY easy to find a box that a pingbattery fits into. I don't get the hang up with the box. Don't get me wrong, you DO definitely need to build something to protect any of the no box batteries.

Cellman, for example, has a pretty good system, even though the bag is soft cover. With his pack, you are good to go to just put it into his bag. With a ping, you'd have to make an inner protective box, before using the EM3ev bag.

Park your bike anywhere, they will take it. Helps a lot if they can't take your expensive battery, because you took it with you.

 

[Arbol]

I think you are right. I almost always carry a soft suitcase with me. Probably the logical step is to use lipos, since they can fit inside my bag. This is unlikely with LiFePO and even with Li-ion.

 

[amberwolf]

I'd use a hard fireproof case if you plan on RC LiPo, for use, charge, and storage. A soft bag does nothing to protect the flimsy packs from damage if the bike falls over at a rack, or is in a crash, etc., and not only can't contain a fire, but would also be burning, exacerbating it. It also can't protect your wiring, preventing a short that coudl start a fire.

As I just posted in another thread for someone else:

*******************
Also, I do strongly recommend with any RC LiPo that you charge/use/store it in a fireproof location. I use ammoboxes with a vent slot cut into it just under the lip of the top for exit of cabling, so any hot gases can escape while displacing any oxygen from inside the box, and prevent any new air from entering, so that a big uncontained fire won't happen. Hasnt' been tested for efficacy yet, but similar containment has been tested (small pack or single cell in a cash box) and it did work for the person testing it (there's a video linked somewhere here on ES about that). There's a thread about ammocan cases, with pics of one by Stochastic and of mine, which is also in my Amberwolf's First RC LiPo Experiments thread, I think it's called.

I store any unused packs/cells in my oven; it might make the oven unusable for food afterward if they did burn, but it would prevent the house from burning with them. Just in case of stupidity, I also take the oven knob off and store it in the cabinet above it, since I do also use the oven to cook stuff.

 

[beast775]

Well this is new to me.http://www.ebay.com/itm/48V15Ah-800W-E-Bike-E-Bicycle-scooter-Waterproof-Lithium-Battery-and-Charger-/121135731211?pt=Cycling_Parts_Accessories&hash=item1c3440920b


case looks pretty good except for questionable cells they use,not powerful enough for you........

 

[Ypedal]

http://ebikes.ca/store/photos/B3609LiF-EZ.jpg

 

[d8veh]

The 500w CST comes with a 30 amp controller. That 10aH Headway pack you mentioned has a BMS that trips at about 20 - 22 amps, so no good. LiFePO4 batteries are heavier and more expensive than LiMnCo (Li-ion). You're right abou the cased batteries. The biggest I've seen is 15aH, which can;t give 30 amps. I wouldn't want to carry lipos round with me. Normally they're safe, but with lots of handling, it's only a matter of time before they get dropped or a wire breaks, or rubs through, which could be disastrous. This is about the lightest battery that can provide the 30 amps, and it's fairly cheap. Myself and my friend have been using them for over a year without problems.
http://www.bmsbattery.com/36v/445-36v-15ah-lithium-ion-electric-bicycle-battery-pack.html

The CST can run at any voltage. The controller can run at 36v, 44v (12S lipos) or 48v. The CST will do about 21 mph with a 36v battey, you can add 2mph by joining the black and green wires on the three-speed switch connector. 12S lipos will increase those speeds by 20%, and a 48v battery a little bit more.

This 48v battery would just about do it, but you'd need a 25 amp 48v controller.
http://www.bmsbattery.com/48v/403-48v-10ah-lithium-ion-alloy-shell-ebike-battery-pack.html
This controller should do the job, but you have to order a display to go with it. I'd get the LCD display.
http://www.bmsbattery.com/controller/552-s06-250w-imitation-torque-square-wave-controller.html

 

[dnmun]

Well this is new to me.http://www.ebay.com/itm/48V15Ah-800W-E-Bike-E-Bicycle-scooter-Waterproof-Lithium-Battery-and-Charger-/121135731211?pt=Cycling_Parts_Accessories&hash=item1c3440920b


case looks pretty good except for questionable cells they use,not powerful enough for you........

duh? you so macho that nothing is good enuff for you but you gotta ask us first?

why do you think they have the maximum charging voltage at 51.4V but say the battery is 54.6V ouput? special chemistry maybe?

 

[d8veh]

why do you think they have the maximum charging voltage at 51.4V but say the battery is 54.6V ouput? special chemistry maybe?

I had to read it a few times before I got it. What they're saying is that the charger's set to 54.6v and the BMS cuts of charging at 51.4v, which seems a bit low.

 

[beast775]