Lithium Polymer instead of LIFePo4 for V 2.0?

[Lenk42602]

Okay, ebike V 2.0 will be ready in several weeks for the batteries. I will be posting updated pics soon. I am exploring any/all options for battery packs. I did some research on the YESA packs, but it seems like their C rate is a little lower than I may be able to find in alternative chemistries for the same or less pricing and stability.
Requirements? Need a 48V, 20Ah pack. Plug and Play, proven track record for durability/stability, and middle of the road pricing seems to be moving me towards this option:
http://66.216.117.91/product_p/48v-lithium-polymer-10.5ah.htm

Two of these packs in parallel would do the trick! Can anyone provide some advice as to whether or not this would be a wise choice?

I was trying to calculate range for just one of these packs on a 48 volt 40 amp controller at full throttle on an X 5303. Does 16 miles seem right for a 170 lb rider on level ground, no wind?

any input would be appreciated. the beast will alive soon......

 

[Lenk42602]

.....the other option is to series two of the 37V 10.5 AH packs.... I would figure a 72 volt controller would do well with ~ 74 volts of battery...but we are getting into hyperspace speeds......

If this configuration was selected, would I be able to get 22 miles range @ say, 35 mph?

need a little refresher course.....

 

[recumbent]

The Lifepo batteries are $200 more per 48V pack and say 1000+ cycles. Twice the life for $200 more, approx. But unproven history from either, but time flies. I had to replace all my NICADS, even $300 was painfull.

As for distance with 37 volts 10 a/h which is what i also have, i get 20 km (16mi) max with some pedalling, But I have li-mn. close but no cigar.

I think they always stretch the distance's, subtract 5km's (3mi) off any claim in my view. Hope that helps a bit.

edit: to convert to milage :?

 

[BiGH]

The Lifepo batteries are $200 more per 48V pack and say 1000+ cycles. Twice the life for $200 more, approx. But unproven history from either, but time flies. I had to replace all my NICADS, even $300 was painfull.

As for distance with 37 volts 10 a/h which is what i also have, i get 20 km (16mi) max with some pedalling, But I have li-mn. close but no cigar.

I think they always stretch the distance's, subtract 5km's (3mi) off any claim in my view. Hope that helps a bit.

edit: to convert to milage :?

the Speed at 48v is a killer - once you're into the 72v + category, its hard to dial back speed. This means you'll chew batteries faster. 72v is fantastic but i'd highly reccommend a Cycle analyst to slow your speed. OR

get two 48v lipo packs, and then make up a set of series and parallel anderson patch leads. That way you can run 96v nominal for a high speed runabout, or 48v for commuting mode. I find 36v a little slow on the 408. 48v is quite nice.

my only concern woudl be that 96 nominal is not 96v at full charge would be closer to 110v. SO you'd want to do this on the new controllers not the old ones.

 

[Drunkskunk]

I just bought 2 of the 37V batteries from them for my bike. Ken, the owner is a good guy, and after I bought the batteries, he contacted me to let me know that the BMS on the 37V batteries shuts down if I used them with a 35amp or 40 amp controller at 74 volts. But he said it would be fine if I ran them in parallel. The BMS can handle 20 amps continues, and so far its been able to handle 30 amp spikes on my bike, but I run a 40X series motor.


You should be fine with the 48V in parrallel. if you want 74 volts, you could move down to the 37v 8.2Ah they have, and run 4 of them, in parallel and series.
For me, Lipo is the answer for now. LiFePO4 cells are still too new and unproven. The technology needs more testing, and its heavier than Lipo. by the time my Lipo need replacing in a couple years, LiFePO4 should be better, and hopefully cheaper.

 

[Lenk42602]

I just bought 2 of the 37V batteries from them for my bike. .

Dskunk - my x5303 showed up saturday - I talked with ken also - after some discussion, we figured for my needs, two of his 37V 10.5 Ah packs would be real nice with a 72V 20A controller. He suggested a switchable relay allowing me to go from parallel ( economy mode) to series (maniac mode) so I can do ~ 40 mph for 20 miles or 20 mph for 40 miles...

I think I like this idea - best of both worlds. Now, What about the packs? Did you use your 37v packs yet? Do you like? Any input would be appreciated.....

Len

 

[Drunkskunk]

yeah, he mentioned that switch. I may eventualy get one. it just sounds too usefull.

So far I love these batteries. I burned up my whattsup meter hooking up the batteries the first time, and then had my volt meter quit, so I can only guess at thier performance, but they seem to be fine. There's a little bit of drop off after the first mile or 2, which is normal for Lipo as they drop to 80% but after that the preformance is flat. after running at full throttle for 10 miles yesterday with the batteries in parallel, they were both no warmer than the rest of the bike frame.

 

[Lenk42602]

Thanks for the reply - keep me posted if you have any more commentary - good or bad.....

My gut tells me this is the pack for V 2.0

 

[magudaman]

You could go with higher price and more DIY by using a123 and get both proven long life and high current capabilities. You could get 66v 9.2 ah for around 800 plus a charger and modification time. With a pack that size you could pull 280 amps continuous.

 

[TylerDurden]

You could go with higher price and more DIY by using a123 and get both proven long life and high current capabilities. You could get 66v 9.2 ah for around 800 plus a charger and modification time. With a pack that size you could pull 280 amps continuous.

Don't forget the safety factor. A few hundred bux could be a lot in the battery world, but not in the fire/smoke damage world.



:?

 

[Drunkskunk]

Don't forget the safety factor. A few hundred bux could be a lot in the battery world, but not in the fire/smoke damage world.



:?

Sure, Lipo are dangerous, but so is gas. Most people think nothing of riding around on a motorbike with a couple gallons of highly explosive, highly flamible gas between there legs, inches from there manhood, but they get nervous about a few pounds of Lipo.

 

[Ypedal]

Gas is predictable....

I could be ( and probably am ) wrong here, but i beleive lipos can spontaniously go for X reasons.. That's what scares me about them.

 

[Lenk42602]

wouldn't a company as large as itelectric.ca ensure the safety of their products before going to market? Liability? If an individual can recieve millions for a scorched crotch from some hot coffee, wouldn't the same be true for this pack?

Strange. Guess I am learning more about the "current" state of battery technology and the industry in general. i just don't want to spend a ton on something that will fail before it is supposed to.

The a123 pack build would at least hold myself accountable. Still alot of money to invest in considering the fact that garage engineer (me) would be responsible for the construction. Unless anyone out there would be willing to build it for me.........

 

[TylerDurden]

The fuel in a motorcycle is one of the minor safety issues compared to the exposed nature of the rider and the failure of auto drivers' ability to see the bikes.

Lipo battery packs and cells are sold with limited-liablity and narrow guidelines for handling. Sony, et. al. recalled the millions of faulty laptop lipos before anybody got killed or an aircraft crashed due to thermal runaway.

Every potential ebiker should be aware of the instability of lipo chemistry. Mishandled lipo can be extremely dangerous. Even new chemistries, while not susceptible to thermal runaway, are capable of damage or death when combined in series for higher voltages.

A number of folks here would build a pack for you... but they might also include a hold-harmless clause as part of the agreement.

Emptor Caveat.

 

[Ypedal]

So can Nicads !!! ( This happened to a chap in Ontario this summer if i recall ) ..

Batteries need to be sized according to application, if you don't know what you are doing Lithium can be a very bad combination, done properly with due care the risk is manageable i think.

Not much abuse tolerance with Lithium Cobalt !!