Advice on ebike upgrade / hill climbing motor

[el_walto]

The town i live in is a giant hill (kamloops bc) and my hub motor does OK up the hills, but sometimes on really steep hills the "gearing" feels very sluggish and inefficient(going 10km at 1300W). My commute to work is about 5KM, 3KM of it is up a large hill. I've used about 4AH by the time i get to work and my battery is starting to get pretty empty.

My batteries are pretty much toast. They provide about 40% of their original capacity so they need to be replaced soon. They start to sag from 52Vdown to about 36V somewhat soon after i start using them. I was thinking switching to a lithium ping 20ah 48V battery, might give me enough more zip to satisfy me.

I was wondering if i could get close to equivalent\better hill climbing by switching to a geared motor, 408, 4011, 5305 or something? I also wouldn't mind a lighter motor but it's not a necessity.

I'd like to keep my current bike frame and possibly switch to a rear motor, my bike has 7 cogs on the back?

I guess I'm just asking if you think i should just buy the 700$ battery and leave it at that, or if a new motor might also be a good investment.

Thanks for any input.

I currently have:
Dual suspension Infinity bike
Front 5304
2x 48V 5AH NiCad batts (with diode between)
35A 48V Crystalyte controller (29 volt cutoff)

 

[pwbset]

There are people here that will tell you "it's a crime" to run a 5304 below 72v. :wink: A 5304 is a tank of a motor (assuming nothing is wrong with it) so clearly it's your batteries that need replacing and it wouldn't hurt to upgrade to a 72v controller also. Have you thought of a "toolpack" battery build? Search around here and you'll see tons of battery build examples. There are also a lot of people that will tell you that a Ping pack won't likely be able to supply a 5304 with the juice it wants.

Good luck! Wish I had a 5304!

 

[johnrobholmes]

A geared motor would certainly be well suited for hill climbing, but I agree that your battery pack needs to be addressed first.

 

[el_walto]

Is there an easy way to setup a charger for the "Tool packs" or do you need to charge each battery individually?

 

[johnrobholmes]

Depends on the setup. Most guys charge individually if the tool pack case is left intact. I took the cells out of the case and just used a bigger charger.

 

[dogman dan]

To really supply the 5304 with enough juice, the tool pack batteries or BMI cells are the best option, and expensive. The ping 48v 20 ah will run your motor, we just don't know for how long, so it could be an expensive experiment. Those cells are happiest at 1 to 1.5 c as best we can tell at this point. They will do 3c, but the test results on the specs are for 1c. quite a few people are running that motor on the 20 ah battery, but it will take years to know how they last under that kind of stress. Two 16 ah batteries and use the diodes is an option. If you buy from ping, email him and buy direct to get the best price. Around $1200 would get you a 72v Bmi 10 ah pack that would no doubt make you very happy, but would require controller upgrades and such. So about $1500 is the tag for that. There is a new vendor on ebay , dy power, that can make you a pack that is 48v 30 ah, and would easily power the 5304 without stressing the cells. That is a cheaper option, but you get to be the guinea pig on the seller.

If you can find a buyer for your old motor kit, geared hubmotors are the best hillclimbers. the Ping 20 ah battery would be a good match for one of those. But the gearmotors are slower than what you have.

 

[Wile E. Coyote]

I've tried various e-bike solution on my hill climb. I think a rear BMC is the way to go.

http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=6067&start=0&st=0&sk=t&sd=a&hilit=nemesis

 

[marvingalaxy]

Li Ping (pingping227@hotmail.com) is a known battery builder on this forum and his price for a 32AH 48V pack is about $1250 with a 5A charger including shipping. The only downsides at this time is difficulty with shipping due to new regulations on lithium batteries and also the most you can draw continuously from this pack is 40A due to the BMS he is using. The good news is that 40A is actually a fair amount of power and the BMS has a 60A short duration rating.

I wish there was an easy way to go to 72V with LiFePO4.

 

[el_walto]

Can you actually run ping packs in series?

If so maybe I should just order 2 36V 16AH packs from ping and a 72V 48A controller from ebikes.

It's also possible i could pick up 6 yardwork batteries and chargers from Canadian tire, but wiring them looks painful.

Does anyone know where to buy the BMC geared hub motors in Canada from?

 

[dogman dan]

I try to keep posts a little short, but often leave out one crucial word. I wouldn't go series with the ping packs, but parralel seems to have been done succesfully with diodes, or bypassing the bms. So I was thinking 48 v with the pings. With the A123 or bmi cells, you can build whatever you want if you have big money. The seller of the hi-power cells is looking shakier that I thought at first. Now there is another seller of the same battery that may be the same guy. Two identities on ebay is sinisterly suspicious of a certain seller.

The easiest thing to do may be to get a ping 20ah 48v, and see how it goes. If you get an ampmeter and can climb the hills with less than 30 amps, you should be fine. If it goes higher, then maybe a gearmotor would be best. The battery will work, it just will wear out a bit sooner. If it's cut in half, that should still be a lot of riding. But a properly matched lifepo4 could go 40-50 thousand miles and still have 70% capacity. If you have the money for it, the 30 ah ping sounds like a good deal. The bms could allways be upgraded to put out more amps later, but if 40 amps is enough, then you have a good set up that will last a long time.

 

[el_walto]

Thanks for all the advise. My bike makes it up the hill OK right now so maybe I won't throw so much money into it. I have a feeling that with a 20AH ping pack the voltage sag will be much less than my 4.5AH remaining capacity NiCad battery(i'm happy with my power for the first 2 minutes of use). A 20AH ping pack should be able to draw 1680W for a couple of minutes i would think, ping said the battery would work well with my setup.

I could always lower the current limit using the cycle analyst to 30A(from 35) if i'm really worried about it.

I'm happy if i get 2 years out of the batteries. I only really need 4-10AH a day so they should last me a couple years.