slow rider HK battery selection

[DaveG]

My wife and I are retired and go on bike rides about 15 miles long at about 10-12 mph. We just enjoy a slow ride on blacktop bike paths. Because of health problems we are both having difficulty on hills or against strong winds, we only need help in those situations.

I have looked at the Hill Topper and Leed products but believe they may not have enough hill climbing power at 24 volts and 250W motors. So we are planning to purchase 36V 350W geared front wheels with a lower speed (higher torque) of 260rpm (17 mph max) from Ebikeling at $190.

I plan to use two 5S 8000 mAh Lipo packs in series for 37 volts from HobbyKing. I see HobbyKing has two battery packs that may to work for us. They are from Zippy and Turnigy and each about $62 from the USA HobbyKing East warehouse. I would appreciate any suggestions on this set up and which battery pack would be better for our use?

TURNIGY nano-tech:
Capacity: 8000mAh
Voltage: 5S1P / 5 Cell / 18.5V
Discharge: 25C Constant / 50C Burst
Weight: 924g (including wire, plug & case)
http://www.hobbyking.com/hobbyking/store/__57610__Turnigy_nano_tech_8000mAh_5S_25_50C_Lipo_Pack_AR_Warehouse_.html

Zippy Flightmax:
Capacity: 8000mAh
Voltage: 5S1P / 5 Cell / 18.5v
Discharge: 30C Constant / 40C Burst
Weight: 1054g (including wire, plug & case)
http://www.hobbyking.com/hobbyking/store/__57742__ZIPPY_Flightmax_8000mAh_5S1P_30C_AR_Warehouse_.html

 

[Ykick]

If things are still like they used to be, Turnigy FTW.

 

[Takemehome]

If the hills are sandy or muddy, I suggest you buy a rear motor.
Most of de weight is on the rear wheel = less skid.

 

[neptronix]

Have you read the lipo tutorial in the battery section by chance? are you aware of the risks?

Because otherwise, your application isn't really going to require such a high power or light battery at all. A battery that is actually safe would be better in this situation.

 

[dogman dan]

Yes, for that kit, you might be much better off spending just a bit more for a 36v bottle mount battery in lifepo4, or NMC cells. MUCH safer to have around the house.

But I agree, if you just want it light and cheap, then an 8000mha hobby pack can come in a bit cheaper.

For your needs, don't spend extra on 50c discharge rate. Look for good 5s turnigy packs in the 20c discharge rate category. Select from the USA warehouse if you are in the USA. Not sure if you can get them in 8000mah. But if cheap enough, you could bump the pack size up to 10 ah.

 

[DaveG]

After reading much more about Lipo packs, I am going to take the recommendation to use a safer and simpler LiFePO4 prebuilt pack with built in BMS and supplied charger. I think a 36V 7-10 AH pack would work just fine for our limited use. A few suggestions on a good place to purchase one would be greatly appreciated.

 

[dogman dan]

Pingbattery.com I put thousands of commuting miles on two pingbatteries. Not the cheapest, but a good reliable supplier you can send your money to without a lot of worry.

 

[jose]

I am getting my 36v 8.7Ah Li-ion batt pack as referenced in this thread:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=61608

It's a little project requiring some soldering or welding, but it fit my budget.

Did you go-forward with the Ebikeling kit? I'm considering that kit, so I'm curious how that worked-out?

 

[motomech]

My wife and I are retired and go on bike rides about 15 miles long at about 10-12 mph. We just enjoy a slow ride on blacktop bike paths. Because of health problems we are both having difficulty on hills or against strong winds, we only need help in those situations.

Hi Dave,
It really doesn't work that way. The added system, lite and free=wheeling as it is, adds enough effort to preclude using the bike without some power.
Those of us who go "low and slow", set the road speed with either the PAS or the cruise control(on a lower speed limit setting on the LED display) and add a couple of MPH with the legs.
Your avg. speed will be higher and you will cover more ground and have more fun to boot.

I have looked at the Hill Topper and Leed products but believe they may not have enough hill climbing power at 24 volts and 250W motors. So we are planning to purchase 36V 350W geared front wheels with a lower speed (higher torque) of 260rpm (17 mph max) from Ebikeling at $190.

The way these vendors describe these motors is dumb, maybe because the "24V" motor is aimed at the restricted Euro market.
The motors don't determine power output, although they might limit in high power applications. And there might be some efficiency diffs, but not enough to be factor here.
Remember, Amps(controller) X Volts(battery)=Watts.
The "260" motor means it spins 260rpm @ 36V(unloaded), while the 24V motor is what we call a "201" wind motor, spinning 201 rpm @36V. A 201 will spin 260 @ 48V.
Of more import, they have the speed numbers off.
A 260 motor on 36V will top out at 19 mph, no pedal, no wind and flat. That's a nice top speed for you'all. You can see for yourself here:
http://www.ebikes.ca/tools/simulator.html
Use Outrider standard motor.
I believe the motor in that kit is a Bafang and the kit itself is ok for the money, but some elements are a little dated(like the connectors).
You are correct to use the frt. mount motor, as you don't want to mess with the gears.

After reading much more about Lipo packs, I am going to take the recommendation to use a safer and simpler LiFePO4 prebuilt pack with built in BMS and supplied charger. I think a 36V 7-10 AH pack would work just fine for our limited use. A few suggestions on a good place to purchase one would be greatly appreciated.

While using small Lipo packs with the correct charger is perfectly safe, there have been some recent developments that make it attractive to start out with a "plug and play" battery.
For one thing, the kit controller has a Low Voltage Cutoff (LVC), of 30V, too low for 10S lipo. You could use 9S, like I do(see second link in my sig.), but,...
Recently BMS Battery, the largest vendor in China, is supplying their Li-on(the chemistry you want to use) batteries with Samsung cells at a very reasonable cost.
These batteries are very well received in Europe and highly recommended by UK Guru D8veh (a member here).
Here is thier range of batteries;
https://bmsbattery.com/70-36v-li-ion
Freight on two batteries will add $100 to $140.
If you are interested in going this route, tell me, or better yet, post a pic. of the donnor bikes and I can recommend a style of batt. and a list of small dodads that will want to have(like the spoke wrench).