Battery distance feedback

Jhorrick

New Member
Thinking about installing a 500W Bafang Mid Drive kit because I think the 1000 would be overkill for me. Looking to get the kind of mileage with the way I ride like I do with my Bionx 500W system. I can get well over 40 miles on a battery charge. They say the trick is getting a battery that has the same or more wattage as the motor installed. The highest battery I see listed is 702 watts 52V 13.5ah. But want to stay in 48V range more for accuracy on display. The 750W or 1000W mid drive does not list a battery with that kind of wattage at least with quality cells. I rode my wifes 350W mid drive bike and has amazing assist and gets about 35 to 40 miles a charge. Just looking for some feedback on what people have experienced with battery life. Going on a Recumbent with only paved trail or street riding, sometimes in hilly San Francisco.

Thanks
 

harryS

Well-Known Member
You might get more responses in the 8Fun forum, which seems more focused on mid-drives. I thought this forum was for the Bafang geared hub motors.

Anyway, I have a 750W BBS02, set to 10 PAS levels and ridden mostly in PAS 1 and PAS2, which will get up to 18 mph with pedaling. With a battery advertised as 48V 11,.5AH, my last range test was 39 miles and the battery is down to 43.5 volts with the display out of bars.

The Bafang battery display is not linear. I had 4 bars after 33 miles, and the next four were used up in 6 miles. I installed a wattmeter today, and noted that I used up 1.6 AH in 30 minutes of riding at 14 mph. A rough calculation suggests my 11.5 AH battery will deliver 9 AH.

I had thought I could expect 40+ miles under moderate pedal assist, but I guess high 30's will be typical. I am a little disappointed, but I have pedalled this bike 20 miles with the motor turned off, so I won't worry about getting stranded.

.
 

George S.

Well-Known Member
People are pushing ebikes in ways they never did three years ago, when I was interested.

One of the things that Eric at Luna recenty tossed out is that the BBSHD is 10% more efficient than the BBS02. I don't know, and I don't know if there are hard numbers. My small direct drive motor is less efficient than my large one, especially going up hills. You don't need capacity versus motor wattage, as much as a high enough discharge rate for the size of the pack.

You want to buy a battery that matches the range you want, for sure. How do you figure that? It's not easy when you consider battery capacity can drop, depending on how you charge and discharge the battery. But if you wanted to go 40 miles with a 700 watt hour battery (48v and 15 AH), you could use 80% of that, or 560 watts, for useable capacity. If you divide that by 40 you get 14 wh per mile. The final element in this equation is how fast you go. The watt hours per mile go up, and fast, as speed increases. To go 40 miles you need to get some experience with the motor and battery, use a meter that totals the watt hours for the ride, see if you are in the ballpark. If you have to, slow down.

Nothing in the sales literature makes this very easy. I average about 14 wh with a Mac front 500w motor and a Golden Motor Pie, 1200w. I average around 15 mph and 18 mph open road cruise.

You can always get a bigger battery. Numbers for the effiiciency of various motors are not easy to find. Riding position matters a lot. Bikes like my cruiser, in the member photo, are terrible. Given that people want range and speed, batteries will have to increase in size. EM3ev and Luna sell huge packs. Don't worry about the calibration of the display. You want a separate meter with full information.

A lot of people say a really well designed torque sensing system extends range, but that may be psychological. As the types of ebikes multiply, some of these things can be tested in the marketplace. You can do exactly what you want to do, right now, but you need to be methodical about it.
 

Jhorrick

New Member
Thanks for the replies and the info. I am using a Bionx 500D system now and can get over 40 miles per battery charge and I ride in level3 assist all the time. I have been having issues with the system and hope they get it figured out. I bought my wife a mid drive bike with a 350W curie drive and was super impressed with its hill climbing ability. She gets great mileage out of a 48V 9.6AH battery and really never rides out of level 1 assist since it has great acceleration. If my bionx system gets straightened out I will stick with it but even though its 500W it can not climb as well as a mid drive in my opinion. What are PAS levels on the bafang kit? Is that levels of assistance or speed settings in certain levels. Again thanks for the replies. My other real question is the battery types PF NCRB GA which gives the best mileage, most say the GA.
 

George S.

Well-Known Member
The difference between NCR-B, PF, and GA is one of trade-offs. The NCR-B is decently priced with a lot of capacity per cell. The PF is good for motors drawing 30 amps, maybe 1500 watts, for more than bursts. The GA is the expensive cell that has great capacity/lb and pretty good performance at 1500 watts.

For a given number of NCR-B cells, you get more capacity than the PF, but less high performance. The GA is a higher performance version of the NCR-B. They are 3500 mAh cells. The PF is around 3000 mAh. For range go for max amp hours in each cell, or get a large pack.

I think there are 5 PAS levels in the BBS, but it can be switched to 9. I have no experience. Setting the PAS in the BBS can be complicated, but there is a lot you can do.

https://electricbike-blog.com/2015/...rying-your-controller-and-losing-your-sanity/

Hope they can fix the Bionx. Supposed to be a great premium motor. I like good hub motors, but they have to be able to climb whatever grades you confront. Luna sells small packs that can be used as a reserve, 3 pounds. Get the Bionx fixed and buy a reserve battery for a seat pack, something like that. A lot of seemingly intractable service or customer service issues end up on this site. Kind of discouraging...
 

fotokot2

New Member
10 months of driving my Bafang8fun Mid motor 500w at 350w level setting. about 3300 km total. Cheap China 320$
LiPO4 36v 20AH battery.
Originally 20km throttle only (no pedals) before recharge. Now: after 10 mo lost 50% capacity and drives only 10km....... Considering to buy new 36v 17 ah using Panasonic 3500mah 50 cells.
 
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Pegasus

Active Member
Hello. I have a Bafang 250w mid-drive motor with 19.2ah battery. I have ridden the bike for about 8 months and have kept accurate figures for my usage. Here is a set from my figures. They are typical of the full set. My system is equiped with Lovo technology which limits/drops the full charging by about 10% and raises the cutout voltage by 10% which means I have a range of about 41.8 to 33.0. The idea of this system is to prevent overcharging and completely draining the batteries. The provider claims it will double the chargin cycles/life of the batteries.

Full Charge 41.6v

1/8 24.6k Diamond Creek 40.6v Used 1.0v

2/8 53.4k Darebin Loop 38.5v Used 2.1v

3/8 42.0k Monty /Kew 36.6v Used 1.9v

4/8 26.5k Koonung/Ruffy Lake 35.4v Used 1.2v

Total 146.5k 6.2v



Full Charge 41.7v

12/8 60.2k Three Creeks Ride 39.4v Used 2.3v

13/8 26.7k Diamond Creek 38.7v Used 0.7v

14/8 49.8k Strathmore 36.3v Used 2.4v

Total 136.7k 5.4v

All the best.