Battery Range Question

geosped · Oct 14, 2020

Hi,
was hoping someone with experience can answer. I'm about to take the plunge and buy a bfang BBSHD 1000w mid drive kit and install on a full suspension mountain bike. I was wondering what size batteries I should consider. I'm assuming it's almost impossible to guess based on the fact that there are so many variable to account for.

Some Context:
1)I'm 250lbs
2) I live in North Georgia, My favorite trails are Chickopee Woods(cumming GA), Blankets Creek(Woodstock), Yellow River(Stone Mountain), Foe Killer Creek(Roswell). Carter Lake and Bull Run, Doubt that helps anyone but just incase.
3) Off road use only. The mountain trail system I use most often has a 1.6mile loop and a 3.4 mile loop. On a very good day I'll do 5 laps. Which is roughly 17 miles with several breaks in between. The track is mostly technical single track a lot switch backs, roots some downhill I would say the highest climb is 400 yards at a 10% grade. I hate getting off and walking half way up. I always pedal so I wont just be coasting. This is supposed to be fun exercise for me.
4) I understand that Samsung, Panasonic, and LG make the best individual cells. I also understand that Luna Cycle, ebikes.ca and EV3EM out of China also make good quality batteries. So I will be purchasing one from one of these vendors. Any other vendors I should consider? Which cells are the best? I understand that Samsung 30q are very good batteries but for my use case I would rather save a few bucks and get something that can provide me with a bit more range. For example a pack with 3500mah cells instead of 3000mah cells.

Based on the above information what size battery would you recommend? Also how long does it take to charge a 14ah battery at 2a vs 5a if depleted at 70%

I was considering a 10ah, 14ah or 17ah 52v pack. Thoughts and suggestions most welcome.

Thanks in advance for your response.

Balmorhea · Oct 14, 2020

I can't help you with off-road information, but I can tell you that I use about 40 watt-hours per mile on my city commute, with 450 pounds GVW, using bikes with 48V/35A controllers comparable to BBSHD. When I had a BBS02 (48V/25A), I got slightly better watt-hours per mile while moving at a slightly faster average speed, with the same load. Like 32-35 Wh/mi.

john61ct · Oct 14, 2020

Get familiar with the Grin simulator, eliminates lots of the guesswork

uuhoever · Oct 14, 2020

I have a BBHSD and use a 48v 10ah battery and I only do trail riding. My regular loop is 12 miles or so with steep incline for 2 miles, and gentle uphill for 5 miles, 5 miles downhill. That gets my battery from 90% to 20%. I weigh 200 lbs. I think my bike weighs 60 lbs :lol: Oh yeah, I do have 2 batteries so on 12+ mile rides I carry both and switch them when one reaches 20%.

I'd go with the 14ah+ so you can easily bike your 5 laps and keep your battery within the 80%-20% charge rate for longevity.

Grautuefel · Oct 14, 2020

EV3EM have provided great service and communication for me, best battery build quality and tech that I've seen. There's even an (older) video of their factory. Its definitely not a grubby humid sweat shop in some Guangzhou basement.

The 20ah pack I got will take my 250kg (it's two people and two dogs!) yuba mundo a little under 100km with some pedaling

Apologies for the OTT commenter in the video
[youtube]oNfTEHBz_bg[/youtube]

qwerkus · Oct 15, 2020

Easy answer: get the largest 3.45mah cells battery your money can buy and that fits in your bike frame. For newbies there is no such thing as a too large battery.

dogman dan · Oct 15, 2020

What you want for sure, is to get that battery mounted in the middle of your bike frame if at all possible. I couldn't because my old Y frame bike simply has no triangle to put it in. I rode with the luna wolf battery on a rear rack, and simply had to live with how it screwed up the ride on single tracks. In short, I had to give up riding some of the hardest trails, desert rock staircases that tend to throw you over the bars into cactus.

DO get the best cells you can, so a 10 ah has less size and weight, if that is what fits on your bike. Dont go with a battery over 10 pounds if it cannot fit in the frame triangle.

Range varies immensely, but it sounds like you can still pedal hard. Lots of us got into e bikes because of age, illness, old ski or football injured knees, etc. Sure we can pedal, but for me if I pedal too hard I tend to re injure that groin I pulled three years ago. So I'm real happy if I get a ten mile trail ride out of 10 ah. But you might easily get double that, by riding not much faster than before, and pedaling hard still.

So what I'm saying, is you might want the smaller ah size, so the bike handles great still, but modify your riding style so you don't blow your range too much on the uphills. Mid drives shine at this, they can still get great efficiency at lower speeds. This riding a bit slower, using 500w average instead of 1000w average will double your range, partly because your pedaling effort of 200w or so is a bigger percentage of the total used if you only run at 500w. ( 300w motor, the rest pedaling)

To figure charge time, at first the battery pulls hard on the charger, but the last 10% it slows way down. So basically do the math, then add about an hour. Watts is amps x volts. watt hours is amp hours x volts. So 10 ah of 50 volts is 500 watt hours. A 2 amp 56.4v ( 48v nominal) charger will put out about 112 watts. At 5 amps, about 270 watts.

Same calculation works the other way for range. if you run average of 500w, a 10 ah battery gets you about an hour of riding, but only 30 min at 1000w drain.

The easy answer is you want the 5 amps charger for sure, so you can charge in 2-3 hours. Otherwise, you end up going to bed with the charger still running. Don't go to bed on a running charger, unless its outside the house.

ZeroEm · Oct 15, 2020

" dogman dan" is from the school of hard knocks. Still feel bad for you. I think about that lesson any time I work with or store a battery.

geosped · Oct 15, 2020

uuhoever said:
I have a BBHSD and use a 48v 10ah battery and I only do trail riding. My regular loop is 12 miles or so with steep incline for 2 miles, and gentle uphill for 5 miles, 5 miles downhill. That gets my battery from 90% to 20%. I weigh 200 lbs. I think my bike weighs 60 lbs :lol: Oh yeah, I do have 2 batteries so on 12+ mile rides I carry both and switch them when one reaches 20%.

I'd go with the 14ah+ so you can easily bike your 5 laps and keep your battery within the 80%-20% charge rate for longevity.

This is very useful information. Exactly the type of info I was looking for. Thank you.

john61ct said:
Get familiar with the Grin simulator, eliminates lots of the guesswork

Yes thanks I took a look at it preconfigured all the settings and the charts looked greek to me it's way off based on the inputs I put in. It predicted a 284 mile range, I cant figure out how to use it correctly, hence why I started this thread. I want to get a real world experience.

I'm just looking for a 220-260lbs Clysdale (weekend warrior) that rides mountain bike trails similar to what I've described that also runs a BBSHD 1000w to tell me what type of pack he's running and how many miles he's getting out of it. I think a real world experience is going to get me a lot closer to what the simulator is going to guess but that's my opinion.

E-HP · Oct 15, 2020

geosped said:
I'm just looking for a 220-260lbs Clysdale (weekend warrior) that rides mountain bike trails similar to what I've described that also runs a BBSHD 1000w to tell me what type of pack he's running and how many miles he's getting out of it. I think a real world experience is going to get me a lot closer to what the simulator is going to guess but that's my opinion.

Hmm, I think my bike uses 10W just sitting idle (probably the same propulsion as standing on the pedals and fartng), so pedaling 284 miles with no assistance would suck.

geosped · Oct 15, 2020

dogman dan said:
What you want for sure, is to get that battery mounted in the middle of your bike frame if at all possible. I couldn't because my old Y frame bike simply has no triangle to put it in. I rode with the luna wolf battery on a rear rack, and simply had to live with how it screwed up the ride on single tracks. In short, I had to give up riding some of the hardest trails, desert rock staircases that tend to throw you over the bars into cactus.

DO get the best cells you can, so a 10 ah has less size and weight, if that is what fits on your bike. Dont go with a battery over 10 pounds if it cannot fit in the frame triangle.

Range varies immensely, but it sounds like you can still pedal hard. Lots of us got into e bikes because of age, illness, old ski or football injured knees, etc. Sure we can pedal, but for me if I pedal too hard I tend to re injure that groin I pulled three years ago. So I'm real happy if I get a ten mile trail ride out of 10 ah. But you might easily get double that, by riding not much faster than before, and pedaling hard still.

So what I'm saying, is you might want the smaller ah size, so the bike handles great still, but modify your riding style so you don't blow your range too much on the uphills. Mid drives shine at this, they can still get great efficiency at lower speeds. This riding a bit slower, using 500w average instead of 1000w average will double your range, partly because your pedaling effort of 200w or so is a bigger percentage of the total used if you only run at 500w. ( 300w motor, the rest pedaling)

To figure charge time, at first the battery pulls hard on the charger, but the last 10% it slows way down. So basically do the math, then add about an hour. Watts is amps x volts. watt hours is amp hours x volts. So 10 ah of 50 volts is 500 watt hours. A 2 amp 56.4v ( 48v nominal) charger will put out about 112 watts. At 5 amps, about 270 watts.

Same calculation works the other way for range. if you run average of 500w, a 10 ah battery gets you about an hour of riding, but only 30 min at 1000w drain.

The easy answer is you want the 5 amps charger for sure, so you can charge in 2-3 hours. Otherwise, you end up going to bed with the charger still running. Don't go to bed on a running charger, unless its outside the house.

Thanks for the info. Yes I agree. I specifically picked a full suspension bike that had the rear shock behind the triangle to maximize space. See pic. Thats a template for the Luna 13.5a pack which from what I understand is a bit bigger than other similar size pack and it seems to fit my triangle with a bit of room to spare. I crossed checked those measurements and it's smaller than the 17ah pack that EM3EV pack. Was also considering a hard triangle pack as they seem a little cheaper based on the same mah capacity. The other thing I was considering is going from the BBSHD 1000w mid drive to the 750w BBSH02 as it's a bit less powerful and lighter. I'm not sure if I really need 1000-1500w of power for trail riding. On my rear hub e-bike with a lot of weight in the back 1200w was a bit too much. I have to say it was a little sketchy but on steep inclines it did provide enough power to climb over anything.

uuhoever · Oct 30, 2020

I believe the battery packs SLIDE into the cradle tray that is attached to the bike frame. You have very little clearance to do that. Just something to think about and double check.

MadRhino · Oct 30, 2020

Short rides, lots of rides. Says to me: you can charge between rides. Then you can carry less weight, making better handling and lighter bike.

I prefer RC lipo. High C-rate. Some can be charged in 5 minutes. I charge just before riding. I charge often. I never charge unattended. I make the batteries modular, meaning I can carry 8, 16, or 24 A/h at will.

john61ct · Oct 30, 2020

Hot new vendor in LiPo's

not the "highest" actual C-rates but very respectable

and blowing everyone out of the water on value for money

https://www.rcgroups.com/forums/showthread.php?t=3683649

John in CR · Oct 31, 2020

john61ct said:
Hot new vendor in LiPo's...
and blowing everyone out of the water on value for money...

Few have the discipline that MadRhino has with his batteries. Far too many experienced users here on the forum have had RC Lipo fires, so they have negative value for any amount of money, and to suggest their use especially to someone new to ebiking is like these days suggesting that someone attend very crowded indoor events where masks are prohibited.

MadRhino · Oct 31, 2020

Lico chemistry is the most common EV battery today. Only it is in the form of hard casing round cells, that is turning a fire danger into an explosion danger. Of course they are commonly small and protected with a BMS, but that is an illusion of safety. Round cells fires and explosions are more frequent than RC lipo fires already. Soon, they will be the vast majority.

Of course there are safer chemistries. Yet if one is going to use lico, modern prismatic cells are safer than round cells. But, more expansive yes.

Battery Range Question

geosped

100 W

Balmorhea

100 kW

john61ct

1 TW

uuhoever

1 mW

Grautuefel

100 W

qwerkus

10 kW

dogman dan

1 PW

ZeroEm

1 MW

geosped

100 W

Attachments

E-HP

10 GW

geosped

100 W

Attachments

uuhoever

1 mW

MadRhino

100 GW

john61ct

1 TW

John in CR

100 TW

MadRhino

100 GW

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