New E-Bike, Please rate my kit choices

[jdwilson4]

Hello, I would like to get everyone opinion on my current kit im putting together

Cruising speed desired: 22 to 25
Max speed: 25
weight:220
Bicycle : 26in mountain bike
Terrain : some small hills
Range: at least 20miles at 20mph

Basic kit:

http://www.ebay.com/itm/371289491857?_trksid=p2055119.m1438.l2649&ssPageName=STRK:MEBIDX:IT

I will never want a higher top speed, but someday i may want to accelerate faster, will this controller support higher voltage ? or would i have to get a different controller?

Batteries:

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=66487

I believe two of these this will give me 48v and 16Ah, is this true? the only reason i went with Li-Po is because it appears to be a little cheaper then buying a complete battery off ebay that comes with charger etc. what do you guys think?

Charger for batteries:

http://hobbyking.com/hobbyking/stor...h_Screen_Smart_Battery_Charger_10A_6S_V2.html

I plan on parallel charging the batteries with this, I really dont want to have to solder anything if i can help it

Final question do i need a BMS for this ? or can i just use a alarm that detects low cell voltage to prevent over discharging the batteries?

Thanks

 

[anoNY42]

I'm not using any of the gear you list, but I just wanted to give you my estimate considering we are both 220 lbs and riding a mtb. I have a 48v 10ah battery and I tend to use level 4 PAS out of 5 and I go 17 miles to work at just over 20 mph with the voltage meter down halfway for the last few miles (not a good indicator of remaining energy, but it's all I have). I pedal constantly, though it feels very easy. I try not to work too hard. My commute is very flat, being in central Florida.

That said, 16ah should be more than enough to get you 20 miles at 20 mph, although the batteries you link state they are 22.2 volt, 2 of which would only be 44.4 volts (unless, as a battery noob, I am missing something).

 

[jdwilson4]

I'm not using any of the gear you list, but I just wanted to give you my estimate considering we are both 220 lbs and riding a mtb. I have a 48v 10ah battery and I tend to use level 4 PAS out of 5 and I go 17 miles to work at just over 20 mph with the voltage meter down halfway for the last few miles (not a good indicator of remaining energy, but it's all I have). I pedal constantly, though it feels very easy. I try not to work too hard. My commute is very flat, being in central Florida.

That said, 16ah should be more than enough to get you 20 miles at 20 mph, although the batteries you link state they are 22.2 volt, 2 of which would only be 44.4 volts (unless, as a battery noob, I am missing something).

Nice, ya i would be happy with 20 miles. Im hoping that with pedal assist on 1 or 2 i could maybe stretch it out to 30 miles range. I see what you mean about the battery, hopefully somebody will chime in with a answer im also a battery noob

 

[jesusjesus]

No Bms needed, however recommended by many.

the problem would be the Low voltage cutoff(lvc) on that controller. you will have 44.4 nominal and it will probably want 48.

you could get the 36v option and overvolt it to 44.4 (will increase the wattage)
http://www.ebay.com/itm/36V500W-26-Rear-Wheel-Electric-Bicycle-Motor-Kit-E-Bike-Cycling-Hub-Conversion-/291334105432?hash=item43d4dda958

but personally I don’t like LIPO that has parallel cells (not for noobs)

 

[jdwilson4]

No Bms needed, however recommended by many.

the problem would be the Low voltage cutoff(lvc) on that controller. you will have 44.4 nominal and it will probably want 48.

you could get the 36v option and overvolt it to 44.4 (will increase the wattage)
http://www.ebay.com/itm/36V500W-26-Rear-Wheel-Electric-Bicycle-Motor-Kit-E-Bike-Cycling-Hub-Conversion-/291334105432?hash=item43d4dda958

but personally I don’t like LIPO that has parallel cells (not for noobs)

Thanks for the advice, im guess im not set on using the li-po cells i mentioned im just trying to find the most cost effective solution for batteries. I have seen some cheaper packs on ebay but shipping seems like it would take over a month to get here so im trying to find something domestic. Are parellel li-po cells a hazard for noobs? I have been trying to read all i can on li-po for e-bikes

 

[wesnewell]

Read this and fill in your location.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=66302
Kit ok. Batteries ok. Charger not. If you build a 12s pack, you want a 12s charger or bms.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw
https://bmsbattery.com/bmspcm/330-smart-bms-513-cells-in-series-bms-pcm.html#/212-discharge_current-20_40a
12s lipo is perfect for a 48V controller with a LVC of 42V. The controller will not let you over discharge a 12s pack. If you put a 12s pack on a 36V controller with an LVC of ~30V you will ruin your 12s pack if you let it discharge to lvc, which is 2.5V per cell, and you don't want to discharge rc lipo below 3.5V per cell resting.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=47294

 

[wesnewell]

Are parellel li-po cells a hazard for noobs? I have been trying to read all i can on li-po for e-bikes

Any battery is a hazard in the hands of an idiot, noob or not. Since rc lipo is so powerful with so much energy stored, extra care should be taken in it's use. Don't over charge it or over discharge it and it will provide better service than most other chemistries IMO. I've got over 3 years and over 12K miles on my 10ah 24s pack now. I'll probably replace it next year, maybe.

 

[jdwilson4]

Read this and fill in your location.
https://endless-sphere.com/forums/viewtopic.php?f=3&t=66302
Kit ok. Batteries ok. Charger not. If you build a 12s pack, you want a 12s charger or bms.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw
https://bmsbattery.com/bmspcm/330-smart-bms-513-cells-in-series-bms-pcm.html#/212-discharge_current-20_40a
12s lipo is perfect for a 48V controller with a LVC of 42V. The controller will not let you over discharge a 12s pack. If you put a 12s pack on a 36V controller with an LVC of ~30V you will ruin your 12s pack if you let it discharge to lvc, which is 2.5V per cell, and you don't want to discharge rc lipo below 3.5V per cell resting.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=47294

Thanks I updated my location. Thank you for the charger recommendations i will buy the first one you listed. Just to make sure im understanding the charger will take care of balancing and charging the 12s pack (two 6s) i wire together on the bike. Once riding the bike i wont have to worry about a bms or separate low voltage cutoff because the motor controller itself will shutdown at 42v?

Thanks for all the help

 

[jesusjesus]

I have a similar setup, but the LVC is 40v. 3.33 per cell with 12s. too low
I personally have never liked controller LVCs, they have given me too many headaches.


He was asking if he could use a different approach to LVC, and that is what i do.
bms, battery alarm (controller lvc or alarm - you are trusting a piece of electronics)
I would take 2 battery alarms over any controller lvc, any day.

but i do things differently, charging all cells via jst only -takes forever at 2 amps- but all cells are monitored every charge cycle, any low volt/broken cells and charging will stop.

i use these, non-parallel lipos(3)

http://hobbyking.com/hobbyking/store/__56844__Multistar_High_Capacity_4S_10000mAh_Multi_Rotor_Lipo_Pack.html

just my 2 cents

p.s and dont forget a fuse!

 

[wesnewell]

Correct. But I'd also get one of these to use as a fuel gauge. Hook up on controller side of battery connection.
http://www.ebay.com/itm/DC-15-to-120V-Waterproof-Red-LED-Panel-Meter-DC-Digital-Voltmeter-Two-wire-NIGH/141365876290

 

[motomech]

I like Lipo and am still using it, but it was at least a year of making mistakes and having close calls before I really learned how to use it.
With the price continuing to come down on "Plug and Play" batteries, I'm of the opinion they are a better choice for someone with Zero Lipo experience.
The Li-Ion batteries with Panasonic cells are a good choice.
If you are stuck on Lipo, repost the links to what Lipo and charger you want to use(those links don't work).
I think you are off-base on your choices and maybe I can help you get to back on track.

 

[jdwilson4]

I like Lipo and am still using it, but it was at least a year of making mistakes and having close calls before I really learned how to use it.
With the price continuing to come down on "Plug and Play" batteries, I'm of the opinion they are a better choice for someone with Zero Lipo experience.
The Li-Ion batteries with Panasonic cells are a good choice.
If you are stuck on Lipo, repost the links to what Lipo and charger you want to use(those links don't work).
I think you are off-base on your choices and maybe I can help you get to back on track.

Thanks i updated my post so the links work. could you tell me a little about your close calls? From what i have read online it seems like most of the danger comes from wiring them to be charged and reconnecting them back to controller

 

[Ykick]

Once riding the bike i wont have to worry about a bms or separate low voltage cutoff because the motor controller itself will shutdown at 42v?

Thanks for all the help

Dangerous thinking when applied to RC Lipo. 42V controller LVC only works if/when all the cells are perfectly IR/capacity matched and balanced.

Take a look at graph of what’s going on when cells in a pack become depleted -

They’re never, ever empty at the same time so if you deeply discharge you can see how by the time a overall pack voltage reaches 42V some cells could be well into dangerously low voltage range.

A BMS monitors and protects from these situation as you can see when the cell reached 2.8V and load switched OFF.


Shallow discharges can work with no BMS but all it takes is that one over discharge and RC Lipo can be cooked.

BMS isn't for faint of heart and probably not a good idea for inexperienced solder jockeys. YMMV...

 

[motomech]

I like Lipo and am still using it, but it was at least a year of making mistakes and having close calls before I really learned how to use it.
With the price continuing to come down on "Plug and Play" batteries, I'm of the opinion they are a better choice for someone with Zero Lipo experience.
The Li-Ion batteries with Panasonic cells are a good choice.
If you are stuck on Lipo, repost the links to what Lipo and charger you want to use(those links don't work).
I think you are off-base on your choices and maybe I can help you get to back on track.

Thanks i updated my post so the links work. could you tell me a little about your close calls? From what i have read online it seems like most of the danger comes from wiring them to be charged and reconnecting them back to controller

Yes, exactly.
I started building complicated packs, 12S/3P and 4P. with splicing and fab.ing balance leads
Now, I feel strongly that the simplest packs is best.
The new Multistar with big bricks allow simple packs. Two of the batteries in your link is 12S/16Ah, lot's of battery and range. But remember, the bigger the brick, the harder it will be to fit them into contoured spaces.
BUT, you do not want to have to dis-connect/connect leads to charge. That is an accident waiting to happen. You absolutly need a 12S capable charger and unfortunaly, the one we like is out of stock;
http://www.hobbypartz.com/75p-1220-charger.html
It could be a month or more before it comes back in stock.
One nice thing about this charger is, it can be used with a single inexpensive server power supply.
There is a bigger brother, Thunder 14something that will do 14S, but it is $190 and I think it would require a more expensive PS.
As mentioned by others, the controller's LVC is all important with Lipo and I don't see the controller in the kit you are thinking about as having the 42V LVC.
There are work-arounds, alarms, etc., but personally, I wouldn't ride with Lipo without a hard and trusted LVC.
I use E Life Bike controllers that give me the LVC I need.
http://www.elifebike.com/peng/pic.asp?ModID=PicS224&TypID=S220094
I really think you should be looking at a Plug and Play battery in this group;
https://bmsbattery.com/71-48v-li-ion
One with the Panasonic cells.

 

[wesnewell]

In regards to the 42V lvc, or 3.5V per cell on a 12s lipo pack. That's 42V under load when it will cut off. Generally that will mean the average resting cell voltage will be above 3.6V and the cliff effect. Still it's just a safety net. You don't want to run it until lvc cuts off anyway. That what the volt meter is for, although I charged a guys battery for him for a year where he ran it down to LVC every time since he didn't have a volt meter, and there wasn't a problem.

 

[dogman dan]

For 12s, I agree, 42v under load should result in a very conservative stopping point. Likely to stop at 44v resting.

Personally, I hate running without a watt meter monitoring my battery usage, bms or no bms. I have 4 Cyclanalysts now, I like the tool that much, and always have multiple bikes. So I know when to turn for home, and not have to rely on an LVC.

Range at 20 mph,,, you should get at least one mile per .75 ah. faster, 1 ah per mile at about 25 mph.

 

[jdwilson4]

I just wanted to post one follow up question, as i have done more reading i have realized that my city riding forces me to do alot of stop and go as well as naturally limits my top speed to 20. Since the 48v 1000w hub motor is rated at 470 rpm does this mean that i will end up using the motor very inefficiently most of the time? would a 36v 250w geared hub be better for my needs? maybe two wheel drive for a total of 500w ?

 

[Grizzl-E]

I have three of those exact lipo packs from hk. Two have a weak cell that continually has to be manually balanced. Not a bad deal for me since I'm pulling 10000+ watts out of them. For the average person that would totally suck. Even a good quality balance charger or bms won't balance these since they have to drain down the high cells which takes forever at 16ah.

Get a cheap pack with a bms so you can plug in and forget it. Stay away from lipo unless you need the high amperage.

 

[Grizzl-E]

I just wanted to post one follow up question, as i have done more reading i have realized that my city riding forces me to do alot of stop and go as well as naturally limits my top speed to 20. Since the 48v 1000w hub motor is rated at 470 rpm does this mean that i will end up using the motor very inefficiently most of the time? would a 36v 250w geared hub be better for my needs? maybe two wheel drive for a total of 500w ?

Like this?


I love my 2wd for the city. Snappy and efficient cause your splitting the torque load between the two motors. They make slightly more noise than a direct drive sometimes but they use less power accelerating.

That kit looks like it comes with a 20? Amp controller? 1000/48=20. Looks more like a 25a in the photo. Anyway you will draw that a lot of the time in stop and go and the bike won't accelerate as fast as with the 2wd.

 

[rsilvers]

Adding voltage will only increase speed, not acceleration. You need more current for more acceleration.

For any given voltage, more current will result in more watts, so if you are already putting 20 amps into it and 1000 watts, you have to use a controller that can do more than 20 amps. Is this controller good for more than 20 amps? I don't know, but I would doubt it.

 

[d8veh]

Adding voltage will only increase speed, not acceleration. You need more current for more acceleration.

For any given voltage, more current will result in more watts, so if you are already putting 20 amps into it and 1000 watts, you have to use a controller that can do more than 20 amps. Is this controller good for more than 20 amps? I don't know, but I would doubt it.

That's not quite right. A higher voltage battery increases the torque more or less in proportion to the voltage as well as increasing the top speed. I've done many tests to confirm that.

 

[Ykick]

Adding voltage will only increase speed, not acceleration. You need more current for more acceleration.

For any given voltage, more current will result in more watts, so if you are already putting 20 amps into it and 1000 watts, you have to use a controller that can do more than 20 amps. Is this controller good for more than 20 amps? I don't know, but I would doubt it.

That's not quite right. A higher voltage battery increases the torque more or less in proportion to the voltage as well as increasing the top speed. I've done many tests to confirm that.

Yes, although current (Amps) remain the same, higher voltage increases power (Watts) calculation.

For example - 50V pulling 20A from the battery will be about 1000W to the motor. 100V @ same 20A = 2000W You'll definitely notice more acceleration (and top speed) with the later.