36V vs 48V

[Eclectic]

I'm a noob with questions so I hope I'm posting this in the right place.

Background: I want an ebike but I have a very small budget (long story). I am trying to justify it by making it pay for itself (saving 2-3 gallons of gas a day) and hopefully losing the 20 pounds I gained in the last 2 years or so (it's a bitch getting old). My commute is a little over 15 miles (24km) with 2 major hills. The first hill is over 500 ft (152m) high with an 8% grade. The second is about 450 ft (137m) at about a 4.5% slope. There is virtually no level ground. The speed limits range from 40 mph (65kph) – 55 mph (88kph). Most of it is designated as bicycle routes but some some is rather scary.

What I am hoping for: Because I want to lose some weight, I expect to provide 20%-30% of the power with my pedaling. I know that in my current condition, there is no way I can make it up those hills on my own.

What I think I know: Volts = speed...Amps = torque.

My first questions:

I thinking of buying from yescomusa.com because they are local and I haven't seen anyone bad mouthing them yet. Any negative comments on yescomusa?

Is there that much difference between a DD rear hub 36V/800W and 48V/1000W. If I understand correctly, they are both (approx) 20 amp motors. The difference may be how much voltage the controller can take and if I am lucky the 36V controller should be able to take 48V. I am thinking about getting the 36V so that I can start with less battery until the savings can pay for better 48V batteries.

TLDR...If I start with a 36V kit, can I put on 48V of battery later?

 

[dnmun]

yes, the 36V controller work with 48V battery.

you should avoid buying SLA and go right to the 48V15Ah pouch pack. the sun-thing28 pouch pack on ebay is $404 delivered. essentiallly the same price as SLA when you add delivery and charger costs to the battery.

 

[john7700]

yes, the 36V controller work with 48V battery.

you should avoid buying SLA and go right to the 48V15Ah pouch pack. the sun-thing28 pouch pack on ebay is $404 delivered. essentiallly the same price as SLA when you add delivery and charger costs to the battery.

How have these packs worked out for you and what have others who have used them said about them. I'm surprised you would recommend such a new and unknown product but you must have had good luck with them to recommend them to a newbie.

 

[dnmun]

friend of alfantastic and allroads are the only ones who have purchased them here. not much info yet so hoping more people will buy them so we can see how they perform.

they seem to be cheapest available on ebay and the the guy who runs sun-thing was helpful to alfantastic's friend.

have not heard more from allroads since he thought the charger was bad, but we never found out.

sure hope more people will post up about them so there is something useful to base reliability on.

also, it is better to use a 36V controller with the 48V lifepo4 since the LVC of the controller will not cut off the lifepo4 pack before it is discharged. a 48V controller will have a 41V LVC which would leave a lot of charge remaining in the pack.

 

[john7700]

I agree that I would also love to hear more reviews on these as well because I will be shopping again this fall for my next build. However, I'm not sure it's the best idea to recommend them to a newb just to be our test monkeys. I know that I have come to trust the info I get on here and think we really should try to be accurate, especially for a newb. If you are going to throw it out there, I think it would be a good idea to at least add that it's not a known product yet.

At those prices, I really hope they pan out!

 

[dnmun]

they look exactly like the ping pack with the 5Ah pouches. except this guy uses a layer of that plastic on the outside i think.

i have no problem recommending him based on what alfantastic said. i think he will also build the pack to order if you call him on skype and arrange the build in advance.

but cheap as lead is a strong argument imo.

 

[Eclectic]

Wow...OP here.

Thanks for the responses. Interesting how the thread has gone. From the comments, it sounds like purchasing the 36V/800W kit from yescomusa makes sense. I haven't decided on batteries yet.

Thanks again

 

[ez-Ebike]

If you have some steep grades just get the 48V 1000W. It's not significantly more than the 36V versions.

I understand you want to contribute "x %" of the power with your legs - but you can control the amount the battery will add by the thumb throttle. You'll thank yourself for getting the more powerful motor later.

You can probably do the 15 trip with cellman's largest battery pack. I can go 16 miles with the 9.2Ah battery, and I floor it everywhere. If I go 30mph for 90% of the time, with jack-rabbit starts, I'll get approximately 12 miles.

Good luck!

 

[winkinatcha]

Hey mate, a bit of Aussie input here...
I started on e-bikes with a kinda similar situation as you, getting old, not certain if I could do my commute to work by human powered bicycle alone, and the perception that an e-bike should be able to both assist, and possibly carry me home if I get knackered or injuries flare up precluding me from peddling too good.

I've built and ridden a range of e-bikes since then, and can pretty much say that an e-bike definately provides a solution to overcome my fear of having to get off on hills and push, and at the same time increased my fitness and instituted weight loss.

I'm building my own bikes now, based on kits pretty similar to thos I see on the yescomusa.com site.

From my experience, n from the hills you mention, I reckon you do want a minimum of a 500w kit, and personally I'd suggest that you go for 36v rather than 48v

Main reasoning behind this is speed... Once you are on 48v with reasonable power, (even 1000w) (note.. based on the kits I use which LOOK similar to yescomusa but may somehow be diffierent) then the bike is capable of speeds with minimal peddle assist of around 25 + mph. trying to peddle that fast, with "standard" gearing (43-48 tooth chainring (peddle gear) and 11-14 tooth on the highest freewheel gear (rear gearing) becomes an issue... you may well find at that speed you are putting more energy into trying to match the motor than actually adding power to peddles. Going up to a higher tooth count chain ring will mean you can add more power cos of slower peddle speeds at max speed, but once you get out of the standard 43-48 tooth chain ring, the costs start to escalate... (eg over here in aus, a retail cheapest crankset at 53 tooth is $100+... not exhorbitant by any means but these costs do add up)

At 36v on a 26" wheel, speed on a standard kit will max out at around 20 mph... this is far easier to match on a standard crankset with a 43-48 tooth.

So personally I'd recommend you go for the lower voltage, to make it easier for you to assist the motor using standard bike components. that way you will be more inclined to peddle and can reap the benefits of stress free exercise with the sure knowledge that yer steed can still take you home albeit not at supersonic speeds, if you run out of puff.

Joe

 

[Eclectic]

Is there a difference in the motors?

800W/36V=22.22A 1000W/48V=20.83A

If I understand things correctly, that means that hill climbing power (torque) should be about the same (actually the 36V amps are a little higher). If I go with 36V batteries, I know the top speed will not be as high but would the torque be any different?

 

[wesnewell]

Is there a difference in the motors?

800W/36V=22.22A 1000W/48V=20.83A

If I understand things correctly, that means that hill climbing power (torque) should be about the same (actually the 36V amps are a little higher). If I go with 36V batteries, I know the top speed will not be as high but would the torque be any different?

I don't know where you are coming up with the amp ratings, but I've bought 3 kits from them, all 48V, 2 500W, 1 front 1 rear, and a 1000W rear. All 3 controllers were 30A max. I can tell you for a fact that the actual motors were not the same. using the same controller and battery pack on the 500w aand the 1000W, the 1000w motor had more power and top speed by about 5-7mph. So between the 500w and 1000w, well, I sold the 500w bikes and kept the 1000W motor. I now run that motor on 24s rc lipo charged to 100V with a 40A controller. When I bought mine, they didn't offer an 800W, so can't help you there. But looking at the 350rpm rating @36V, I'd tend to think it's different motor too. At 48V you should get over 450rpm, so it should work pretty good. It may even be the same motor as comes with the 48V 1000W kit.
Raising amps will raise the watts to the motor thus increasing torque. Oh, just noticed how you came up with the amp. Forget it. That's not how it works. That's just the amount of amps required at those voltages to produce that many watts.
Raising voltage will increase both speed and torque. Example with 30A controller.
36Vx30A=1080W to motor.
48Vx30A=1440W to motor.
100Vx40A=4000W to motor
One other thing I should mention. The battery and phase wiring with the 1000W kit was bigger wire, so will handles more power.

 

[dnmun]

you may be able to modify the LVC resistors too in order to use the controller down below the 41V level if you get the 48V controller.

i just bot a 800W yescomusa controller so i may eventually open it up to see.

 

[wesnewell]

you may be able to modify the LVC resistors too in order to use the controller down below the 41V level if you get the 48V controller.

Why on earth would he want to do that? Certainly not to run sla or RC lipo. And not even with 16s lifepo4 from what I've read. Recommended discharge for lifepo4 is 2.5V per cell. 16*2.5=40V. I've seen you recommend to take lvc down to 31V before for a 48V lifepo4 pack which puts the voltage per cell under 2.0V. Under 2.0V lifepo4 cells become damaged from everything I've read from the manufacturers. So could you please point me to something that says otherwise.

 

[dnmun]

the battery has a BMS to protect it from dropping the cells below 2.1V. you don't use a BMS so dropping your lipo to 2.5V would be fatal.

 

[wesnewell]

This has nothing to do with me. I'd never use lifepo4. So you're advocating disabling the controllers ability to keep a lifepo4 pack from falling below not only the recommended discharge level, but even the level that will damage the battery pack. What happens if the battery pack bms fails to do so? Bms's never fail? Of course they do. Lots used to. Disabling the controllers ability to save the pack is just ridiculous imo. Would you sky dive without a reserve chute?

 

[john7700]

they look exactly like the ping pack with the 5Ah pouches. except this guy uses a layer of that plastic on the outside i think.

i have no problem recommending him based on what alfantastic said. i think he will also build the pack to order if you call him on skype and arrange the build in advance.

but cheap as lead is a strong argument imo.

Well, because I'm curious about these packs myself, so I went to see what alfamtastics had to say about them. His recommendation and I quote

"You may well be better off buying a Ping 48v 15Ah, as I have run one for a few weeks now, and it's seriously the dog's danglies.
Well worth the extra premium"

So even he won't recommend them. Again I say to you that it is a really mean thing to recommend something to a newb that we have no real idea about. If you are so all fire curious about them, perhaps you should spend your hard earned money on one and be the gini pig rather than telling unsuspecting newbies to go out and buy this unknown pack.

 

[dnmun]

so this where alfantastic mentioned his friend had bot one of the sun-thing packs:

http://endless-sphere.com/forums/viewtopic.php?f=14&t=40299

and here is the negative feedback from ebay. appears to all be about length of time for delivery:

http://feedback.ebay.ca/ws/eBayISAPI.dll?ViewFeedback2&userid=sun-thing28&iid=140671396366&de=off&items=25&which=negative&interval=365&_trkparms=negative_365

but he uses surface freight for shipping so i think it is normal anxiety about not getting the stuff in a week like one would with air freight.

i still do not see how they are any different from the ping packs. except he includes a 5A charger instead.

 

[dogman dan]

First off, we seem to have a guy with a sunthing battery with a problem that is not the charger. here. http://endless-sphere.com/forums/viewtopic.php?f=3&t=42374

Still a thread in progress, and much will depend on how sunthing handles it. I will keep recomending a pingbattery for those needing a reliable lifepo4 for a long commute.

Unfortunately, a good supplier of an inexpensive kit does not match well with 15 ah pingbatteries. 30 amp controller is a bit much. All my positive experience on an extremely similar commute has been with 20 amp controllers, that in reality are set to about 22 amps. Since my setups have been working so well for about 10,000 miles of commuting, I'm going to recomend the exact same thing.

I've been really happy with 9 continent or similar muxus motors for at least 6000 of those miles. You can get the muxus kit from Emissions Free quite cheap. Or a similar kit with usa based CS from E-BikeKit. Or you can get a genuine 9 continent 2807 motor kit from Grin Cyclery in Canada. You will want a 48v 15 ah pingbattery for the power. It will give you about 27 mph max speed, and easily make the 15 mile range including the hills. By lowering the throttle to less than max, 35 mile range is quite possible at 18 mph. The kits will come with a very compatible 20 amp controller. If you choose a kit from Grin, don't select a bigger controller. A cycleanalyst is highly recomended, so you always know if you need to slow down to make your range. Uphill and into wind for 15 miles might require that, but most days you'll discharge the battery a perfect 80%.

The 2807 winding will make it up hills up to 10% with some pedaling. The way to get your fitness, is to select a speed with the throttle, and then pedal up about 1 mph more. It will take just the right amount of effort to increase your fitness, yet not arrive too tired to work or too sweaty. Ride no pedal for the last mile to cool down.

Oh, duh, this pingbattery. http://www.pingbattery.com/servlet/the-12/48V-15AH-V2.5-LiFePO4/Detail

 

[kentlim26]

you wrote ..
TLDR...If I start with a 36V kit, can I put on 48V of battery later?

i was using this 48v 12amps headways cells, i also upgrade this + 2 cells lipos of 20amps. so upgrading volts is okay. is safe also. i charge them with different chargers is fine. becos i have upgrade my controller to 60v which cannot go with a 48v lifepo4 cells, it cut off when i full throttle. by adding another 2 cells makes the full throttle spin without problems.

 

[dnmun]

i just don't think there is anything wrong with that guys pack. i don't think he has a dead cell but he refuses to measure it while it is on the charger so we can see how the BMS is balancing it. until then i don't know how we can evaluate what his problem is.

i recommended the sun-thing because it is so cheap and the eclectic said he was gonna be buying lead to save money. i think if he was willing to spend $800 from ping or $1000 from paul, on a battery, he would have said that but my impression is that he wants to build up something now that is just cheap.

allroads is the only other person who we know bot a sun-thing and he started a thread saying his charger was bad but there was no evidence the charger was defective. then he disappeared.

if that other guy can show there is something wrong with his pack then i would change my opinion, but he never did show that the pack would not balance and he did charge it up to 58V finally. i don't think there is anything wrong with his pack.

kent explained the problem of using a 48V controller with a 48V lifepo4 pack. his was a 60V controller so the LVC is 51V so the LVC is activated as soon as he draws current from the 48V lifepo4 pack and the voltage sags below the LVC.

 

[lbz5mc12]

Just a comment about cheap chainring sets. You can get a square mount, I believe I have a 54 tooth, crank set for around $25.00 plus shipping on amazon.

 

[john7700]

i just don't think there is anything wrong with that guys pack.

You don't think there is any thing wrong with them but you actually have no idea what so ever what
kind of pack it is. You have never even seen one and the only actual member of ES that has tried one has
reported a problem with it. All you know is that it's cheep and suppose to be pouches. That is all you know. You have no idea and just want other people to spend their money to satisfy your curiosity.

Sure the guy is looking to go cheep. He is also looking for a battery that works. You have no idea what so ever whether it is any good or not and the only evidence we have had (e-bay feedback and allroads) have been bad. Like I said before, if you are that curious, spend your money on it and let us all know how they are.

With all that said, I really do hope they turn out well. The price really is attreactive.

That is all I have to say on this matter but please stop playing newbies as chumps just to be your personal test monkeys.

 

[USAEBIKECO]

36 volt system is pretty standard. Its also less expensive. Ebike kit and amped bikes sell kits that are 36 and 48 volt capable.

Most people new to electric bikes start with 36 volts and later move up to 48 volts.

You can upgrade as long as your controller and motor can handle the 48 volts.

 

[Samd]

Tight budget?
Just fit a $10 voltmeter and monitor your own voltage. Calibrate it with an external DMM.
You will get to know a lot about your battery's behaviour and how it changes with time and temp. Buy a controller with a LVC that becomes irrelevant and do your own control.

 

[Eclectic]

Hi... Eclectic here. Sorry I haven't been able to really check in before now. Thanks for all the interesting posts. Yep, budget is important (OK call it cheap if you have to). Maybe I'll have the “Need for Speed” later but right now I just want to get started. After all my name is “Eclectic” which means I could be just a little ADD. I might just lose interest in 6 months (I really hope not but...) so I want to keep the investment small but I want to do it right. The biggest reason I'm looking at yescomusa is because I am literally driving by it tomorrow afternoon. No shipping, no credit card, no waiting for weeks and a very good price ($250).

I think a CA is a bit much right now but I am interested in the idea of a (cheap) voltmeter. If someone could point me towards info on finding and connecting one, I would appreciate it.

Can't wait to ask for opinions on batteries.

Thanks everyone