WOW! Brain overload.

[FeralDog]

With the 48V 1000W kit I suggested, and 20ah of 12s lipo that weighs <15lbs, you could make 20 miles wot at about 28-30mph or 40 miles @20mph for at total cost of ~$700. You can have these parts at your door in a week since they will ship from the USA. Or you can spend a lot more and not get as much. Your choice.

I may do that, although I probably won't use LiPo. If I was already into RC, that might make sense for me, but since I'm not, I don't see that making the effort to go that route would save me anything but a little weight. Pretty heavy downside there too. If I get it wrong then I burn my house or job down.
and would it really only cost $400 for the LiPo, and chargers, and balancers, and a soldering iron, and connectors, and wire...and the stress of not burning things down.

I think you are making a good logical decision for your skill level.
Note: The Charger may also be the Balancer, but you still need to add the Power Supply Unit (PSU) to the cost, and also the time spent in educating yourself on the Lipo methodology. Burning your house (or job) down may not even be a result of "getting it wrong" , it may be the minute fraction of catastrophic combobulations of self-immolation those Lipo's have been reported to perform .

Wes is correct in his advice, but the devil is in the detail with those Lipo's. I think it is essential to understand every part of the Lipo ritual
of using AND charging/caring for those Lipos before embarking on having a bunch around the home or office. For instance, I charge my Lipo inside 2 nested metal "trash cans": and store them at ~3.85v in M80-M62 Mil-Surp ammo/tracer cans on a cool concrete floor away from any other combustibles: water, sand, & fire extinguisher handy. Never a problem, yet.
But I am experienced in military ordinance that would make a crater on the moon ... so I reduce the risk with good practice.
IMHO --- Lipo , today Jan 2014 is for "intermediate skill' difficult Blue to Blue-Black users. They are getting more and more user friendly, just not quite there yet on bigger electric bike applications for Noobies.

 

[wesnewell]

The cost of the lipo will vary depending on how you put it together. My 888wh pack only cost $275. A 300w 12s balance charger is $90. A PSU is nothing if you have an old PC psu laying around, or $35 for a new 15V 350w power supply. You're going to need a soldering iron and connectors no matter which battery you buy. The likelyhood of burning your house down is 50/50 if you're an idiot and don't use a little caution and common sense when charging. If you're cautious and have half a brain the likelyhood is as close to 0 as you can get. AFAIK, there's never been a house burnt down charging rc lipo with a balance charger. The one perosn I know of that did burn their house down left a huge lipo pack bulk charging unattended. And I believe it was determined that the bulk charger actually started the fire when it malfunctioned. The same thing could have happened with an sla pack.

 

[alsmith]

Why not just get a ready built LiFePO4 battery? Plug it to charge. It's easy to use, long life compared to LiPo but more volume to carry.

 

[wesnewell]

Why not just get a ready built LiFePO4 battery? Plug it to charge. It's easy to use, long life compared to LiPo but more volume to carry.

Because lifepo4 sucks imo. It's too heavy. It's too big. And most importantly it's too weak. And because it's so weak, the life cycle isn't near as long as is advertised unless you can keep the amp draw and charge rates low.

 

[Punx0r]

I think this may have been missed earlier on, but you need about 500W to do 20mph and 1000W to do 30mph. With pedalling and doing more like 28-29mph I pull 800W on the level, but I'm not a big guy.

RC lipo probably isn't the best choice here. I say that as a lipo user. lifepo4 or commercial lico, whichever, as long as it's some sort of consumer grade ebike battery would be a nice, safe, plug-and-play option, just costlier. To be fair, those types of batteries have been getter better in quality and their performance capabilities.

 

[hjns]

1) 48V through a 500-750W motor is definitely required to get the maximum speed that I want.

Hmm. I have a 6TMac on 48V with a 15Ah battery for my 30km round commute and my CAv3 tells me I need 900W continuous to maintain 40kmh. At 900W acceleration from 0 to 40kmh takes half a minute (slow) but it is more than enough for my commute.

2) 15ah would be fine if I stick to 20mph, just barely enough if I run at 25mph, and not enough if I max it out. I do have the option of charging at work, so I can decide whether I want to carry all that battery (15-20ah) around full time or go with a smaller package (10-15ah) and buy an extra charger to keep at work.

Depends on whether you need to stop and go often. Again take into account that you probably need the 500W continuously to maintain 20mph, but if you stop, you will need much more to get back from 0 to 20mph, and then only the batterypack/bms/controller/CA/motor combi will tell you the limits of Ah that you will eat away. Another way would be to limit the watts/current on the way to work to less than 500W, so that you are sure you have enough juice to get home again with more power.

This is what I do: on the way to work, I limit max power using the CA to 900W. This gives me a maintainable max speed of 40kmh (remember, I have a fast 6T Mac in a 24" big tire). With all stop-and-go's on the commute, the way to work takes 5.5Ah with a 28min ride. For the way back, I have limited the power to 1600W, giving me a max speed of 50kmh, and I make the way back only 3 minutes faster, but much more enjoyable due to the increase in power. I only charge at home.

3) Neither of the bikes that I was considering would be ideal. I do have this frame laying around .

...but it doesn't have discs and for the money I would spend converting at least the front to disc, I could just find something more appropriate on Craigslist.

Would not bother with discs. Just invest in some Avid Single Digit V-brakes with Kool Stop pads, put them on, and you are fine.

I think I'll keep an eye out for some kind of road hybrid or crossover. Something sporty, but with good tire clearance. The type or specific bike I use is my least concern because I'm pretty confident in the mechanical stuff. I think my situation is probably pushing the limits of what I'd want to put through the front end, so I'm going to limit myself to a rear drive application.

Rear drive is the way to go. Note that you may get a 48V 20Ah battery (big) and put that with a dedicated rear rack above the rear wheel. Disadvantage is obviously the increased weight on the rear, but main advantage is that you can get such a large battery with rack for easy assembly and won't need to charge twice. Obviously that would need a hardtail.

 

[dogman dan]

48v 20 ah of lifepo4 on a rear rack on a rear motor bike will suck balls. Too big, too heavy.

48v 15 ah will be better, and run a 25 amps controller fine. But you might need something better if you run a 30 amps controller. One of EM3ev's triangle batteries would be good, with plenty of range if you charge at work. Carrying it in the EM3ev triangle bag will be perfect on that bike. The EM3ev triangle packs are not as big or heavy as a lifepo4 pack.

Lico, the RC stuff will be lighter and easier to carry than lifepo4, and power any honking big controller you get later. But don't figure it to be as cheap as Wes claims. The price he got is gone, and you will spend more on charging and wiring. That stuff does recycle into future packs though. I run lico now, because it's cost is less for a 2 year pack. But I got 3-3.5 years from lifepo4. Lico costs me MORE per mile. For sure. But I get to run a big fat controller and haul ass.

In any case, slap it on that antler equipped 26" bike you have for now, and put some decent pads on the brakes. You can upgrade the bike to a better 26" wheel bike later. Or if the bike has the right headset, upgrade to some very nice forks with disk.

 

[wesnewell]

The 4s hardcase packs are $23.65 each if you wait for the discount. I think I paid about 75 cents less 19 months ago.

 

[SkyknightJohn]

Some experience I have to give you more food for thought since you're considering the MAC as a option:

System: MAC 8t geared rear hub in 26” wheel
Schwalbe Big Apple 2.35” at 33 lbs. pressure
36v 11.5Ah A123 (12s5p 26650 cells)
Cell_man 40a 12fet (3077) controller
Genesis V2100
Marzocchi DJ3 100mm travel with Avid BB7 180mm rotor
Rear rim brakes
Bike weight approx. 50 lbs.
190 lb. rider

Typical pleasure ride with moderate pedaling:
14.5 miles using 7.09 Ah
39.28 max amps
268.58 Watt-hrs
18.6 Wh/mi (no pedal is typically 25 Wh/mi)
1215’ total climb over the round trip
32.1 mph max speed (downhill)
18.1 mph average

One advantage the geared motor may give you that I didn't see mentioned is less resistance when not powering the motor. I have zero DD experience, so I'm just speaking out of my own research. It may be negligible enough to disregard. Also, since you plan to pedal a fair amount, on road, and are not looking for a powerhouse near e-motorcycle, your chances of destroying the gears is greatly reduced, although I'm sure it's still a consideration in the long run. 36V WOT on the 8t, 26" wheel, no pedal, gives 25mph (at the 130% setting on the three speed switch) 48v should get you where you want (and I now wish I would have started out there.)

And yes, the shipping is a hard pill to swallow, but my research lead me to purchase a ready made battery from an ES-trusted vendor, (and there are quite a few to choose from) and at the time the A123 chemistry was considered a good choice between low discharge Lifepo4 and the safety concerns/more complicated LIPO.
Hope this helps. And welcome to the e-bike world.

 

[dogman dan]

I stand corrected, the 4s hardcase packs in 20c are still pretty inexpensive.

Including shipping, I just paid 29.33 for each 5 ah 4s turnigy 20c pack. That was last months price, from the USA warehouse. Seemed to me like a lot of money when I clicked buy, but much cheaper than the best I could do last spring when stocks were so low.

12s 15 ah would then cost $264. 20 ah would be $352. That's this springs price, while the 4s turnigy packs remain in stock.

6s packs tend to cost more per wh, but they may be more convenient depending on your charging method.

 

[cal3thousand]

48v 20 ah of lifepo4 on a rear rack on a rear motor bike will suck balls. Too big, too heavy.

48v 15 ah will be better, and run a 25 amps controller fine. But you might need something better if you run a 30 amps controller. One of EM3ev's triangle batteries would be good, with plenty of range if you charge at work. Carrying it in the EM3ev triangle bag will be perfect on that bike. The EM3ev triangle packs are not as big or heavy as a lifepo4 pack.

Lico, the RC stuff will be lighter and easier to carry than lifepo4, and power any honking big controller you get later. But don't figure it to be as cheap as Wes claims. The price he got is gone, and you will spend more on charging and wiring. That stuff does recycle into future packs though. I run lico now, because it's cost is less for a 2 year pack. But I got 3-3.5 years from lifepo4. Lico costs me MORE per mile. For sure. But I get to run a big fat controller and haul ass.

In any case, slap it on that antler equipped 26" bike you have for now, and put some decent pads on the brakes. You can upgrade the bike to a better 26" wheel bike later. Or if the bike has the right headset, upgrade to some very nice forks with disk.

Even 10Ah of LiFePO4 at 48V on a rear rack SUCKS!!! Never again for me and I would suggest against it for anyone else.

 

[el_walto]

I would strongly suggest you charge the bike at work, so you have can buy less battery, and carry less weight

If your cruising mostly on flat, you might want to consider the 500w direct drive kit, likely a bit more efficient on flat, cheaper, and will not produce noise when running at a high rpm. You will only really need the 25amp controller for running on mostly flat.

The battery and charger from em3ev has been really good to me A+ rating on that.
I'd also give his mac motors A+ ratings, very nice rims compared to some cheaper motors from other venders.

 

[worldpax]

Why not just get a ready built LiFePO4 battery? Plug it to charge. It's easy to use, long life compared to LiPo but more volume to carry.

Because lifepo4 sucks imo. It's too heavy. It's too big. And most importantly it's too weak. And because it's so weak, the life cycle isn't near as long as is advertised unless you can keep the amp draw and charge rates low.

I'm halfway sold. I found this charger, which if I limit myself to 6 batteries, would seem to be an easy solution for charging 6 batteries at once.

http://www.buddyrc.com/icharger-306b.html used with this http://www.buddyrc.com/paraboard-v2-xh-xt60.html

I would probably build a 12s2p pack using 4- 6s 8000mah which should give me a 44V/16ah

Later I think I could easily expand to 12s3p and have 44V/24ah. (There's a chance that my commute may double in the next year.)

I'm guessing with this system I would have about a 4 hour charge time, maybe less?

This feels like a pretty well balanced package using a 500-1000W motor (MAC or something similar). I should be able to achieve 25+mph with a sacrifice in range, or plenty of range by limiting myself to 20-22mph or adding some human power.

What I like about this idea is that it gives me a smaller lighter package without greatly increasing the complication. I think the initial cost is a wash compared to LifePo, but less cost going forward after that.

What say the masses?

 

[el_walto]

Prebuilt pack is much easier to use than lipo bricks, especially for ones first ebike. Just one decently small sized charger to carry, one connection to make, one wire coming out of the battery, and no buttons to press. Just plug it in and it starts charging. The amount of cycles you get will also likely be much more if you get a prebuilt pack instead of hobby king bricks.

 

[wesnewell]

If you're going to build a 12s pack, this is the charger you should get os you don't have to break up the packs to charge.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw

 

[worldpax]

If you're going to build a 12s pack, this is the charger you should get os you don't have to break up the packs to charge.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw

OK but as a noob here's what I see.

With the 12s charger I won't have to break up the packs, but will have to parallel the balance plugs and decipher which plug goes where and if I get it wrong I kill cells or damage the pack. Not saying it's not a good solution, but maybe above my skill level.

With the 6s charger and paraboard, I have to breakup the pack, but the connections are more straight forward (at least to me) and there's less chance that I will mess it up. That is of course assuming that I'm not completely misunderstanding all this stuff.

Assuming my plan of 4-6s 8000mah wired 12s2p for 12s 16ah, that's 4 batteries to charge.

Option 1) charge each individually with a single charger.

Option 2) charge each individually with 4 separate chargers.

Option 3) Charge all 4 at once with one 6s charger using the paraboard.

Option 4) Charge all 4 at once with one 12s charger.

Is my logic faulty?

 

[wesnewell]

You'll want to build your 12s2p pack like this.

Use 2 of these to parallel the the cells.
http://www.hobbyking.com/hobbyking/store/__32040__JST_XH_Parallel_Balance_Lead_6S_250mm_2xJST_XH_.html
Use a red marker to mark the high side plug. Use a black marker to mark the low side plug. Do the same on the boards that come with the charger, Hard to screw that up unless you're colorblind.

If you decide to go with a 6s charger and parallel charge, forget the paraboards and get one 1 each of these.
http://www.ebay.com/itm/JST-XH-6S-Parallel-Balance-Adapter-Balance-6-Once-/230626922768
http://www.ebay.com/itm/Parallel-6x-HXT-4mm-Bullet-Charge-Cable-/390639720613
These were used as examples only. HK website was down. These prices are higher than HK. many places sell these cables.

 

[worldpax]

Hmmmmm.....

 

[Rutiger]

If you're going to build a 12s pack, this is the charger you should get os you don't have to break up the packs to charge.
http://www.hobbypartz.com/75p-1220-charger.html?gclid=CNa3z9_N57ICFayPPAod10MAPw

How does this compare to the Hyperion EOS 1420i?

 

[wesnewell]

It's a lot cheaper, but only does 12s max and 300W compared to the 1420i which is up to 14s and 550W. Some prefer the Thunder 1220 over the Hyperion. I only have the 1420i but I bought it for my original 14s pack. I'm now running 24s and charging at 12s, so the Thunder 1220 would be my choice today.

 

[worldpax]

Well you guys were a big help. I think I've got a handle one what I want and some options that will get me there. Lately I've really been trying to decide what bike I would apply whatever kit I get to, even if it meant I needed to buy something new. But I think my best option to start with is a bike that I currently have.

It was last on my list because it's a 9-speed and drop bar, but after thinking about it, it really won't be hard or expensive to convert it to a flat bar and 6 or 7 speed. I think it will be a decent compromise between aerodynamic and cushy ride, but has the option to add an 80mm travel fork if I decide that tire volume alone isn't enough.

I have my kit choices narrowed down to 3, but I doubt I'll be disappointed with any of them. And the batteries are going to be 12s2p Lipo, so packaging shouldn't be a problem. Just waiting until I sell off a bike or bonus time at work to throw down a sweaty wad of cash and put my first ebike on the street.

 

[ronnbot]

I have my kit choices narrowed down to 3, but I doubt I'll be disappointed with any of them. And the batteries are going to be 12s2p Lipo, so packaging shouldn't be a problem. Just waiting until I sell off a bike or bonus time at work to throw down a sweaty wad of cash and put my first ebike on the street.

12s2p (10 ah) is a good choice. I started with a 12s2p and that was enough for my commute, which is 30km each way (60km round trip) with quite a bit of elevation changes and charging the batteries before/after each way. Also, I'm heavier and my bike is too probably. So, charging once for your 20mi round trip while reaching 20-25mph should be doable. I've recently gone up to 16s for more speed.

And the best way to build that pack is to use 6x 4s or 4x 6s lipos, with the 4s being cheaper (my 6x 4s packs cost me around $150 + shipping) and the 6s being simpler. Here's my 12s2p from 4s packs:


The harness is basically just a series adapter (made from 14awg wires + Deans connectors) and 3 parallel adapters:


If you're going with 4x 6s, then the harness is easier. You can just buy a series adapter and 2 parallel adapters and you don't need to solder anything except for changing the connectors of the lipos and ESC. So let's say you want to use xt90 connectors, then you can simply get the following:

 

[d8veh]

Here's my schematic for what it's worth:

 

[dogman dan]

Your 6s 2p diagram looks good to me, similar to how I do it.

But your 12s diagram look wrong to me. One 6s bundles + connects to the other's -. Then the remaining + and - connect to the bike.

I think you mean that, but it just looks funny to me in the drawing.

I can't say what's the best charger. I do it two ways myself. But the next charger I buy will be one like the 12s charger, one that charges each cell through the balance plugs, individually.

If you have a small pack that has to charge at work, would you build a fire where you will be charging?

 

[wesnewell]

Simple way for 12s2p.