Build Help - Commuter (10Mi RT) For GF. (Update: Now for me)

[nlhaines]

Can we all at least agree that a good battery is worth the extra cash?

I guess that depends on what you call a good battery. To me, it's one that will deliver the amperage I need without overloading it. Since my 24s2p lipo pack rated for 200A has served me more than 8K miles in a little over 2 years and I expect it to last at least another 4K miles and another year. I consider it an excellent battery. And the fact that it only cost me ~$275 makes it more than an excellent battery. it's lighter and smaller in volume than most other types. And it's modular. I can switch between 24s2p to 12s4p in under 3 seconds. I've used it on 2 bikes which required 2 totally different shapes. So I really don't see any need to spend more 31 cents per wh for any battery.

That sounds amazing. Where do you buy such a pack?

What exactly do you do when you "attend" a charging battery? Just keep near it with a fire extinguisher ready? I'm not sure a potentially hazardous pack would be a good thing for my girlfriend, but I am definitely intrigued. If she could just charge it at home outside on a brick patio in a grill then that would probably be pretty safe. If it's a matter of actively monitoring the battery and different readings then it definitely wouldn't work.

 

[Raged]

It means he didn't cheap out and got a BMS to bulk charge.

With lipo you have 3 options.
1. High risk but cheap - bulk charge the whole pack and watch it like a hawk
2. Med risk but more a pain in the ass than cheap - use a balance charger and break your lipo packs every time you want to charge
3. Spend the $50-100 on a BMS (battery management system) and let electronics do the work for you.

If you use the bike to commute, everyone choses option 3.

 

[wesnewell]

What exactly do you do when you "attend" a charging battery? Just keep near it with a fire extinguisher ready? I'm not sure a potentially hazardous pack would be a good thing for my girlfriend, but I am definitely intrigued. If she could just charge it at home outside on a brick patio in a grill then that would probably be pretty safe. If it's a matter of actively monitoring the battery and different readings then it definitely wouldn't work.

It means staying close enough to it to notice a problem if it should occur. Most people will recommend to charge in a place where if a fire should occur, it won't jump to other close by flammable objects. I'd consider charging outside in a grill about as safe as you could get. I charge mine on a wooden desk in my computer room using a balance charger. It takes ~2 hours to fully charge. Most of the time I'm in another room close by, but I'm never more than a few seconds away should something ever happen. I may check on it by running my hand around the packs to make sure they aren't getting hot once in a while, but after years of charging like this I've never had that happen. But there could be a first time, and you need a plan to disconnect the charger fast and get the pack to a safe place quick. I have a window 3 feet away if I ever need to toss the pack out it. Then I'll have to run outside and turn the hose on or just turn my sprinkler system on so the grass won't catch on fire. Maybe I should bring in my fire extinguisher in from the garage, but it may cause more damage than a small fire. All but the unlikely problems can be avoided by simply checking the condition of the pack before charging, and using one of several proper charging methods.And that does not include bulking charging in a place where fire will ignite something else while you go off someplace where you won't notice it.

 

[nlhaines]

Wesnewell: Where did you buy your battery. I'd fork over $280 for that battery right now.

I'm working on selecting a bicycle, looking mostly at Montagues. How do I know if it has steel dropouts? How do I check the size of the dropouts?
I'm thinking it's either going to be the X50 or the Crosstown, but I can't find info about the dropouts anywhere. There are plenty of places selling e-bikes with these frames, but as a newbie I don't want to have to modify the frame in any way.

 

[tln]

Montagues are all aluminum, so you do need torque arms.

I think wesnewell is advocating this:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=18631
You'll also need:
- chargers
- wiring harnesses
- ideally, a BMS
- rear rack bag

You might find that a rear rack type battery is not much more expensive and
easier to install and use. Some vendors will even include the rear rack I believe.

 

[ARod1993]

If you want an El Cheapo lithium battery capable of 10-15 miles round trip with a bit of extra juice left over (say 20-30% more capacity than strictly needed to do a round trip) then you can go the Hobbyking route (preferably with a BMS or balance charger). If you're only looking to pull currents of 30-50A peak out of the bike (a 44.4V system at 50A peak, 30 continuous is about 2220W peak, 1332 continuous, and probably more than you're actually going to pull on a low- to mid-power kit; on flat ground you should be able to hold at a speed somewhere between 20-25mph, maybe a bit higher, using well under 20-30A continuous current), then you can go with 9 of these 4S 5000mAh hardcase packs for a total battery cost of $230 plus shipping. Arrange them 3s3p (three packs in parallel for 15Ah capacity, then three 15Ah blocks in series to give you 44.4V nominal at 15Ah), and then get yourself a BMS rated for 12s LiPo (Supower has them for about $45 plus shipping) and appropriate wiring harnesses (both for connecting the battery balance leads to the BMS and connecting the main power leads in a way that produces 44.4V nominal between B+ and B-) and that should give you a reasonably safe, cheap (<$300-350) battery system that's easy to assemble and will provide pretty good performance at the discharge rates you're using. I honestly wouldn't recommend bulk charging naked (no BMS) LiPo, especially the stuff you get on Hobbyking, and especially if you're new to ebikes.

 

[nlhaines]

I was going to go with the Yescomusa 1000W kit. I think that means at 44.4 V (why not add an extra cell somewhere to get to 48V) I need to be able to pull about 23 Amps. If I get 9 of those Hard packs and build it 3s3p I have a 44.4V 15ah battery and I need a rating of something like 1.6C. They are rated 20C, but that's bogus, so I'm wondering whats a good guess, 2C?

If my reading of the Wiki is correct that would sustain speeds of 30MPH on a mountain bike. There are no hills here, and 30MPH is more than fast enough for my girlfriend.

 

[ARod1993]

I was going to go with the Yescomusa 1000W kit. I think that means at 44.4 V (why not add an extra cell somewhere to get to 48V) I need to be able to pull about 23 Amps. If I get 9 of those Hard packs and build it 3s3p I have a 44.4V 15ah battery and I need a rating of something like 1.6C. They are rated 20C, but that's bogus, so I'm wondering whats a good guess, 2C?

If my reading of the Wiki is correct that would sustain speeds of 30MPH on a mountain bike. There are no hills here, and 30MPH is more than fast enough for my girlfriend.

The reason I suggested the 44.4V nominal configuration is because those hardcase packs seem to only come in multiples of 14.8V nominal, and they're one of the cheapest sources of decent lithium power per Wh that you can get your hands on ($0.3378 per Wh). As far as C ratings are concerned, you want to downrate by a factor of 3-4; I wouldn't try to pull much more than 4-5C out of them but 2C should be not a problem.

 

[wesnewell]

If you're looking at a yescomusa 1000Wkit, this would be the one to get imo. This is the ebay seller for yescom, and this is their newer kit.
http://www.ebay.com/itm/48V1000W-Electric-Bicycle-LCD-Display-26-Front-Rear-Wheel-Motor-Kit-E-Bike-Hub-/291107275178
A 10ah 12s2p made of 4s hardcase packs will run ~$150 and should be plenty for what you want. You can get ~20 miles at 20mph. ~11miles at full speed of ~28mph.
For her, I'd put this or similar bms on it.
http://www.bmsbattery.com/smart/330-lifepo4lithium-ion-smart-bms-for-513-cells-in-series.html
Select 12 cells, 4.2V OVP, 3.3V UVP, and 50.4V. 20-40A version.
And then you'll need a charger. Might as well get it from the same place to cut down on shipping.
http://www.bmsbattery.com/alloy-shell/25-alloy-shell-240w-lifepo4li-ionlead-acid-battery-ebike-charger.html
Set for 50.4V and 4A max charge current
I didn't add up the cost, but it should be within your budget.

 

[nlhaines]

I'm just about ready to place the orders. Just a few more questions.

Is there any way to make these packs look nice on the bike? I'd like to mount them near the middle of the frame. Also a locking mechanism would be awesome. If I could throw them into something like the bottle battery case that would be ideal, but I'm guessing thats not possible.

Also, does anyone know of a cheap kit, like Yescoms, that will fit a 700c bike?

 

[nlhaines]

Would this be a good buy? Looks like it would charge/balance the packs and has a built in power-supply.

http://www.amazon.com/Power-Charger-Balancer-Lithium-Battery/dp/B00HED90RU/ref=lh_ni_t?ie=UTF8&psc=1&smid=ABBHZP61MZ1PX

Also, I have an extra universal laptop power cord, can't those be used as a power supply as well?

 

[wesnewell]

You can only charge up to 6s batteries with that charger. You will have a 12s pack, so that means you will have to disconnect all your wiring to parallel charge the 4s packs. You;ll need to a 6x parallel balance cable and a 6x charge cable to parallel charge them at once. You battery pack is 444Wh. That's an 80W charger, so it will take ~6 hours to charge the pack, and then you'll have to reconnect all the wiring again to use the pack. All this will have to be done every time you charge. It will be a pita, and leave room for lots of mistakes that can damage both the batteries and your GF. If you want to use an rc charger, then you need to get a 12s or larger charger. make adapter cable to turn 3 4s balance leads into 2 6s leads to fit the charger. In short, no, this is not a good option. You want to keep this simple for your GF, and a bms setup like I proposed is the best option for that. She will simply plug the charger into a 2 wire connector to charge and never have to touch anything else. And the 4A charger will charge the pack in ~2.5 hours from empty.

 

[nlhaines]

You can only charge up to 6s batteries with that charger. You will have a 12s pack, so that means you will have to disconnect all your wiring to parallel charge the 4s packs. You;ll need to a 6x parallel balance cable and a 6x charge cable to parallel charge them at once. You battery pack is 444Wh. That's an 80W charger, so it will take ~6 hours to charge the pack, and then you'll have to reconnect all the wiring again to use the pack. All this will have to be done every time you charge. It will be a pita, and leave room for lots of mistakes that can damage both the batteries and your GF. If you want to use an rc charger, then you need to get a 12s or larger charger. make adapter cable to turn 3 4s balance leads into 2 6s leads to fit the charger. In short, no, this is not a good option. You want to keep this simple for your GF, and a bms setup like I proposed is the best option for that. She will simply plug the charger into a 2 wire connector to charge and never have to touch anything else. And the 4A charger will charge the pack in ~2.5 hours from empty.

Okay, that sounds easy enough. Just looking at the BMS, I know she will be intimidated, so I was hoping for something with a little more conventional appearance. I think it would be worth spending some extra $ for something that looks normal (as stupid as that sounds).

 

[wesnewell]

Once you assembly the pack all she should see would be the receptacle she plus the charger into. All the batteries and bms should go into a box/bag of some kind.

 

[nlhaines]

Once you assembly the pack all she should see would be the receptacle she plus the charger into. All the batteries and bms should go into a box/bag of some kind.

Ah, okay. How do you recommend preventing the BMS from being damaged?

Just to get this straight, if I have 9 4s packs, arranged 3 in series, 3 in parallel I can balance charge all 3 of them just by plugging in a couple of wires? Thats amazing.

 

[wesnewell]

Don't step on the bms, drop it off a building, drench it with water, etc., etc. Mount it securely to something.
The bms will balance charge as many as you want it to from 3 in series to as many as you want in parallel. 3,6,9,12,15,18, etc. This is a typical config for 12s3p using 4s packs.

It does not show the bms.

 

[nlhaines]

Wesnewell and others: thank you so much for the help. Without it I would have taken 5 times as long to figure all this out, and probably would have wasted a bunch of money on the wrong parts.

A few more questions:

Is that charger from BMS necessary or can I get some equivalent in the US? I only ask because they want $50 for shipping.

In addition to the BMS, batteries, and power supply, what harnesses do I need to set that up. I figure HXT 4mm - a couple for in series and a couple for in parallel - but I'm probably wrong.

 

[mark5]

I'm just about ready to place the orders. Just a few more questions.

Is there any way to make these packs look nice on the bike? I'd like to mount them near the middle of the frame.

Maybe keep batteries in a frame bag?

Frame bag for folding bike:

HPC Montague / Hummer bike frame bag review by Rollodo
http://endless-sphere.com/forums/viewtopic.php?f=4&t=57882

Frame bag for regular bike:

EM3EV / Cellman Triangle Battery Bag review by dogman
http://endless-sphere.com/forums/viewtopic.php?f=4&t=51549

 

[nlhaines]

I'm just about ready to place the orders. Just a few more questions.

Is there any way to make these packs look nice on the bike? I'd like to mount them near the middle of the frame.

Maybe keep batteries in a frame bag?

Frame bag for folding bike:

HPC Montague / Hummer bike frame bag review by Rollodo
http://endless-sphere.com/forums/viewtopic.php?f=4&t=57882

Frame bag for regular bike:

EM3EV / Cellman Triangle Battery Bag review by dogman
http://endless-sphere.com/forums/viewtopic.php?f=4&t=51549

The HPC frame bag looks perfect, but $120 for a bag seems insane. I guess it is waterproof, but that is still pretty steep.

 

[Simple818]

Why not just buy this bike. Located in San Diego .

http://endless-sphere.com/forums/viewtopic.php?f=9&t=61988

 

[wesnewell]

The HPC frame bag looks perfect, but $120 for a bag seems insane. I guess it is waterproof, but that is still pretty steep.

It is insane. This should hold 9 4s packs and the bms.
http://www.bikepakmart.com/ib-fb1.html
Or just buy some wood/plastic.sheet metal, etc. and fab your own.

 

[mark5]

The HPC frame bag looks perfect, but $120 for a bag seems insane. I guess it is waterproof, but that is still pretty steep.

Maybe a $39 Leed bag then. IF it'll have enough space to fit what you want. They don't specify their bag's width.

Leed Battery Frame Bag
https://www.youtube.com/watch?v=hRrsLzodE6Q

Bicycle Frame Bag (S, M, L) Leed Protection Bags for ALL BIKES
small 17" x 6", medium 19.5" x 6", large 21 x 6"
http://www.ebay.com/itm/Bicycle-Frame-Bag-S-M-L-Leed-Protection-Bags-for-ALL-BIKES-/251368544029

2015 HPC LARGE Half Bicycle Frame Bag
http://www.ebay.com/itm/2015-HPC-LA...Electric-Bicycle-E-bike-Lithium-/121041584304
"HPC HALF FRAME BAG (Large)- 18”-23” Hardtail Frames and some Full Suspension
Approximate dimensions (LxWxH): 21.0” x 4.0” x 5.5” (Front 6” tapered to front of frame)"

 

[nlhaines]

Why not just buy this bike. Located in San Diego .

http://endless-sphere.com/forums/viewtopic.php?f=9&t=61988

500Watts is one reason. I feel like shipping would kill the deal. I think I can do quite a bit better for $1000 ($900+ Shipping). I might make an offer though.

 

[Simple818]

Why not just buy this bike. Located in San Diego .

http://endless-sphere.com/forums/viewtopic.php?f=9&t=61988

500Watts is one reason. I feel like shipping would kill the deal. I think I can do quite a bit better for $1000 ($900+ Shipping). I might make an offer though.

I'd offer $850 shipped. 500w is plenty for your gf. Trust me, 30mph is fast on a bike. My gf won't even ride mine.

 

[nlhaines]

Why not just buy this bike. Located in San Diego .

http://endless-sphere.com/forums/viewtopic.php?f=9&t=61988

500Watts is one reason. I feel like shipping would kill the deal. I think I can do quite a bit better for $1000 ($900+ Shipping). I might make an offer though.

I'd offer $850 shipped. 500w is plenty for your gf. Trust me, 30mph is fast on a bike. My gf won't even ride mine.

I feel like to me it's worth closer to $650 (300 for the bike, because its an old discontinued model, 180 for the kit, 175 for the battery). I doubt he'd go that low, and I don't want to low ball him. Then again I don't know anything about Bafang motors or their kits.