Building a buying list for two e-bikes, short range

[ewert]

So, I'm gonna finally start making electric moving a reality for me since I will finally have a sensible commute (7km 1way).

Currently I'm thinking and have asked for a quote for the geared hub motor kits cell_man sells. For everything but the batteries that seems hard to beat.

For a battery pack, I'm looking currently at the 10S nanotech Turnigy's 4,5Ah being very cheap. Having just 7km 1-way, and low ("euro" low) speed is enough for me (25-30km/h), I have looked around and it seems 10Wh/km is maybe around there pure electric, and with a little boredom pedal assist, that 37x4,5 of 166,5Wh sounds barely enough. I guess could go for the 10s 5Ah, not that much costlier TBH /Wh.

I'm doing everything double, for me and "her". Next up is charger, and that I haven't found very many options so far. iCharger 1010? Any way to charge two packs from the same charger without sparkysparky connection sparks? =P Though the time to charge such a small pack is minimal, so I think 1 charger is enough.

Is there much need for anything else, like a monitor, with only a single pack? The kit has some sort of basic h/l monitoring in the handle itself.

 

[MadRhino]

Running a single pack of Lipo makes for a very simple setup. I'd run the balance wires to the handlebar, to mount a cell monitor. The battery enclosure could be made to attach to the water bottle mounts. This kind of setup would be very neat, and with a small geared hub, very stealth too. Not a long range bike for sure, but could make for a nice pedal assist, and could be easily upgraded by adding the GF's pack in parallel, when she does not use hers.

 

[Drunkskunk]

Sounds like a good plan, But I sugest a Wattsup meter, or one of the $15 Hobbyking clones. You need a way to moniter the watts used. Its impossable to tell how much power remains in a Lipo battery by the voltage. The discharge curve isn't linear, and if the batteries were in a cool house, but the bike is riden on a warm day, uits possable to see the voltage Rise as the battery is discharged, So the only way to guage how much power remains is by the Watts used.

Also, get a bigger battery than you need. the less you drain from the battery each time, the longer they will last.

 

[ewert]

Looks like the 10s chargers etc. cost a lot more than 6s ones. So maybe go with 2x 6s packs, that's 20% more capacity too. Then maybe get one of those 4x6 chargers (http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10327), that will enable to charge all packs simultaneously so won't have to go around and disconnect/connect packs if both have used their bikes ... The money saved from not getting a 10s charger will pay for the extra capacity and bit higher $/Wh price pretty much ...

I've found iCharger and Cellpro 10s chargers, any others around?

 

[BikeFanatic]

Welcome to the forum,

I think you have a good plan for a lighter weight short range Ebike, and you can add more Lipo later for longer range as needed. I have a similar set up - I run either 2 x 5 series bricks or two time six series bricks. I rarely need more than
5 amp hours of battery- because all my trips are short. the Battery weight of my 5 series pack is 1.2 KG- and that will get you ten miles 15 kilometers.

I do recommend that you buy the GT voltage monitor from hobby king for easy low voltage warning , the gt voltage monitor
also records your lowest cell voltage during the ride. Works at the cell level. plugs in on the balance wires. Also you should get a Turnigy watt meter so you can learn about yor commute and how much juice you use. You do not have to extend the wires as mentioned earlier, short wires will work and you can just write down your numbers at the end of the ride for future anaylsis if you are into learning about the battery and how your system utilizes the battery.

lastly charging, There are so many ways to charge lipo, so many chargers. If you want my two cents I like the accucell six chargers because they are simple, and cheap, I use 2 chargers to chage two packs. It will Fully charge a 5 amp hour 5 series battery in about 2 hours from dead. I have gotten a couple with bad screen or a stubborn button though.
here are some hobby king links to what I referenced above

cell log eight low warning buzzer and or gt voltage buzzer

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=8980

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=10952

charger
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7028

and power supply for charger
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6256

 

[spinningmagnets]

With the delay times because of shipping, I know it can be frustrating to wait, but...

I highly recommend you starting by building up one bike in the configuration you like. I am certain you will develop an opinion about several aspects of the build after using it a week or so. After a few small changes to suit your new preferences, the second build should be near perfect for you.

I bought the least expensive power supply I could from Hobby-King. When I ran my charging system at 2A to gently cycle and break-in my LiPo, the small PS got very hot. When I ran it at the labeled rating of 5A, it died the very first time. I have just purchased an upgraded PS-model for $40 that I hope will be adequate.

http://endless-sphere.com/forums/viewtopic.php?f=16&t=23465

I also recommend buying the LiPo batteries by themselves, and any other China-stuff in a separate order, preferably getting the LiPo from the USA warehouse (if you are in the US). Be aware, if you want 4 working LiPo packs, you may need to buy 5. Very important to get some type of low-voltage warning system.

http://endless-sphere.com/forums/viewtopic.php?f=4&t=17958&p=346746#p346746

 

[neptronix]

I say spring for the 5ah or 6ah batteries. When you start hitting some hills or headwinds, your power requirements will suddenly change.

Also, as the batteries age they will lose aH. Doesn't hurt to have an extra buffer.
At lower speeds, 5ah will work. I can pull about 12km total ( with light pedaling ) of lightly hilly terrain on my setup.

As for the cell_man kits go, the geared ones are power sippers but not very fast. You will need to pedal to keep the top speed going, and if you are hitting serious hills you should probably just go DD. Geared motors' internal planetary gears are strained during hill climbs. do a search for peanut butter gears!!

 

[ewert]

Thanks for the replies.

Lets just say the toughest hills around are pretty much going through an underpass, pretty much.