Sell Insight to buy E-Bike?

[sendler]

Originally Posted by vskid3

I went with a Ping 48v 15Ah LiFePO4 battery

The kit is a great deal including the intelligent speedo. How much was the battery?
.
Assuming you want to stay in the 80% range of the battery, if you can get 30 Whr/mile consumption you will have a range of 20 miles.

[vskid3]

Battery was about $650 with shipping.
LiFePO4 don't seem to have any issue with complete discharges, and I'll probably be looking at 20-25wh/mi (just from what I've seen with similar setups and speeds). I will be pedaling at least a little, like when accelerating and coming up to stops to make my deceleration a little slower (maybe I should just coast to try to save my brakes a bit). I'll also plug in the charger when I'm home for lunch to give the battery a little boost.

[Grant-53]

Check to see if there is a way to use dynamic braking with the motor. This involves cutting power to the motor and connecting the two motor terminals.
Now you can think about streamlining.

[Grant-53]

Must be good biking weather and no problems since there are no recent posts!

[BarelyAWake]

Originally Posted by Grant-53

Must be good biking weather and no problems since there are no recent posts!

Agreed Grant... or at least that's been my "problem" lol

[vskid3]

Yep, pretty good weather and no major issues. It has been windy a few days (20-30mph), so that's not very fun. Streamlining would probably help a bit in the wind, I'll have to see what I can do after I get the rest of the bike worked out.

I've put about 150 miles on it since converting. Everything is working great. My biggest complaint is the battery on the rear rack, just too much weight back there. Building a triangle box seems like its beyond my skills and tools. It would have to be very precise to not interfere with the cranks (there's less than 1/4" of clearance on each side, and that's just the battery). I'm going to try to get it set up nicely in a backpack and see how that feels. I think mounting the battery would have been easier if I'd ordered the it split in half like BarelyAWake. I can see why guys like using RC packs despite the fire risk, those would be a dream to mount compared to this beast.

Here's a couple pics of how I've had it set up, with and without the "stealth" bag.

[Grant-53]

Putting the battery pack on your back is going to mean more pressure on your seat. Could you tip the rear rack forward toward the seat post?

[BarelyAWake]

Originally Posted by vskid3

I've put about 150 miles on it since converting. Everything is working great...

Congrats! There's just something wonderfully addictive about ebikes

Originally Posted by vskid3

My biggest complaint is the battery on the rear rack, just too much weight back there... I think mounting the battery would have been easier if I'd ordered the it split in half

It's not too late if you're feelin' handy - the cells within the pack are pretty much what you'd expect, each has a single positive & negative terminal & it's just a matter of lengthening the wiring for the cells & BMS feeds you'd like to relocate. The Ping 48v 15Ah LiFePO4 you've got likely is the same as mine, so it's got the round cells in a plastic rack with a terminal at the top & bottom, they're a bit bulkier then the flat cells but are easier to work with.

Here's a coupla pics of what's inside the wrap - first pic (not mine) would be very similar cells to what you've got, minus the wiring & BMS ofc & the second is the flat cell design, included to show wiring;




You'd just need to label each wire & the cell it goes to while modifying, it only seems daunting at first... but... unless you've sorted out a way to put the pack within the frame's triangle, it may not be worth the effort.

When I first threw Mongo together I just stuffed one pack into each side of the panniers. While the weight is lower then on top of the cargo rack when I later changed panniers and relocated the pack to the top of the cargo rack I learned it didn't make that much of a difference - it does help some to have the weight lower, but as it's still behind the bike's center of mass it still feels odd, even a little sketchy on slippery surfaces & a hard turn (wet leaves/painted stripes/etc).



I can say however it is something you get used to, it isn't as bad as it may feel at first - it's actually only 16lbs or so on the rack and interestingly that "top heavy" feeling goes away as soon as I put stuff (groceries or w/e) in the panniers.

At this stage I'd humbly suggest you just continue on doin' what you're doing, riding & enjoying the thing lol - if come next season you're still not used to it, odds are you'll be lookin' to modify it anyway


*whispers* get rid of that ax head torture device they call a "saddle" man, yer not pedaling so much anymore

[vskid3]

Yep, its a ton of fun. Makes me smile when I see someone riding a regular bike.

I went ahead and put the battery in a backpack over the weekend. In some ways its better, like the rear of the bike seems happier going over bumps. However, the extra weight on me makes my rear unhappy going over bumps (maybe I should get a squishy seat). The bike does seem a little less stable with the battery in the backpack, but maybe I'm just mistaking responsive for unstable. I'll leave it in the bag until I can figure out something better (or give up and just put it back on the rack). It'll probably help if I can find a place to mount my U-lock on my bike instead of adding its 4lbs to my backpack. Unfortunately, it seems perfectly sized not to fit anywhere on my bike.

Are you sure it uses cylindrical cells? All the pictures I've seen of Ping batteries show pouch cells. If they are cylindrical, I might be able to rearrange them and make a custom battery box in the triangle like guys do for Li-ion. I've also seen some setups where the battery is split between two bags that hang over the top tube. It wouldn't get the weight lower, but it would at least get more of it over the front tire.

I've been considering getting a smaller battery made out of higher C-rated cells like A123. Then I could have a 5-7Ah battery that would fit in the triangle and I could charge or swap out between trips. Li-ion would solve my problems, but there's the whole problem of me not wanting to burn my house down. :P

[BarelyAWake]

Originally Posted by vskid3

...Are you sure it uses cylindrical cells? All the pictures I've seen of Ping batteries show pouch cells. If they are cylindrical, I might be able to rearrange them and make a custom battery box in the triangle like guys do for Li-ion. I've also seen some setups where the battery is split between two bags that hang over the top tube. It wouldn't get the weight lower, but it would at least get more of it over the front tire...

No, I'm not 100% sure as I can only attest to the one I've got. It's two years old now & they may well have changed their methods & materials.

I'll freely admit battery tech changes so quickly it's difficult to keep up with, but peeling back a corner of the shrink wrap isn't too much trouble, I'm sure they'd be happy to answer should you call or email Ping. The wrap itself can just be taped back in place or replaced, it's the same stuff they use to wrap cargo, boats & ATVs so it's common & inexpensive.

Whatever the cells may be, working with them is as easy as legos... ones you hafta solder & just may blow up - but legos jus' the same lol


Glad to hear it's puttin' a grin on your face, I honestly feel like a kid flying down a perpetual hill with mine