Ping 36v 20 ah, 5000 mile review.

[dogman]

I've run my "cheap" bms down to cutoff many many times. Usually, to get a bit further, I reset it, ride some more real slow, and drain it even more. Took me awhile to trust it though. For a long time I was real freaked out every time I drained the pack that far. It is a good Idea though, to explore how far it can go carefully, rather than just start riding till it quits immediately. The trouble with a bms, cheap or expensive, is that it doesn't know the status of individual cells, just the status of a paralell string of cells. At some point, you have to just trust your cells and trust your bms and ride the thing, or you will worry yourself sick every ride. It is important though, to know what the pack normaly can do, so you can tell if it starts to do less.

[needWheels]

Yeah but your cells are ping's which are better quality. I wouldn't call them cheap but midgrade.
You also have a reasonable warranty on your cells. On the really cheap packs I would never push them past cutoff (2.80-2.85 volts per cell?)

That's why I overbought the capacity I needed in the hopes they will last slightly longer if I never deep drain them. If I could have afforded a ping I probably would have gambled on a 36v 16ah to keep down weight and rely on 2C.

With a "20ah" pack (really 16-18ah by my calculations, at least I can cruise at (under?) 1C.

dogman do you know the real amps used by a BD36 at WOT on level ground on your 48v ping? I can't remember if you have a docwatson. I know you have that $5 harbor freight meter which I am debating getting myself even though it's analog.

[dogman]

Well, this is the pingbattery review thread. The point I was trying to make was that all the bms on duct tape batteries are pretty similar and if they are functional, they seem to work pretty good. The scary part is finding out if it functions . By the time you find out it doesn't, you have a dead pack. Once you have carefully found out that the lvc works ok, then you can start riding with less worry.

Yes you are right, I may be able to get away with stuff on my ping that might kill cells on a round cell pack. But mine is just a v1 pack, with pretty weak 1c cells in it.

Others with real ampmeters have reported level ground amp levels of about 20 amps 36v on a full throttle bd36. The brushless motor pulls about 15-17 which seems to confirm the 20% better efficiency. My calculated average was about 20 amps too. They can pull a good spike on an uphill start though. 50 amps for a half second wouldn't suprise me on the bd36. I never ran the bd36 at 48v all that much since my ping is a 36v. I ran it some on slas at 48v till I got my ping, and recently ran it some on 48v nicads. I never put the cheap ampmeter on the bd motor though, and now I've sold it.

[RTLSHIP]

dogman, you have 3000 miles ++ on your Ping pack. Is 15,000 miles possible presumably with limited capacity/range?

[dogman]

At first, I figured my 36v 20 ah pack, could possibly go 20,000 miles. 20 miles per cycle, 1000 cycles. Over the summer, I decided that might be a bit optomistic, since the last 500 cycles would presumably have less capacity than the first 500. By fall, reading about all the problems with many types of lifepo4 packs, I began to think that 10,000 miles would be a more realistic expectation, at least in terms of it being still able to do my pretty hard ride home. So I was thinking, maybe it will go 20,000 miles, but as soon as it can't get me 15 miles, I'll need a new battery or a booster pack to be able to make it home.

But, I was thinking that at about 1500 miles last fall. Now, with 3400 miles as of today, and still no hint of lost capacity..... I begin to wonder if I'll be getting a lot more out of this thing that I was thinking. 20,000 miles? 30,000 miles? who knows. But I'm getting pretty sure that a good set of cells can go an amazing distance. One stinker in there though, and its a different story. For once I'm lucky and have one that may last me 5 years, even at 4000 miles a year.

So I'm starting to think that yes, 15,000 miles out of a good lifepo4 pack is not a fantasy, but the expectation will still take most of us a few more years to prove. For a 48v pack, with perhaps 25 miles in it at 80% discharge, the number gets even higher, say 25,000 miles life expectancy. Ride slower, on a more efficient motor, and it goes through the roof. Say you have a 200-300 watt motor, and ride 15 mph all the time. Now you are looking at 30-40,000 miles. Wow, that will mean your battery outlasts quite a few saddles! I have to wonder, if not abused, how long does the motor last? A few bearing changes maybe, and a couple controllers, and your cost per mile could get too small to measure. Cool.

[needWheels]

You are right and I apologize for drifting away from the "ping" theme.
I didn't know v1 was only rated for 1C continuous, it was pricey back then for that.
It will definitely be interesting to see how long it lasts.

I just noticed you actually updated the thread which was originally a 1500 mile review!
So you are doing 3000 miles per year?! Nice!

[miro13car]

dogman,
you should remember what climate do you use yours LiFePo.
I bet your pack is mostly not subjected to freezing temp, unlike in Canada, here in praires/Alberta, Manitoba/ even in April you start your ride in below zero .
What is never mentioned that this chemistry loves hot climate- your climate.
There is no doubt it prolongs life of LiFePo.
my LB/BMI cells are almost like termometer - in mid of summer my 10Ah battery would deliver 11Ah easly, in fall close to freezing temp will not deliver even 9Ah.
It agree with Sandia Labs tests done on LB cell.
MC

[RTLSHIP]

15 to 20 k is a real possibility with a healthy pack. I've read about 70,000 miles for some car batteries. 30 year claims, too.
With these kinds of possiblities, money can be saved with less damage to our environment.

[dogman]

Absolutley right about the climate. When I realized what the working temp of this chemistry was in farenheight, I stopped worrying about charging it in a garage that is 120F. my nicads though, I'm never charging in a hot garage.

Last winter, in my mild climate, I would be riding home in 40-50 F, and riding to work in 20F. On the cold mornings, I would use a lot more capacity getting there, and since I work a real short day, I would not be able to get a full charge by the time I left. I found I needed a full charge to get all the way home, 14.5 miles, using the bd36 motor. So my range had dropped about 25% in weather under 50 F. Another reason I object when people calculate exactly the size they need. Better add about 20% for cold weather buddy. So to have a 20% reserve in winter, thats a full 40% bigger that you calculated! I quickly learned that in the winter, I needed to put some insulation in my battery box, so the heat from discharge could warm it up some. That seemed to help with the range issue. Starting out with the battery at room temp would help but that's not always practical or possible. I would have some cut outs from the bms too, till it warmed up after a quarter mile when it got really cold. ( to me anyway)

3400 miles on the ping v1 36v 20 ah as of yesterday. It seems to behave as though it was brand new, but I haven't actually rode the standard range test since about 1000 miles ago. The range test is done at 80F or above, and little wind. So it's pretty much impossible to find the no wind conditions in springtime in NM. yeah I know, get a cycleanalyst.

[RTLSHIP]

what's the logic or "dogma" behind charging up a life pack only 90%?

[dogman]

It has to do with avoiding too much overcharging. Personally, I prefer knowing it's balanced. With other chemistries, like the prius, it may make more sense. I seem to remember somebody saying lifepo4 is more tolerant of overcharging, like compared to older lipoly, that liked to catch fire. I really don't know how full charging vs 90% charging would affect cycle life. My own opinion is staying balanced is real important, and that is why I try to avoid 100% discharges. I ride so much, my battery has been on a charger 22 of 24 hours five days a week for a year.

[RTLSHIP]

ok. I understand now. deep discharges can/will reduce lifepo4 lifespan. Fully charged pack is good so the BMS can balance, etc. Any harm in leaving a pack half charged for a day or 2? I have never done that with my pack.

[dogman]

Shouldn't be any harm in leaving lifepo4 undercharged for a few days. I have heard it is supposed to like being left partially charged for long term storage. Problem is, some have had a mysterious trickle discharge they didn't know about happen that ruined cells after a whole winter. but a day or two , uncharged, with the controller disconnected shoud be ok. Mine just sits on the charger 24-7 and only gets taken off if I drive a truck to work. So it gets about 14 hours and gets unplugged in the morning.

[RTLSHIP]

Mr Dogman, you've said a geared hub motor is on the way. Will you use ping 36v? What kind of speed?

[dogman]

It arrived last night, and will have to use the ping, since it is a strictly 36v kit. See the World wide bikes fusin review thread for details. I am going to have to do a lot of math to keep track of the mileage on the ping with two bikes going on it at one time. Good excuse to get another ping in 48v for the aotema bike, but the pay off charge cards program must continue.

[RTLSHIP]

I test rode almost 13 miles on my 48/15 lifepo4 nonping. The voltage was at 51.9 after the ride. I suspect that on my bike the range is going to be over 20 miles. I just got tired of riding and quit. average speed was 20 mph. riding time about 37 minutes. 95% thumb throttle.
Right on about the near absence of voltage sag in lifepo's. Negligible Peukert effect.

[dogman]

Yeah, 25 miles would not be at all suprising at 20 mph, and more possible without a lot of hills.

[ajtest]

By way of a comparison I recently managed 31.5 miles on a cammycc 36v 20ah with moderate effort (still had about 10% left) - here's the plot, using a service I think others may well find interesting.

https://sportstracker.nokia.com/nts/wor ... id=1025774

[dogman]

At about 15 mph, my personal best is 39 miles on flattish terrain, some headwind, and brisk pedaling. 36v 20 ah battery also. I could do even better at about 12 mph, but I find it hard to keep the throttle that low for long.

[RTLSHIP]

My tests consist of all throttle and only occasional pedaling when starting and going up bridges etc. Unfortunately or fortunately, it has been raining every afternoon for the past week and a half. We have wet and dry seasons here in S Fla.
Consequently, I'm not riding to work much. I suspect that my 48/15 Lifepo4 is still breaking in. Maybe 150 miles in 3 1/2 weeks so far.
Dogman, on that geared motor you can probably get 40 miles+ running on the slow turtle mode.

[RTLSHIP]

ajtest, what kind of ebike you ride?

[dogman]

Lots of tests yet to be done on the fusin gearmotor. I got real busy last weekend helping at a balloon rally. I earned myself a place on the crew of a balloon shaped like darth vader's hemet. We ( my balloon crew) really impressed the pilot with our skills. Very cool, now I get to go to the Albuquerque balloon fiesta with the most popular special shape balloon there the last 2 years. Very exclusive club. My wife thought I'd lost my mind wanting to hook up with a special shape balloon since they are freaking hard work to pack up. Then I reminded her that we both have pilots licences. Now she gets it That balloon is going to be in my logbook someday. Google darth vader balloon to see the thing.

[RTLSHIP]

Dogman, you once mentioned that wind is the bane of every cyclists existence. Lack of wind means bugs in your face
down here. lots of gnats in the summer months.
If there is less than a 5 mph wind or wind is blocked off, gnats can be a problem, except at night when they go for the lights. Close to the beach we get less of them because of the breeze.
I'll live with wind.

[dogman]

One nice thing about the desert, a lot less bugs. One year we got crazy rain, and we remember it as the summer of the chiggers. Never knew we even had chiggers here. With the city growing, we need wind or choke on smog. But like all good things, too much is no fun. 40 mph afternoon breeze is hard to bike in even with a motor.

[RTLSHIP]

you guys get alot more hail. I saw this in Albuquerque. But the storm only lasted an hour.
Water-wise, most ebikes may have a basic water resistance. But additional steps need to be taken for duct tape packs. Of course, practically any ebike or battery pack would be damaged by heavy rain, falling into a pool, canal etc.