Breaking in new lifepo4 battery, ping 48v 15 ah

[dogman dan]

I picked up my new Pingbattery 48v 15 ah V2.5 yesterday from the post office. I have dished up lots of advice how to break in a new lifepo4 over the last few years, so here is a thread to say how I am actually doing it myself. On my ping v1, I simply charged it for a few minuites, and went out and rode till the bms cut out. The capacity was about half what I expected, and I got all pissed off, thinking I'd been ripped off, or I'd screwed up royal. Later on after a few cycles the battery perked up noticeably, and at about cycle 10 I tested capacity again and It seemed ok..

So this time I unwrapped the package, found no damage, and connected the bms leads. Two plugs this time, the v1 only had one. Real long leads, so I taped them to the battery. Also repositioned the bms to the side of the pack, to fit in my battery boxes. The charger is all wired, so I simply plugged it in trusting ping to have tested it at the factory. It took quite a while to charge, about 4 hours, which suprised me. The charger and battery were on top of my kitchen stove, a relatively fire resistant location. Voltage was 53v and it seemed to take forever for each .1volt to increase. The charger puts out about 60.4v It's the 2 amp one.

Finally after what seemed like eternity, the volts began to climb a bit faster, and finally began to climb much faster. Soon I saw the first blinky lights come on, somewhere around 57-58v. Quickly now, the voltage reached 60v, and then more slowly climbed to 60.4 where the charger turned off. At this point, after an hour on the green light of the charger, and just a few brief cycles to red, 12 of 16 leds are lit. I thought, Ok this is about all the balancing I get on cycle one, and took the battery for a 1 mile ride. I didn't limit throttle, 27 mph with my 2807 9c from ebikekit.

After the quick ride, the voltage is back to 53.5. Charging again, about 30 minuites had the pack back up to 60.4, and this time I got 15 lit led's. The same 4 cells that wouldn't light were slow to light up, and one didn't. So I have initially got 3 that are undercharged, and 1 that is even slower. Cool thing about this bms, you can see if one particular cell is acting up. Leaving the charger on for an additional hour, the charger turned on for very brief periods, like 2 seconds, periodically, but the last led still remained dark.

I repeated this procedure again, again taking about 20-30 minuites for the charger to turn off. This time the 3 runts lit up faster, but the last one still wouldn't light after an hour on the balancing. Dark by now, I did two cycles where I put the battery on the bike, and ran the motor no load for a minuite or two, to get the led's to turn off. On the last of these cycles, each of them including 1 hour of the charger on green, the runt cell finally lit up.

Now considering the pack fully balanced for the first time, I took out the bike and rode 3 miles, put it on the charger. An hour later, the pack fully balanced as the charger shut off, with the slowest to charge cell again the last to light, but not long after the others. The other 3 slow cells now balance about the same time as the others. So clearly the 4 cells are ok, but TOOK A FEW MORE CYCLES to break in or rather get fully charge than the others. This is why I consider a few light cycles on a new battery to be so important. If one cell is really taking less charge than the others for a few cycles, I would think it possible to damage it right away with a long ride on cycle one. Remember, this is 3p 16 s in the pack, so only one of the 3p cells could be very low, while the others are ok. Under continuous discharge, the low one could fail. Once all the led's light, the pack should be safe to ride some distance on, but I will still wait till about cycle 10 to try a 100% discharge.

So now I am on charge cycle number 5. The pack is off the charger for about 45 minuites, and has been slowly dropping down to 57.6 volts. As the voltage dropped, I am seeing lots of blinky lights on the bms. It almost seems like it's trying to balance as the surface voltage bleeds off. One light remains constant, while others blink on and off. The 4 runts are dark, not blinking. I don't plan on a full ride to cutoff for some time, The weather is not good this week, I've been sick and not riding lately. But I consider this pack ready for a 10 mile ride anytime now, using perhaps 60% of the capacity.

 

[Velocipede]

On my pack, I notice that it's not always the same cells that takes time to light. I worried sometime, but they eventually lit up. This feature is very nice, but may induce some over checking during charging

Ping advises to leave the pack balancing overnight and you would have all red LEDs lit up eventually. That's what I did and it worked out great. I'm not criticising you. Just think that all this process is not necessary for someone who wants a more "plug and play" option that Ping offers.

 

[dnmun]

the cells are not 'runts'. there are just some cells don't end up with the same amount of charge when you get them in the mail. it is not clear if this is an indicator of their life expectancy either. it just takes a little longer to fill them with charge.

when the leds are burning, they do consume some current. the leds turn on at a specific voltage, and off when the voltage drops below a fixed level. as the led consumes some current, it drops the cell voltage, this turns off the led. then as the voltage in the cell recovers a little, the led will relight, discharge a little current, drawing down the voltage again, and so on until the voltage on the cell drops below the level that will turn on the led.

i found the shunt balancing current was 70mA on the v2.5 signalab with the leds all lit.

 

[dogman dan]

Yes, I'm using the term runt cell poorly. Less charged initially is no doubt the true situation. I'll go back and edit in another term. Thanks for busting me on that one. Techincally, I still know squat till you guys correct me.

I still think a few less than 100% dod cycles is a good idea for the first few cycles. I'm just having fun with the new toy mostly, and trying to get the battery up to par for the first long commute. I hammer the battery daily when I commute, so I can't just go ride like normal right away without a lot of worrying about it.

Just got back from a 6 mile ride. No work because of weather. The pack dropped to 52.5v after 6 miles of full throttle, so I expect that to be the voltage of the pack for most of my riding, when you measure voltage at rest. It's looking like I have a good pack, and now feel like I could take er out on a long long ride if the weather didn't suck.

 

[Velocipede]

What upgrade in speed do you have over 36V?

Now you have 27mph.
Before you had??

I'm hitching for 48 volts too (have a 36V 20Ah) and I wonder what difference it would make.

Thanks

 

[dnmun]

the neat thing about the leds is you can see how they balance together. seems like one was always first then they would follow a common sequence. and when blinking off too. i think that is more in the variation of the shunt bridge resistor values.

but if the pattern changes, it could indicate early on a problem with individual cells, and how they age too. but it will take a few years to see that start to develop.

 

[dogman dan]

Yeah, now that I'll be splitting the use between two packs, I could be looking at a battery lasting a lot more years. I was on track to wear out my 36v ping in about another 16 months.

Previously my ebikekit motor was going about 21-22 mph, mabye 23 hot off the charger. So now I'll be able to go 25-26 mph for sure on most of the ride. It took a long run to reach 27 mph for a few seconds. 25 mph is the legal speed for a moped in NM. I was only getting about 24 mph out of my 48v nicads.

 

[Vim]

Dogman, what is your average amp draw full throttle on the flats, and how much voltage sag do you see there?

 

[Velocipede]

I do 24 mph without pedaling at 36 volts with the same motor that you have (ebike.ca 9cont 2807). Probably because I have 700c wheels.

Vim, I'm under 10A (maybe 7A minimum) at full speed and my voltage is over 38V. When I start to see some 37V I'm over 75% DOD.

I remember a ride with strong frontal winds. I was drawing 20A the whole ride, the motor was hot and my speed was down. But It still did a good work considering pedaling only in this situation would have been awful.

 

[dogman dan]

Sorry vim, but I'm still in the stone age with no wattmeter. When I do my tests of range at 100% discharge I can calculate an estimate for the average, which falls in the range from 10 -15 amps. About .75c Those numbers are for the 36v 20 ah battery though.

What I predict is that the amps will stay about the same for full throttle riding, since the same controller is used, but of course the battery is smaller, so the use will be about 1c discharge rate.

 

[dogman dan]

Weather finally improved enough to ride a bike. The first fulll cycle on the ping went well. I stopped before the cutoff, but I could feel that it was coming. The bike had slowed several mph, and I had ridden 23 miles, about half of it at 20 mph, and the other half full throttle. Climbed and dropped about 1000 vertical feet along the way. I started with a room temp battery, but it was about 38F out there. So judging by the performance compared to my original ping, I feel like I have a good one, and am now ready for long distance riding with two pings.

After a month or two, when I have more miles on it I'll start a review thread. But like the first ping, this one looks like a winner.

 

[StevenR]

I have watched my 48V20aH Ping v3 for better than 2000 miles and it seems that the BMS is charging for a long time after the lights come on. I have a WattsUp in the charge line and the lights come on when the charger is delivering 200mA or so. It can take several hours for the current to drop to 80mA where it seems to sit forever. I have taken cell voltages at intervals after the LED's light. After 30 minutes the difference in cell voltages is 0.069V (3.806-3.737). After 2 hours it is down to 0.041 (3.794-3.753). It is interesting to note that the high cell and the low cell were both different after two hours and that the high cells were dropping and the low cells were coming up.

**EDIT: These values are typical. I just picked an early dataset more or less at random and they are pretty much the same. I don't have too many datasets that have the longitudinal dimension; I usually just check before riding and the battery has been balancing for about 10 hours.**

I said I was going to break it in nice when I ordered the v3 to replace a v2 that I was killing. The v2 was so dead though I had to charge it to perhaps 80% then do a 40% discharge before charging to completion. I then left it on overnight and started using it for commuting. When I am commuting on the bike - 10 miles/500wH morning and afternoon - I leave the charger on all the time. It went like this for almost 2000 miles; either being discharged at 2C or charged at 0.25C (5A). I checked the cell voltages daily for a while and never saw worse than 0.1V max to min and usually saw better than 0.05V delta; +/-0.025V! These values repeat although I can't vouch for the absolute value due to VOM calibration issues.

It seems to love it. The battery stays nice and warm which it also seems to like. In a cold basement or outside I leave the BMS in a closed bag with the battery so the whole thing seems to heat to 90-100F. I get 1100wH and do not hit LVC - never have and most cycles were 50% DOD or less. I consider the balancing to be excellent - usually +/- 0.02V.

 

[StevenR]

BTW: do you get the random blinking if you leave a charged battery sitting off-charge?

**EDIT: DOPE! I guess I should read the posts better!**

 

[dogman dan]

I agree, the all lights lit indicates a pretty balanced battery, but leaving it charging with the green light on will continue to balance it better.

I have rode home 15miles many times with only a partialy charged v1 ping with no harm done. Sometimes the bms would cut off 1/2 mile from home, but the battery is still ok after 5500 miles. So charge as much as you can, till the lights all light if possible, and longer than that if possible. The bms and the chargers current limiting prevents the high cells from overcharging too much so don't worry about that.

It's nice to know the bms doesn't get so hot in the balancing. The v1 bms gets hot, one of the reasons I have it in a metal box.

 

[RTLSHIP]

Dogman, good luck with your new 2.5v Ping pack. You seem to be saying that the BMS has LED's on it to indicate balanced or imbalanced cells. Is that correct? What's the resting voltage on that pack 55 or 56?

 

[dogman dan]

The pack is resting now at 57.4, but some of that may just be surface charge. It was ridden yesterday 12 miles , about 50% dod and charged overnight, and sat about 7 hours. It drops to 56 after a ride of one mile, and down to about 53 when mostly drained

The bms lights start going on as each cell reaches a certain voltage. Just before that, the pack which is at about 56v for a long time will start to climb voltage fast, and the lights are just about all lit by the time it gets to 59v, and the charger led goes green at 60.4v. If the charger stops and not all of the bms lights are lit, you have a low cell on the unlit one. If you leave it on the charger, the led's all stay lit. When you unplug, the led's wink out one by one as the pack drops to resting voltage.

 

[RTLSHIP]

My 48/15 pack is at 54.1v. It's been sitting for a week, though. Not a Ping. I had a charger that would go beyond 60v, but dropped my back pack. Busted charger. It smoked thereafter. It is a good idea to have an extra charger. Got 3 48v chargers, 1 is SLA.
The lowest I recall going was about 51.8v and I must have travelled 14 or 15 miles. I'm happy with the pack. It is normal to see a voltage of around 54 for an hour or so, then very suddenly it will shoot up in voltage and then turn green.
The 48/20 ah pack is different in that charger will go off/on (at the end) several times until it settles on green. this could be because it is a bigger pack of 18650 cells.

 

[RTLSHIP]

Hey dogman, any updates on your new ping 48 pack? any bad cells?

 

[dogman dan]

No problems at about 20 cycles now. I haven't rode much yet since It's hard to cart off a cord of wood on a bicycle. Tree pruning season at work.

The bms takes very little time to balance it now, pretty much all the led's light at about the same time, with one or two taking about 5 minuites longer. I haven't run it to cutoff yet. I ordered some 5 amp chargers from ping. One 48v and one 36v for my old ping. They rock compared to the cheap chargers I've used for years. I should be able to fully charge the 48v 15 ah in about 3.5 hours, and the 36v 20 ah in about 4.5. When the weather improves, I'll be able to ride for 50 miles, charge a few hours and ride 50 more. Definitely planning on a few long rides on weekends.

Mostly I'm riding mountain bikes with no motor on the weekends now. Enjoying less than 60F while it lasts.

 

[BLUESTREAK]

HI MR DOGMAN: Just got my (2) 48 volt 15 amp ping battries today and i will start my breakin slow and easy just like suggest, THANKS COOPER

 

[dogman dan]

Cool. Some will say it's a waste of time, but better to wait just a few cycles before hammering the throttle for 25 miles.

I'm on cycle 27 now, about 100 miles of riding. The pack is performing marvelous now, staying very well balanced.

 

[dogman dan]

I am now at about 90 cycles on this battery. Today after a ride of 10 ah, I did a check of all the cells. All 16 cells are at 3.28 v. Sweet.

I have yet to ride it to cutoff, but I will this weekend, and report back how it does now that I have a CA.

 

[dogman dan]

Just got back from an evening blast, chasing rabbits across the desert after a rain. Finally the pack hit cutoff at 15.6 Ah of 48v , or around 780 kwh.

Ending voltage was aobut 42v resting, but I saw glimpses of 38v on the CA while riding. Reset the bms three times before giving up on it.

Cell group voltages were one group 2.9 and the rest split pretty evenly betwen 2.68 and 2.79. So it's a bit out of balance from a 100% discharge. Nothing leaving it on the charger overnight shouldnt cure though.

But it's very interesting to see how balanced it was at 66% discharged compared to 100%. Kinda fun having a CA, and watching the voltage dive off the cliff at the end.

 

[Doctorbass]

That's an intersting thread Dogman :wink:

Maybe i can share my own experience with these V2.5 48V 15Ah battery

I bought and installed and tested 7 of them on the ebike for my familly.

I can confirm sime fact that i know are often discussed:

-12 out of 16 led blink most of the time and the 4 first take more time to blink. .. that remember me the Gary V2.x BMS first 4s that are connected to supply the 12V section that draw current on these 4 first cells....

-They can few cycles to be balanced... or just leting them connected on the charger for few days fully balance all cells to the maximum

-They are great quality and deliver the expected 15Ah or more.

On all battery i tested at 1C constant discharge i got the lowest was at 743Wh and the highest was at 792Wh.


Something to understand about balancing cells on these battery:


let say the lowest cell and the highest cell have 5Ah difference.

And that the BMS balance at 70mA.

that mean that the charger will need to be connected to the battery for at least 5000/70 = 71 hours !!!.. that's 3 days...

This is the reality.. unless we manually charge the lowest cells and manually discharge the highest to the average voltage level of other cells.

All these battery have around 75 cycles on each and they are stil very good and still give around 15.2Ah average for each.

These are the best solution for powerful ebikes for 2000W and under.

Doc

 

[dogman dan]

Yup. Apparently the balancing on the signalab bms takes nearly forever. That's why I keep telling people with a problem to keep it on the charger nearly permanently. It's pretty much what I do. I get home, put it on the charger, and leave it for about 16 hours till the next ride in the morning. If I leave the bike at home the next day, I may eventually notice and un plug the charger in a day or two. Essentially, it's on a charger any time my butt is not on it.

And my pings are fine. This particular one had me a bit concerned after using it in the death race. It got severe voltage sag when only 30% discharged, and was very out of balance for about a month. Now it's just fine, and acts like I never pounded it in the race. Balances up quite fast, as nicely treated cells tend to, when discharge rates are low and depth of discharge is shallow. I think keeping these pings to 1c average discharge rates is a key to sucess with them.