ping battery woes?

E

electricridefl

1 kW
Joined
Jan 5, 2008
Messages
374
Hello all. I built my current ebike several years ago. I have a clyte rwd 409 26". I bought 2 ping 36v10ah lifepo4 a year or 2 ago when ping first started selling on ebay. The batts are conneceted in series for 72v. My controller limits current to 20amps. The batteries have performed flawlessly since then...until now.
I was commuting daily 10miles total each day. Pretty much full throttle most of the time. 30+mph and 15+ mile range. And also ride during freezing temps in winter. Charge batteries outside. So no problems until I stopped riding my bike. I notice batteries losing charge from sitting. The power is off. I charge. After batteries sit idle for one month, they are completely dead. I measure voltage over 60v and then when turn power on, voltage dropped to about 15v, so bike did not run at all. So I charge up for 4 hours. So then I'm all set, and head out down the road. But I only get 20 feet, then power cuts off. And no power until I turn off power switch, and then turn back on. Then bike will go until I twist the throttle and then shuts off. I test controller with power at rear wheel while stalled. The controller cuts off, then turns back on, like usual. I connect voltmeter to blue (charger) and red wire to measure voltage with rear wheel in air and spinning while rear brake applied for load. The voltage in each 36v10ah battery holds around 40v through shut-off. The power will only return after my main power switch is flipped off then back on. I noticed I had to do this previously when power cut off on me before as I reached 15 mile range. I have no diodes between my batteries in series. All of the cells in both batteries seemed to self discharge equally and completely when sitting. I would venture to say that this self discharge is related to the age of the batteries. The only other thing I noticed after cutoff after my 20 ft ride was a tiny hot spot in each of the battery's
bms'. I have the first version of pings I think, but they have a better bms, allowing for 2c continuous current. The batteries have less than 500 cycles on them.
They have been sitting idle now since January. They will not work at all. Well, they will if no load applied. And they will self discharge fairly rapidly. I will connect each 36v battery separately to test each separately at 36v to check equality and operation and cutoff amps. I will then bypass the discharge bms and then monitor the voltage under load. Like I said, the batteries were fine until left to sit for a couple months. Supposedly they should last for thousands of cycles. Now when they were completely dead (60+v), I put on charge (a ping charger for each). I went back to check 4 hours later and the charger lights were green and they were not very warm. The chargers output about 1.3amps each, so it would appear that they did not charge anywhere near the time required for 10ah. I had high hopes for these batteries lasting me a while...My initial gut conclusion is that the batteries are done...I sure hope this is not the case. I will test further.
I have not kept current with posts here. Has anyone else experienced an extremely short life with pin batteries?
 
Hey. I originally bought 3 10ah36v ping. Part of the 3rd battery is near front wheel of bike in picture. I made a 5ah 72v battery....but I continued to have problems (lose cells). First I changed to 22 cells. Now I separated and made an 11cell, 36v and an 8 cell 24v 5ah. See my new forks? I bought on ebay...they are sweet. And I enjoy my fenders. And I really wanted to post about my mirror. Having a rearview mirror is very important for me. I bought a couple nice $15 ones at the lbs....But too easily my bike would fall over or hit obstacle and break the easily breakable mirror....Finally...a solution! I make my own mirror that functions fairly well and is indestructable! It has withstood everything! And it cost only $2! And never break! And need no hardware or tool!
The mirror is on my bike in the picture. At the end of the left handlebar grip. I go to autoparts store and buy various little stickon wide angle plastic mirrors.
A medium size works best (to see with). Then I drill 2 tiny holes in one side of mirror plastic. Then I connect tiny bungee cord through handlebar to other side. Then hook bungee through holes in mirror. The bungee holds the mirror in place against rubber grip. It may move over bumps, but very easy to readjust with finger while riding. And bungee mounted mirror becomes immune from breakage....Just one less thing to maintain.... my motor and controller have lasted for years. The bike is good...flat tire sometimes, lube chain and suspension links, replace rear spokes regularly....very reliable and tough over all....except for one thing...the battery....my 36lb sla lasted a year....I think this lifepo4 has lasted longer....so that's $700+ for 2 sets of batteries so far. I sure hope I don't have to buy another battery! Is that what happens to lifepo4? Self discharge grows with age? Maybe it is related to the bms. I will post follow-up. Surely the battery will work if I bypass the discharge bms...I just need it to last until dec 2012 and go from there...
 
My guess is that 2c daily commutes on a 1c cell was kinda hard on em. Don't know why they self discharged, but maybe that is what old lifepo4 does. Too bad they didn't last longer, they may have done so if they hadn't sat for a month. You'd think it would have taken a lot longer on the shelf though, something for all of us with a year old lifepo4 to be aware of next winter. Was there anything connected to them that month? Maybe you just have a trickle of current flow even with the controller shut off?

If I were you, I'd be looking at headways for the next pack. You have a good bms already so that helps. Cool that you got a year using a ping v1 that way, I would have predicted less. But till guys like you report from the real world test, we are all just guessing where the limits are.
 
I wanted to post this quick follow up. I kind of pointed blame at the ping batteries as failing. I think the batteries are fine. We like to point the finger....at somebody other than ourself, right? Operator error, that's the problem. my problem is evident in the picture. The bottom battery used to be on top of my frame. But I moved it down under. The only difference is the large steel clamp around the bottom battery. and the bms is also within this clamp. not the best idea. I'm sure a bad connection has developed inside the duct tape and bms somewhere. Nothing a little surgery can't repair.
life begins at conception. I conceived this thought prematurely. So this case calls for an abortion of my initial conception. This problem with my ebike is no different than every other one. Operator error each and every time! Cya
 
Wow, that battery looks pretty exposed. Good to hear that the battery is okay.
 
All Better! I cut open the bottom battery to reveal the bms. The top battery worked fine. The main neg into the bms maintained voltage fine, but power cut off on the neg out when medium load applied. The bms and wiring appeared fine visually. i do have a spare bms. But I simply spliced the out neg to the in neg, bypassing the over current and low voltage cutoff circuits. I reconnected the in neg to the bms board, as I measured erroneous voltage reading on the charger neg to bms when neg disconnected. Also, I installed spdt switches onto each battery pos so that either pos goes to power or pos goes to charger. In the past, I had left the batteries connected in series while charging the batteries with 2 chargers. Also, previously, I had connected the batteries to series-parallel switch to use for regen braking. This had worked with my original sla batteries, but it had no effect with ping batteries. So I then checked the discharge neg wires from batteries at that time, and discovered that they only allowed discharge (diode protected). So I discontinued that experiment. So the bms's were subjected to over 60v input on the 36v output several times. This may have affected the electronics in bms also. I don't think I ever hit lvc until I moved the top battery to beneath the frame. I was surprised when I tripped lvc after only 14 miles. Now methinks my range may be greater. Also i am not sure about the self discharge
either, as the faulty lvc was giving me erroneous voltage readings. And also, having one battery cut off while in series with the other may have affected the bms somehow, as I have read on this forum. I figure i still have over current and lvc through one battery. No need for double. I rerouted the clamp underneath the bms and beefed up the corners of the battery. Then I installed a fresh layer of white duct tape, put all together, and went for a ride! Yeah! That felt good!
Cya
 
i feel so sorry for your batteries.

kinda like watching the guy with dogs beating them because they don't do what he says.

a defective LVC? that is why you bypass the BMS and you wanna say mr ping had something to do with your problem?

not many can kill them.

dogman should be over 3k miles this week.
 
Yeah but it's soooo boring, to see me slogging along at 36v, on a dinky little controller, discharging at 1c. Electric Ed is much more entertaining 8) If I could afford it, I might be doing the same thing on a dirt bike.

3150 miles on the ping now. Ranshom has the mileage ribbon so far, 5000 miles.
 
This guy has courage. I would be too scared to do that to my battery.
 
Hi. I have a job now. My ebike would be perfect for the 10 mile commute. I haven,t ridden my bike except once after bypassing the discharge bms. Then the bike seemed to do fine. Well it ran now. But then as it sits, the battery voltage slowly drops over days to 38 or so. So then I dug into the battery for a closer look. I measured all the cells after charging. After charging, in 12 cell ping 10ah battery, 9 cells read 3.8v, the cell on one end read 4.2v, the cell at the other end read 4.4v, and a cell in the middle read 0.3v. Then, after sitting a little bit, all the cells were 3.8 or 3.7v, except for the first cell which was still 4.2v, and the one next to it was 3.6v. And the other end one, which was 4.4v, showed3.7v. But also, in the first test, the cell next to the 4.4v showed only 3.3v. But second test showed the cells equal (these two). Now the first test was done with the bms plugged in. For the second test, I unplugged it. But the charger was not connected for either test. And for the 2nd test, the middle cell read 0.2v. And also the cell showed continuity on the voltmeter with around 200-300 ohms. But there are some other things going on. First of all, before I did anything at all, whenever I checked the voltage of the batteries, I would test pos and charger neg (blue wire) because I had spliced in extra connectors on the charger neg wires, so it was handy. I had found previously that the voltage measured on the charge neg and the discharge neg was always identical whether charging or not. So first thing I check is this and find 31v on charge wire and 38v on discharge wire. When I put to charge, the charge wire always less than the discharge (direct from the battery), but eventually the charge and discharge both get to 45.1v. But once the charger is unplugged, the voltage on the charger wire drops to perhaps 5v less, and up to 10v less. I separated the discharge completely from the bms. If I connect charger to the charger wire, so small a current runs so that the charger light would not even come off green. But the battery voltage would eventually rise. Then I connect charger to discharge wire only, and charges good, however, the voltage measured on the charging wire while battery is charging through the discharge wire, does not even change at all. It may stay at 31 or 32v, while the battery goes to 45v.
So there, that is what I measured. Now I will present my conclusions and questions, ok?
Now many are of the school that says to replace what is broken, that that is the only logical ans sensible thing to do. This post and my questions are not for those people. The answers I seek would be like something on Macgiver or survivorman see? As if I am stranded in the middle of a desert and I have to make do with what I have. So the first conclusion I draw, based on the voltage of these cells after charging is that the bms is not protecting from overvoltage. So then is it balancing the cells? Perhaps, but with one cell bad, the extra voltage ends up going to the other cells. So either my bms is broke or it doesn't really do much in the first place. .
Now a couple of questions. From my experience with these ping cells, these questions seem plausible. I know they will sound blatantly wrong, but, for me, I cannot disprove them. So my question is based on my experience with ping lifepo4 cells--that is what happens when a cell goes bad, and the effect it has on the output of the remaining cells. I am very familiar with lead acid type batteries, when a cell goes bad, usually it cause a power loss, like a poor or bad connection, so that one bad cell will cause the whole system to lose power. Now enter lifepo4. I made one with single cells. It never lost power. When the bike felt a little slower on top speed, I found bad cell in series. The cell read 0v, yet the bike ran as if the cell was a wire instead of a battery. And I may have rub several cycles before I tested for a bad cell. And so it is now with this battery. But this one had a bms, so that after fully charged and powed up, a slight twist of the throttle would cause power to shut off. So when I disconnect discharge bms, the bike will run fine, except for 3.3v slower speed, but the torque feels the same. I don't have an amp meter in the circuit, so I can't be for sure. So my question is will I harm or have danger or lose range if I am running the battery with a bad cell in series? I could easily charge the bad battery with a 36v sla charger to compensate for the voltage drop. Will the 200ohm restence throught the .2v battery suck my power away? Or will the cell eve3ntually reach zero and have better continuity? Because that is what I want to do. I'm tired of taking this fricken thing apart all the time. Anyone have experience . I don't think it will catch fire or anything. ??? I will listen to the posts in this forum because you guys are the bomb of e-vehicle knowledge!
Oh, and 2012? perhaps I will blab more in the general forum...
 
When the packs were running well did you leave them on the charger or disconnect the charger right after they were fully charged? I ask because the ping charger goes through cycling after getting to full charge, and that cycling is the cell balancing. The low voltage cell is obviously dead, and those end cells with the voltage over 4V are probably quite damaged, and with those cells in the mix I'm not sure if the BMS will properly balance the cells or not.

FWIW, I run my two 36v15ah pings in series. I bypass the BMSs for discharge and charge through the BMSs. I rarely discharge mine below 50% and don't run at a high discharge rate, so my cells stay healthy and well balanced.

John
 
Still think your basic problem is the early v1 cells discharged at 2 c, or at least 2c when you are starting up. This is what likely killed the cell that died. Others that bought a 10 ah pack early had bms cut out issues running a 20 amp controller. A new bms for 18 cells might be a good way to wring a few more months out of your existing pack, but the c rate remains the same. Paralelling the two packs would really help, but I doubt you are interested in a 36v ride.

If you just bypass the bms and keep riding, keep the ride nice and boring, with no hard accelerations, or long hill climbs, and never ride further than 5 miles. Despite the fact that one cell died, the others may be fine. Pack surgery to replace the bad cells would be the best way to go and then buy more, so you have a 72v 20 ah batttery.
 
Thanks for the responses. I would usually let the chargers run a bit after turning green. I never had a problem until I stopped riding and the bike sat for months. A have a new result from my last test of the battery. I unplugged the bms and let the battery sit for several days. I had a suspicion that the bms was draining the battery. Then I found the bad cell. So now after sitting, my battery with the bad cell reads 40.4v, and my good battery measures 40.0v. The bad cell measures 0v and 20 ohms. The batteries I got from ping were right after he made 20amp discharge for 10ah battery. They never cut off on me. I haven't decided what to do with the battery at this point.
 
if your voltmeter gives such erratic measurements, you may wanna invest in a new one. i assume you are using a dial type, you can buy one with a digital readout for $3 on specials at harbor freight. accurate to 1%.

are all your packs now dead with this low 40V output? do you realize yet that it was reversed when you rode it that first time while the cell was not charged? that's why i hate it when people use mr ping's name and imply it is his battery that is the problem.

maybe a more fitting title for these threads would be "how i destroyed a perfectly good battery by bypassing the BMS", or "going full blast on a new, and/or uncharged, and/or unbalanced pack", i could go on, what's the point?

you can buy a replacement pouch or 2 from mr ping and solder them in place of the dead cells and it should work fine. i just ordered a 10Ah pouch from mr ping and it was $24. plus shipping, but i bot three 48V BMS from him too. so shipping for all is $30.

if you did not break your original BMS, it should still work. the extra wires on the charger lead that you added are not in direct contact with the battery negative and you should move them to the main battery ground. they go through the charger FET which is not rated for high power. and it turns off when the pack is fully charged.
 
My bike is working now. I haven't ridden it long for about 6 months. I rode 7 miles, then charged, then another 6 miles. But let me recap the story with my ping batteries. I'm running two 36v 10ah ping packs in series for 72v. I bought these batteries a little over a year ago. I rode my bike to work and back, for a round trip of 10 miles. Then I would charge once a day. I'm running a brushless rear 409 hubmotor with controller limited to 20 amps. My maximum speed was about 33mph. My maximum range was just shy of 15 miles. I probably ran the batteries 200-300 cycles @ 80% dod. Then I parked my bike in Jan. And it sat unused for at least 6 months. Now the batteries had always been fine prior to parking the bike. Then, after four months, I tried to ride it....but it didn't work. The bms turns the battery power off when one cell gets too low. I checked the bad battery, and one cell was bad. I disconnected the discharge part of the bms, but left the charging part connected. The bike worked now....but I only rode it about a mile. Then it sat some more. I would periodically check the battery voltage. I noticed that it would drop about 1 volt each day (in the bad battery). So then I disconnected the bms completely, and then I noticed that the voltage did not drop over time. So the bms was draining the battery because there was a bad cell.
At long last I took off on an 8 mile round trip ride. I rode fairly easy....about 25mph. At the 3 mile mark, the battery cut off. I reset the power switch several times and applied slight throttle to make it the last mile....and then I loaded my bike in the van to get it back home. Of course, the battery with the dead cell had no bms, so it could not be at fault. I opened up the other battery. I checked the cells before recharging. All of them measured 3.3 or 3.4 volts, except for one cell, which showed 2.3 volts. Ok....time to fix it for good. I ripped the bms out of my 2nd battery too. I didn't replace any cells. And then I put in my series-parallel switch so that I could charge both batteries with a single 36volt sla charger. I don't plan to ever open the batteries again to check the individual cells. I'm just going to ride it and charge it with no bms' at all and see how that goes. I've found that when a cell goes bad in my ping battery, it will go to 0 volts, yet it will permit full power from the other cells to pass right through it. I have yet to notice or experience any power loss whatsoever when running my ping lifepo4 batteries with bad cells. Hopefully the bad cell in my second battery will go completely bad so that then the batteries will be equal with 11 good cells each. I'm going to charge both batteries in parallel from now on -whether they are equal or not. I plan to ride my bike to work tomorrow. I need a simple charging solution---a single charger at each location. Now for those who think this will not work, I have some news for you. I went for a 7 mile ride this morning. The bike ran great the whole way. I did flip my series-parallel switch a couple of times to test the regen braking. I then put the batteries on charge (in parallel) connected to a n old wilderness energy 36v 2amp sla charger. To my surprise, the charger switched to float in only 3 hours. I checked the batteries to make sure that both were charged...and they were. So then I headed out for another 6 mile trip. The bike was perfect. It did not run out or low on power. Also, my controller has a low voltage cut-off set for 36v, around 31-33volts...I'm not for sure. So that if I do detect a power loss, I can switch the batteries to 36v, and if they are too low, the controller lvc will protect them from over discharge. I measured the voltage of the parallel battery connection at the end of my last trip. It was 36.2v. My meter is fairly accurate. It does tend to read a tad high sometimes as the battery in it is likely getting weak. But still, the other 11 cells in each battery appear to be working ok. I am now charging the batts with a single ping charger to see how long it takes, because I measured the ping charger as charging at 1.3amps. In fact, I don't really want to subject the batteries to 46volts if I can help it. Does anyone know if the voltage in the ping charger can be turned down? To somewhere between 42-43 volts? I will open my other charger to see. Otherwise I will procure another 36v sla charger. I'm hoping that no more cells will go bad any time soon....I got my patch kit, tire pump, spare spokes, and I'm heading out with a good degree of confidence that I'll make the 9.2 mile one-way trip. Now if my batteries were all 100% and right, then where would the adventure be? Just playin with my rhyde and my reason....I'll let you know. Cya!
 
my bike kicks. 24 cell with 2 bad for 11cell/22cell. No bms'. 9.2 miles no problem. On way home go through massive downpour and throttle stick wide open, so I switch to series-parallel to 36v and 15mph speed, which is top speed in storm. Then when downpour lighten, speed control return to normal. No problems with battery now. And as these battery cells go bad, they pass all the power through, unlike sla. And also I have subjected the cells to occassional overcharge to 4.4v to a cell. Yet this does not indicate a bad battery as of yet. Now I am wondering if I can make it 18miles on the 36v 20ah setting....
 
I just wanted to post this followup. Each of my ping 36v10ah batteries each has a dead cell. I removed the bms's from both. I ride to work 9.2 miles on 22 cells, 10ah. I charge at work with 36v sla charger. I swith the batteries to parallel. The 2amp charger takes about 5 hrs to charge the 20ah 36v battery. So it would appear that I have much more capacity remaining. I charge at home with a single ping 36v, 1.5amp charger, which takes about 6hrs or so. I placed two golf cart charger diodes in series on the ping charger to lower the finish voltage to about 44.8v, down from the 46.1v. I always discontinue charging when light turns green. The batteries have been working fine, but I did have a few problems. The first I caused as the charger with the bare wires and diodes....well, I moved the wires and the pos connected to the neg. It took me a second or two to get the charger unplugged from my battery. And I don't believe in fuses of any sort...so anyway....I left for work the next day. The bike quit less than a mile from home, so I switched from 72v to 36v and rode back home and took the car. My 409 hubmotor made a funny screeching noise. I investigated later. I connected each battery separately to the controller. One of the batteries was dropping below 30v. So then i found out that my controller did not have any low voltage cut-off. Turns out that at 30v and below, the motor still works (barely) and makes a horrible noise. So I looked at the battery. I noticed a 1/8" tiny black hole at the corner of my white duct tape. I opened up the tape and this burn hole was right where the black wire connected the two 18v halves of the battery. And this was where my bad cell was also. I verified the problem with my voltmeter under load. I simply resoldered this black wire to the other side of the bad cell--bypassing the bad cell. Now the batteries are working fine again....except for one other odd occurence. My other battery developed a strange symptom. I had thought the duct tape and padding where the bms had been had worked loose, as the top section of my second battery was sticking out about 3/4" fatter than the bottom half. When I went to redo the duct tape, I realized that the top half of battery was solid. Apparantly (perhaps where the bad cell is) a cell has swollen up from 6mm to 3/4". I did not undo the tape to investigate further, nor did I attempt to bypass the bad cell, as it is functioning fine at this time. I only use surgery as a last resort...A few more broken ss spokes and the sweet ride continues....The other day on my way home, as I pedaled leisurely down the sidewalk, these girls in a car drove next to me hollering...that's awesome...you're going thirty miles an hour! And then there was the guy who for some reason felt I was very wrong for crossing the intersection in the crosswalk, when he had a red light, and so he felt he had to blow his horn over and over and act like he didn't have to stop for me....a mile down the sidewalk and he was still honking....he tried to run me down, but couldn't...so my point is....the battery is fine, if not better, with no bms at all...cya
 
i think the acid has been bad for you.

did you end that by saying the batteries are ok?

it may be possible to save what's left, but leaving your pack uncharged for 4-6 months is not healthy.

yes the BMS takes current out of the battery to run, and it will discharge the battery if left uncharged for long periods of time.

the other guy who did that had cell #1 swell up and create so much resistance to discharge that it created an open circuit that kept the pack from discharging more through the BMS, except for the comparators on each sense line. we never found out if he was able to recover the pack because he never posted again after we told him he had to fix it himself.

but that was only maybe the end cell, maybe the first 4 were weaker, but the #1 cell was the only one with swollen pouches. was fixable, imho.
 
You must log in or register to reply here.

Similar threads

S
PING battery rehab...?
Replies
5
Views
218
fechter
fechter
B
Battery pack shuts off after a while
Replies
2
Views
308
bogddy
B
B
Parallel Charging into three different batteries with separate BMS's
Replies
10
Views
399
999zip999
999zip999
K
Inductance question when connecting 2 batteries in parallel using ideal diodes
Replies
13
Views
295
Roviil
Roviil
M
Double bms issue
Replies
13
Views
387
maarkmohamed
M
Back
Top