power problem on a new build. (might be solved maybe ?)

[Diamondback]

Hi all.

on my newly finished ebike conversion, using an Ezee geared hub motor, i purchased a 48V 15ah ping v2.5 battery.

i was under the impression that it would be suitable for the ezee.

turns out it's not capable, and the BMS is constantly shutting off the power.
i have set the current limit on the CA as low as 7 amps, and the BMS is still shutting down.
with the limit set at 7A the CA is still reporting an A max or 16.82 and V min of 49.6.

i have emailed ping and purchased a high rate BMS for the pack, but i fear that even the high rate BMS
will not work, due to voltage sag.

i am probably going to have to sell this pack on ebay, and hope that i can get some of my money back.

anyone have ideas on what i should try next ?

i have thought about lipo (8x 6s for 48V 20AH) but then charging them all takes an age.
and i wouldn't have a LVC for safety either.

please help me....

Jason.


EDIT:

this problem now seems to be solved. you can read the rest of this thread if you wish, but to sum it up, i had a wiring
issue, and the problem was not battery related at all.

EDIT 2: my wiring problem wasn't the cause after all. it looks like bad connections on the BMS sense wires.
im still testing, and hope this is the end now of my problems.

Mr Ping deserves credit for trying to help me get to the bottom of my issue.
he was always quick to answer emails and questions i had.

his reputation for good batteries and great customer service is well deserved from my point of view.

 

[MadRhino]

Lipo can charge very fast, especially hi C rate. LVC can be set on the CA or controller.

 

[Rassy]

Jason, what you report is not normal for a 48V 15AH V2.5 Ping battery. I purchased one about two years ago and my daughter-in-law is currently using it on her delta trike. The trike has an old WE BD36 (Brushed) front hub motor with the original 35 amp controller. These systems pull a full 35 amps during acceleration and hill climbing and have never caused a bms cutout on the V2.5 Ping. With the same motor and controller using a 48V 20AH V1.0 Ping equivalent (Anna), the BMS would cutout.

Since the battery is only sagging a little under 50V I would guess that either the BMS has a problem, or the controller has a problem. You could test the BMS by cutting the main - wire on both ends of the BMS and installing a temporary jumper, i.e. bypassing the BMS during discharge. You will have to cut these wires anyway to install your new BMS, but at least this test will help you isolate the problem.

I am currently using a 48V 10AH V2.5 Ping on my trike. On every ride I hit a peak of 23 amps and have never had a BMS cutout. I think the 15AH battery should be a good fit for your system.

Good luck.

Edit. If the jumper does solve the problem, there is probably just a problem with the resister (bridge?) the BMS uses to determe where to cutout. On those 20AH batteries I mentioned earlier, I just added either some extra wire or solder to raise the current cutoff, so that might be an easy fix for your original BMS.

 

[Diamondback]

maybe my BMS is overly sensitive, and shutting down early.

i hope it's not the controller, as it's brand new (as is the rest of the system)

i just went and double checked the specs for the V2.5 48V 15AH battery,
and according to pings site, it's supposed to be able to sustain 2C (30A load) mine is shutting down at just over 1C.

here's the specs copied from pingbattery.com.

Rated Discharging Amperage: 15 Amps
Max Continuous Discharging Amperage: 30 Amps
Maximum Discharging Current: 60 Amps
Discharging Cut-off Protection: 40-50 Amps

maybe my BMS is faulty. but i would have thought that Ping tests that batteries before shipping them out ?

i will wait until i have the new high rate BMS installed, then if it's still having issues,
i will investigate LIPO as a possible solution.

i didn't think of using the CA for LVC duties for LIPO power.


thanks for the input guys.

Jason.

 

[Rassy]

Jason, I added a little edit to my previous post.

 

[Diamondback]

thanks.

in one of my emails to ping on the problem, he suggested i add some solder to increase the current a little.

im not the worlds greatest with soldering. so i took the easy path and just ordered the high rate BMS.
that way ill only have to solder 3 wires.

i hope to have the high rate BMS in under 2 weeks. i have ordered and paid already.
ping has told me he will ship it on the 12th. hopefully it doesn't take as long to ship as the battery did.

Jason.

 

[amberwolf]

How long have you left the Ping charging? Long enough for it to finish balancing? It's possible that a cell group or two is running low and triggering the cutoff, if they're not all fully charged.

If you have the v2.5 BMS it should have LEDs on it to tell you when it's balanced, AFAICR.

It's not that uncommon for a brand new pack of many types to be unbalanced when it first arrives, and need a "break in" period of shallow discharge and then recharge/balance cycles. I've never had a new pack so I haven't done the process myself on a new one, but on a used repaired Vpower/CammyCC LiFePO4 pack, it seemed to help it after it's repair.

I'm suggesting this primarily because a Vmin of 49.5V seems pretty low at only 16-17A (1C) on a 48V 15Ah Ping, which should be nominally about 54V or more when fully charged (close to or past 60V hot off the charger, IIRC).

A low group would cause the BMS to cut out when current draw causes voltage drop in it, the same as if the BMS registered overcurrent. Also, I would expect the BMS to handle 2C of the pack, since AFAICR that's what Pings are rated for (at least).

 

[neptronix]

Good luck with the high rate BMS.

Heh, lipo can charge as fast as the ping battery can discharge!! You just need a mega charger like a hyperion 14s net duo or a meanwell >1000w + cc/cv board rig.

For example, i can dump 5 amps into my 5ah 20c zippy pack and the pack remains at room temperature.
Meanwhile a ping 15ah pack will want to charge at about 5 amps..

I say kick those saggy cels to the curb if the high capacity BMS doesn't work for you :lol:
BTW your 20amp setup on a 15AH ping isn't *too* bad. Voltage sag will be less than desirable, but it will work okay for that amount of amps.

 

[Diamondback]

i left the pack on charge for about 3 hrs (with the 5ah charger)
all 16 leds light up at about the same time, so the pack is fully charged and balanced.

it reads just over 57 volts straight off the charger.

ill try the high rate BMS, and maybe a few light discharge cycles with the motor running, but no load on it.
if that doesn't work, ill be buying the lipos.

have to figure out a series / parallel combo harness to give me the volts / amps i want though.
only disadvantage to running the lipo's is that ill have to charge 8 individual packs, and that could take
8 - 10 hrs im guessing. unless i buy 8 balance chargers (not something i want to be doing)
2 chargers might be ok. not 8 of them !

im really hoping that the ping comes good with the high rate BMS, as i paid over $600 US delivered for it.
i would hate to then have to spend another $500 for 8 lipo's and a decent AC balance charger....

Jason.

 

[neptronix]

If 14s is enough for you ( ~52v nominal ), the hyperion net duo will do a 14s ( 5s + 5s + 4s or some other configuration ) strand connected in serial simultaneously.

Also, you do not need to balance charge the lipo every time. I am building serial harnesses for each of my 10s packs ( 2x 5s packs ), and a parallel harness for everything. If i need to balance charge a single block, i disconnect the parallel harness and plug a single 10s block into my iCharger 1010 10s charger.

Often times i don't though. I run my lipo packs down to about 10% - 20% of their total AH, and have not needed to balance them going on 10 rides now.

Not as easy as a ping, but not so difficult either.

 

[Diamondback]

if i end up running lipo's i was thinking about running 8x 5000mah turnigy 20C packs.

i could wire them up in 2 strings of 12S 1P for 44.4 V at 20AH. (i think that's correct ?)

the voltage would be somewhat higher fresh off the chargers though. the controller i have is rated for 60V max 20A.
so i guess as long as the voltage is under 60V charged, it would be ok. the ping shows about 57 volts fresh off the charger,
but quickly drops to about 55 volts.

Jason.

 

[Diamondback]

something strange is going on....

i just went for a quick test.

i had the battery on the charger for about 5 hrs today (after the leds lit up)
i took the battery down to the bike, plugged it in, and the voltage read 58.0 fresh off the charger
(with all 16 leds still lit up).

i did a no load test with the rear wheel off the ground. i ran it for about 3 minutes at full throttle.
i then went for a ride round the block. no battery cut off with the CA set at 11A !

the CA read a Amp max of 28.18 and a V min of 49.3 and not a single cut out ?
i dunno whats going on. maybe i have another issue, and it's not the battery / BMS ?

it's a long shot, but if there are any sydney australia ebike guru's that can check my work ? (i don't mind travelling to you)

this is only my second ebike build, so im still reasonably new to all this.

Jason.

 

[neptronix]

if i end up running lipo's i was thinking about running 8x 5000mah turnigy 20C packs.

i could wire them up in 2 strings of 12S 1P for 44.4 V at 20AH. (i think that's correct ?)

the voltage would be somewhat higher fresh off the chargers though. the controller i have is rated for 60V max 20A.
so i guess as long as the voltage is under 60V charged, it would be ok. the ping shows about 57 volts fresh off the charger,
but quickly drops to about 55 volts.

Jason.

That is correct. And they would come 50.4v hot off the charger and balanced, or 49.2v if you charged them conservatively to 4.1v per cell.

 

[Diamondback]

49 or 50 volts would be fine.

though as per my above post, i might not need them (in the short term anyway)
if i can get to the bottom of my battery issue, ill be ok.

if and when i need to replace the ping, i probably will go with lipo's.

im still trying to figure out why the ping is intermittent now.
earlier today, it was no good. cutting out at only 16A and tonight it was fine with 28A load and
not a single cut out.

im going to leave the battery on the charger all night, and test it again tomorrow afternoon.

Jason.

 

[dogman dan]

Your battery is possibly not cutting out. You have a bad connection somewhere on the bike.

Look very hard at ALL connectors, and particularly look for a plug with one contact backed out of the housing. You might have an prob with the CA, have you tried the bike with the CA disconnected?

If it is the battery, it could be one of the bms wires. Not real likely because they all light up, but maybe a bump, and something breaks contact intermittently. Talk to ping first though, about unwrapping it to look for that. If it is the battery, he will help you figure it out, and get it fixed.

Lastly, if it is the bms itself cuts out early, the new one will fix you up in a jiffy. If you just are frustrated now and want to go lipo anyway, 15s lipo charges to 63v. 12 s is easy, and 14s charges to 59v.

 

[jbond]

Just a thought. What's the LVC set to on the controller? Are you sure it's the battery cutting out, or could it be the controller?

BTW. What's a recommended Controller LVC for a LiFePo 48v battery? (and a LiFePo 36v).

 

[Diamondback]

It's definitely the BMS cutting out, because all my lights and the CA go off at the sane time.
Everything on the bike is running from the same battery.

I will double check all of the connections tonight when I get home from work.

I'm leaning towards a connection issue now.

BTW the LVC on the CA is set at 41V.
No idea what it is on the controller. It's the stock 20A ezee controller.
Running at 48V

Thanks for all the suggestions guys.

I'll keep this thread updated.

Jason

 

[dogman dan]

At least then it's not a phase wire connection or something of that sort then. Narrows it down a lot, if it's a bad connector, its on the battery to controller plugs. Or, if the CA has a shunt, it could be that.

Another possibility, that's happend to me more than once, is an intermittent disconnect on the plug from charger to battery. When the plug breaks, the charger light turns green, and off you go with a partial charge. Not very likely though, since you have a CA. You'd notice the low voltage I'm sure.

 

[John in CR]

Yep, first thing is unplug the CA, and give it a try without. CA calibration issues can stop you right out of the gate. Get her running first with the bare minimum connected...throttle, controller, battery, motor. Then introduce things one at a time.

No, you don't have to sell your new ping on ebay. You'll get fixed up. Could be the BMS got smashed a bit in shipping, could be a loose connection. Best odds out of the chute are the CA is blocking it from running. That one got even Liveforphysics last year when he was down on a first time hubbie connection. Next would be a bad connection.

Try running a number of light bulbs off your battery, or a blow dryer, or electric drill...something to put some load on the ping and see if it trips the bms. Be careful of shorting the leads or using too thin a wire when load testing a battery.

John

 

[amberwolf]

I'm still thinking it's just not really fully charged and balanced, and there is a not-really-full cell group or groups, regardless of what the LEDs are reporting, simply because leaving it on the charger longer (even after the LEDs said it was done) appears to have made it work better/longer, at least once.

I'd vote for leaving the Ping plugged into the charger constantly for a while, perhaps testing periodically on the bike to drain it a bit and see if the cutouts are less (or gone) and then recharge it a good long while again.

You can test if it is a cell group that's low by using a voltmeter on each wire of the BMS's cell-balance-wire plug plus the ground wire, one at a time, and noting down the voltages under load (motor, light bulbs, whatever). If any of them are significantly lower than others, it's an unbalanced group or groups causing the problem, and most likely fixable simply by continuing to charge it for a while (perhaps days).

 

[Diamondback]

i left the battery on charge all day while i was at work.

got home, plugged it into the bike, and it the bike worked for about 5 meters.
i unplugged it, wiggled the wires round a little (between the battery and controller,
and it then worked flawlessly on a ride round the block !

draw was 29A v min was 51 v.

so i am now convinced i have a wiring issue somewhere between the battery and controller.
im going down to the garage now to strip all of my wiring to look for a short somewhere.
it must be there somewhere.... even though i have a 50A fuse in the power line, and it's not showing signs of blowing.

maybe the BMS is quicker at disconnecting the battery before the fuse can blow ?

ill report back my findings soon.
hopefully i find something really simple.

Jason.

 

[Diamondback]

ok, i think (fingers crossed) i might have found the problem.

where i taped into the main power line to run the rear led light, there was one wire that might have been able to short.
it was so close that it might have occasionally been able to touch when the harness moved.

i re taped the main power line from the battery to the controller, and went for a 10 minute ride.
several small tests rides actually. i incrementally upped the amp limit on the CA, and with it now set on 15A
i didn't get one cut out. max current was 24 amps. minimum voltage was 52V.

im not gonna say it's 100% the problem, till i have a few cycles on the pack with no cut outs.
(apart from the LVC cut that is...)

thanks to everyone for your comments and suggestions.

if in a few weeks i still have a reliable power source, ill start commuting to work.
it's a 18 km trip home in the dark. not something i would want to have to do with no lights or power.

Jason.

 

[dogman dan]

Glad to hear we helped you sort it out.

I'm not so smart, I've just put enough bikes together now to have done it wrong quite a few times. So I smelled a rat in the bikes wiring right away. It just made no sense that the battery was at fault. Had you been having that bad a balance, you wouldn't have been likely to have all the led's light up so quick.

Just shows you how good a ping can work, every time that thing shorted out, it shut itself down and prevented any fire or damage.

Just shows you how good a battery vendor Ping is too. Others would have ignored you till you started a pay pal dispute.

 

[Diamondback]

Yeah I agree that battery seems great.

And now I'll have a high rate BMS as a spare
Should I ever need one.

I have already emailed ping and thanked him for the support
And trouble shooting information.

I really hope I have it sorted out now.

Thanks again

Jason.

 

[Diamondback]

some more testing today showed that the problem was not my wiring after all.

i deliberately used very light throttle to see how the system would go with low loads.
it cut out again with only 4A max on the CA.

But, this time i noticed that the power cut when i hit a small bump.
so i reset the BMS, and started to tap and poke the black plugs that go to the BMS with my fingers.
after about 3 or 4 taps, it quit again. (no load at all this time)

it looks like i have a bad connection on the smaller of the two plugs.
what can i do to help to ensure that these plugs fit tightly, and do not break contact ?

unplugging the large black plug has no effect on the power (i didn't ride at all with this plug apart)
but unplugging the smaller black plug immediately cut power.

so my suspect for the power cuts is now the smaller black plug is a little loose on the contacts
and sometimes doesn't make contact properly, and the result is that the BMS powers down.

any ideas on what i can do to solve this issue ?
is there any real reason that i cant solder and heat shrink these wires and remove the plug altogether ?

i know that soldering the wires will make it harder to replace the BMS in future should the need arise,
but if they are soldered, there can be no connection issues.

i would only be soldering the 4 wire plug, not the much larger one, as that one seems to be ok (for now anyway)

Jason.