HVC tripping fresh off charger

[john7700]

Aaaaaargh. This is starting to drive me nuts. It's a good thing that my BFH is stored in the shed and not where I work on my bike or I might turned my battery in to a Ping Pancake !

It appears that my battery is accepting an over charge and when I try to run my bike fresh off the charger it continuously trips my HVC. I have had this problem intermittently from time to time but the last few days it has been horrible. Normally, I would lift the rear wheel and run it no load for a few minutes and it would settle down. Now it is continuously tripping the HVC even under no load. Eventually, it gets to the point where it blows the minute I reset it by disconnecting and re-connecting the battery. At this point, only plugging in the charger will re set it but then it still blows the minute I ease the throttle on. The only way I have been able to get it to run is to leave it plugged in to the charger and running it no load for about twenty minutes. This is unacceptable and driving me nuts.

Any ideas to mitigate this problem ?

Thanks Folks,

John

 

[FMB42]

Sounds like a BMS problem.

BTW, are you using a Ping charger?

Either way, I'd contact Ping about your problem (he has a very good reputation for both standing behind his products and/or being very helpful with issues such as this).

 

[dogman dan]

Hitting the hvc. So what voltage battery is this, and what kind of controller. Are you that mismatched?

 

[john7700]

Yes I am using a ping charger.

36 v 20 amp Ping with the basic 9C 25 amp controller.

It took me about 40 minutes total to bring down the power enough to be
able to ride today. I think I'm going to run over to the orange roof and
get a like socket and solder it up with some andersons and see if I can use
a light bulb to hopefully bleed if some voltage that way. Does this sound
plausible or safe to any one?


Thanks for any input,

J

 

[DAND214]

Like Dogman said. What is the voltage when pulled from charger?
There is no way a 36v battery should trip the controller. It sounds more like a BMS concern as FMB42 stated.
It sounds like the BMS is tripping not the controller.
And if you ran it for 20 minutes, no load you are using a lot of lost power.
Dan

 

[John in CR]

I recall someone mentioning that Ping chargers have a trimpot to trim the top of charge voltage. What about something as simple as a diode inline with the charger output to drop the voltage half a volt or so?

 

[john7700]

Like Dogman said. What is the voltage when pulled from charger?
There is no way a 36v battery should trip the controller. It sounds more like a BMS concern as FMB42 stated.
It sounds like the BMS is tripping not the controller.
And if you ran it for 20 minutes, no load you are using a lot of lost power.
Dan

Dogman asked "So what voltage battery is this" that's why I replied 36v. When I unplug the charger the CA reads 44.1V. I don't know what it "should" be. I cant get it to stay running until I drop it to around 42V and used up around 1.3A. I wouldn't think this can be good at all for the battery.

John in CR, hate to say it but I really have no idea what you just said I am a newb on his first build with little electronic experience. I am however fairly handy and mastered taking the motor apart and fixing a broken hall. If you are suggesting there is something inside the charger that I can go in and adjust I would certainly be willing to try but, isn't that what the BMC is suppose to do?

Right now my bike is my transportation so I would really like to keep using it. If I need a new BMS it is going to take a while to get here. Anyone have an opinion on the light bulb idea? I don't want to damage anything or myself I'm going to give it a try in the A.M. unless someone says otherwise. Also, is this voltage (44.1) going to damage the battery?

Thanks again fir any advice,

J

 

[NeilP]

I have not owned a ping battery, and from the pics on the site, they look pretty sealed up, but is there any way you can easily open it and check the voltages of individual cells?
Try checking at full charge and empty

I am just wondering if maybe you have a few low cells, that are pulling overall pack voltage down, BMS not working properly, so when the charger is bringing the pack up to full charge, it is actually overcharging some cells to compensate for the low voltage cells

The only way you will tell this for sure is to take pack apart and check the voltages per cell

 

[Rassy]

I had a couple of thoughts reading this, for a temporary fix until you get the charger sorted out properly.

If the battery is a V2.5 with the LED's that light up, just remove the charger when they all come on. If it doesn't have the LED's, check it with a voltmeter and quit charging at about 42 volts. It wouldn't hurt to check the individual leads to make sure the cells are balanced.

It sounds like you leave the battery on the charger until you are ready to ride. If you charge it up and leave it set, the voltage will normally drop a couple of volts in a matter of hours. But I like the idea of cutting off the charge earlier, since the battery may be over charged with that current charger.

Good luck getting it all figured out.

EDIT: Neil posted a question about checking individual cells on a Ping. There is a 12 pin plug where the leads to each sub cell (4 cells actually) are connected to the BMS. You may have to cut a little plastic from the BMS, but you can catch each of those wires with a pointed probe on you voltage meter. Be careful not to short between adjacent wires! On one end, I think the positive end, you have to put the probe on the actual positive battery lead to measure that end cell.

Edit 2: I was wrong, it's the negative end where you need to do an extra probe for the end cell. You can just put the negative probe on the negative charger lead.

 

[NeilP]

That is good, to hear that you can get to a lead like that without a complete pack strip down.

Definitely worth doing, to check the balance. How many cells in series in a pack like this? From what Rassy says it sound like it is a 4 parallel pack, but wondering how many in series?

If this plug is easy enough to get to, I would be tempted to try and splice some extra wires into it...with a JST XH plug on the end..so you could then monitor the balance with something like a HK battery medic. Ok, no use for your immediate problem, but after having heard about problems like this...and someone else here on the forum...(Luke...LFP ? ) renaming BMS a Battery Murdering System. I would like to see the balance myself rather than rely on LED's and a BMS

 

[John in CR]

Ping uses a 12s structure for his 36V batteries, so 44.1 is 3.675v/cell and not dangerous if the cells are in balance. My version 1 ping 36's cut off at a more conservative voltage though.

For balancing Pings, you do know that you need to leave it on the charger for an extended period to balance, right? The charger turns on an off during that period. If you do open up the plug to check each cell, the best way to avoid a short is just put one of your multimeter probes on a battery lead and use just one probe to get the voltage at each cell level. Guys using both probes so close together on something so small are asking for trouble just because they can't perform the simple math operation (subtraction) to get the voltage of each cell.

A pot (potentiameter) is just a variable resistor. If the charger has one, then that's certainly a simpler mod than changing motor halls, something I've been lucky enough to avoid. The best advice is to tell Ping the issue and ask him what to do. Let him know that if it's just opening up the charger and making a simple change, that you can handle that with simple instructions...much preferable, quicker and cheaper than sending something back to him.

At this point you don't know if it's the controller or the BMS that is not liking the voltage. I had the same issue 3 years ago with 2 Ping 36's in series. My controller didn't like the top of charge voltage. I needed a good headlight anyway, so my solution was to use a DC/DC converter to supply 12V to a halogen running light as my headlight. If the controller didn't like the high voltage, I just turned on the headlight first, which drew enough current to drop that surface charge down to a level the controller liked.

A diode is an electrical component that allows current to flow only one way. When current goes through a diode there is a voltage drop across them, typically something like 1/2 volt, but it's a fixed small amount. That should be enough of a drop in voltage for you. A diode in line with the charger wire I think would work to reduce the top of charge voltage as a simple solution.

A resistor would drop the voltage too, but the charge current tapers down at the end, which would cause the voltage drop across the resistor to vary with the current, so simply putting a resistor in line with the charge wire won't work.

 

[dogman dan]

I don't see how it could possiblly be an HVC on the controller. I've never heard of one, only a partcular voltage above which you fry something. Iv'e run the same controller at 63v, as have others. Even a 48v ping shouldn't be charging any higher than 60v.

I think you may need to get a new bms.

Also a possibity as always, is something random and wierd. Like a cold solder on one of the wires to the bms board, or the controller board, or the plug between them causing intermittent disconnects. We all know well, how frustrating those intermittent disconnects can be to troubleshoot.

Actually, the more I think about it, an intermittent disconnect is very likely your problem. You think it correlates to lowering the voltage, but that's the randomness of this problem that makes it so easy to mistake for something else causing it. Check the balance wires to the battery too, one of those disconnecting would trip the bms off. Could be as easy as unplugging the bms plug and replugging it to fix.

 

[john7700]

I just wanted to add a post to give a wrap up for those who were nice enough to respond
to this thread or for those who may have a similar problem.

Indeed the BMS was at fault.

Contacted Ping and they quickly responded asking me to shake
the wires etc when at full charge to look for a short and double
check the connectors. On a Friday they said they would ship it
on Monday, I received it last Sat. Put it in on Tues. (after the
hurricane) and have gone through two charge cycles with every
thing working normal again. I still haven't checked the LVC but
I'm confident that issue is corrected now as well.

Thanks for the great service Ping and thanks also to the ES crew for responding.

J

 

[dnmun]

the HVC on the signalab does not have anything to do with the output fets. it only controls the charging fet. your problem was not caused by HVC in any way.