My Ping Battery has one bms led not going on

I bought a 36v 15ah lipo 4 battery a few months ago and I have been doing a little charging here and there because I havent used it that much. The last time I charged it I saw all led's solid except for one. Is that a problem?

I also just read that the sensor wire(?) should be disconnected during longer periods of storage/inactivity. By sensor wire are they talking about disconnecting the grey data ribbon? I have heard that this is stated in the papers/pdf you get when you get the battery. I did not see it but i don't doubt it is there somewhere.

Should i always keep the bms ribbon cable connected except for storage?
I have had it connected for 3 or so months and i have charged it 2 or 3 times.
I have only tested the bike our once and the battery has basically been stored.
Any help would be appreciated.

If you have not tried leaving the battery on the charger for an hour or so after all of the other LED's have lit, try doing so. Maybe even overnight. It wont hurt anything. Sometimes with a newer Ping battery it takes a few cycles for all the cells to balance. If after that it is stil a problem, contact Ping via email. He will help. I have not heard of the storage part where the ribbon is disconnected but it makes sense. Once again, Ping will help. Customer service is top notch.

I believe what happens when you leave the 'sense' harness connected for long periods of time, is that the BMS will drain power from the 1st cell to power itself. Over a very long period of time, this will kill a parallel group of cells.

Unfortunately, many of the cheaper BMSes act like this. The term 'battery murdering system' was invented for this reason.

This is not fun to fix, but it is fixable.
Measuring the voltage on each cell individually would be helpful at diagnosing this issue.

Hopefully it's just out of balance, from the one cell running the bms. End one won't light?

In any case, put it back on the charger, and leave it on the charger till the light comes on.

Definitely worth while to get a voltmeter. Unplug the bms so you can acess the wires to the battery on the ribbon cable, and see if any read 0v. low v means the wire is connected but the cell group needs a charge. Zero volts may mean that one sensor wire got disconnected. A disconnected wire can happen, but it's unlikely. Pings construction method makes a wire pulling loose pretty unlikely.

Storing for more than a few weeks, a bms should be disconnnected if possible. If not, charging every few weeks will work.

Thanks for the responses. I will throw it back on the charger longer this time and see if the led pops on. Hopefully it just needs a tad more balancing. I'll let you guys know what happens.

On another note I bought a headlamp for my bike. Should i buy cheap small battery with the proper voltage or should I run it through the Ping battery? I'm not to keen on forking out the money for a converter though.

Chances are your headlamp would cook off on 36v or 48v. I used to run a 24v bike light on a drill nicad pack. So that's a convenient option if you happen to have a drill with the right voltage in the garage.

asking general questions gets generalized answers.

which led?

how long do you charge? the led has never ignited?

do you have a voltmeter? if so then measure the voltage on each cell where the sense wire plug is soldered into the BMS. measure with the pins of the voltmeter stuck into the solder on the pcb where the pin side is soldered on. measure while charging.

when we have some info then we can give real advice.

Update: I let the battery charge overnight and all leds are lit up. Interesting how much longer the last one took.

This happens occasionally with ping's battery and bms. Sometimes the charger even cycles on and off toward the end of the charge to balance the last few cells. dnmun is the one to ask about ping batteries for sure. Make sure you leave your ping plugged in occasionally overnight to balance the pack.. :wink: :wink: :wink: :wink:

a week later, but still no knowledge about the pack since he did not measure cell voltages. he never said which led either, so now he thinks everything is ok, but he could have a problem starting, but no way to offer him advice since we don't know anything.

it is not just the ping signalab that consumes the battery charge on the first cells for the circuit current. all the BMS do that too.

this is what gets to me, try to direct people to start with the fundamentals to analyze battery problem and instead they think it is a waste of time.

i try and try to get people to make a list of cell voltages so if they have a problem, they can refer back to the previous balanced voltages, but people think the total pack voltage after sitting for a day is the only thing that matters, so they never can catch a failure in advance.

dnmun said:

this is what gets to me, try to direct people to start with the fundamentals to analyze battery problem and instead they think it is a waste of time.

Click to expand...

Well first off thank you for your concern and willingness to help. I had a presentation to complete for college and haven't had any real time to analyze the problem. I think I have a volt meter in storage; I will have to check on that.

I did not think that the lifepo 4 was so high maintenance and unpredictable.
The led that was out was the 2nd led (assuming I am looking at it from the right angle). My vision is pretty bad so I will have to ask someone else to check the voltages for me in all likeliness.

ok, that helps, count #1 from the end where the shunt and ground and all the mosfets are. that is the bottom. the circuit current for the v2.5 signalab comes off the bottom 3 cells so when you leave the pack uncharged for long periods, the circuit current will drain down those cells and push the pack far out of balance.

if the dark led was at the top, say #11, it would mean something totally different was happening, but i would guess it really is because of sitting unused. you can unplug the sense wire plug and the BMS will no longer drain down the first 3 cells.

but you need to realize that if those 3 cells drain way down below 2V from the circuit current, while the pack is unattended as has happened to others, it can destroy the first 3 cells and make the pack too expensive to repair. that is why we recommend you disconnect the sense wire. then the pack will stay happy for years unused. with no need to charge it until you plug in the sense wire again.

you need a voltmeter, the most important thing to analyze problems. harbor freight has the cheap ones everybody uses.

knowing what the cell voltages of the normally balanced pack are allows you to catch a deviation in how the pack balances, so you can have an idea of what happens when the pack has problems in the future. when you run into capacity shortage problems.

I also found that the pins going into the bms can back out of the plastic plug. Not that it is the problem the pins and wire can back out of the plug. Hope you have fixed the problem. Good luck.

Hi Blueshift,

I have found that my Ping batteries like to be used, in terms of seeing all the LED's light up together. So I try to use each battery at least once a week, and at least put it on the charger once a week.

I gave my son and his wife a 48V 15AH Ping a couple of years ago, and last winter they didn't use it very often and didn't ever charge until all LED's lit up. By the time I was able to pick up the battery a couple of cells were very low. It took me several days of close attention (i.e., letting the LED,s discharge their respective cells, then plugging in the charger again, then repeating the process) to bring the low cells up where they belonged.

Their charger does not drain the battery when it is unplugged, so we set it up on one of those little timers, and now the charger comes on every day for 15 minutes. Seems to be working good, and the battery is always fully charged and ready to use. May have some long term effect, but I long ago adopted the ES attitude that when a battery dies it gives me an excuse to get a new and better one.

be careful about assuming a charger does not drain the pack if the charger is turned off and the pack is still plugged into the charger. if the charger does not have a zener diode on the output, the 5.6kohm drain down resistor across the output caps can drain the pack back into the charger. but slow for sure through 5.6k.

Good to hear that leaving it on the charger for a longer time allowed it to balance. That means you have a good pack. I had the same issue when I got my Ping and did not use it for a while. Cells 1-3 took longer. Sounds like all is well. I will also follow the advise provided here to disconnect the balance leads as there are times where it does not get used for a couple of weeks. Thanks to all other ES members that have replied.
Dan