Help! Ping Disaster...

Batteries, Chargers, and Battery Management Systems.
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chvidgov.bc.ca   10 kW

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Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 08 2010 12:52pm

Hi...I was riding and I noticed that I was still able to get electricity out of my ping, but riding without a CA I didn't realize my voltage was only 38V (on a 48 volt ping). When I got home I realized that the BMS was fried, blackened/burned, and that I had been pulling juice out without the BMS LVC or any LVC protection. There is observable minor swelling on 2 of the four cell groups it looks like, but I haven't taken it apart. The current voltage is still 38. I have another Ping battery of the same type (48V 15Ahr). The battery is still working but week of course.

Is the battery, as well as the BMS doomed?

Can I still charge the ping battery somehow, through the BMS negative charging wire? Or the negative discharging wire.

Should I take the battery apart and check the voltages of the cell groups?

Any advice is appreciated. This battery could be toast. On the other hand if I can get the voltage up to 61 again, I might try a BMS replacement from Ping.

Unfortunately I was using a controller with no CA outlet for another LVC protection.

Chris

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 08 2010 12:57pm

It has recovered now to 42.8 volts, measured on both the charging negative and the discharging negative. Maybe the LVC trip on the BMS was what tripped the burn of the BMS. Is this likely?

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Rassy   10 MW

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Re: Help! Ping Disaster...

Post by Rassy » Mar 08 2010 1:06pm

When I got my first LiFePO4 batteries (Over 2 years ago, from Anna, but same as Ping V1) one of the BMS units was bad. So, before getting the bad BMS replaced, I just cut both BMS units off the batteries and added connectors so I could use the good BMS on either battery. This also allowed me to bypass the BMS for using both batteries in a parallel configuration, and also to insert a Watts Up ahead of the BMS when desired. So far, both of these batteries are still performing as good as ever.

Anyway, this would allow you to get that weak battery recharged without having to wait for a new BMS. Good luck. :D
-Rassy-
One Tadpole Trike equipped with a Bafang BBS02
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One Delta Trike equipped with a Bafang BBS02
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chvidgov.bc.ca   10 kW

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 08 2010 1:32pm

Thanks Rassy...

here are the estimated voltages, from the BMS sense wires...

2.2 1
2.08 2
2.28 3
2.19 4
3.07 5
3.15 6
3.16 7
3.07 8
3.1 9
0.1 10
3.1 11
3.2 12
3.2 13
3.1 14
3.2 15
3.1 16

Looks like cell 10 is shot around zero volts...maybe cell 1-4 also around 2.1-2.2 I'll see if I can get those 4 up to a better amount.

999zip999   100 GW

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Re: Help! Ping Disaster...

Post by 999zip999 » Mar 08 2010 2:06pm

How old are are your batteries, number of cycles ? Ping has new BMS at a good price, and will help you though it. Good change if your pack has swelled there is damage. It's pretty easy once you open it up. Because if it swells the tabs can tear.

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dogman dan   100 GW

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Re: Help! Ping Disaster...

Post by dogman dan » Mar 08 2010 2:44pm

Any swollen cells are toast I think. Those would be the ones at .1 volt I would guess. You could take the thing apart, test every cell, and order new ones to replace em, along with a new bms.

Or rebuild into a 36v pack with remaining good cells.

Or just dump the remaining good cells in the for sale section of the forum.

chvidgov.bc.ca   10 kW

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 08 2010 3:03pm

Silly question...if I rebuilt the pack as a 36 volt, with only 11 cells, would I need a "special" BMS designed for exactly 11 cells, or would I purchase 1 cell and get a predesigned 36V BMS made for 12 cells? I'm kind of a newbie with this.

I've got about 200 cycles on the pack, and I've only been to LVC once before, in all of those.

Is it possible to buy Headway premade pack with functioning BMS <no BMS issues> from somewhere? I don't want to build it myself.

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dogman dan   100 GW

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Re: Help! Ping Disaster...

Post by dogman dan » Mar 08 2010 3:11pm

Somewhere there is a thread about removing some channels from a bms.

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Re: Help! Ping Disaster...

Post by dnmun » Mar 08 2010 4:42pm

other doc has a thread on his attempt to use less than the number on his BMS.

it would help if there was picture of the BMS and what burned up.

not having info on current and how it was wired up makes it hard to even evaluate what happened.

the BMS should have shut off the pack if it really had cells that dropped below 2.1V so this is curious. not sure how he could discharge it with a cell that low.

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 08 2010 5:54pm

I think the BMS got too hot - as there is some melted yellow foam on it, which burned something out, in such a manner that the LVC function failed, yet current was still flowing from the pack, and it appeared to operate normally. The thing is it seems that the BMS runs hotter in the second half of the pack, which I didn't normally use, hottest near LVC. I'm thinking if I put a spare hub motor cover, convexly over it, between the BMS and the Arkel Tailpack the battery is in, air will circulate around it better, and the metal of the cover will transfer heat away from it. I should have followed Dogman's advice - I may need to find a better solution.
I'll single/group charge the whole set of cell groups and see where they end up voltage-wise with a 3.9 volt wall wart which would hypothetically result in a total of 62.4V which is about what a full charge was before - 61.7 - with surface charge. So it really is my own fault. Maybe a thermistor/thermometer in there with a digital readout.

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Re: Help! Ping Disaster...

Post by dnmun » Mar 08 2010 6:38pm

first, is this a ping pack? can you take a picture of what you use for the BMS? it has one cell that is at 0V and you want to charge to 62V? is there any way to estimate the true current flowing through the BMS from whatever you use for a motor and how steep the hill was? 40A, 60A?

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 08 2010 7:37pm

Yes one cell is at zero, 4 are around 2.1. The BMS shows visible black/burn damage - it is a PING v2.0 Signalab 16cell BMS. No charging occurs through it. There is visible swelling in some cell groups. See above for the resting voltages. But I'm pretty well ready to give up on it, as I don't want to get into pack deconstruction/soldering etc. Just want to ride. So I'll get another and take better precautions against heat. I got a good year of riding out of it, and saved a ton of gas.I'm moving my old Mom next month, so no time to mess with it much. My motors pull a max of 25 amps, usually much less, so I don't think it was Ping overload C-Wise, but BMS catastrophic heating with LVC bypassing - it just didn't shut the pack down when it should have, at least that's my theory. Thanks.

999zip999   100 GW

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Re: Help! Ping Disaster...

Post by 999zip999 » Mar 08 2010 10:26pm

So you have over 200 cycles, Is it over a year old ? You were running a 35amp. controller maybe up some hills ? 48v15ah Ping V-2 ? What motor ?

chvidgov.bc.ca   10 kW

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 08 2010 11:10pm

Crystalyte 405 with HighTekBikes sensorless Aotema 25amp. A few hills around Victoria, British Columbia, nothing major. I only went 6 miles this morning, then poof.

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Re: Help! Ping Disaster...

Post by SpeedEBikes » Mar 09 2010 12:12am

I'm not familiar with the Ping BMS, but I had BMS failures with three other brands of BMS. Hitting LVC can be a failure point. Often it happens while at a high current and while battery and BMS are already somewhat hot. BAnd MS units on many batteries have inadequate heat sinking for use in an enclosed environment. Bike motors can have a lot of inductance and if the BMS isn't robustly designed for that the inductive voltage spike can zap the BMS at it tries to cut off power. This is aggravated further when using multiple packs.

I've switched from using a BMS to using cell monitors that trip an audible alarm if anything goes amiss.

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Re: Help! Ping Disaster...

Post by BikeFanatic » Mar 09 2010 8:56am

I'm sorry to hear about your battery failure. I too have an old Ping( version one I think from 2008) and I may need to replace a cell group myself, but not looking forward to it. If you do decide to give up your battery for sale I bet some other ping owners could use the cells -maybe you can recoup some of your costs, try the for sale used threads.

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Re: Help! Ping Disaster...

Post by dnmun » Mar 09 2010 9:16am

you should be cautious about buying cells which have been overcharged. he already had 4 poof up from overcharging so the others are suspect too, imo.

ping now sells replacements where the pouches are already soldered to the cut 1/2 subconnectors so all you need to do is cut out the old cell and solder the new one in place. GDinDC was the first to get them after we came up with the idea on snowranger's thread.

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 09 2010 9:23am

Thanks guys. I don't think I will inflict the remains of the battery on anyone. I've already ordered another Ping, strangely enough. I'll try to keep that one cooler, and if it doesn't work out, I'll switch to another solution. This could get expensive, but need my lithium fix every day.

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Re: Help! Ping Disaster...

Post by SpeedEBikes » Mar 09 2010 10:14am

If you no longer trust the cells for a motor pack, use them to build packs for some other purpose that won't work them as hard. I'm powering a trailer mounted stereo system with 7 year old lithium batteries. They only hold about 60% of their new charge and they have screaming high IR but work fine for low power stuff. Still much better energy density than a brand new lead acid battery.

Get an RC hobby charger that can do balancing for LiFePo cells and a cell monitor and you don't need a BMS. If you ride at night a lot build a 4 cell / 12 volt pack and set your bike up with 12 volt lighting. Or make an external booster pack for your laptop computer - roughly match the voltage output of your AC adaptor and wire the pack with the same plug. Or make up a fat belt pack or back pack to use with your cordless tools. If you have an old dead cordless pack, cannibalize it for the plug.

Lots of good possibilities. Until you make up you mind put the old cells in ziplocs and store them in a freezer or fridge. Kept cold they will store a long time with little further degradation.

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Re: Help! Ping Disaster...

Post by 999zip999 » Mar 09 2010 3:23pm

Ask Ping if it is under warranty. You may get a price break my cells were 8.50usd. 3.2v 5000mah. it came with pcb broards. The bms came with the 16 wire plug. Get a 36v BMS if you have enough cells to make a back up, then you need a 36v charger and a single cell charger for 19.00 to help balance. It adds up. Good luck. Love B.C.

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 09 2010 6:04pm

http://endless-sphere.com/forums/viewto ... ng#p186375

This is exactly what my BMS looked like after the accident.

The charging FETs(?) were burned. It seems you need to unshrink wrap this area, to enable more heat to get away from them, and not wrap the area with any foam.
I think maybe the BMS actually got too hot while charging, packed it in, and then I rode the battery to well below LVC, not knowing the situation.
It's a bit of a dilemma, keeping the area exposed to air, yet protecting the BMS board from physical damage. I was thinking maybe a stainless steel flask abutting the area, filled with cool water,
which has a high ability to absorb heat might funnel away a lot of heat. Some others have soldered a big piece of wire or copper to the area to suck heat away.

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Re: Help! Ping Disaster...

Post by dnmun » Mar 09 2010 6:11pm

but that is not your BMS. i actually have that one here and it was the output FETs that overheated. greg was using it in series with his lipo.

chvidgov.bc.ca   10 kW

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Re: Help! Ping Disaster...

Post by chvidgov.bc.ca » Mar 09 2010 6:29pm

It's not mine? Well not literally, of course. But mine is a V2.0 BMS like the one in the thread. My newer ping is a 2.5 version

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