Home Ruination by Ebike Battery Fire Expulserating PreTerminator™®©℠

guerney

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Consider this a trailer promoting my easy to assemble ebike battery safety contraption. Photos with details and an ever so slightly better video will follow.


 

guerney

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But what is the normal temperature of my charging battery? I bought this in the Great AliExpress Winter Sale of 2023/24, which will long be remembered as one of the good ones:


57024

...which will be switching this 12V bike horn on at 30°C or thereabouts:

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...via a 12V wall wart, because I bought the 110V-220V version of the STC-1000. Back to the question... I had tried measuring battery case surface temperature a couple of months ago using the thermocouple on my Neoteck DVM, but could't detect any temperature change while my battery was charging. IIRC @Sturmey suggested on another thread, that I should use a thermal insulator, so I went with a small block of polystyrene foam; carved a little groove for the STC-1000's heat probe.

Ambient air temperature:

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Heat insulated probe - I pushed it a bit to the right before...

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...securing the probe to the charging battery, mid way along the top because heat rises, while the battery is switched off as per instructions supplied with my battery, held on with a velcro strap. Temperature rose a little straighaway, despite the charger not having been switched on. Temperature lowered to this after 10 minutes:


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Here's how temperature changed with time, in minutes, charging while battery was turned off - I couldn't watch the thing like a hawk, because I was running about doing other things at the same time, hence the irregular time intervals between readings.

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Highest temperature was 24.6°C - so when are the bleeding resitors supposed to start bleeding to balance charge? The charger's light was still showing red at the hottest point, and for quite a long time afterwards. I decided to turn the charger off after the charger light turned green because temperature kept falling... then I turn the battery on, turn the charger back on and resume charging hoping to see indication of a balance charge. Here's what happened when:

57030


The voltage after charging with the battery off, was 41.98V/41.99V - I doubted there was going to be any balancing, because temperature kept falling. With the battery turned on and charging, temerature stabilisd at 22.7°C, presumably held there by the bleeding bleed resistors bleeding bleeding heat into the battery case. After an hour of balance charging, the temperature remained 22.7°C...


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... and the battery measured 42.05V/42.06V, with my reasonably accurate ANENG AN8008 DVM skipping between the two values. This is higher voltage than usual, and for the past three years I have been mostly charging my battery while switched off, because that's what it says on the instruction leaflet. On the odd occasion after I had acidentally done an actual balance charge with the battery switched on, when I thought it was off, my bike felt slightly more powerful, so the "is it balancing?" question has been irritating me - I can't get my fingers in between the plates of the BMS to feel the temperature of the bleeding bleed resistors, and I don't have a thermal camera to see if balancing is happening. The heatsink is riveted onto the BMS.

57031


...therefore it's a jolly good thing I did this test! Voltage after 30 minutes was 42.04V, and 42.02V after 90 minutes, compared to a couple of months ago when I did a "balance charge" with the battery switched off: back then 'twas 41.7V after 30 minutes, and still 41.7V after 90 minutes. On the bright side, perhaps my BMS will last longer than it would have, because clearly, I haven't been using it's balancing functions much. I can't be bothered to check cell bank voltages just now. :rolleyes:

After over 3 years and 4,000km+, this battery with LG MH1 cells which I ordered with my BBS01B kit from IEBIKE on Amazon marketplace was a good purchase, I think. But supplied with wrong charging instructions!!!!

I think it's safe to assume a battery charging temperature of 30°C in winter justifies my Roger Moore impression shortly before Jaws bites him: one eyebrow raised in alarm, at the very least.

Time to discharge my battery, using my 7800LM headlights...

EDIT: It's taken my lights about 4.5 hours to discharge the battery to 39V.
 
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thelarkbox

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Aug 23, 2023
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Auto logging of temp/humidity/relay status from a STC1000 can be accomplished with a 433mhz transmission module when you have reflashed the stc1000 firmware with the wonderfull stc1000+ project from github.

the 433mhz rf signal uses a weatherstation protocol so hooking a 433mhz reciever to an esp8266/arduino etc is all you need to pick up the readings and broadcast them via wifi/mqtt for logging on any network device you have. The code should be a simple edit of example sketches a couple of github projects provide arduino libs for the coms.

(while quality 433mhz h/w can transmit for significant distances, my limited experience with el cheapo ebay components is best limited to a few meters of range for reliability)
 
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guerney

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Auto logging of temp/humidity/relay status from a STC1000 can be accomplished with a 433mhz transmission module when you have reflashed the stc1000 firmware with the wonderfull stc1000+ project from github.

the 433mhz rf signal uses a weatherstation protocol so hooking a 433mhz reciever to an esp8266/arduino etc is all you need to pick up the readings and broadcast them via wifi/mqtt for logging on any network device you have. The code should be a simple edit of example sketches a couple of github projects provide arduino libs for the coms.

(while quality 433mhz h/w can transmit for significant distances, my limited experience with el cheapo ebay components is best limited to a few meters of range for reliability)
Very cool, I knew you'd remind me of the automation possibilities. I gather these STC-1000 units are very popular with your homebrew crowd, and I can certainly see why. At the price I paid:

57042

...it's safe to assume, I think, that I have bought a firmware incompatible cheap knockoff of this:

https://vi.aliexpress.com/item/32863068632.html

57043


But I've tested it, and the 12V bike horn sounds alarmingly loudly when it's easy to set settings are set:




When I grow up and save up enough money, maybe someday I'll be able to afford buying the genuine article and program the window to open for the drone to fly my overhot battery along a GPS defined flightpath to release into a water butt, in a place far far away...


 
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Nealh

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STC1000 is popular amongst us apiarists for temp control of honey.
 
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saneagle

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Very cool, I knew you'd remind me of the automation possibilities. I gather these STC-1000 units are very popular with your homebrew crowd, and I can certainly see why. At the price I paid:

View attachment 57042

...it's safe to assume, I think, that I have bought a firmware incompatible cheap knockoff of this:

https://vi.aliexpress.com/item/32863068632.html

View attachment 57043


But I've tested it, and the 12V bike horn sounds alarmingly loudly when it's easy to set settings are set:




When I grow up and save up enough money, maybe someday I'll be able to afford buying the genuine article and program the window to open for the drone to fly my overhot battery along a GPS defined flightpath to release into a water butt, in a place far far away...


You're making it too complicated. All you need is one of these and a temperature sensor. When the battery gets too hot, the arm drops it out the window.


This method has other advantages. The robot arm can do any other task you program it to do - only limited by your imagination. If you can't think of anything, re-watch the Big Bang Theory series.
 
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guerney

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F1 = 23.04°C (arbitrarily low for easy activation, I'll set it to 30°C [winter] or 40°C [summer] before the probe is trapped to my charging ebike battery)

F2 = 0.1°C (smallest possible differential)

F3 = 0 seconds (delay)

The 2.5A power supply is from the Virgin Superhub they didn't want returned after I cancelled their ueseless "service". The very loud 12V horn requires at least 2A. (Hair dryer test occurs after about 1m 46s in my slightly updated video advert below)





Wiring is dead easy. Because everything is low load, the power supply and the STC-1000 use the same plug:


57067


AC power to the STC-1000 is on the right, live wire for power to the horn is on the left, on the switch for cooling:


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For a hint of drama, I've also wired on a Bafang headlight made red:


57069


For me, this scratches an itch.

Upload pics if you assemble a GuerneyHome Ruination by Ebike Battery Fire Expulserating Pre-Terminator™®©℠, or you're welcome to buy a much higher quality one direct from my Cayman Islands warehouse, for my usual price of £3 million + VAT + parts + labour + delivery + currently unspecified and unknown but highly unreasonable costs.

STC-1000 manual
 
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thelarkbox

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Since your using the 'cooling' relay be mindful of the compressor delay built into the logic of the stc1000 and that once triggered on/off a subsiquent switching within a defined period will be blocked. Probably not relevant to final use as once switched and the battery has been lobbed out the window your problem has been solved, but could throw a spanner in the works while testing
 

guerney

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Since your using the 'cooling' relay be mindful of the compressor delay built into the logic of the stc1000 and that once triggered on/off a subsiquent switching within a defined period will be blocked. Probably not relevant to final use as once switched and the battery has been lobbed out the window your problem has been solved, but could throw a spanner in the works while testing
Isn't that F3? I've just tested it with F3 = 0 three times, light and horn switch on with very little delay, and once the probe is cooled (used a pair of pliers), subsequent switchings on via are unaffected. On my STC-1000 clone, there's no startup delay for cooling after switching the unit on.
 

thelarkbox

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Isn't that F3? I've just tested it with F3 = 0 three times, light and horn switch on with very little delay, and once the probe is cooled (used a pair of pliers), subsequent switchings on via are unaffected. On my STC-1000 clone, there's no startup delay for cooling after switching the unit on.
Thumbs up, My recall of the specific settings is way worse than that of a common gotcha that you have not fallen for ;)
 

guerney

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Thumbs up, My recall of the specific settings is way worse than that of a common gotcha that you have not fallen for ;)
The alarm horn and light were delayed as you described in post #9, and I wasn't happy about that at all: 59 seconds closer to an unextinguishable battery fireball in my home? That's much too long! Looking at lithium-ion battery fire videos on Youtube, inextinguishable progress to armageddon is very rapid. Before ignitable smoke escapes the case, there must be overheating within, demonstrably detectable on the battery case. By the time smoke alarms sound, it's far too late to do anything but kiss your house and belongings goodbye and run. Happily fixed by setting F3 to "0" - seems Big Clive doesn't know because he doesn't use these devices, said it was "built-in", rather than being a changeable setting in post #7.
 
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saneagle

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The alarm horn and light were delayed as you described in post #9, and I wasn't happy about that at all: 59 seconds closer to an unextinguishable battery fireball in my home? That's much too long! Looking at lithium-ion battery fire videos on Youtube, inextinguishable progress to armageddon is very rapid. Before ignitable smoke escapes the case, there must be overheating within, demonstrably detectable on the battery case. By the time smoke alarms sound, it's far too late to do anything but kiss your house and belongings goodbye and run. Happily fixed by setting F3 to "0" - seems Big Clive doesn't know because he doesn't use these devices, said it was "built-in", rather than being a changeable setting in post #7.
Make sure that you don't get a short or over-loaded component in your device. It would be a shame if it caught fire and set off the battery before it had a chance to save you.
 

guerney

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STC1000 is popular amongst us apiarists for temp control of honey.
You keep apes too? How do they get on with your cats and bees? And how do you regain control of your honey from the apes?

Would turning crates full of honey jars using a hub motor every half hour (or continuously, very slowly) prevent the formation of sugar crystals, and enable storage at a lower temperature than usual, saving heating costs? Or perhaps the apes could be trained to do it? Might be best to select very furry cold weather apes. I imagine it'd be easier to regain control over one's honey if they were really small apes, unless there were loads of them and they were very upset.


Make sure that you don't get a short or over-loaded component in your device. It would be a shame if it caught fire and set off the battery before it had a chance to save you.
Good point - clearly two further sets of STC-1000s, horns and power supplys are required to establish normal working temperature of my existing STC-1000 and power supply, and to sound warnings when those also overheat.

The STC-1000 can be located as far away from the battery as the 1m heat sensor's lead allows (1m [currently]), the horn can be situated many meters away. The only thing in close proximity to the battery is the heat probe.
 

guerney

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Sep 7, 2021
10,196
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Auto logging of temp/humidity/relay status from a STC1000 can be accomplished with a 433mhz transmission module when you have reflashed the stc1000 firmware with the wonderfull stc1000+ project from github.

the 433mhz rf signal uses a weatherstation protocol so hooking a 433mhz reciever to an esp8266/arduino etc is all you need to pick up the readings and broadcast them via wifi/mqtt for logging on any network device you have. The code should be a simple edit of example sketches a couple of github projects provide arduino libs for the coms.

(while quality 433mhz h/w can transmit for significant distances, my limited experience with el cheapo ebay components is best limited to a few meters of range for reliability)
...it's safe to assume, I think, that I have bought a firmware incompatible cheap knockoff of this:

https://vi.aliexpress.com/item/32863068632.html

I should have simply recorded video for hours, or timelapse, using the GoPro and skipped forwards to read temperatures.


57088
 
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guerney

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With the controller set to 18A, me and my ickle 20" wheeled Dahon folding BBS01B mid-drive conversion went on a short 21.5km ride over hilly terrain tonight - ascended all the slight ones at 25kph, the cut-off cut in and slowed me to something over 23kph, then back to 25kph after pedal assist re-activated etc. One the slightly steeper and steeper ones I managed over 24kph, and the steepest only slowed me to 15kph! Suddenly tempted to increase controller limit to 20A.


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I would have downhilled faster, but I was being uncharacteristically careful. It was a very pleasant night to be out riding. Average speed also increased.


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Hearing cops approaching very fast, of course I assumed they wanted to have a word about my crazy lights, so I pulled over for the inevitable tasering - I prefer being tasered whilst stationary. Safer.


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...but they ignored me.


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When I got home, my battery felt warm to the touch, so I plonked on the Home Ruination by Ebike Battery Fire Expulserating Pre-Terminator™®©℠...


57167


...there's no need to throw my battery out of the window tonight.
 
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AndyBike

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Ebike

The E stands for Explosive ;)
 

guerney

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Sep 7, 2021
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Ebike

The E stands for Explosive ;)
Eeeee bikes were invented in Yorkshire. Here's my eeeee battery charging box. Not putting the STC-1000 unit inside with the battery, because that would increase temperature, so it'll just be the temperature probe. I'm making a better shovel. When in doubt, sling it out! EXPULSERATE!! EXPULSERATE!!!


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Yes it's a steel bread bin. Doesn't have to be particularly sturdy, because it won't get to the point of catching fire - not in my house anyway. It will bloody well be expulserated before home ruination happens. Why anyone puts up with a lithium-ion battery fire in their home, I don't know.
 
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