Heat & smoke detection for batteries

killerbyte

killerbyte

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So family member had a little scare yesterday.
One of his Shoto LiFePo4 batteries started smoking. I am not sure of the cause but thankfully their maid was there to alert them.
I think the BMS got fried and that's what was smoking since when the batteries were disconnected it stopped smoking.

But this did get me thinking and researching.
A smoke alarm wouldn't be good enough for batteries since once you get smoke from the cells its already too late, so a heat alarm is needed.
So does anyone know of any heat & smoke alarms in SA that can do app based alerts (as well as the obvious sound alert)?
 
killerbyte said:
So family member had a little scare yesterday.
One of his Shoto LiFePo4 batteries started smoking. I am not sure of the cause but thankfully their maid was there to alert them.
I think the BMS got fried and that's what was smoking since when the batteries were disconnected it stopped smoking.

But this did get me thinking and researching.
A smoke alarm wouldn't be good enough for batteries since once you get smoke from the cells its already too late, so a heat alarm is needed.
So does anyone know of any heat & smoke alarms in SA that can do app based alerts (as well as the obvious sound alert)?
Click to expand...

Smoke alarm is essential above all solar / battery installs imo and I'm surprised the insurers don't insist.

Heat alarm not so sure. The device should already be monitoring heat and if it can't safely shut itself down neither can you. But I suppose if you attach a datalogging thermistor you can establish a baseline and maybe catch anomalies...

I would personally stick with a simple smoke alarm because you don't want unnecessary complexity and failure modes in a lifesaving device.
 
Tomtomtom said:
Smoke alarm is essential above all solar / battery installs imo and I'm surprised the insurers don't insist.

Heat alarm not so sure. The device should already be monitoring heat and if it can't safely shut itself down neither can you. But I suppose if you attach a datalogging thermistor you can establish a baseline and maybe catch anomalies...

I would personally stick with a simple smoke alarm because you don't want unnecessary complexity and failure modes in a lifesaving device.
Click to expand...
Well I wasn't thinking it needs to shut off anything, just needs to alert since the inverter can be shutdown remotely to stop current flowing to the batteries. .
 
Batteries report temp so if you get home-assistant to monitor the temp data you already have

maybe you can have a notification from it when it goes over x temp
 
There are a few OTT devices like the Sonoff TH series that can take temperature probes.
You can then configure it to trigger an alarm if the temperature goes over a threshold or loses connectivity.
Can also notify you via your mobile device, email etc depending on how its configured.
 
B-1 said:
There are a few OTT devices like the Sonoff TH series that can take temperature probes.
You can then configure it to trigger an alarm if the temperature goes over a threshold or loses connectivity.
Can also notify you via your mobile device, email etc depending on how its configured.
Click to expand...
Its not a bad idea.
I was thinking I could use the Shelly 1 with the add-on, but the cost of that solution is the same as getting the Shelly H&T which can just sit on top of the batteries.
The Shoto batteries are getting replaced with Freedom Won LiTE units, likely 4x 10/8. They do report the temp to the Victron system which will hopefully give the peace of mind we are after.
 
That's a scary situation to be in. We've installed a smoke detector and a lithium battery extinguisher for some peace of mind. Using a bit of tech to back this up seems like a good idea.
 
Thestealth said:
That's a scary situation to be in. We've installed a smoke detector and a lithium battery extinguisher for some peace of mind. Using a bit of tech to back this up seems like a good idea.
Click to expand...
I thought there was no extinguishing a lithium fire once it had started.

Where did you buy your extinguisher?
 
Last edited:
killerbyte said:
Well I wasn't thinking it needs to shut off anything, just needs to alert since the inverter can be shutdown remotely to stop current flowing to the batteries. .
Click to expand...

You can't rely on being able to shut down a developing situation this way. If it were possible in all cases, the system itself would be engineered to do that. In most cases, it does safely shut down. But clearly not all, or there would be no such thing as a smoking BMS.

So you need to focus on catching the smoke with a basic alarm or maybe two for redundancy. No point spending money on complexity, you just want robustness and long battery life.

Then maybe add some temperature logging and logic to see if you can avoid the next fire but I wouldn't bet on it.
 
Tomtomtom said:
You can't rely on being able to shut down a developing situation this way. If it were possible in all cases, the system itself would be engineered to do that. In most cases, it does safely shut down. But clearly not all, or there would be no such thing as a smoking BMS.

So you need to focus on catching the smoke with a basic alarm or maybe two for redundancy. No point spending money on complexity, you just want robustness and long battery life.

Then maybe add some temperature logging and logic to see if you can avoid the next fire but I wouldn't bet on it. An arc for example generates heat for all of a fraction of a second before it ignites the nearest flammable thing.
Click to expand...
I have no intention on them relying on the ability to kill the current to the batteries.
The first step is a smoke alarm that not only alerts this family member on this phone but also has its own built in siren to alert anyone in the house.

That Shelly Smoke alarm has a 5 year battery life which I like. Maybe a secondary dumb smoke alarm would also be a great idea.
 
I installed a Netatmo smoke detector for my inverter / batteries.

Pricey but I wanted something that could connect with my smart home, and was cheaper than the ones my security company wanted to install. I don't think the Shelly was available when I installed mine as I may have considered it (depending on HA / Homekit compatibility).

www.audicoonline.co.za

Netatmo Smart Smoke Alarm | South Africa

The Netatmo Smart Smoke Alarm is a photoelectric (optical) smoke detector that enhances your home's safety. When a fire starts and the alarm is set off, the Netatmo Smart Smoke Alarm sends real-time smoke alerts direct to your smartphone.
www.audicoonline.co.za www.audicoonline.co.za
 
wingnut771 said:
NMC catches fire, LFP doesn't.
Click to expand...

This is a pretty irresponsible assertion. Everything catches fire. And the exact hazards depend on circumstances. Here they're talking about the risk the batteries cause other stuff to catch fire.

www.pv-magazine.com

How safe are lithium iron phosphate batteries?

Researchers in the United Kingdom have analyzed lithium-ion battery thermal runaway off-gas and have found that nickel manganese cobalt (NMC) batteries generate larger specific off-gas volumes, while lithium iron phosphate (LFP) batteries are a greater flammability hazard and show greater...
www.pv-magazine.com www.pv-magazine.com

(NMC) batteries generate larger specific off-gas volumes, while lithium iron phosphate (LFP) batteries are a greater flammability hazard and show greater toxicity, depending on relative state of charge (SOC).
Click to expand...
 
I am a Fire Detection System expert.

I can tell you that for thermal runaway in Lithium batteries, the absolute best method of detection is the detection of the Volatile Organic Compounds (VOCs) (essentially toxic gases) released during the battery's chemical breakdown process.

This is a deep-seated chemical fire so smoke and heat will both pick up the fire after it is too late.

This is a big topic at the moment. So the best way to do it is to put a gas analyser in close proximity to the battery (above the battery) (these are too expensive for home use typically) and then you have to have a relay output to cut all power supplies to the battery (normally done via the Battery Management System (BMS)).

In a home, and in 99% of industrial implementations a burn-in-place strategy is the way to go. These things are being designed so that the cells are modular and can be replaced easily after they have burnt.

You need to install lithium batteries away from living areas (not inside the house), put them in a garage. Leave some space around them (don't pack boxes right next to the thing) to prevent fire spread. You can install a smoke (or heat) detector above the device in accordance with SANS 10139 recommendations to ensure that your detection device is effective. This will warn you that the thing is burning. Then let it burn in place (you can use lithium battery fire "extinguishers" - keep in mind this won't extinguish the fire just keep the thing cool while it is burning).

Lithium batteries burning due to thermal runaway produce their own oxygen from the chemical reaction so there is no real way to extinguish the fire once it starts.

That is it really. Good luck.
 
DrJohnZoidberg said:
I installed a Netatmo smoke detector for my inverter / batteries.

Pricey but I wanted something that could connect with my smart home
Click to expand...

I honestly have no idea what the appeal is of a "smart" smoke alarm. You don't want a ping on your phone. You want a loud siren that wakes everyone up. Sure maybe it does both, but then what's the point of the alert? That one time your house burns down while you were away? How has that helped, nobody was home?

More importantly it's a complex system and nobody tests even the simple stuff like RCD breakers often enough, so chances are it won't actually work the one time it's needed.
 
Athos said:
I am a Fire Detection System expert.

I can tell you that for thermal runaway in Lithium batteries, the absolute best method of detection is the detection of the Volatile Organic Compounds (VOCs) (essentially toxic gases) released during the battery's chemical breakdown process.

This is a deep-seated chemical fire so smoke and heat will both pick up the fire after it is too late.

This is a big topic at the moment. So the best way to do it is to put a gas analyser in close proximity to the battery (above the battery) (these are too expensive for home use typically) and then you have to have a relay output to cut all power supplies to the battery (normally done via the Battery Management System (BMS)).

In a home, and in 99% of industrial implementations a burn-in-place strategy is the way to go. These things are being designed so that the cells are modular and can be replaced easily after they have burnt.

You need to install lithium batteries away from living areas (not inside the house), put them in a garage. Leave some space around them (don't pack boxes right next to the thing) to prevent fire spread. You can install a smoke (or heat) detector above the device in accordance with SANS 10139 recommendations to ensure that your detection device is effective. This will warn you that the thing is burning. Then let it burn in place (you can use lithium battery fire "extinguishers" - keep in mind this won't extinguish the fire just keep the thing cool while it is burning).

Lithium batteries burning due to thermal runaway produce their own oxygen from the chemical reaction so there is no real way to extinguish the fire once it starts.

That is it really. Good luck.
Click to expand...
These batteries are installed against the firewall that separates the garage from the living room. Because of the design of the house the bedrooms are on the complete opposite side of the house with an escape through the kitchen (or the bedroom windows) if necessary.

I figured it would be a "burn in place" situation just given that the batteries weigh a lot and would burn at pretty intense temperatures.
 
Tomtomtom said:
I honestly have no idea what the appeal is of a "smart" smoke alarm. You don't want a ping on your phone. You want a loud siren that wakes everyone up. Sure maybe it does both, but then what's the point of the alert? That one time your house burns down while you were away? How has that helped, nobody was home?

More importantly it's a complex system and nobody tests even the simple stuff like RCD breakers often enough, so chances are it won't actually work the one time it's needed.
Click to expand...
It's a regular smoke alarm that is wifi/bt enabled.
 
Athos said:
I am a Fire Detection System expert.
Click to expand...

Suggest you get in touch with the journos here I'm sure they'd love to run this as a story. Useful advice. We're way behind on fire protection in homes generally in SA and now with lithium batteries everywhere we're asking for trouble.
 
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