Battery pack, fire detection and management?

[Pink7]

Regarding danger of fire on solar/battery equipment: Any of you mounted smoke detectors to early detect any smoke?

 

Pink?

[Muhendis]

11 minutes ago, Pink7 said:

Regarding danger of fire on solar/battery equipment: Any of you mounted smoke detectors to early detect any smoke?

 

Pink?

I thought about fitting a smoke detector, but my feeling is that by the time smoke is detected it is too late to save anything electronical.

Circuit protection is the best anti-fire regime.

My battery balancers were connected direct to the batteries without any current limiting devices or fuses.

It would have been nice if the company which supplied them had included a word or two about safety but, as usual, it is left to the individual to take whatever precautions are necessary.

Batteries are chock full of big heavy power just itching to get out so any electronic devices connected to them need to be protected by a fuse.

If a component in said electronic device were to fail short circuit, it would be nice if the thing failed to catch fire.

 

[Pink7]

I was looking into this:

 

DAYTECH SM12 9v claim 1 year battery life

 

and

 

DAYTECH SM06TA 3V lithium battery 17335. Claim 10 year battery life

 

Pink

 

[Pink7]

22 minutes ago, Muhendis said:

I thought about fitting a smoke detector, but my feeling is that by the time smoke is detected it is too late to save anything electronical.

Circuit protection is the best anti-fire regime.

My battery balancers were connected direct to the batteries without any current limiting devices or fuses.

It would have been nice if the company which supplied them had included a word or two about safety but, as usual, it is left to the individual to take whatever precautions are necessary.

Batteries are chock full of big heavy power just itching to get out so any electronic devices connected to them need to be protected by a fuse.

If a component in said electronic device were to fail short circuit, it would be nice if the thing failed to catch fire.

 

Its good to have solution who can save the electronic but in my case I was mainly thinking about safety for my family since i have my inverters and batteries inside home.

 

Pink

[Crossy]

Ignoring (for now) the actual chemical energy that's contained in the various battery chemistries (some are rather more "energetic" than others).

 

It is worth remembering that a 10kWh battery pack (about 200Ah @ 48V) contains about as much energy as a litre of petrol/gasoline.

 

Treat your batteries as you would the gas can for your mower!

 

Once our packs are fully configured, we will have >60kWh of storage, about 1.5 US gallons of gas! That's staying well away from our home!!

 

If it decides to go "whoosh" we may lose the car-port and the car but the house should be well out of range.

 

 

 

 

 

[degrub]

How far above grade do you have to mount the cells for flood risk ?

[Muhendis]

2 hours ago, degrub said:

How far above grade do you have to mount the cells for flood risk ?

I think that may be dependant on global warming/sea level rise. 

[Muhendis]

4 hours ago, Crossy said:

Ignoring (for now) the actual chemical energy that's contained in the various battery chemistries (some are rather more "energetic" than others).

 

It is worth remembering that a 10kWh battery pack (about 200Ah @ 48V) contains about as much energy as a litre of petrol/gasoline.

 

Treat your batteries as you would the gas can for your mower!

 

Once our packs are fully configured, we will have >60kWh of storage, about 1.5 US gallons of gas! That's staying well away from our home!!

 

If it decides to go "whoosh" we may lose the car-port and the car but the house should be well out of range.

 

 

 

 

 

The point  is that the stored, extremely high energy, should be isolated from the rest of the low power electronic world by normal protective procedures.

 

If the battery itself should become unsociably unstable, then there is very little you or I can do about it. 

[degrub]

6 hours ago, Muhendis said:

I think that may be dependant on global warming/sea level rise. 

I was thinking about the annual flood events that @Crossy tracks rather than more esoteric causes 😉

[sezze]

6 hours ago, Muhendis said:

The point  is that the stored, extremely high energy, should be isolated from the rest of the low power electronic world by normal protective procedures.

 

If the battery itself should become unsociably unstable, then there is very little you or I can do about it. 

True , once the temp gets too hot , the reaction will start and nothing will be able to stop it .

So as protective measure , make sure you got all the electronics right and when selfbuild make sure you use a non flammable box . Also when possible, check on regular intervals the connections for heat/burn marks.

[BritManToo]

2 hours ago, sezze said:

True , once the temp gets too hot , the reaction will start and nothing will be able to stop it .

So as protective measure , make sure you got all the electronics right and when selfbuild make sure you use a non flammable box . Also when possible, check on regular intervals the connections for heat/burn marks.

Would point out Lithium fires are hot enough to burn through concrete and steel.

Best to keep your batteries in a shed outside the home.

[Crossy]

4 hours ago, degrub said:

I was thinking about the annual flood events that @Crossy tracks rather than more esoteric causes 😉

 

At least the flood will put the fire out!

 

Seriously, Lithium-Iron-Phosphate (LiFePO₄) chemistry is much safer than the NMC (or Li-ion) chemistry used in your smartphone, scooter, hover-board, monowheel and a lot of EVs and has a much-reduced tendency to "thermal-runaway". Many suggest that they are at least as safe as lead-acid (which have a different set of safety issues).

 

LiFePO4 will burn if persuaded but most incidents involving them seem to be of an electrical rather than chemical nature. At least, that's how they start, a shorted LiFePO4 cell will out-gas and one of the products is hydrogen which is somewhat flammable.

 

Concentrate on good electrical design and implementation, adequately rated cables protected by suitable breakers and/or fuses.

 

It's far better to avoid starting a conflagration rather than to try to extinguish one.

 

Our friends at the National Fire Protection Agency (NFPA) have things to say about ESS installation and location. Chapter 15 is the relevant bit for domestic systems.

 

<Removed copyrighted document, plenty of places to download it>

 

EDIT You can view direct from the NFPA website for free (you have to create a free account) start here: -

https://link.nfpa.org/free-access/publications/855/2020

EDIT 2: - Actually, you can view the latest version too.

 

 

 

[Muhendis]

What a hefty tomb that NFPA document is.............

I had a quick skip through it and note there is a requirement for smoke detectors to be fitted for all ESS's.

[degrub]

1 hour ago, Crossy said:

LiFePO4 will burn if persuaded but most incidents involving them seem to be of an electrical rather than chemical nature. At least, that's how they start, a shorted LiFePO4 cell will out-gas and one of the products is hydrogen which is somewhat flammable.

Good design practice for hydrogen releases inside structures with roofs is to use a ridge vent design where the ridge of the roof is removed and a “hat” is placed over the opening with a few cm of gap to allow the hydrogen to naturally flow out of the structure. With open soffits under the roof edge, a thermosiphon can be established to further aid hydrogen escape. 
 

Confined hydrogen is a good way to suddenly disassemble a structure 😉

[Crossy]

12 minutes ago, degrub said:

Good design practice for hydrogen releases inside structures with roofs is to use a ridge vent design where the ridge of the roof is removed and a “hat” is placed over the opening with a few cm of gap to allow the hydrogen to naturally flow out of the structure. With open soffits under the roof edge, a thermosiphon can be established to further aid hydrogen escape. 
 

Confined hydrogen is a good way to suddenly disassemble a structure 😉

 

Indeed, although in the case of LiFePO4 packs if the hydrogen is being emitted there're rather more serious issues afoot.

 

Now, if we are using lead-acid then ...

[sezze]

Hydrogen is nearly never a problem . You really need to have a sealed box to keep hydrogen somewhat in . Even the smallest vent will be enough to get trapped hydrogen out  ( i work with hydrogen at low and high pressure compressing it to 200bar ) . Only make sure the vent it at the highest place , as hydrogen is soo light , it will move straight away to as high as possible.

 

Yes lithium will burn through metal , but it will take some time . Better put that in a concrete box , as that is unflammable , and indeed a shed outside is much better then inside .

[Crossy]

Take care out there chaps, mitigate against the worst possible outcome ...

 

https://diysolarforum.com/threads/house-burned-down.83098/

 

[Georgealbert]

To answer your original question about smoke detectors, the answer for life safety will always have to be yes.

 

Any risk in your home has to be looked at in two ways, fire prevention and fire protection. NFPA 855, is a good, detailed guide, but maybe will be over the top in some parts with your set up.

 

Fire prevention, is based on quality of  products, quality of installation, certification, regular maintenance and inspections, automatic isolation devices, the control and management of other combustible materials/storage, using everything correctly, and  no cutting corners if any problems occur.

 

Fire protection, has 2 elements, life safety and property protection.

 

Life safety needs,

 

Containment - what you can do to stop the fire spreading from the room/point of origin, how you construct or enclose the packs, 

 

Detection - install suitable fire detection.

 

Communication - how the detection will alert everyone, at all times.

 

Means of escape - how everyone can get out when alerted to a fire, plus a secondary route. Home safety plan.

 

Suppression - suitable extinguishment for dealing with a minor fire, but as the saying goes, “if in doubt get out”.

 

Property protection - suitable insurance to cover all losses, would be a good idea to have details of your system to give to local responders in Thai.
 

Commercial premises will use air sampling detection systems (such as Vesda) and suitable shut down protection devices and fixed firefighting system, which is not going be installed in most, if any, homes.

 

Data indicates that fires related to solar systems are relatively rare, but worse case planning will protect your family, because how ever good your systems are, you are never going to reduce the fire risk to zero.

 

Link to free access to NFPA 855, without have to sign up.

<Edited to remove live link to copyright document, copy and paste into your browser>

https://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/JVR/AdminRecord/IBR/326a NFPA 2020.pdf

 

Edited April 30 by Crossy

[Muhendis]

13 hours ago, Crossy said:

Take care out there chaps, mitigate against the worst possible outcome ...

 

https://diysolarforum.com/threads/house-burned-down.83098/

 

 

You have my sympathies Crossy.

 

When did that happen?

[Crossy]

3 minutes ago, Muhendis said:

You have my sympathies Crossy.

When did that happen?

 

Absolutely NOT us!!!

 

The linked thread is an interesting read. Fire investigators determined that it was a fuse that continued to arc after it had opened that initiated the conflagration. Many forum members do not necessarily agree.

 

[Muhendis]

11 minutes ago, Crossy said:

 

Absolutely NOT us!!!

 

The linked thread is an interesting read. Fire investigators determined that it was a fuse that continued to arc after it had opened that initiated the conflagration. Many forum members do not necessarily agree.

 

Joking aside.

All electronic components, even fuses, have a voltage rating for this very reason.

For example.

Fitting a correct value resistor in a circuit may seem like a good idea but, in a high voltage circuit, the physical dimensions may allow for a current path to exist over the surface of the component.

Same thing with fuses and fuse holders. 

 

[Crossy]

3 minutes ago, Muhendis said:

All electronic components, even fuses, have a voltage rating for this very reason.

 

Yeah, using 48V rated fuses in a "48V" system may not necessarily be a good idea, battery voltage can be over 58V at times. Although in this case the fuses were apparently correctly rated.

 

[lom]

1 hour ago, Crossy said:

Fire investigators determined that it was a fuse that continued to arc after it had opened that initiated the conflagration. Many forum members do not necessarily agree.

 

I don't think it is possible after such a big fire to determine when the fuse blew, before the fire or after because of a short during the fire.

If the fire was related at all to the fire then it is much more likely that the bolts were not enough torqued  so there was an arch it the fuse connection. Compare to Pink7's "brown spot" arch in his battery switch.

Edited April 30 by lom

[OneMoreFarang]

One or multiple temperature sensors will show you if something starts to get wrong. 

[Pink7]

On 4/30/2024 at 8:57 AM, OneMoreFarang said:

One or multiple temperature sensors will show you if something starts to get wrong. 

Yes i have set JK BMS temp sensors on each breaker so it will stop charge/discharge if hot. I did see some limitation because of the parallel connection will still feed some power to the hot breaker. I will try find a stand alone sensor with alarm/warning if hot.

 

Pink

[Pink7]

Researching W1209 Temperature relay controller with buzzer as alarm. So the controller power a buzzer at the set temp.

 

Pink

 

 

Pink