Is there an Air Flow Data PDF for 25.6 200ah LiFeP04.
Lithium batteries need very little ventilation, more needed is an over-pressure release from the battery enclosure in case of emergency cell venting.
Thanks Mike, that sounds good to me. Unfortunately, engineer believes that if specific air flow data is not provided the requirements of lead acid ventilation shall be applied. It would be good if Victron included your analogy in the manual.
only thing that surfaced is this:
be better to know what your application is.
easiest way is to put in what the engineer wants, then remove it after…
Hi Mike. That solves my issues with engineer. Can you recommend an over-pressure release?
I’ve recently read the spec sheet of my EVE prismatic cells and it said that the maximum swelling force is 2000Nm!
This fact might explain why a complete backward of a house in Germany was blown away, a year ago, after a 15kWh LG home battery went into burst mode. Here there are rules that instruct us to install a fan system (for systems over 20kWh) to suck the hydrogen gas when a cell/battery starts to blow the hot gasses. We also need to install a CO meter and a combined heat and smoke detector, that are also linked to the inverter(s). To shut them down in case of an emergency. Automatically.
A 40Ah cell generated up to 165KG in swelling force during tests. But it all depends on the C factor, apparently, and how much the cell was overcharged.
What is a good co2, smoke and heat detector with potential free contact (to the inverter) ?
This is what I have: Rook- en CO melder set voor Victron koppeling kopen? - Helion Energie
which country is that? where does it blow the hydrogen gas?
is it enough if the inverter is off? You think, in Case the MP2 Voltage goes to high, the BMS cpold also be broken?
Wouldnt it make more sense to observe the cell voltages, have something like a rule in NodeRed that switches the inverter off?
From the same brand they have combined smoke and/ or heat and co2 sensors, I have already installed an Ei smoke alarm in the batteryroom linked to the home smoke alarm, from Ei I will ad the heat and co2 sensor with relais base.
I don’t know about ventilation of the battery room with so many sensors (and a link to the inverter)
Lithium batteries don’t produce hydrogen ( The redOx equations can be looked up on line). However, the Organic lithium dielectric fluid is very flammable, and can explode violently. Hence the AU/NZS standard requires batteries to be outside of accommodation / populated areas of a dwelling. It is possible to design a “Blow out panel” type arrangement to safely vent a big explosion. However, this takes a professional designer.
Best protection is a distributed heat sensor in the battery, with shut down if the temperature exceeds a certain level - typ 60C, or starts to climb rapidly. The latter can also trip a fire shutdown if needed.
Usual requirement is : The BMS blocks charge to any cell that has been discharged to under 2V. Over voltage shutdown at recommended level (figures depend on chemistry). Over-temperature shutdown.
The usual source of a fire type fault is ignoring these, or a short circuit.
So 55% of the vented gasses coming out of the pressure relieve valve is flammable H2 which by the way also caused an electric narrow boat in England to explode.
Under normal circumstances No hydrogen is produced - unlike lead batteries.
The paper you quote involves a destructive test of the battery.
Good evening,
What we do is very simple and is applicable to all types of batteries, lead acid, salt, lithium and accepted by all Class societies (IMO ships) and insurance companies, exceptions exist.
The GX Cerbo has temp and volt inputs and relay outputs which can be programmed easily for this.
Program for lead to switch the relay (fan) above 26.50V (24V, or equivalent for other voltages, e.g. 12V/13.25V, 48V/53V , etc) as gassing starts to occur.
Program for salt 27.10V (24V), or equivalent.
Program for Lithium, 35 degrees C on, 25 degrees C off, also 40/35 degrees can be used acc the local laws, if above 40 degrees C in any case, cooling needs to be switched instead of just a fan, mostly filtered fresh air from outside will do, but e.g. in Dubai no change, then a cooler (airco) needs to be installed.
Next thing is, above the door to this closed room a red warning light should switch on during the above settings, and the light switch (even outside the door) of the light there inside inhibited (immediately when this occurs and a 30 minute timer to re-establish the lighting switch), this to avoid a spark switching on the light and then boom (even with the door open, most likely to get a bigger boom with fresh air mixing), specially with lead and salt!
Light, however can be switched on, when it is an intrinsic switch (like an IP 68 or better) and with Intrinsic light covers (explosion proof), then the light switch does not have to be inhibited.
Anyway, batteries in a closed room are not a good idea, the above systems need to be approved once a year by a specialized company to give you the certificate, so, costs.
If there is a possibility to place them in a big area; pending again local laws, say 1KWh of power to 2M3, then nothing is needed for Lithium, but lead is about 8M3 with unforced fans but with one hole of 25cm on ground level and one on ceiling level, etc, we advice to place a fan anyway, always, IP68 or better ones, and the controller of the fan outside the battery room…of course….
I hope this explained the enclosed battery compartments entirely.
With regards, Jeroen.
be happy you earn your money with that - but in my eyes, really strange
Good evening KR,
Yep, for most DIY people I meet or tell it is strange, as this is not very well known, ask your insurance company for your vessel or home, they know very very well, and do not pay after a burn out when they find out it was not installed according their rules and/or common known rules.
Btw, we do not make money with that at all, it’s just that we always install accordingly to the (local, national or even international) rules, as it is a part of the job, nothing else, as all Victron installers (and so many other inverter/battery brands installers) do btw, as we are aware of these rules, otherwise not one IMO vessel, hospital, data centre, light house, submarine, telecom centres, etc could have been built in safety the last 100 years, you see?
With the very best regards, Jeroen.
But of course! It’s just that we need to install the extraction fan et all, in case something bad happens. That was luckily only 8 times last year in the Netherlands. Even the fact that in some cases the end-user was to blame won’t change the rules that applies to us here.
Tip: check the local law and your insurance company what applies to you.
Do note that with all safety rules applied, that even the best brand can go bad. Recently I’ve seen a video of a van with LiFePo4 batteries from Victron that had swollen up. The guy started to smell a weird odour and looked at his battery compartment to see a massively swollen battery. The battery was still hot and he ended up calling the fire brigade. But a simple CO detector would have caught it. And sleeping in a van with potentially lethal gasses when something does go wrong, once in a lifetime, you better be prepared for the worse case scenario.