Here a neat device , ideal for Lipo particualrly
I’ll stick on in the LiPo battery box….
Thor,
I’m curious but a bit uncertain about their effectiveness. They sound promising for ordinary flame reduction, although I’d like to see if they have UL (Underwriters Laboratory) accreditation.
The only test I found of them was a British auto magazine that said they put one near some flammables, lit them up, and the Ferosticker put them out. So, not a precision test, but promising for standard fires. The Ferosticker description of how it works is a standard oxygen-displacement chemical approach.
From what I understand based on articles by Practical Sailor and Boat/US (which I’d trust on this topic because they’re effectively a subsidiary of an insurance company, Geico), LiPo battery fires have the lowest incidence of any battery technology so far. The primary risk is said to be thermal runaway, when a chemical reaction inside the battery causes overheating.
The catch is that the chemical reaction generates its own oxygen, so no temporary oxygen-deprivation approach works. Instead, what seems to be recommended is precautionary – avoid abusing them. I’ve seen some suggestions for isolating them in fire-proof battery boxes, but I don’t think there’s consensus on that one.
The latest from Practical Sailor notes that:
LFPs are Less At-Risk for TR Events
While LFP [aka LiPo or LIPo4] batteries are a member of the Lithium-ion family, they are characterized by being the most chemically stable and therefore at least risk of a TR [thermal runaway] event. While no hard statistics seem to be available, TR events with LFP batteries would seem to be a tiny percentage of the overall total…
…TR events only arise from “abuse.” What does abuse of an LFP look like? Broadly speaking, abuse might take the form of mechanical damage, heat or excessive load, short circuit, or overcharging.
In the fairly unlikely event of a LiFePo thermal runaway fire, the recommendation is to continuously cool it with water below the point where the reaction occurs, for up to 24 hours.
This seems promising for regular fires, but may not be the solution for LiFePo owners.
-- Bob
I’m upgrading Aloki with a new Victron LifePo system presently. I’ve contracted a Victron Engineer to customize drawings for me as to install. What surprised me is the amount of monitoring systems , fuses ( lots of fuses) and thermal sensors in this design/install.
I also asked about these ‘ferrostix’ as an addition to the enclosed boxes being used to house the various components. His reply was ‘ sure , but a well designed system is far better protection.’ I’ve searched to see if any recorded ‘thermal runaway’ reports and have found none. Regards , Gary
Below comment is from this website - one of many I’ve read or consulted.
The Chemistry of Safety: LiFePO4 vs. Other Lithium Chemistries
The core advantage of LiFePO4 lies in its molecular structure. The cathode is made from lithium iron phosphate, a remarkably stable material. The oxygen atoms in this structure are held by strong covalent bonds within the phosphate (PO4) tetrahedron. This makes it extremely difficult for oxygen to be released, which is a key step in the process of thermal runaway that leads to fires in other battery types.
In contrast, chemistries like Nickel Manganese Cobalt (NMC) or Lithium Cobalt Oxide (LCO), common in laptops and some electric vehicles, have a layered oxide structure. These structures can release oxygen at lower temperatures, making them more susceptible to catching fire if damaged or overcharged
Interesting device. It has potential, but after spending half the morning researching this, I don’t think it’s likely to do much. If it ever gets UL or ABYC approval, then it might be one of those “can’t hurt” kind of devices, but right now it can’t actually do most of the things it is advertising - either legally or physically. I could not even find any evidence that it’s been independently tested by anyone.
They suggest putting it inside of a circuit breaker panel. But it is illegal to put any non-approved device inside of a circuit breaker panel, and I think the ABYC has similar rules (though without the force of law behind it.) Also, most fires inside of a circuit breaker panel are arc-faults and will not be extinguished by inert gas. The company’s own YouTube videos show their device putting out a fire in an electrical panel, but if you watch, the fire is actually a burning wad of paper that they put in there. That would easily have been prevented by not putting the illegal wad of paper in there (burning or not.)
A lithium battery contains immense energy - which is released very quickly in a battery fire. And it happens within the battery. A tiny puff of inert gas cannot physically do anything to mitigate that. It cannot slow or stop the fire because that’s all internal to the battery. It cannot absorb enough heat to even be noticeable. It really cannot do anything. Fortunately, LiFePo4 batteries are extremely resistant to runaway and fires.
The best way to prevent LiPo battery fires is to buy top quality LiFePO4 batteries with top quality BMSes. Put them in a non-flammable enclosure which has a vent path away from flammable materials. (Don’t know how you’d actually do that on a small boat like ours, but it’s desirable if possible.) And keep the rest of the electrical system robust, using adequate gauge wire, proper circuit breakers, and a way to quickly disconnect the batteries if they begin to overheat.
Some may say the best way is not to use lithium batteries at all, but they forget that lead/acid generates highly explosive hydrogen gas when charging. Electricity follows the laws of physics regardless of what we wish and you always need to get it right, whatever tech you are using.
Adding on to Gary and Brian’s points, the article Gary recommended is very informative and mentions that the thermal runaway point for a LiFePo battery is 270 C or 518 F.
This is about 10% higher than the fire point of wood, which suggests that the boat’s has more potential to set fire to LiFePo batteries than the batteries have to set fire to the boat.
However, this also suggests that if your batteries do go, your boat WILL go, too. Which takes us full circle to Brian:
-- Bob
Of interest
I know there are temp sensors ( four) that tie into the Victron Cerbo control unit which then also provides info/data to the Battery Mngmnt Sensor and the dc/dc charger .
I believe there is a setting on the Cerbo to shut down the charging aspect of the dc/dc charger based on a temp setting - preventing a runaway. That’s a simple on/off setting which would cancel/stop the charging of the LifePho system. I’m not at the programing part yet and will update these comments once I hear back from my consulting engineer.
Follow up to the question - can the temp sensor in my Victron system turn off the charging cycle if temperatures exceed set points.
Yes, temperature sensors in a Victron lithium setup can turn off charging if configured correctly
, but how it happens depends on whether you are using Victron’s native Smart Lithium batteries with an external BMS or a configured VE.Smart Network. [1, 2]
How High/Low Temperature Cutoffs Work in Victron
- Victron Lithium BMS Integration: If you use Victron lithium batteries paired with a Victron BMS (such as the VE.Bus BMS or lynx smart bms), the BMS actively monitors cell temperatures. If temperatures exceed or drop below preset safety thresholds, the BMS triggers an “Allow-to-Charge” (ATC) signal that immediately commands connected Victron solar chargers, inverter/chargers (MultiPlus/Quattro), and DC-DC chargers to shut off charging