So - How safe are battery powered aircraft. If a melt down happens. Example - Tesla battery fire at Moorabool

[SSCBD]

Crews battle Tesla battery fire at Moorabool, near Geelong (msn.com)

[turboplanner]

Well I guess you saw how safe.

Other than finding out this big battery could power South Australia for 120 minutes (vs the SA battery's 40 mins) we haven't  learnt much publicly from this fire, other than to add another factor into any "zero emissions claims", so before it's started operaton it's racked up a huge IRAE event (Industrial Residual Air Emission) which will need to be factored in to future forward planning of the electricity grid, along with the CO2 required to produce the exotic batteries. From the South Australia experiment we know that any dream of a battery powered future from sun or wind is out of the question, but these big batteries have a part to play in speeding up the addition of power to the grid during the time it takes to crank up coal-fired power plants to peak production. In any comparisons we need warts and all figures.

 

[Flightrite]

Boeing experienced first hand at how Lith Ion batts can make for a source of concern! With any technology comes risk. Batt powered flying machines will only be a curiosity for a long time yet!

[extralite]

Agree that for aircraft, battery power may be a way off except for perhaps some training due to energy density. But it is curious the pushback against batteries because one caught fire. Imagine if we had been using batteries for 60 years and someone was pushing petrol as a new technology. Have you seen that stuff explode? Similarly the often stated argument "But they are charged usually from coal powered power stations." Really? Just have a think about the relative efficiency of a power station compared to everyone driving around with their own little engines, plus the alternatives available.

 

In any case it is all a bit late unfortunately, The tribalism and xenophobic tendencies for us humans probably makes us unsuited to acting collectively to stop the carbon buildup, meanwhile enough ice melted off the greenland icecap a few days ago to cover Florida in 2 inches of water (https://www.theguardian.com/environment/2021/jul/30/greenland-ice-sheet-florida-water-climate-crisis)  and almost all the hottest years in record have occurred within the last decade. And it is not up to individuals as we all have individual wants,  it really needs to be a government response. Won't happen in my opinion so may as well make the best of what we have for now.

 

 

[onetrack]

This is the risk everyone faces every day, just refuelling your vehicle (or aircraft) with petrol!

 

It is very important that you do not keep getting in and out of seats (usually made from synthetic materials), while you're wearing clothing that facilitates static buildup!

 

A lot of anti-battery people seem to forget that they're already carrying a sizeable electrical power hazard, just in your regular lead acid battery! At the scene of any crash, the first thing you should do, is cut or unscrew battery terminals!

 

 

 

Edited July 31, 2021 by onetrack

[turboplanner]

27 minutes ago, onetrack said:

This is the risk everyone faces every day, just refuelling your vehicle (or aircraft) with petrol!

 

It is very important that you do not keep getting in and out of seats (usually made from synthetic materials), while you're wearing clothing that facilitates static buildup!

 

A lot of anti-battery people seem to forget that they're already carrying a sizeable electrical power hazard, just in your regular lead acid battery! At the scene of any crash, the first thing you should do, is cut or unscrew battery terminals!

 

 

 

All the potential hazards and characteristics of a fuel/power type should be included in any analysis, and the includes the potential frequency of the event.

Also what it takes to reduce the risk of the event.

[tillmanr]

The first thing you do in an accident is see that the doors are unlocked and if necessary for rescue that the windows are down. Then cut the battery.

This saves a lot of smashing of glass and rescue equipment use caused by haphazard battery isolation which is mostly done by cutting the battery cables.

Edited July 31, 2021 by tillmanr
Added text

[RFguy]

It is WHY aircraft users should  use Lithium Phosphate batteries ( LiFePO4 ) 

Not "Lithium Ion" (various chemistries- cobalt polymers etc) .

 

You don't get runaway meltdowns like classic  "Lithium Ion".

 

There is an energy  density penalty with LiFePO4, about 25%, but you get safety. Nearly unconditional stability.

 

Edited July 31, 2021 by RFguy

[Marty_d]

3 hours ago, tillmanr said:

The first thing you do in an accident is see that the doors are unlocked and if necessary for rescue that the windows are down. Then cut the battery.

This saves a lot of smashing of glass and rescue equipment use caused by haphazard battery isolation which is mostly done by cutting the battery cables.

Don't people put a battery isolation switch in their aircraft?  I was in Repco today looking at this - https://www.repco.com.au/en/globes-batteries-electrical/electrical-accessories/switches/narva-rotary-battery-master-isolator-switch-with-removeable-keyed-knob-contacts-rated-100a-12v-61036bl/p/A9758517

Would like to hear from the electrically qualified here, would it be a good idea to have that going straight from the battery before going anywhere else?

[RFguy]

Now, that NARVA unit you mention, Narva stuff is OK, but there is little quality control and variable manufacturers.

Consider you want to be able to cut the battery very close to the battery. A hand mounted switch might not permit a suitable mounting location.

 

All GA aircraft I've looked at have a contactor (relay) near as damn to the battery.

 

I have bought a high ambient temperature , vibration rated  and  250A rated , contactor, with screw bolt terminals.  for my Jab to install...was about $40-60 I think.

 

The ones  (isolation contactors) I see in most aircraft are not rated above 70C, and the armature (coil) runs continuously, and so is quite life span-sensitive to where you put it.

 

The Narva circuit breakers that Jabiru have been putting in series with their Gen4 alternators- quite alot of those have failed and where they are mounted on the engine they are  running way way above max specified operating temperature......

 

 

 

 

 

 

 

[Marty_d]

1 minute ago, RFguy said:

Now, that NARVA unit you mention, Narva stuff is OK, but there is little quality control and variable manufacturers.

Consider you want to be able to cut the battery very close to the battery. A hand mounted switch might not permit a suitable mounting location.

 

All GA aircraft I've looked at have a contactor (relay) near as damn to the battery.

 

I have bought a high ambient temperature , vibration rated  and  250A rated , contactor, with screw bolt terminals.  for my Jab to install...was about $40-60 I think.

 

The ones  (isolation contactors) I see in most aircraft are not rated above 70C, and the armature (coil) runs continuously, and so is quite life span-sensitive to where you put it.

 

The Narva circuit breakers that Jabiru have been putting in series with their Gen4 alternators- quite alot of those have failed and where they are mounted on the engine they are  running way way above max specified operating temperature......

 

I guess the problem is accessibility - if the switch is on the firewall for example then there's either the chance of hitting it with your foot or not being able to reach it in an emergency.  Where did you mount it?

 

Would be interested in the details of your isolator.