STC for moving the battery location

[jamesm]

What !!!!! No  'C' model   Will it support Electronic ignitions  SureFly or Electro Air??

[Ragsf15e]

17 minutes ago, jamesm said:

What !!!!! No  'C' model   Will it support Electronic ignitions  SureFly or Electro Air??

Good question… deconflicting STCs is left up to the installer…

[vik]

On 1/8/2023 at 10:36 AM, ArtVandelay said:

I would think a new voltage regulator would be necessary.
Lithium battery can catch fire if overcharged.

As far as I know it is designed to work with the same voltage regulator.

[vik]

On 1/8/2023 at 3:29 PM, ArtVandelay said:

That’s a deal breaker.

Really? Your lead acid battery actually has only 1/2 capacity stated on the sticker. And this is only when it is new. On contrary, Li-ion battery can be discharged all way down and it will keep higher voltage through the whole discharge cycle. And your ancient battery probably has much lower real capacity after couple of years. It is often dead after 3 years.

Check for yourself. Discharge it by connecting a bulb that will consume ~ 3A current (like 55W halogen headlight) and check the discharge current you will get after 3 hours. Compare with the charts. You will be surprised.

EarthX battery comes with STC for about $700 last time I checked.

[vik]

2 hours ago, Ragsf15e said:

Good question… deconflicting STCs is left up to the installer…

Why should a different chemistry battery hurt anything? All your electronics see the battery as huge capacitor. It does not care how it s made. Capacitance is a capacitance.

Since they got STC, the voltage is within acceptable range. LiFePo4 chemistry helps a little here.

You can also shoot LiFePo4 with a bullet while under load or charging. It will die slow and probably painful death, but it does not show its pain by heating up or catching fire. Really brave! 

[ArtVandelay]

Really? Your lead acid battery actually has only 1/2 capacity stated on the sticker.

Not exactly, yes draining the battery past 50% isn’t good if done often, but the battery does have its full capacity. And yes the voltage drops as it drains but the modern electronics won’t know the difference thanks to voltage regulators.
And lithium batteries performance declines just like lead acid batteries.
And yes the current drops for a incandescent light because the voltage drops, but that’s not an issue until it’s mostly drained.

[Ragsf15e]

1 hour ago, vik said:

Why should a different chemistry battery hurt anything? All your electronics see the battery as huge capacitor. It does not care how it s made. Capacitance is a capacitance.

Since they got STC, the voltage is within acceptable range. LiFePo4 chemistry helps a little here.

You can also shoot LiFePo4 with a bullet while under load or charging. It will die slow and probably painful death, but it does not show its pain by heating up or catching fire. Really brave! 

Well, since it has its own internal voltage regulator and warning system, it might be prudent to check how it works with some of the various systems.  It’s probably fine, but the Surefly mag system is hardwired to the battery and has a very small draw, even when everything is shut down. 
 

Im sure it’s probably fine, I was just saying that it’s up to the installer to determine any conflict between different STCs during installation.

 

[Bobaran]

On 1/6/2023 at 1:52 PM, Yourpilotincommand said:

My empty CG has become a bit aft through the years and would like to move it forward. Does such an STC exist to move the battery up to the engine compartment?

There is an STC for the EarthX battery for Mooneys.   I bought it for my 67 M20F.  The 28 pound + wet lead battery is replaced with a 3 pound EarthX LIFePO battery that really packs a punch with starting the engine!  It also does not drain and loose effectiveness like the lead acid battery.  I paid $900 for the STC'd kit.  sales@earthxbatteries.com.  I'm very glad I bought it.  I learned about initially on Mooneyspace from Brent Olsen.

[jetdriven]

it only has half the capacity of a lead-acid battery.

[A64Pilot]

On 1/9/2023 at 8:56 PM, ArtVandelay said:

Not exactly, yes draining the battery past 50% isn’t good if done often, but the battery does have its full capacity. And yes the voltage drops as it drains but the modern electronics won’t know the difference thanks to voltage regulators.
And lithium batteries performance declines just like lead acid batteries.
And yes the current drops for an incandescent light because the voltage drops, but that’s not an issue until it’s mostly drained.

Almost all of what he said is correct. Lithium chemistries voltage drop is much smaller than LA, in slow discharge and more importantly in high amp loads like starting.

We are only talking LifePo4 here by the way Li-po and Li-ion are not safe to use in an aircraft, so whenever you see Lithium battery and aircraft, it’s LifePo4

Lithium  batteries can be discharged much faster without harm too, and can accept much higher rates of charge and therefore can be fully charged in less time, MUCH less time. A Tesla can pull 400,000 Watts and add a couple hundred miles range in 15 min, huge battery of course but lead acid can’t even come close, think how fast your drill charges compared to a motorcycle battery for example.

That can actually be bad, as lithium batteries can accept much higher charge rates, they have a tendency to burn out non thermally protected alternators, and I’m sure our alts aren’t thermally protected.

Two issues as I see it in our aircraft, first is if I lost ten lbs of battery, then I’m going to have to add ballast to get my CG back, sure if I put it way back in the tail I would save some weight, and secondly as I said a Lithium battery can and will overheat an alternator as it will take all the current our alts can make, a Lead acid battery can’t, it self limits it acceptance rate and doesn’t burn up alternators.

But if an electrical system is designed for LifePo4, its a clearly superior technology than lead acid, but as a drop in for lead acid it’s very likely your alternator may not last long, not a fault of the LifePo4 battery, but a fault of the system not being designed for LifePo4.

We just need a modern voltage regulator with thermal protection and the proper charge profile for LifePo4, which as far as I know doesn’t exist for aircraft.

I’m surprised the FAA issued an STC with what lithium can do to an alternator if it’s discharged much, without a “proper” voltage regulator being a part of the STC.

When we put a LifePo4 bank in a cruising boat we needed a Balmar 614 regulator or similar, it sensed both bank temperature and alternator temp and was programmable, I programmed my alternator to 80C, when it hit that temp the regulator would turn down field current to not exceed 80C, that protected the alternator otherwise it would overheat and burn up.

https://balmar.net/balmar-technology/multi-stage-regulation/

Edited July 11, 2023 by A64Pilot

[jetdriven]

On 1/9/2023 at 8:43 PM, vik said:

Really? Your lead acid battery actually has only 1/2 capacity stated on the sticker. And this is only when it is new. On contrary, Li-ion battery can be discharged all way down and it will keep higher voltage through the whole discharge cycle. And your ancient battery probably has much lower real capacity after couple of years. It is often dead after 3 years.

Check for yourself. Discharge it by connecting a bulb that will consume ~ 3A current (like 55W halogen headlight) and check the discharge current you will get after 3 hours. Compare with the charts. You will be surprised.

EarthX battery comes with STC for about $700 last time I checked.

Actually, we capacity test batteries all the time, and for example, Concord, says that it must have 80% capacity and ithe test is to discharge for one hour at the C1 rate, which is the amp hour.  So you do get 30 amps out of a battery for an hour.  

[A64Pilot]

Where the 50% comes from is the recommended daily depth of discharge for a bank of deep cycle batteries, like a sailboat for example. Going deeper than 50% is possible of course but it significantly reduces life, it’s a curve not a cliff and 50% is just a generally agreed number. Smaller banks take up less room, weigh less and cost less but have shorter cycle life because to get the same AH they are discharged deeper. A race boat will have a tiny bank, a cruising boat a large one. LifePo4 really changes things as it’s half the weight to start with but you can safely use almost all its capacity so that’s another half weight reduction, it can be discharged at high amperage so you can use your inverter to cook with or make Coffee etc. plus it can continuously take a very high amp charge, every bit of what your generator, alternator and Solar can make, additionally it’s best not to fully charge it unlike lead acid which must be fully charged or it will sulphate.

Of course our batteries aren’t cycled at all actually, while the current required to start is high, it’s a very short time so almost no AH are used and it’s immediately recharged. So while LifePo4 is a game changer for sailboats and golf carts etc and anywhere weight is very important, it’s just not as valuable for aircraft that use the battery as ballast. However a quality one ought to last at least 10 years so there is that, if not there are going to be a whole lot of unhappy electric car owners

Oh, and the FAA requires us to capacity check out batteries yearly, but most aren’t.

Edited July 11, 2023 by A64Pilot

[cliffy]

So you want to move your battery for CG reasons?

Have you run the calculations to see just what the amount of CG movement you'll get IF you move it and is that what you want ? 

Don't go to all that work without running the numbers first. 

I find it hard to believe that you are close to the rear mark I had to move mine to the back as I was at/over the front edge on mine with no pax in the back. 

If you duplicate the factory installation with all/only factory parts it is a Minor Alteration and no STC is needed. Refer to 43.13 it shows you how.  

[Pinecone]

On 7/10/2023 at 8:58 PM, A64Pilot said:

That can actually be bad, as lithium batteries can accept much higher charge rates, they have a tendency to burn out non thermally protected alternators, and I’m sure our alts aren’t thermally protected.

The EarthX has circuitry in the battery.  Since they have the STC, I figure the battery takes care of limiting charge rate to within the capabilites of the aircraft that are STCed for install

[A64Pilot]

10 hours ago, Pinecone said:

The EarthX has circuitry in the battery.  Since they have the STC, I figure the battery takes care of limiting charge rate to within the capabilites of the aircraft that are STCed for install

The circuitry you refer to is most probably a BMS or battery management system, usually almost always Li-po batteries have a BMS, a good one monitors individual cell voltage and balances cells, that is as each cell will have a slight resistance difference they will charge at slightly different rates, overcharge is of course a very good way to get one to burn so that each cell has to be monitored and charge stopped prior to that point, they usually also monitor temp and will cut current if temp gets high to prevent a fire.

LifePo4 though usually doesn’t have a BMS, basically the disadvantage of LifePo4 is it’s only about half as energy dense as Li-po, but it’s extremely tolerant of abuse, you can charge it to 100% much more often than Li-po, hit it with a hammer and destroy it, but it won’t burn etc. It also has a longer cycle life, but it’s much heavier than Li-po.

It tolerates overcharge well etc. Earth-X may limit charge voltage, I don’t know to be honest, I’ve not heard of anyone that does, but they could.

Look, I’m a great proponent of Lithium batteries, I’m the electric car guy that has gone to stupid lengths to dispel EV myths here etc. Wife drives a Tesla.

But there is no single best for everything, even our Grandfather's technology sometimes is best for a specific mission.

Did you know that a Tesla has a 12V lead acid car battery in it? Now I don’t think Elon or his Engineers at Tesla are stupid, so why does a Tesla have a 12V lead acid battery?

https://service.tesla.com/docs/Public/diy/model3/en_us/GUID-2588F809-41E3-43F1-84E5-6745C7C18DBE.html

Its the battery that is used to boot the computer and run diagnostics on everything before the big traction battery is connected and brought online. In other words a lead acid battery “starts” a Tesla.

I suspicion that Tesla chose a lead acid battery not because they are cheap and heavy, I think they did because even though they are heavy they are extraordinarily reliable and give ample warning of impending failure and its well known.

Of course there are many who are smarter than Tesla Engineers who will sell you a LifePo4 battery for your Tesla

https://www.ohmmu.com

But sit back for a moment and consider that if someone who pushes technology like Elon Musk, chooses a dinosaur battery to “start” his cars, perhaps there is a reason?

Is it better to replace the Tesla lead acid battery with a LifePo4?

Maybe our Grandfathers lead acid battery just might be best for our aircraft for reason we don’t know about or understand?

Edited July 18, 2023 by A64Pilot