Battery Relocation on M4-220C

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kenja
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Battery Relocation on M4-220C

Post by kenja »

We're in the process of upgrading our avionics on our M4-220C and are looking for options to address the sizable weight and balance penalty of the existing battery. We've heard of people using EarthX lithium batteries and mounting them on the firewall or under the passenger seat, but it sounds like there are no STCs out there for that. I reached out to Maule and they sent me a drawing for relocating it under the passenger seat, but the M4 is exempted. Has anyone successfully done a battery move on one of these? I've heard of people filing a 337, but have not found anyone who knows about it.

The cryptic message I got back from Maule was that moving the battery without gap seals might make the plane not able to 3-point land with a dead stick, empty fuel tank and full flaps. Gap seals have never been approved for the M4.

Thanks for any info you might be able to share!

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Mog
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Re: Battery Relocation on M4-220C

Post by Mog »

My vote would be upgrade the wire size from the battery to the starter, then use an EarthX or similar in the stock location. Then add some lead in the tail to get it back in balance. You won’t loose a ton of weight but we all know every bit counts.

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gbarrier
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Re: Battery Relocation on M4-220C

Post by gbarrier »

You could split the difference and install the Hawker SBD-J16. The little 16 amp, 16 # wonder spins a 235 big time. Lots of 337s out there for M5, M6, and 7s. Probably some for the4 M-4 also. It is also STD for super cub so should be pretty easy to get field approval for your M-4. Not as cool as earth x but probably easier to get approved.

Maule also offers several tail weights (P/N 1299A and P/N 1322B) which are 5 or 6 pounds respectively. They bolt in the tail with the tailspring bolts. Lets you move weight and gain the pounds.

Dkuber
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Re: Battery Relocation on M4-220C

Post by Dkuber »

Mine is in a tray under the front left seat. Survival gear lives in the old tray behind the rear bulk head.

I could look and see how they wrote it up if anyone wants.

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asa
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Re: Battery Relocation on M4-220C

Post by asa »

kenja wrote:
Mon Feb 06, 2023 12:39 pm
We're in the process of upgrading our avionics on our M4-220C and are looking for options to address the sizable weight and balance penalty of the existing battery. We've heard of people using EarthX lithium batteries and mounting them on the firewall or under the passenger seat, but it sounds like there are no STCs out there for that. I reached out to Maule and they sent me a drawing for relocating it under the passenger seat, but the M4 is exempted. Has anyone successfully done a battery move on one of these? I've heard of people filing a 337, but have not found anyone who knows about it.

The cryptic message I got back from Maule was that moving the battery without gap seals might make the plane not able to 3-point land with a dead stick, empty fuel tank and full flaps. Gap seals have never been approved for the M4.

Thanks for any info you might be able to share!
Are you sure it's not applicable for you or "exempted" as you said? The table doesn't show it because it wasn't factory installed, but Note 6 gives a list of M4 serial numbers it can be installed in. This does require welding though.


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TimB
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Re: Battery Relocation on M4-220C

Post by TimB »

The gap seals can be field approved for the M4, did one a number of years ago and it worked out great.
TimB

kenja
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Re: Battery Relocation on M4-220C

Post by kenja »

Dkuber wrote:
Mon Feb 06, 2023 5:07 pm
Mine is in a tray under the front left seat. Survival gear lives in the old tray behind the rear bulk head.

I could look and see how they wrote it up if anyone wants.

Image
I’d love to see the paperwork if you wouldn’t mind digging it up. The front seat location would help a lot.

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Re: Battery Relocation on M4-220C

Post by kenja »

asa wrote:
Mon Feb 06, 2023 5:28 pm
Are you sure it's not applicable for you or "exempted" as you said? The table doesn't show it because it wasn't factory installed, but Note 6 gives a list of M4 serial numbers it can be installed in. This does require welding though.


Image
Good call on the note. That looks promising. Honestly, I wasn’t sure how to interpret what Maule had to say. He said:

Please see the attachment drawing 7042 of the forward battery location (under the seat) especially the chart in the lower left showing none for the M-4-220C. The criteria for approval of the forward CG is that the airplane can make a 3 point landing with single pilot, full flaps, minimum fuel, and no power (engine dead). This is the reason the M-6 and up airplanes have the gap seal required on the stabilizers/elevators to give the elevators enough authority for this test. The gap seal is not approved in the M-4 models and has never been flight tested.

I asked for clarification, but never heard back.

kenja
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Re: Battery Relocation on M4-220C

Post by kenja »

TimB wrote:
Mon Feb 06, 2023 6:08 pm
The gap seals can be field approved for the M4, did one a number of years ago and it worked out great.
Good to know. How big of a difference does it make? Noticeably more elevator authority?

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Re: Battery Relocation on M4-220C

Post by Maule988ms »

Is earthx approved?! This would be great news

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Re: Battery Relocation on M4-220C

Post by Dkuber »

I’ll look today in my books.


“Good to know. How big of a difference does it make? Noticeably more elevator authority?”

That’s interesting of the 6 M4’s I know up here every one of them has gap seals. Elevators only not rudder. I just assumed most dId. My knowledge base is very limited and local.

Dkuber
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Re: Battery Relocation on M4-220C

Post by Dkuber »

My log states:
“Obtained FAA Field Approval for battery installation. See 337 form and drawings for details.”

Done in ‘07

kenja
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Re: Battery Relocation on M4-220C

Post by kenja »

Dkuber wrote:
Tue Feb 07, 2023 6:38 pm
My log states:
“Obtained FAA Field Approval for battery installation. See 337 form and drawings for details.”

Done in ‘07
Thanks! You don't happen to have the 337 and drawings do you? I'm trying to convince my mechanic to do this for us and that would be helpful.

asa
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Re: Battery Relocation on M4-220C

Post by asa »

kenja wrote:
Tue Feb 07, 2023 7:56 pm
Dkuber wrote:
Tue Feb 07, 2023 6:38 pm
My log states:
“Obtained FAA Field Approval for battery installation. See 337 form and drawings for details.”

Done in ‘07
Thanks! You don't happen to have the 337 and drawings do you? I'm trying to convince my mechanic to do this for us and that would be helpful.
Did you end up checking your planes serial number against the note 6 on the maule drawing? If it’s in that range, approval is done, just install it. Seems a lot easier and faster than pursuing a field approval.

kenja
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Re: Battery Relocation on M4-220C

Post by kenja »

Dkuber wrote:
Tue Feb 07, 2023 6:38 pm

Did you end up checking your planes serial number against the note 6 on the maule drawing? If it’s in that range, approval is done, just install it. Seems a lot easier and faster than pursuing a field approval.
Yes, our serial number fits in that range. Maule's response sounded pretty dire, so I didn't even notice that note. Like our A&P, I saw the "None" on the lower left table and through it meant it wasn't applicable. I sent Maule a follow up question about it and it's been crickets ever since. I now read it as being an approved configuration, tho.

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