Relocate the battery

[Kmac]

This seems to be a pretty old topic, however, my 62 C has the battery in the back.  It had a ray-jay turbo which is when the battery was moved.  When the ray-jay was removed the battery stayed.  I can run out the back of the envelope fairly easily.  

[steingar]

Cherokees have the battery mounted in the back below the back seats.  Because of the one distance there's a big current draw when you go to start he engine, if the battery isn't seriously tip top it won' have enough juice.  I'd sooner put a lighter prop on the aircraft.

[cliffy]

Juice to the starter is governed by the length and thickness of the wire. Bigger wire for longer runs and no loss of voltage . 

Look up the chart in 43.13

[Guest tommy123]

On 8/27/2018 at 10:15 AM, steingar said:

Cherokees have the battery mounted in the back below the back seats.  Because of the one distance there's a big current draw when you go to start he engine, if the battery isn't seriously tip top it won' have enough juice.  I'd sooner put a lighter prop on the aircraft.

Wrong. My E had a aft battery, no problems starting, current draw no different. Do some research before posting incorrect information.  It’s easily found in 43:13

Edited August 31, 2018 by tommy123

[Raptor05121]

The Cherokee series came from the factory with aluminum cables which corrode easily and do not conduct electricity like copper cables. The Bogert mod is very famous for them. What's funny is a lot of Cherokees have 337s to move the battery into the engine compartment to shorten the run and increase starting capability whereas Mooney owners are doing the opposite

[steingar]

8 hours ago, tommy123 said:

Wrong. My E had a aft battery, no problems starting, current draw no different. Do some research before posting incorrect information.  It’s easily found in 43:13

Sorry, just speaking from a decades worth of experience.

[RobF15E]

Gentlemen,  I am still hoping to do this mod, but would really like to duplicate what someone else has already done.  There are several different ways to mount the battery box and run the cables which is why I was hoping someone with an E model, or a C with the battery in the tail could take some pictures.  Words are nice, pictures are better.  I have already done W&B calcs to see where I would be after the Mod.  I am also looking to the future (many years from now) when I replace the flooded cell battery with a Lithium battery that will be much lighter.  I am also hoping to pull the Oil cooler back behind the baffling, so weight isn't my only concern.  Thanks for your time.   Last request.  I and Jstickler76 have asked for people's opinions.  Please don't slam folks who's opinion doesn't match yours.  It is fine to disagree, but I see a lot of unnecessary insults tossed at folks.  That's not helpful.   This forum is better than many of the auto forums I participate in, so I appreciate that.

[TX-Champ]

Same here - still hoping to see a 337.  Pictures would be great too.

[BDPetersen]

Too bad the EarthX battery is not approved for certified a/c.

[Guest tommy123]

9 hours ago, steingar said:

Sorry, just speaking from a decades worth of experience.

I spent 30 years as a airline mechanic and inspector and another 10 as a contractor on such things as the X47B. One thing I learned early on was to believe the books and not rely on anecdotal evidence. Voltage drop is easily calculated and accounted for with the proper wire size. Piper also made the poor decision to use aluminum wire. My anecdotal evidence of batteries mounted more than 10 feet from the starter is that it makes little difference if the properly sized wire is used.

[takair]

9 hours ago, RobF15E said:

Gentlemen,  I am still hoping to do this mod, but would really like to duplicate what someone else has already done.  There are several different ways to mount the battery box and run the cables which is why I was hoping someone with an E model, or a C with the battery in the tail could take some pictures.  Words are nice, pictures are better.  I have already done W&B calcs to see where I would be after the Mod.  I am also looking to the future (many years from now) when I replace the flooded cell battery with a Lithium battery that will be much lighter.  I am also hoping to pull the Oil cooler back behind the baffling, so weight isn't my only concern.  Thanks for your time.   Last request.  I and Jstickler76 have asked for people's opinions.  Please don't slam folks who's opinion doesn't match yours.  It is fine to disagree, but I see a lot of unnecessary insults tossed at folks.  That's not helpful.   This forum is better than many of the auto forums I participate in, so I appreciate that.

Not the best picture, but this is the battery location in my 64 E.  Note that it is mounted to the bulkhead using some formed brackets.  The easiest place to install it for a retrofit would be on the forward shelf, but that places the weight even farther aft.  I can get you more pictures over the weekend, have to do some work anyway.  

[takair]

Of course it shows up sideways and I can’t recall the @Marauder photo editing technique.

[N201MKTurbo]

I have fixed two Mooneys that were having hard starting problems with the battery in the back. The problem wasn't with the big wires, it was with the grounds. Specifically the connection between the shelf and the airframe. You see the negative battery lead bolted to the shelf. All the current needs to flow from the shelf to the airframe. the shelves and airframes were painted with zinc chromate then bolted together. It doesn't make a very good connection. take the bolts out of the shelf and lift it up and clean the paint off with scotch brite and bolt it back together. It helps a lot.

[Marauder]

Not the best picture, but this is the battery location in my 64 E.  Note that it is mounted to the bulkhead using some formed brackets.  The easiest place to install it for a retrofit would be on the forward shelf, but that places the weight even farther aft.  I can get you more pictures over the weekend, have to do some work anyway.  

Sent from my iPad using Tapatalk Pro

[RobF15E]

Marauder,  Thank you for the picture.  That is where I was wanting to install it.  I don't want all the weight on the rear shelf since I'm not certain it is stressed for it. What kind of bracket does the battery box sit on?  I was thinking about an "L" shaped shelf attached to the baggage compartment wall and the rear shelf.  Does your negative ground just attach to the rear shelf as N201 mentioned?  I assumed the Negative cable would run all the way to the front and ground on the engine mount.  I was worried using the skin that there might be issues with the avionics and ground loops causing noise in the audio equipment.  If that isn't an issue, that would save weight and cost.  Does the positive cable just run underneath the floor?  Where does it pop up and into the engine compartment?  Sorry for so many questions, but I'd rather copy a successful install, and the "E" is obviously a successful install.  Any additional pictures are great.  No hurry as I am working on my ground transportation this weekend, but I know some others are also interested.  I would imagine if Sabremech starts producing a cowl for the "C" model, there will be quite a few who need to move the battery.  CG can be a real issue.  I have the 3 blade prop and a thicker 201 mod windshield.  I did lose nose weight with lighter alternator mod and lightweight starter.  My "C" was tail heavy before the 3 blade prop and it was pitch sensitive.  It is more stable now that it is nose heavy, but I think it cost a couple of knots.  It is difficult to tell since the 3 blade was installed with an overhauled engine.  Climb improved as expected with the 3 blade.  I knew cruise might suffer some.  I didn't get specific numbers as the plane was with my Cuz for all the mods and 8-9 years after that while I was stationed in Alaska, then California.  Now the kids are out of the house, I got my bird back and I am tinkering away....

[RobF15E]

Tommy123,  thanks for your inputs.  The batteries on all the Mercedes, BMWs and Audis I have owned are in the trunk for CG.  OK, so I like German sports cars.... They start just fine - as long as the battery is in good shape - which is the same if it is in the engine compartment.  I'll ensure my cables are of the correct gauge and are copper.

Edited September 1, 2018 by RobF15E
Punctuation

[Marauder]

Marauder,  Thank you for the picture.  That is where I was wanting to install it.  I don't want all the weight on the rear shelf since I'm not certain it is stressed for it. What kind of bracket does the battery box sit on?  I was thinking about an "L" shaped shelf attached to the baggage compartment wall and the rear shelf.  Does your negative ground just attach to the rear shelf as N201 mentioned?  I assumed the Negative cable would run all the way to the front and ground on the engine mount.  I was worried using the skin that there might be issues with the avionics and ground loops causing noise in the audio equipment.  If that isn't an issue, that would save weight and cost.  Does the positive cable just run underneath the floor?  Where does it pop up and into the engine compartment?  Sorry for so many questions, but I'd rather copy a successful install, and the "E" is obviously a successful install.  Any additional pictures are great.  No hurry as I am working on my ground transportation this weekend, but I know some others are also interested.  I would imagine if Sabremech starts producing a cowl for the "C" model, there will be quite a few who need to move the battery.  CG can be a real issue.  I have the 3 blade prop and a thicker 201 mod windshield.  I did lose nose weight with lighter alternator mod and lightweight starter.  My "C" was tail heavy before the 3 blade prop and it was pitch sensitive.  It is more stable now that it is nose heavy, but I think it cost a couple of knots.  It is difficult to tell since the 3 blade was installed with an overhauled engine.  Climb improved as expected with the 3 blade.  I knew cruise might suffer some.  I didn't get specific numbers as the plane was with my Cuz for all the mods and 8-9 years after that while I was stationed in Alaska, then California.  Now the kids are out of the house, I got my bird back and I am tinkering away....

This was Takair’s picture but I can answer what is on my F. The ground is on the rack in the avionics bay. It does not run up to the front.

As for where the power line run; it comes up the left side underneath the roll cage and then through the firewall.







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[RobF15E]

Great!  Running it along with all the other wires should be fairly easy.  Takeair, Thanks for the original photo.  Your back bay looks a bit different from mine.  I have a large bellow for the retractable step that sits right about where the jump receptacle is.  How is your step retracted?   Thanks for all the arrows, they make it easy to trace the path of the cable.  Once I tackle this project, I'll take lots of pictures and copy the paperwork for anyone else who wants to undertake the project.  If it weren't for my follow on project of moving the oil cooler, I probably wouldn't do this.  Even with one of the cowl closure mods on my 65 C, I still get some reverse air flow at higher air speeds.  The doghouse on my "C" isn't quite big enough to house the oil cooler like it is on the "E".  Time to be creative.

[takair]

27 minutes ago, RobF15E said:

Great!  Running it along with all the other wires should be fairly easy.  Takeair, Thanks for the original photo.  Your back bay looks a bit different from mine.  I have a large bellow for the retractable step that sits right about where the jump receptacle is.  How is your step retracted?   Thanks for all the arrows, they make it easy to trace the path of the cable.  Once I tackle this project, I'll take lots of pictures and copy the paperwork for anyone else who wants to undertake the project.  If it weren't for my follow on project of moving the oil cooler, I probably wouldn't do this.  Even with one of the cowl closure mods on my 65 C, I still get some reverse air flow at higher air speeds.  The doghouse on my "C" isn't quite big enough to house the oil cooler like it is on the "E".  Time to be creative.

Your vacuum step actuator is likely above the receptacle.  The picture captures part of our electric step conversion.  There is an active thread on it, as we speak.  You can see part of the actuator and cables in the picture.  They should be right about where your actuator is.  Are you doing the oil cooler move due to high temps?  

[ShuRugal]

Anyone ever come up with the paperwork to make this a legal conversion?  I just ran the numbers on what this would do to my W&B, and it would take me from  being right at the forward limit in any config involving a copilot to being centered in the CG envelope in all configs - Definitely want to do it at some point.

[cliffy]

43.13-3A Chapter 10  Battery Installation.   One might start by reading this. It tells you just how to do it. 

A good A&P can use this as "Approved Data" in install your battery in the back end using 43.13 3A as the "Approved Data" for installation sign off with the appropriate W&B calculations changes to the airplane W&B.. 

[Kodiakflyer]

I have a nose heavy M20A with a M20C tail. Does anyone have a battery relocation 337 to share?

[cliffy]

Don't need a 337  Its all in AC 43.13 Minor Alteration

Its all spelled out in that AC

 

Only A&P sign off needed IF-

factory parts are used. Get all the parts from a wrecked C model ( battery box and all the mount plates

rerivit it  into your airplane. 

I did it on mine

[Hank]

2 hours ago, cliffy said:

Don't need a 337  Its all in AC 43.13 Minor Alteration

Its all spelled out in that AC

 

Only A&P sign off needed IF-

factory parts are used. Get all the parts from a wrecked C model ( battery box and all the mount plates

rerivit it  into your airplane. 

I did it on mine

Cs were built with the battery on the firewall. The OP wants to put it in the back. It may be possible to use E or F parts to do this, but not C unless it's a modified C.

[cliffy]

"from a wrecked C model" (with the battery in the back) or other EFG and  J with the battery in the back.

It doesn't matter which one. The parts should fit fine.