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Those battery backup units and GA


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Got one of those all too popular but very useful battery backup/jump start things last Christmas (only 195 days to go LOL). They look like this: https://www.google.com/search?q=battery+backup+jump+start+car&source=lnms&tbm=isch

 

 

Question:

 

Couple years ago I saw on the TV show Airplane Repo one of the Repo guys connect a couple 9 volt batteries together (I think he used series for 18v) to jump start a private jet. LOL (I can almost hardly believe it since I would think the batteries would explode on Amp draw overload). So, I got to thinking. Absent of jet powered aircraft, I'm sure GA has a battery like a car in the 12 - 24 volt range (I'm thinking 12). Can these battery jump start units work in GA?

 

And as I type this I just pondered that if you had to use a jump starter it means your aircraft isn't airworthy - violating some FAA rule or something? Maybe useful for bush pilots? Like in Alaska?

Edited by CRJ_simpilot
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Most light aircraft since the 1960s-1970s use 12V batteries, though there are exceptions that use 24V batts today, and there might still be an old one with 6V, but those are rare.

 

So yes, those jumpers might work, BUT, you have to be extremely careful where you place the jumper box, and where the path from box to batt is (cables), as well as careful with the engine cowling, even with where you stand, since you have a large slicer just waiting to grab you (the prop). Before those jumper boxes existed we'd sometimes use jumper cables from a car. Also note that a number of aircraft have a specific plug to accept a different kind of jumper connection, a couple of which you can see (cables) here:

https://duckduckgo.com/?q=aircraft+jumper+cable&ia=web

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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Ah, very interesting about the unique jumper cable.

 

 

Yeah, being caught up in the prop would be something to be conscious about. But with a battery jump starter unit like these for cars you're not anywhere near the engine when you turn the key. However, once you do turn the key for a plane then you have to contend with removing the battery box. LOL! So I guess those jumper cables would need to be used or something.

 

How in the world do you remove aircraft jumper cables after the engine had been started? LOL In hindsight, perhaps the connector should be inside near the door or something?

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How in the world do you remove aircraft jumper cables after the engine had been started?

The details depend on the aircraft. Some might not be much of a problem, since battery is behind the cabin, but most light singles have the battery somewhere under the cowling. So if you jump direct to the battery you must be careful where you put the J box in the first place, then must use extreme care to retrieve it. On many aircraft there is NO place available to put the J box on the aircraft at all (unlike typical under-the-hood on a car), so you'd need a stand (not very good) or a set of jumper cables to attach to the J box cables, not very desirable with uninsulated clamps near each other.

 

Usually you'll want help, but in any case, it's a potentially hazardous situation.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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  • Founder

I'm only really familiar with Piper aircraft (aka Archer) and those are easy to jump start. The battery is in back, behind the luggage compartment. There is even a jump start port on the side of the plane and if you have the right cable:

 

https://www.sportys.com/piper-aircraft-jumper-cable-single-pin-plug.html

 

you just plug it into the side of the plane and you're good to go.

 

That said, in all my years of flying I've never actually done it!

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That said, in all my years of flying I've never actually done it!

That speaks well for the way you maintain your bird, Nels. And it's much easier because of that special port). In the L-21 I used to have the battery is behind the baggage compartment (no door, no external port, and you have to open a cover back there, then get the jumper inside, somehow (might be OK with the J boxes), which is awkward with normal jumper cables from a car. But many are under the cowling or other awkward places.

 

Batteries are often placed for weight and balance reasons, as well as considering cable lengths to the starter, so locations DO vary a lot.

 

In any case, I've propped planes more than I've jumped them to start.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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I'm only really familiar with Piper aircraft (aka Archer) and those are easy to jump start. The battery is in back, behind the luggage compartment. There is even a jump start port on the side of the plane and if you have the right cable:

 

https://www.sportys.com/piper-aircraft-jumper-cable-single-pin-plug.html

 

you just plug it into the side of the plane and you're good to go.

 

That said, in all my years of flying I've never actually done it!

 

I replace the battery on our Cessna every three-or-so years. Tech has come on a long way since my Cessna was built in the 70's and now it's cheaper to replace than repair or renovate.

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Absolutely ridiculous how they can charge $150 smackers for a cable. It's really no different than a car's counterpart other than the unique plug at the end. I'd be apt to craft my own plug with a 3D printer somehow.

 

You can even craft your own circuit boards with a circuit board CAD program and have a company in China silk screen the board.

 

Absolutely amazing the times we live in.

 

Next question if I may. Cars have a data port for diagnostics. Do planes have the same thing? I mean, for GA? I'm pretty sure the maintenance crew for a 737 et al has laptops and what not for the FMC and NDs, etc.

 

 

Are Cessna aircraft all "chiped up" with a chip to control fuel flow and a MAP sensor and what have you?

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Next question if I may. Cars have a data port for diagnostics. Do planes have the same thing?

Newer cars have lots of onboard electronics running everything, where most light aircraft don't have that for the aircraft systems themselves. Granted they have avionics, but that's not the same. So no, other than avionics, no data ports -- nothing that could use them.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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  • Founder
Absolutely ridiculous how they can charge $150 smackers for a cable. It's really no different than a car's counterpart other than the unique plug at the end. I'd be apt to craft my own plug with a 3D printer somehow.

 

Pretty much everything in aviation is more expensive than in the automotive world.

 

But consider this example: that custom plug probably only fits on Piper aircraft, and probably not all them. So the maximum number of potential customers is probably in the thousands, vs a similar car part which could be used in millions of cars. Design and tooling for manufacture still has be done, whether you sell 1000 or 1,000,000. With no economy of scale, things are going to be more expensive.

 

This example isn't even all that bad. The worst one I ran into as an aircraft owner was the electric trim switch. Though it had a very specific shape to fit into the yoke, it was actually nothing more than a DPDT switch, the kind of thing you used to be able to get at Radio Shack for about $1. Piper's list price: $800.00.

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I don't know current price, but back in the 1970s the alternator for a Cessna 172 was actually a Ford product. For a car it cost about $60 or so at that time. For the Cessna (exact same part) it was almost $400, but it had an FAA approved data plate and, more pertinent, it had gone through the FAA's rigorous certification process making it an approved part.

 

And while it might have had more customer's than Nels' trim switch (which also had to have FAA approval, an expensive process) it still wasn't very many customers, since any car manufacturer at the time (and more so today) sold more cars in a day than Cessna sold aircraft (ALL of their aircraft) in a decade- Cessna at the time had sold OVERALL, since the first 172 in 1956, about 17,000 C-172s, and that was a LOT, compared to most other aircraft on the market.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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  • 4 months later...
Got one of those all too popular but very useful battery backup/jump start things last Christmas (only 195 days to go LOL). They look like this: https://www.google.com/search?q=battery+backup+jump+start+car&source=lnms&tbm=isch

 

 

Question:

 

Couple years ago I saw on the TV show Airplane Repo one of the Repo guys connect a couple 9 volt batteries together (I think he used series for 18v) to jump start a private jet. LOL (I can almost hardly believe it since I would think the batteries would explode on Amp draw overload). So, I got to thinking. Absent of jet powered aircraft, I'm sure GA has a battery like a car in the 12 - 24 volt range (I'm thinking 12). Can these battery jump start units work in GA?

 

And as I type this I just pondered that if you had to use a jump starter it means your aircraft isn't airworthy - violating some FAA rule or something? Maybe useful for bush pilots? Like in Alaska?

 

I carry a good quality Lithium starter pack in my aircraft it weighs little and turns my little prehistoric 4 cylinder engine over just fine it also has a USB power point.

Re: airworthiness, well that depends..it could be that you have a flat battery due to a charging problem which might be an airworthiness issue , but it could also be flat due to you leaving the master/on overnight (we;ve all done it), in which case there is likely no airworthiness issue and the starter pak could well get you out of a fix at a remote airstrip. (I do lot of fly-in and camp trips)

Edited by Hyperdark
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It is only now I'm see responses to this thread.

 

The whole price market given the "niche" market makes sense I guess. From that perspective it makes one just want to fly experimentals. I'm sure you could use a car alternator replacement at that point, right? Or are you still having to buy FAA certified parts?

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A lot depends on how the airworthiness certificate is worded, but in many (most?) cases you could substitute that Ford alternator I mentioned above for the one that came on the Cessna (with FAA data plate, but then you probably wouldn't have used the Cessna part in the first place.

 

BUT, you do have to be careful what you substitute, since size, weight, mounting mechanism and perhaps other factors may play a part in whether it's safe to do so or, in some cases, whether it is legal to do so. Homebuilt aircraft (one class of experimentals) are still under FAA jurisdiction, and there are still rules about what you can and cannot do -- it even matters whether you were the actual builder of that specific aircraft -- and with many changes from the original configuration you would have to go through the examiner check and the 40 hour flight test/proving period again, with all the restrictions that that entails.

 

So it's not a complete free-for-all out there. BTW, in using the term experimentals you need to be specific since, for example, warbirds such as a B-29 or a P-51 or even a T-6 are experimental, too, but the rules for them are quite different.

 

Larry N.

As Skylab would say:

Remember: Aviation is NOT an exact Science!

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