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Jump Start Receptacle

rv8gibbo

Well Known Member
I'm going to run a jump start receptacle about 4-5 feet from my battery on the firewall, would 6AWG be enough to carry the starter AMPS? I can do it in 4AWG but I'd like to make it as light as possible.

Many Thanks
 
I'd be cautious jump starting an airplane. Even the bigger planes with ground power connectors and nearly always start on ground power have minimum battery states required even to plug in the power.

If there's a dead/weak battery, charge it first. Ground power is generally used for lessening wear on the battery during start, or running electrics with the engine off. Both of those situations will need different wire sizes than starting the engine solely on ground power.
 
Use This ...

If you are not using this chart already for wire sizing, you might want to consider it.

HFS
 

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Thoughts...

The longer the wire run, the larger the voltage drop and thus the slower the starter will spin.

The longer the starter spins, the hotter the wire will become.

Consider the wire size used in some of these LiFePo+ "Jump Packs" -- the cable provided is ~5ft and 10ga and should only be used for 4 minutes.

With that in mind, you should be fine at 6ga -- just keep the cranking in this case to under a few minutes (4? 6?)
 
I suggest you consider ANY option other than a jump start. If you abused your battery to the point it no longer cranks the engine, charge it. If you abused your battery to damage reserve capacity (e.g. left the master(s) on), replace it.

Jump starts are a relic of the past when flooded batteries sat in corroding battery boxes.

Carl
 
Thanks guys,
It'll only be used in situations where the battery is dead and access to help is minimal or no existent. I'm going to have a lithium jump pack in my tool kit which are very light weight, small and are more then capable of starting and engine safely. I'm also going to have a ground receptacle so it's plugged in and not clamped on.
 
Cables

After close no-start situation with a cold temp start at an airport away from home base, I'm also planning to add emergency jump capability. I have a Nocco jump pack and they sell an extension cable that you can attached to the battery that can also be used to connect their battery charger/maintainer. It's an 8ga cable and only 18 inches but I think it will be long enough to reach out through the oil filler door in case I needed to use it with the pack.

Years ago, a DA42 was jumpstarted due to a dead battery and took off shortly after. The battery hadn't had a chance to recharge enough and when they retracted the gear, the electric motor drew enough current to pull the system voltage so low that the ECUs went offline. Result was a dual engine failure after takeoff and crash. They redesigned the system after that, but one reason why some planes have minimum battery charge levels.
 
After close no-start situation with a cold temp start at an airport away from home base, I'm also planning to add emergency jump capability. I have a Nocco jump pack and they sell an extension cable that you can attached to the battery that can also be used to connect their battery charger/maintainer. It's an 8ga cable and only 18 inches but I think it will be long enough to reach out through the oil filler door in case I needed to use it with the pack.

Years ago, a DA42 was jumpstarted due to a dead battery and took off shortly after. The battery hadn't had a chance to recharge enough and when they retracted the gear, the electric motor drew enough current to pull the system voltage so low that the ECUs went offline. Result was a dual engine failure after takeoff and crash. They redesigned the system after that, but one reason why some planes have minimum battery charge levels.

I too have thought about something like this. Those jump starters are quite effective and light. I often fly with mine because my personal courtesy car battery is often drained when I land. (really old truck)

Wasn't aware Nocco had an extension. I may just have to copy that idea.

Something like this.
 
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Cheap insurance on the “road”

I installed a ground power receptacle on the aft baggage floor of my RV8. This was not done to “help” a weak battery but mainly to provide some cheap insurance in the event that the battery master was accidentally left on at a remote location, discharging the battery and preventing a normal start. I chose the aft baggage floor so that no one is near the prop during start, and because it’s near the rear battery location reducing the necessary wire runs. A vehicle parked aft of the wing line can safely provide power with standard jumper cables. I used Bob Nuckolls diagram and instructions and carry a jumper plug in my travel tool kit. This is no different than jump starting your car to get you home IMHO.
 

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Years ago, a DA42 was jumpstarted due to a dead battery and took off shortly after. The battery hadn't had a chance to recharge enough and when they retracted the gear, the electric motor drew enough current to pull the system voltage so low that the ECUs went offline. Result was a dual engine failure after takeoff and crash. They redesigned the system after that, but one reason why some planes have minimum battery charge levels.

This is exactly the accident I was thinking of when reading the OP. My memory tells me it was a brand new airplane undergoing factory test flights prior to delivery. My memory might be wrong, so don't quote me. While we don't have a landing gear motor, instantaneous loads can sneak up on an alternator and cause problems with a very weak battery. I'd hate to move the flaps, transmit on the radio at the same time a strobe light decides to flash and cause a problem.

Relays and contractors also take a minimum volts to close. If the battery is too low, that may not happen. Then an electrical system starts to do weird and unsuspecting things.
 
I'm going to run a jump start receptacle about 4-5 feet from my battery on the firewall, would 6AWG be enough to carry the starter AMPS? I can do it in 4AWG but I'd like to make it as light as possible.

Many Thanks

I have an Anderson connector and 6AWG, but my run is only 8 inches, and the ground is #4. It is accessible via the oil door on my -7.

It has limited usage and if the engine is hard to start and battery completely dead it would only be used after several minutes of charging.

I consider it helping a weak battery to get a good spin, not for extended cranking, maybe 100A for 15 sec.

Actual usage is certainly problematic, and extreme caution advised.
 
I have an Anderson connector and 6AWG, but my run is only 8 inches, and the ground is #4. It is accessible via the oil door on my -7.

It has limited usage and if the engine is hard to start and battery completely dead it would only be used after several minutes of charging.

I consider it helping a weak battery to get a good spin, not for extended cranking, maybe 100A for 15 sec.

Actual usage is certainly problematic, and extreme caution advised.

Bill you wouldn't happen to have any pictures of your setup would you? Any motive/rational for wire size?

I have really been thinking about this mod a lot lately. Mainly to avoid a pissed off wife when my plane can't start multiple hours drive from home. :)
 
+1 on the Anderson connector. I installed mine under the panel shelf on the passenger side with the external power contactor just above it. On/Off Switch and Ext Pwr light are on the panel. I used #6 wire as it was not really intended for starting an aircraft with two dead batteries.

Primary use is plugging in a Ground Power Unit to run the avionics for service work. I do fly with a 12V EarthX Jump Pack that can be plugged in if needed to run the ECU, Fuel Injectors and Fuel Pumps in the event both batteries and the alternator die in flight before I find a place to land.

I purchased the Jump Pack's EC5 connectors on Amazon to make an EC5 to Anderson SB cable. IIRC, the Jump Pack cables are #10 silicon wire, so there is no point in to going to a much larger wire size.

John Salak
RV12 N896HS
 

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What I Use ...

A built-in, polarized plug/socket combination. Wired both for trickle charging/maintenance & jump starting.

Mounted on the right side, aft fuselage, adjacent to the battery. Easily accessible without compromising safety when using in jump start mode.

The plug, from AW Direct, is a GL-9A; and, the socket is a GL-101.

Both of these items are much smaller than conventional AC battery plugs - a little more in keeping with the size of our aircraft.

YMMV - and probably will.

HFS
 

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I have a trickle charger for Concorde SLA RG25XC aft placement in addition to a Piper style Ground Power receptacle I got from ACS.

The trickle charger probably shouldn’t be used with avionics because of the pulsing nature of its operation. So the trickle charger is used for keeping the battery topped off and the GP setup is used for working on avionics with an external power supply and external start, if necessary.

I used a Bob Nuckols design which has a push to test power light when power is available, circuit breaker which switches external power to the battery through the ground power contactor and also an over voltage fuse which trips the breaker open in case too high external voltage is applied.

Here is the Bob Nuckols description and a pix of my setup. I didn’t want to cut a hole in the side of my plane so put it in rear baggage.
 

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I'm putting a standard 3-pin ground power socket (AN-2552 / MS3506) in my RV-10. There's one in my Mooney and I use it with a Schauer charger/power supply to power the airplane on the ground and charge the battery. In the unlikely event I would need to jump start or charge at a remote airport, it will make it easy to do--most FBOs have a cart that can plug into an AN2552.

I did have to use mine once for jump-starting--a car. After a week-plus trip, we got back to the hangar to find my girlfriend's car battery was dead, so we hooked the car up to the airplane and jump-started it. Very handy.
 
I did the same

I also added the same Anderson type plug to my RV8 when I did my engine/prop upgrade this past year. I feared the learning curve of a FI engine and wanted a way to start the engine if I killed the battery. I installed this on the back of the lower luggage compartment on the right side in front of the gear tower with #6 wire. I'm using it with a cable I made for the Hulkman Alpha85 lion jump pack. Any good jump pack will work, but you need one that will work with a totally dead battery like the Hulkman or the NOCO brand packs (I'm sure there are others). Testing works fine, but by installing it will surely guarantee I'll never actually *need* it! :).
 

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Bill you wouldn't happen to have any pictures of your setup would you? Any motive/rational for wire size?

I have really been thinking about this mod a lot lately. Mainly to avoid a pissed off wife when my plane can't start multiple hours drive from home. :)

Sorry, the only photos found were mock ups for location and no final. I have been moving to a different hangar the last 2 weeks, I'll get you a picture on my next visit, it should be soon, more organization to be done :).

Regarding wire, I figured that the use at high amps will be rare, and that it should be helping a weak, not dead battery. #6 is good for ~100 amps at ~100C so I "decided" it should be adequate for the rare case. If worried, then some charging prior to crank would be in order.
 
Sorry, the only photos found were mock ups for location and no final. I have been moving to a different hangar the last 2 weeks, I'll get you a picture on my next visit, it should be soon, more organization to be done :).

Regarding wire, I figured that the use at high amps will be rare, and that it should be helping a weak, not dead battery. #6 is good for ~100 amps at ~100C so I "decided" it should be adequate for the rare case. If worried, then some charging prior to crank would be in order.

No worries, thanks Bill. I think I have a connector sourced. Just need to decide on wire size now. I'm thinking of just using 4awg (or 2 since I have it) and calling it good. Will only be about a foot long.
 
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