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Discussion in 'Maintenance Bay' started by Peter Ha, Feb 11, 2020.
If my battery dies, is there way to jump-start using cables like car?
Yes, but dangerous. The battery is in a box on the firewall, so the cowling has to come off or you have to work through the small access panel, the battery box lid has to come off, and the clamps applied without shorting the positive clamp against the box or the engine mount or cowling. The fit is close, the prop is way too close, and it's an ugly, expensive accident waiting to happen. Don't do it.
Get a small lithium battery jump pack. They work 5 times stronger and faster than car jumper cables, are light enough to take in a flight bag, and can fit entirely inside the cowling so you can start up, leave it attached while you charge your battery for a few minutes and warm up the engine, then shut down and get out to disconnect, remove, and you should be able to easily restart and be on your way.
The jump pack clamps are totally plastic shielded and it would be hard to short them out. Plus they don't deliver full current until they sense your starter working, so you can't damage things just hooking them up. Any they have reverse polarity protection, so you can't hook them up incorrectly.
As a factory option, some 150s came equipped with an external power jack. This requires the use of a Cessna power plug and cable. Even without this option, it's possible to jump start the engine by taking off the battery box cover and accessing the battery where you could use car jumper cables to affect a start. You have to be careful you don't short the battery to the battery box as some jumper cables have large spring clips and there isn't a lot of space around the battery terminals. If you were to hand prop the engine, you might get it started but many alternators need some excitation voltage from the battery in order to put out any juice so the engine would run without charging your battery.
Depending on what model you have, early 150’s have the battery Behind the baggage bulkhead. Much better off hand propping if the battery dies.
I prefer this method, seems safer:
Remove the battery, and charge it. then find why it does not stay charged.
hand propping is dangerous, as is starting with the cowling open.
doing it right, is the way.
the 150 has a battery in the cowling. I'm not certain what the 152 has.
And like I said the early 150’s have it behind the baggage bulkhead.
Seriously, the lithium jump packs are amazing. If you don’t have one for your car already, get one. But the fact that you can place the entire unit inside the cowling, close the door, start up the plane and let it run/warm up/charge and then shut down to remove the jump starter makes it safe and easy. The second start is super easy even on a dead battery - unless you have one of those engine where hot starts are a pain. Not an issue for a C150
Prop it? I have propped 150s and 172s it isn't rocket science. The angle is wonky compared to a tail dragger but it works. Have someone train you how to do it safely.
I agree, do it the smart way, and don't prop it unless you have experience.
Hand prop the thing.
I agree with the 'charge the battery and find out why it's dead' line of thinking.
Having said that, I've jump started my 172F with its "close-to-the-fan" location when we knew why it was dead (masters left on.)
For me it depends where the plane is located. At home base or multiple legs from home, no sense fooling around. Charge the battery and figure out why it was discharged. One leg away from home, jump it, check for alternator/generator operation, and if OK fly it home. I've jumped my 172 once in 20 years. I expect the 150 has less clearance to the prop so jumping might be a less attractive option.
See this thread: https://www.pilotsofamerica.com/community/threads/stupid-question-about-jump-plugs.124337/
I've hand propped many times, the danger is still there. it is better to correct the discrepancy.
you still have to repair it some day
The 150 I fly has the battery moved to the tail cone due to the 180hp STC. The 150 I fly also doesn't have a mag with an impulse coupler, so hand propping it is not an option. The 24 volt battery in a 152 makes finding a donor jump a bit more difficult.
Sure it is. An impulse coupling makes it easier and less likely to kick back, but it can still be done without one.
Yes. Done it. Extremely dangerous and wouldn't do it again!
I agree about fixing the plane.
Could you please explain why, even with the proper training, hand propping a C-150 is so much more dangerous than hand propping a Piper Cub?
That would just be stupid. Hand propping a 150 with a impulse coupling is problematic to begin with--I'd do it if that was my only option. Without an impulse coupling, no way.
Which is quicker? getting the battery charged, or getting a new arm/leg?.
The angle when propping a taildragger like a Cub is naturally safer because you're moving away from the blade on the down stroke. In fact, when I'm solo I always prop my Cub from behind. The 150, like all nosegear planes, is more dangerous because the natural motion on the down stroke has you leaning towards the prop. You have to be a lot more conscious of what you're doing. I've hand propped my wife's 150 once or twice when we were stuck away from our home field and I'd do it again, but I recognize that it's more dangerous than propping a small taildragger.
I'm not picturing it, sorry. I'd think that propping any plane solo need to be done in a way that one can get to the throttle quickly, so hence the reason from propping it from behind?
So all planes should have starters?
Sounds like you've never tried it. A trike is a pain whether from the front or the rear, party because of the vertical plane of the prop but also because it's so low, forcing you to bend way over as you carry through. A taildragger's prop is much higher and you're moving away from it as the blade comes down toward you, and even from behind it's easier simply because it's higher.
Light airplanes were commonly built without starters in the '30s and '40's and into the '50s, because they were usually taildraggers and had little engines that were simple to hand-prop and had no electrical systems. Accidents still happened and people got killed or chewed up. Engines got a lot bigger and needed more aggressive hand-propping, adding to the risk. I've done enough of it to last a lifetime.
No, I have never tried it. I've never claimed to do so.. I had a line on a nice Flybaby a few years ago, and comments such as @Tom-D has made in this thread (maybe even by him, I don't remember) was the thing that stopped me.
I understand about the engines getting larger making hand starts more dangerous, but the C-150 engine isn't that big, either.
I've had colleagues hand prop my AA1A when I owned one, but really don't recommend it. Jump starting is dangerous as you may have to disassemble the battery box as well as open the cowling. Charging the battery with the alternator is much poorer than putting the battery on a proper charger. If the battery is dead flat, you don't want to put a high current charge on it from the alternator or partially charge it during a short flight. And if you don't know why the battery is flat, you want to find out. Did it internally short? Is the alternator dead? Voltage regulator fail? Etc. Hand propping or jump starting is avoiding the important issue.
I feel like hand-propping is 100x more dangerous than accessing the battery box through the pajama-bottom cowl access door in the 150. In fact, I'm not even sure I understand what the perceived danger is. If the plane goes forward, the prop gets further away. The prop blast is annoying. If you drop something on the ground, don't pick it up.
It's a two person job without the cessna jump port. I've done the jump-box and re-secure battery trick dozens of times. I have no intention of ever hand-propping a plane.
From flight school experience, while "recharge, assess and repair" probably makes a lot of sense as a theory, 99% of the time, the "repair" is for the pilot to not leave the master on next time he shuts down.
OP, do you have one of these oval ports under your cowling?
If the battery is dead flat it won't charge anyway because there needs to be at least some voltage to the field windings to generate power.
If you're used to hand propping it's really not a big deal. For years I owned planes that didn't have starters. Had a dead battery in my plane last year when I was ready to go to a fly-in at a local private field. No big deal, hand prop it. Battery wasn't charging, no voltage at all, so I just left the master off and flew anyway... uncontrolled fields at both ends so no need for the radio. At the other end, a buddy propped me and I flew home. Replaced the battery the following weekend.
DC generators are self excited. It is call residual magnesium. Alternators are not. but most are.
BUT.. the master relay can be wired to connect, we don't know if each circuit is or not.
I have hand-propped the C150 and it's really awkward, way worse than my Jodel. Almost worse than a 172. I'd rather hand-prop a 185. Done that, too.
It's not so much the prop, though it will still kill you if you happen to trip or something goes wrong. And that thing that can go wrong is shorting those big jumper cable clamps on the battery box or the engine mount. I've taken the battery out of 150s through that access panel, as have thousands of other mechanics, and they know as well as I do how tight stuff is in there and the awesome risk of shorting something. All it takes is the briefest arc on that engine mount tube to require the whole engine to come off and the mount taken out and rebuilt, then everything put back together. If it's the box that gets touched, a bunch of that thin aluminum disappears in a flash and some smoke, and a new box is something like $700.
Why is it that so many pilots feel they can offer advice without any experience in the subject?
Here's a short video on replacing a 150 battery:
Now, this fellow is not working safely at all, using pliers to loosen the terminal nuts, and loosening the positive one first is definitely not standard aircraft practice due to the shorting risk. That tool could easily have contacted the engine mount tube and arced and wrecked the mount. The acid isn't hydrochloric acid either; it's sufuric. So much misinformation here. When he tightens the terminal bolts on the new battery, you can hear the socket extension contacting the engine mount, and only the paint on the mount saved him. Since the negative was already connected, the mount was at ground potential and any contact with the positive means a short, with hundreds of amps ready to burn things up. Never, ever, do this. Negative terminal off first and on last, with the positive never even being touched with a tool if the negative is connected.
At any rate, the positive terminal is the one nearest the firewall, so note the proximity of that terminal to the firewall, box and engine mount, and think of that big automotive jumper cable clamp trying to sit in there without causing damage when it touches ground somewhere.
Here is 24 volt lithium jump starter
And for all of you who don’t actually have any experience with the new small lithium jump starters. The cables are completely safe until the starter is engaged. There is not voltage or current through the cables or clips until it senses the starter motor turning. And the clips are totally shrouded in plastic except for the very ends. Gives you plenty of time to double check that it is all installed correctly before starting. Not hard as all.
If this is a purely theoretical question, then you've got lots of advice from the gang above, especially not to prop the sucker without a LOT of professional training.
HOWEVER, if it is just due to sitting around for a few months without any attention and the battery has self-discharged, Harbor Freight sells a cheap 15 watt battery charger. if your cigarette lighter (I guess the current pc term is auxiliary power connector) is hot to your battery through the 5 amp keep-alive that the regs allow, just plug that sucker into the hole, sit it in the sun for a couple of days, and bingo, battery charged.
I stated my experience and its context. Sorry you found it lacking and detrimental to the topic of conversation.
Thanks. I never had that issue, but can see where it could be a hazard. I still don't rate it in the hand-prop levels of danger potential, but it's just my own view.
I've done it but don't recommend it, battery access is just too close to a spinning prop. I haven't tried the small booster packs that would fit in the cowl, but that sounds much better. I have hand propped mine (yes I've had good instruction). The lower prop and angle of a nose gear plane makes it harder to do safely, but the 0-200 is small and low compression so it's possible to flip the prop over the top of it's arc, instead of down, which keeps your motion from leading you into the prop arc. Ultimately, you better figure out why it went dead and correct it, but in a pinch there are ways to get it done.