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So this evening, I had my first hit start experience since bringing my F home. I tried every procedure I could think of but it wouldn’t start.

 

My question is if my battery is dead or almost dead, can I use an automotive charger to charge the battery? I have a Schumacher battery charger with a trickle charge option and a “quick charge” option. I wouldn’t use the quick charge, but could I put the battery on trickle charge and be Ok?

 

Unfortunately I don’t know exactly what battery I have. If I can’t get it started tomorrow after work, I’ll pull the battery and update this post.

 

 

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Safest bet is to determine type of battery before proceeding.  AGM gets different treatment.  Older style needs to have electrolyte checked before reconditioning.  Regardless of type, once battery is reconditioned, it should pass a capacity check using the correct equipment.  Even if it will start the airplane, it may not pass a capacity check.

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I would not use a car charger on rapid charge.  The aircraft battery is like a motorcycle battery, delicate.  Trickle charge would be the safest route.

My charger has a 2amp trickle setting. Think it might be OK?


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3 minutes ago, gwav8or said:


My charger has a 2amp trickle setting. Think it might be OK?


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Probably not. Depends on the type of battery. If it is a Concorde AGM, it is recommended to charge it at constant voltage and as much current as the battery will take. 
1458573931_Screenshot2022-10-26at7_26_12PM.png.e5b9b77bc4f7cc48cc5863b74ef01726.png

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Any automatic car charger will not hurt your battery. They all charge to a preprogrammed voltage and then shut off. AGM batteries should be charged to a higher voltage, so a lower voltage charger will not hurt them, they will just not fully charge them. But they will charge them enough to put back in service. Some in trickle charge will not shut off when the battery is charged. You are better off putting them in normal charge mode. You can put them in high charge mode for a while, but don’t leave them that way.

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So this evening, I had my first hit start experience since bringing my F home. I tried every procedure I could think of but it wouldn’t start.
 
My question is if my battery is dead or almost dead, can I use an automotive charger to charge the battery? I have a Schumacher battery charger with a trickle charge option and a “quick charge” option. I wouldn’t use the quick charge, but could I put the battery on trickle charge and be Ok?
 
Unfortunately I don’t know exactly what battery I have. If I can’t get it started tomorrow after work, I’ll pull the battery and update this post.
 
 
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You ever figure out why it wouldn’t start? I’ve learned in my F that cold starts come in two flavors. A cold start and a cold cold start. If I am starting cold with outside air temps above 40°F, I run the boost pump until I develop full pressure for 3 seconds. I then pull the mixture to idle cutoff and crank.

When it is cold cold (below freezing), even after preheating, I do the same with the boost pump but leave the mixture full in.

There are a number of hot start recommendations but I found shutting down with the idle RPM at 1000 and on subsequent startup, cranking with everything exactly as I left it at shutdown works about 95% of the time. The problem most people have with hot starts is they don’t let enough prop swings go through.
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10 hours ago, Marauder said:


You ever figure out why it wouldn’t start? I’ve learned in my F that cold starts come in two flavors. A cold start and a cold cold start. If I am starting cold with outside air temps above 40°F, I run the boost pump until I develop full pressure for 3 seconds. I then pull the mixture to idle cutoff and crank.

When it is cold cold (below freezing), even after preheating, I do the same with the boost pump but leave the mixture full in.

There are a number of hot start recommendations but I found shutting down with the idle RPM at 1000 and on subsequent startup, cranking with everything exactly as I left it at shutdown works about 95% of the time. The problem most people have with hot starts is they don’t let enough prop swings go through.

Yeah, I'm pretty sure I flooded it trying hot start, then normal start with boost pump.  I forgot to do a flooded start.

How many prop swings is enough?  I would keep the starter engaged for about 10-15 seconds and that felt like too much, but I'm no expert. lol

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Yeah, I'm pretty sure I flooded it trying hot start, then normal start with boost pump.  I forgot to do a flooded start.
How many prop swings is enough?  I would keep the starter engaged for about 10-15 seconds and that felt like too much, but I'm no expert. lol

On a really hot start (like right after fueling on a 90 degree day), it could take 8 to 10 prop rotations. If you anticipate a quick restart, open the oil access panel and let some of the heat out.

I have only needed to resort to a flooded start a couple of times in 31 years of owning my F. Maxwell’s hot start technique works, just need to have patience sometimes.




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2 hours ago, Marauder said:

On a really hot start (like right after fueling on a 90 degree day), it could take 8 to 10 prop rotations. If you anticipate a quick restart, open the oil access panel and let some of the heat out.

I have only needed to resort to a flooded start a couple of times in 31 years of owning my F. Maxwell’s hot start technique works, just need to have patience sometimes.




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Yep I did Maxwells hot start first and when that didn’t work, I tried the normal start. That’s when I believe I flooded it.

Temperature was 65F. 5 minute taxi to the pumps. Oil was 90-100 and CHT was just below 200. I really wouldn’t think that would be a hot start but idk if there is a “warm start” procedure.

Back in Sept on a 90F day and after about 1.5 hours flight time, we shut down, got fuel, went into FBO for about 20 mins. Came back out and did the Maxwell hit start and it fired right up.

So I was really surprised when it wouldn’t start yesterday. I just hope it starts right up this afternoon.

**edited to remove a dirty word** lol
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Edited by gwav8or
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Yep I did Maxwells hot start first and when that didn’t work, I tried the normal start. That’s when I believe I flooded it.

Temperature was 65F. 5 minute taxi to the pumps. Oil was 90-100 and CHT was just below 200. I really wouldn’t think that would be a hot start but idk if there is a “warm start” procedure.

Back in Sept on a 90F day and after about 1.5 hours flight time, we shit down, got fuel, went into FBO for about 20 mins. Came back out and did the Maxwell hit start and it fired right up.

So I was really surprised when it wouldn’t start yesterday. I just hope it starts right up this afternoon.


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Yep I did Maxwells hot start first and when that didn’t work, I tried the normal start. That’s when I believe I flooded it.

Temperature was 65F. 5 minute taxi to the pumps. Oil was 90-100 and CHT was just below 200. I really wouldn’t think that would be a hot start but idk if there is a “warm start” procedure.

Back in Sept on a 90F day and after about 1.5 hours flight time, we shit down, got fuel, went into FBO for about 20 mins. Came back out and did the Maxwell hit start and it fired right up.

So I was really surprised when it wouldn’t start yesterday. I just hope it starts right up this afternoon.


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You’re in that 5% range I wrote about earlier. 95% of the time after the engine has some heat, the “leave everything where it was” technique works. If the engine is slightly warm, you may need to try something closer to a cold start to get it to start. I would try one of these techniques:

- push the mixture in and then pull it immediately back to idle cutoff, then start cranking
- leave the mixture at idle cutoff, turn the boost pump on for a couple of seconds and then try cranking
- use your normal cold start technique

As Maxwell mentions, “after you start your own airplane all the time, you’ll see what it takes”. He’s right. It seems some of the F models I have flown or been in all have some variation of what works for them. Once you figure it out, burn it into your memory. And if your tried and true technique doesn’t work, you probably have something going wrong on your plane.


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14 hours ago, N201MKTurbo said:

Any automatic car charger will not hurt your battery. They all charge to a preprogrammed voltage and then shut off. AGM batteries should be charged to a higher voltage, so a lower voltage charger will not hurt them, they will just not fully charge them. But they will charge them enough to put back in service. Some in trickle charge will not shut off when the battery is charged. You are better off putting them in normal charge mode. You can put them in high charge mode for a while, but don’t leave them that way.

Wait... is that backwards?  I thought AGM's needed slightly lower float voltages than flooded?

Any charger that is rated for 6 amps is NOT going to hurt your battery (that's about 0.2 C1 for the RG-35AXC) over a few hours.   It's not going to be able to pump the voltage high enough anyway until it gets to about 75% charge, and that'll take a few hours.  Since most car charger manuals I've seen don't publish the voltage specs of the constant-voltage and float phases, though, I wouldn't leave it on for more than a few hours.

FWIW, I have a schumacher 6 amp charger that does have an AGM setting, but I still only run it while I'm in the hangar.  I've had to charge from a dead battery once, and after a couple hours of charging, it started up fine.

Edited by jaylw314
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38 minutes ago, jaylw314 said:

Wait... is that backwards?  I thought AGM's needed slightly lower float voltages than flooded?

Any charger that is rated for 6 amps is NOT going to hurt your battery (that's about 0.2 C1 for the RG-35AXC) over a few hours.   It's not going to be able to pump the voltage high enough anyway until it gets to about 75% charge, and that'll take a few hours.  Since most car charger manuals I've seen don't publish the voltage specs of the constant-voltage and float phases, though, I wouldn't leave it on for more than a few hours.

FWIW, I have a schumacher 6 amp charger that does have an AGM setting, but I still only run it while I'm in the hangar.  I've had to charge from a dead battery once, and after a couple hours of charging, it started up fine.

Flooded batteries float at 13.6 and AGM float at 14.1

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1 hour ago, gwav8or said:


Yep I did Maxwells hot start first and when that didn’t work, I tried the normal start. That’s when I believe I flooded it.

Temperature was 65F. 5 minute taxi to the pumps. Oil was 90-100 and CHT was just below 200. I really wouldn’t think that would be a hot start but idk if there is a “warm start” procedure.

Back in Sept on a 90F day and after about 1.5 hours flight time, we shit down, got fuel, went into FBO for about 20 mins. Came back out and did the Maxwell hit start and it fired right up.

So I was really surprised when it wouldn’t start yesterday. I just hope it starts right up this afternoon.


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These “tweener” ones are sometimes worse than a hot start that’s been sitting for a while. I find it easy to flood it.  You are just looking for the right fuel to air mixture, but you have no idea how much fuel has or has not been shot into the cylinders. Nothing wrong with starting at full throttle and slowly retarding it until it fires. That’s basically a flooded start. When she fires you have to do a dance to get the throttle back to 1000 RPM and the mixture in to keep the engine running.

Here’s something you did right. Try the hot start first. Then if that doesn’t work, prime it. But now you’ve committed to a flooded start. Once it’s run and you’re in the “tweener”, there really isn’t a place for a “normal start” as much as you want that to be the case. I’ve been there and tried the normal start. You’re better off trying hot start, then flooded start if it doesn’t start.

finally, if this keeps happening or it’s taking more than 8 to 10 blades as @Marauder suggested, look into your plugs and ignition system. They need to be solid to get quality Hot starts.

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1 hour ago, N201MKTurbo said:

Flooded batteries float at 13.6 and AGM float at 14.1

Weird, I had to go look that up, this is from the Concorde site:

"The recommended voltage settings at room temperature are 14.125 ± 0.125 (28.25 ± 0.25V for 24-volt batteries) in bulk and absorb stages and 13.2-13.4V (26.4-26.8V for 24-volt batteries) in float stage."

I found a couple others manufacturers that suggest as high as 13.8V for AGM, but I couldn't find anything in the Gil manual for flooded batteries

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1 hour ago, Fly Boomer said:

@gwav8or if you have a Concorde AGM, you might want a BatteryMINDer for that specific battery.  They sell a different version for the Gill battery, so there may be subtle differences.

Agree.  I'm gonna find out what battery I have and will plan on getting a Battery Minder.  Had one on my Cherokee and loved it.  Wish I hadn't let it go when I sold the  plane.

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As PT20J posted you want to charge an AGM battery with as many amps as possible. The faster it’s charged the less time for it to sulphate, and high charge rates can help desulphate a battery.

Unfortunately special desulphating chargers that pulse or whatever are snake oil

As long as the voltage is correct a battery will only accept the correct amount of current and as the battery charges that amperage comes down automatically.

So even if you had a 1,000 amp charger the battery will only accept the amount of current it can handle, (if the voltage is correct) too high a voltage will cook a battery, the idea of don’t use too big of a charger came from both wet batteries and the fact that our Fathers chargers were pretty much junk, many outputted way to high a voltage but due to the fact they were such small amperage chargers the battery acceptance kept the voltage within limits, known as current limited.

Ideally a battery goes through three stages during charging.

1. Bulk, meaning the charger is current limited, it’s trying to output say 14.3V but the battery can accept more current than the charger can supply, so the voltage starts low and builds to set point, say 14.3

2. Absorption,  the amperage has slowly dropped to where the charger can output all the battery can take and you hit the voltage set point, say 14.3, from this point on the voltage remains constant and the current drops until the battery is fully charged, often quoted as 1/2 of 1% of the batteries capacity, so a 100 AH battery is fully charged when the current drops to 1/2 amp.

3. Float, the charger drops to float voltage, for the Concorde that should be about 13.3V, this is just enough voltage to not charge the battery, but enough to hold it fully charged preventing sulphation and slows aging down greatly, a battery kept on float can last a very long time. Best thing you can do to a Concorde battery if you want it last as long as possible is float it at the correct voltage.

Cut-n-pasted from Concorde

“Maintenance chargers should include a 3-stage charging profile that includes a bulk stage (current limited), absorb stage, and float stage. The recommended voltage settings at room temperature are 14.125 ± 0.125 (28.25 ± 0.25V for 24-volt batteries) in bulk and absorb stages and 13.2-13.4V (26.4-26.8V for 24-volt batteries) in float stage. These voltage settings should be compensated for using a temperature coefficient of -0.024V/°C (-0.048V/°C for 24-volt batteries). Concorde has tested various models of maintenance chargers and recommends the use of BatteryMinder S5 models (i.e., 128CEC1-AA-S5 for 12-volt batteries and 244CEC1-AA-S5 for 24-volt batteries). If other makes/models are contemplated, contact Concorde for our recommendation.”

For AGM batteries, this is the Bible, it’s the manual for Concordes terrestrial batteries usually used as deep cycle, same battery just not FAA approved and usually much larger and lower voltage than aircraft as they are usually used as banks of batteries.

https://lifelinebatteries.com/wp-content/uploads/2015/12/6-0101F-Lifeline-Technical-Manual-Final-5-06-19.pdf

Mostly it’s just a much deeper dive than the Concorde aircraft battery manual, but as the banks were often many more times as expensive I guess that makes sense.

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