Bad battery?

DesertNomad

DesertNomad

Pattern Altitude
Joined
Jul 5, 2013
Messages
2,442
Location
Northern NV
Display Name
Display name:
DesertNomad
I have a Piper Dakota with a Concord RG35AXC that is about 5.5 years old (415 hours). Today after flying it for 2 hours, we parked on the ramp and after just 2-3 minutes, decided we wanted to move the plane to a different part of the ramp. It would not start.

It tried to turn but it seems like it was on a compression point where it just didn't have the ooomph to do it. After 2 or 3 tries, I gave up and left it tied down where it was. In recent days it started fine after getting fuel but that was after 20 minutes of shut-down or so.

We're here overnight so I am hoping it starts ok when it is cool. The shops on the field do not stock batteries. It goes into annual in two weeks and we had already decided to replace the battery. Does this sound like a battery or starter? The starter (Skytech 149-NL) is the same age.

The battery still has some power obviously, but I was planning a lunch stop on the way home that is now probably going to get cancelled. If we need a jump start, is there any problem flying it with the alternator trying to charge a battery in this condition? Our next stop is our home field.

Thoughts?
 
Last edited:
If it’s a 12V depending on access to the battery you can jump it.

You can also just hand flip the plane.
 
Not enough information. A 2-3 minute shutdown from charging usually wouldn't be long enough to prevent a restart. However if the battery was not charging during the flight that would be typical failure mode. 5.5 years is probably a pretty typical life span for a battery. could also just be a bad connection causing it also. Needs some troubleshooting to isolate the cause.

Brian
 
There is power since the master came on, fuel pump worked fine and it tried to turn. I am pretty sure it was charging during the flight as I saw no low voltage warning and all the radios worked perfectly on the 2 hour flight.
 
It's not uncommon. It'll probably start fine when it cools down. This may be a good time to buy a lithium ion Jump Pack. Cheap insurance and less stressful than hand propping if you aren't used to doing it.
 
Any chance that it is actually the starter? What is an estimated life span on these?
 
There is always a chance it is the starter...

Here is an easy test to see if the problem is a bad connection between the battery and the starter (and/or the circuit through ground back to th battery). Turn on the master and the landing light. Then try to start the plane with an outside observer watching the landing light. If it goes out or goes very dim, you have a good battery but a bad connection somewhere in the starting circuit.

-Skip
 
was the charging circuit working properly on the way in?
 
IMO, very likely to be the battery, very unlikely to be the starter, but there's plenty of other things it could be in between.

5.5 years is longer than I would normally expect out of a battery (3-4 years) unless you have it plugged into a battery minder in your hangar.
 
Same battery here, mine lasted 4 years on the dot. I jumped it home the last time to get home. I replaced it with the same. Sounds like time to get a new one bud. Dispatch is king for me, batteries are cheap in the big scheme of things.
 
Tom-D said:
0-540 = No
Click to expand...

steak-house.jpg
 
Tom-D said:
was the charging circuit working properly on the way in?
Click to expand...

As far as I know, yes. I certainly did not notice any warning lights or engine monitor alerts. I'm hoping it starts in the morning to fly 200 miles home and I'll have a new one by Tuesday.

If it is fully dead I guess it is not a good idea to jump it and fly out with a dead battery. Seems that can fry the alternator or vent out the battery even though it is a sealed one.

Just wondering if I should try starting it int he morning or call the local shop to see if they can test it for me first. I've been advised that it can cook my alternator.
 
Last edited:
Just curious do you use a battery minder to maintain battery?
 
Personally I would try to trouble shoot and find out what is going on before makeing a cross country. Start with the simple stuff.
 
I don't use a battery minder but fly it a couple of times per week. I have flown it 5 of the last 10 days.
 
DesertNomad said:
I've been advised that it can cook my alternator.
Click to expand...
In certain circumstances that can happen, That said, it really depends upon the condition of the battery. If the battery tries to crank the engine I would not be afraid to jump it and fly it home.
That would mean the battery is still integral and just not enough plate area to hold enough electrons to do the job.
If the battery does nothing you run a pretty good chance of it being a dead short, that will run your alternator at full capacity and heat it.

Just know, that with a very weak battery, that cooks your alternator you will be in a black ship.
 
DesertNomad said:
I don't use a battery minder but fly it a couple of times per week.
Click to expand...
That must be nice being able to fly a couple of times a week. Here in Juneau, weather is the biggest factor. This year I we have had great weather for flying..:)

Do you have both a voltmeter and an ammeter?
 
AKBill said:
Personally I would try to trouble shoot and find out what is going on before makeing a cross country. Start with the simple stuff.
Click to expand...
Like what? we already know the battery is TU
 
If it has the power to start it this morning, should it be ok to fly? It has the Piper ammeter and I know where that needle sits with everything on. If it is much higher, I'd scrub the flight.

My JPI 830 has a volt meter.
 
DesertNomad said:
If it has the power to start it this morning, should it be ok to fly? It has the Piper ammeter and I know where that needle sits with everything on. If it is much higher, I'd scrub the flight.

My JPI 830 has a volt meter.
Click to expand...
I have the Concord RG-35AXC as well. Voltage with engine running is 14.1 Volts. My ammeter is the original Beechcraft as far as I know not real accurate but it does show a state of charge after start up. Within 10 to 15 minutes after starting the ammeter reads a slight charge with everything on. Check out the owners manual for the Concord, it has some good information.

Hope it all goes well today, happy flying.
 
DesertNomad said:
Thoughts?
Click to expand...
FYI: the most neglected system on an aircraft is the electrical system. Most people tend to troubleshoot with their checkbook. But you get what you pay for literally. There are a number of past threads that discuss how to check/verify the health of your electrical system. Since the plane is going into annual, this would be an opportune time to perform a check-up of the entire system to include parasitic drain, wire connection condition, alternator output, and other items. Also, if you follow manufacture recommendations on battery upkeep and maintenance, the odds of getting more than 5.5 years out of your battery go up dramatically.
 
DesertNomad said:
If it has the power to start it this morning, should it be ok to fly? It has the Piper ammeter and I know where that needle sits with everything on. If it is much higher, I'd scrub the flight.

My JPI 830 has a volt meter.
Click to expand...

Depending on the weather and airspace you can always turn the electrical system off after starting it and fly home
 
DesertNomad said:
Flying from a Class D to Class C, IFR but VFR conditions.
Click to expand...

Ahh

Depending on the condition of your battery, and if it’s a charging system issue, you could leave the alternator off, go VFR and just kick in the battery to talk to get in/our of the airspace and than turn in off the majority of your time enroute
 
I always thought battery performs better when its warm. In my experience after refueling stop on a hot day , during the start it spins the propeller like crazy. The battery is 6 + years old and it sits right behind the engine underneath the froward baggage compartment
 
You can hand prop that thing if you're strong enough. And yes, you can fly on a weak battery, just don't count on any of your electrical stuff to work.
 
Good moring, boys and girls. It's time to review Ohm's Law:

E = I x R. Volts equals current times resistance.

If there is a resistance of oh, let's say one twentieth (0.05) of an Ohm somewhere in the path between the battery and starter, and that starter needs 250 amps to make it turn the engine, we can expect a voltage drop of 12.5 volts between the starter and battery. Another way of looking at it: If the starter needs 250 amps at 12 volts, it has an internal resistance of about .05 ohms. E = I x R; E = 250 x .05 = 12.5 volts.You can see that it wouldn't take even a twentieth of an ohm to cause trouble. A fiftieth would be enough.

Let's see. A 100-watt landing light draws 8.3 amps. P = E x I. 100 = 12 x 8.3. Actually, it's less than 8.3 amps at 12 volts, since that current is rated at the 14-volt operating level. Anyhow, a .05 Ohm resistance between the battery and light will drop the voltage 0.4 volts. You'd barely notice any difference in illumination. Does it look like to you that turning the landing light on is a realistic test of the electrical system? Nope.

Gill and Concorde make lots of profit off people who put new batteries into their airplanes without intelligently troubleshooting the system first. I've lost count of the times I have found the master and/or starter contactors shot. Everybody fools with the battery cables and starter cables and everything else, but since the contactor goes "click" they think it's OK. If it's an old contactor it's probably not OK. They have massive copper contacts in them that oxidize with age, and they also burn a little every time they open and a brief arc is generated between the contacts. After enough years and starts it's real easy to get .05 ohms, and often so much more that even the turn coordinator is sluggish, and it draws a lot less than a landing light. Replacing the battery will fix nothing at all. And new contactors are a lot cheaper than new batteries.

Connect a voltmeter across the master contactor's big terminals. You should see battery voltage. Turn the master on; the voltage should drop to zero. Try to crank the engine. If that voltmeter indicates any voltage during the cranking, that's your voltage drop across the contactor. Replace it. Do the same with the starter contactor. It, too, should read zero during cranking (and battery voltage while not cranking). Those contactors need to act as dead shorts across the voltmeter's leads, making it read zero. If the contactors look good, do voltage drop tests across the cables and their terminals, across ground connections, across the engine mount-to-firewall, whatever. I have a long jumper wire that I use to measure the voltage drop across the whole line between the battery terminal and starter terminal. It allows a measurement of the total voltage drop. Might do that first.
 
Update... it started fine, had good readings on the ammeter and volt meter. New battery being ordered.
 
Heat kills batteries. Maybe you need to find a way to keep yours cooler? We Alaskans don't have to worry about that.
 
DesertNomad said:
I don't use a battery minder but fly it a couple of times per week. I have flown it 5 of the last 10 days.
Click to expand...

That may keep it at a reasonable voltage, but it won't prevent sulfation and in fact may encourage it if your flights are short. Battery minders work, as I understand it, by applying short pulses of AC at a frequency that helps to break up the lead sulfate crystals that accumulate on the negative plates (reducing the plates' effective area), and allows them to dissolve back into the acid.

I've got one four-year-old battery and one eight-year-old battery (long-body Mooneys have two batteries and you can switch between them) and both start the plane well. I have both on battery minders when I'm not flying.
 
Interesting. I never knew that Mooney's had two batteries. My average flight is about 2 hours. I look into a battery minder. I have one for the cat but my research says the Concord RG's need a different one.
 
flyingcheesehead said:
Battery minders work, as I understand it, by applying short pulses of AC at a frequency that helps to break up the lead sulfate crystals that accumulate on the negative plates (reducing the plates' effective area), and allows them to dissolve back into the acid.
Click to expand...

The sulfate does more than insulate the plates. The sulfate is a product of electrolysis of the sulfuric acid as the battery discharges, thereby tying up the sulfur and weakening the acid. A totally discharged battery's electrolyte is mostly water. But I wouldn't drink it.

disch-600x563.png
 
By increasing or decreasing the plate thickened you determine the life length of any lead acid battery, you increase the plate thickness, the battery gets bigger and heavier. You decrease the plate thickness, you will shorten the battery life span.
So the manufacturers know exactly how this to make a plate to get the battery life to 4 years.
 
DesertNomad said:
Interesting. I never knew that Mooney's had two batteries.
Click to expand...

Only the long-bodied, big-engined ones (M20M Bravo, M20R Ovation, M20S Eagle, M20TN Acclaim).

The earlier ones had a single battery, on the firewall in most cases I think. When they lengthened it and put the bigger engine on, CG would have been way too far forward so they took the one battery from the firewall and made it two batteries in the tail to balance things back out. :)
 
flyingcheesehead said:
Only the long-bodied, big-engined ones (M20M Bravo, M20R Ovation, M20S Eagle, M20TN Acclaim).

The earlier ones had a single battery, on the firewall in most cases I think. When they lengthened it and put the bigger engine on, CG would have been way too far forward so they took the one battery from the firewall and made it two batteries in the tail to balance things back out. :)
Click to expand...

So both are required if only for ballast?
 
Just a thought most Taxi drivers carry a set of jumper cables if your ever stranded call a Taxi just might save you.
 
You must log in or register to reply here.
Back
Top