Plane-Power vs B&C (2019) also: Parts info wanted

[rv6ejguy]

Likely the brushes finally wore down to a nub, tilted in the holder and you heard the "ping" as the wires snapped off them as the parts got carried through the spinning rotor.

This is the most common failure on high mileage Hitachi and Denso alternators at least that I've worked on for several decades. In fact, about the only type of failure I've ever seen on them and I used to run an auto repair shop for mainly Japanese brands eons ago.

The Hitachi in our shop car had 360,000 km on it when the same thing happened to it. Let's call that around 6000 hours.

[skylor]

Originally Posted by rv6ejguy

A few points. If your engine is in proper tune, you shouldn't have to turn it over for more than 5 seconds. This takes very little out of the battery and therefore won't result in very high charge current from the alternator to replenish it in the first minutes.

If you're concerned with too much charge current, keep the engine at idle for a minute or so. A 60 amp alternator will be lucky to produce 30-35 amps at slow idle.

If you run a lithium battery and it's really discharged for some reason, think about delaying your flight and getting a low rate charge on it for a while and be sure you know WHY it was so discharged to begin with. If you're electrically dependent, treat that battery with respect and care. Your life may depend on it.

If you firewall mount your battery, be aware that it will almost certainly see temps over what the manufacturer recommends without some air blast cooling. High temps reduce life and may have more serious consequences in some cases with certain battery chemistries.

I did some ground testing with my Plane Power 60 AMP alternator, and it will produce nearly a full 60 Amps at 1000 Engine RPM!

Skylor

[chaskuss]

Originally Posted by scsmith

An interesting data point on alternator reliability, from the automotive world.

My 2000 Chevy Astro Van went 180,000 miles on its first alternator. It failed last month. Not feeling like working on the van (poor access to most everything on the front of the engine) I paid a shop to replace the alternator. At the time, I walked out of the shop thinking that was the most expensive alternator I ever bought (because of the installation labor charge).

Today, that new alternator failed, after just a couple of hours of run time. Infant mortality I guess. The shop said it was "highly unusual". He wasn't sure if it was an ND or a Bosch (he wasn't the tech that did the replacement). This time I walked out thinking it was the best deal I ever got on an alternator, because I didn't have to go through the chore of replacing it twice!

I don't know the exact failure process, but I can tell you that it made a distinct whine/whirring noise, and then started to smell strongly. Then I noticed it wasn't charging.

I don't know if this experience is relevant to any of our alternators or not.

Steve, your experience shows that Nippon Denso alternators aren't the only ones that can provide excellent service. Your Chevy came with an alternator that was manufactured by what used to be the Delphi division of General Motors. In 2009 General Motors spun off the Delphi Division and they now an independent Corporation. The fact that the reman alternator came in a box that said Nippon Denso or Bosch doesn't mean that that is the corporation that actually originally manufactured the alternator. That just means that the alternator was remanufactured by a Rebuilder who is approved by Nippon Denso and or Bosch.
The description of your replacement alternators failure sounds very much like a shorted stator. Most electronic devices that have a manufacturing defect will fail within the first 6 weeks of service. Most retail Electronics have a failure rate of about 6% during that first 6 weeks.

Charlie

[vic syracuse]

[quote=rv6ejguy;1383599]A few points. If your engine is in proper tune, you shouldn't have to turn it over for more than 5 seconds. This takes very little out of the battery and therefore won't result in very high charge current from the alternator to replenish it in the first minutes.

If you're concerned with too much charge current, keep the engine at idle for a minute or so. A 60 amp alternator will be lucky to produce 30-35 amps at slow idle.


My experience differs quite a bit from this. The current generation of alternators (PP and B&C) that I have tested will put out full rated amps at low idle on our airplanes, except the stnadby alternators on the vacuum pad. Even with a very quick start the lithium battery will take a full load for a few seconds, so it is not uncommon to see 60 amps for 10-30 seconds after a startup. I tell new owners of lithium batteries to not be concerned, as it is normal operation.

If you've sat there for a while with the power on prior to engine start while you o perform a checklist or receive a clearance, the high amp load will last much longer, perhaps a minute or 2. Usually by the time the runup is completed, the charging output is back to normal, around 20 amps or whatever your wsteady state load happens to be.



Vic

[rv6ejguy]

[quote=vic syracuse;1384045]

Originally Posted by rv6ejguy

A few points. If your engine is in proper tune, you shouldn't have to turn it over for more than 5 seconds. This takes very little out of the battery and therefore won't result in very high charge current from the alternator to replenish it in the first minutes.

If you're concerned with too much charge current, keep the engine at idle for a minute or so. A 60 amp alternator will be lucky to produce 30-35 amps at slow idle.


My experience differs quite a bit from this. The current generation of alternators (PP and B&C) that I have tested will put out full rated amps at low idle on our airplanes, except the stnadby alternators on the vacuum pad. Even with a very quick start the lithium battery will take a full load for a few seconds, so it is not uncommon to see 60 amps for 10-30 seconds after a startup. I tell new owners of lithium batteries to not be concerned, as it is normal operation.

If you've sat there for a while with the power on prior to engine start while you o perform a checklist or receive a clearance, the high amp load will last much longer, perhaps a minute or 2. Usually by the time the runup is completed, the charging output is back to normal, around 20 amps or whatever your wsteady state load happens to be.

Vic

I ran some actual numbers here.

Average drive ratio is about 3.9 to 1. Using an alternator test graph I have on my 70 amp ND alternator, it generates 51 amps at 2500 rotor rpm (641 engine rpm). Starter draws around 150 amps for 5 seconds which is 12.5 amp/ minutes. That would mean the alternator would top up the battery in about 15 seconds with no other load on. Nothing is going to get very hot in 15 seconds.

You could slow this rate down by throwing on extra load before turning the alternator on.

My estimate of of 30-35 amps was based on my installation which has a much smaller pulley ratio than the average Lycoming installation. My bad there.

This again speaks to the advantage of larger alternator pulleys, both to reduce bearing and brush wear, and charging rates at idle for more sensitive Lithium batteries. Dropping the rotor speed to 1500 rpm at idle would drop my alternator output to around 23 amps.

[jdmrv7a]

Good information above on alternators and Earth-X batteries. Every airplane has unique electrical systems. I decided to test and log my amp draw at the time of engine start-up. The following is my Hartzell (PP) Alternator, Earth-X battery and Garmin G3X system results:

Airplane RV14-A- ALT Test:
Actual AMP Draw for Hartzell/PP (AL12-C60) Alternator - Serial # date code ?S?= 2018
Hartzell date code ?R?= 2017 and later are improved manufacturing process. (According to Hartzell)
Battery: Earth-X; ETX-900 (15.6 ah) 13.2 volts; CCA AMPs 400 (4.9 Lbs)
Test Date: Nov 4 2019
Airplane Status: hangered for 48 hours (cold)
Ambient air temp when started: 70 F
Engine Start Procedures Used:
ON: TCW ? IBBS-12v-6ah Backup Battery ?(G3X Checklist reviewed, ATIS)
ON: G3X Touch GDU 460 screens and GEA 24, GSU 25 ? (120 seconds IBBS)
Master- ON for 30 seconds, Strobes- ON; Fuel pump- ON
Started Lycoming IO-390 ?
Hartzell (PlanePower) 60 amp Alternator amp draw results displayed on G3X:
48 amps ? first 7 seconds, then Alt draw drops to 23 amps for 10 seconds, then 13 amps for 15 seconds.
Avionics and AP Masters ? ON ? (Garmin IFR GTN 625, Dual VHF?s, GTX 45R, GMA 245, others).
Engine RPMs =1000 - Hartzell/PP (AL12-C60) Alternator Amp Draw - 9 amp load after 2 min.
9 amp load includes recharging: TCW ? IBBS-12v-6ah Backup Battery
Add: 5 amps for the Garmin Pitot heat if needed; 3 amps for the Fuel Pump and 2 amps for the LED Land lights.
Normal in-flight alternator amp draw is 9-10 amps. (No fuel pump, pitot, defroster or landing lights)
Full Amp draw with every switch in the airplane- ON = 22 Amps in-flight at 2300 RPMs.

My alternator and Earth-X 900 seem to be a good match for the Garmin G3x IFR panel given the 10-20 amp normal draw. Every airplane is different, I would be interested to see results of other similar electrical systems.

[emsvitil]

Is there a simple/cheap external regulator that's 2-stage?

Initially have a lower voltage so that the charging amps (and alternator output) is lower.


I suppose you could have 2 (switchable) external regulators. lower voltage could then be a hot spare.

[flyride]

Originally Posted by chaskuss

Tim,
So if you want to have a Nippondenso alternator that's externally regulated but you don't have to do surgery on, go to your local favorite auto parts store and order an alternator for a 1995 Dodge half ton van. These trucks came with a V6 and V8 engine option. Engine doesn't matter. Both the V6 and V8 were available with a 90 AMP or 120 amp alternator. You want the 90 AMP unit as the 120 amp unit is considerably more expensive.

Not trying to thread drift, but adding this bit of info - that 90 amp alternator Denso p/n is 210-0143. Turns out it is the optional high output alternator for the '95 Dodge line; the standard Denso alternator 210-0682 is a 75 amp unit, which matches nicely with EarthX's recommendations to limit to 80 amp alternators for the ETX900 battery. My intention is to pair with the B&C LR3C-14 regulator as I have one in my other aircraft, and to have an easy swap option if necessary.