new alternator

I have a 1993 RV6A I bought last Oct. O360 A1A. I just finished upgrading the panel to GRT HXr, A/P, ADSB, ECI, etc. Just after I got the plane home, the alt froze. I had i rebuilt and discovered it is a 30 amp alt. I now find it is maxed out when everything is on, pitot heat, lts, charging, etc. It was just working too hard for the last 20 years. Santa left some Aircraft Spruce gift cards under the tree this year so it is time for a new alternator.

Which one?????
Regulator????

I am leaning towards the Plane Power AL 12-EI60. Does this need an external regulator? The one review on A-S the reviewer said it puts out 14.7v and is not adjustable. The description in the catalogue says "internal regulator".

What is the difference between "boss mount" and "case mount"????

Thanks in advance.

[email protected]

So the jury is out in my opinion as to brands at the 60amp size: PlanePower or B&C. Also some use a regular car alternator but there's pros and cons to that as well.

See this thread for more info. http://www.vansairforce.com/community/showthread.php?t=138805

I had a 70amp PlanePower and had no issues, but I just went down to a 60 amp and switched to B&C.

The PlanePower (PP) alt's come in both externally (EE in the model#) and internally regulated (IE in the model#) models. Personally if you go PP I'd go internal if for nothing more than simplicity in wiring. B&C only come in externally regulated models. If you that route I'd get their LR3C-14 regulator.

A boss mount uses a pad located next to the starter as the alternator bracket mount:


If there's no pad then you use a case mount that uses case bolts to mount the main bracket t the engine.

Check out this thread

Deweyclawson said:

alternator.

Which one?????
Regulator????

Thanks in advance.

[email protected]

Click to expand...

As Todd has indicated, everything you ever wanted to know about potential RV alternators is contained within the thread he recommended. It's from June 2016 so quite current data.

The thread was 98 posts long and included a very enlightening reliability poll survey. The survey revealed that in the first 250 hours of service B&C had a failure rate of 1.2% compared to a failure rate of 21.8% for auto alternators and a failure rate of 24.5% for Plane Power alternators.

The survey and the associated posts on the thread clearly indicate that Plane Power's record has been worse than abysmal and that B&Cs well known reputation for reliability is completely justified. It just proves that, as with everything else in life, you get what you pay for. It just depends on what value you put on the reliability of the electron flow in your aircraft.

Get a cup of coffee and start reading.

If considering B&C,

Call and talk to the B&C guys, they frequently have a special where the regulator comes free and not always advertised. A pretty good deal, if you are considering the B&C.

Captain Avgas said:

The survey revealed that in the first 250 hours of service B&C had a failure rate of 1.2% compared to a failure rate of 21.8% for auto alternators and a failure rate of 24.5% for Plane Power alternators.

The survey and the associated posts on the thread clearly indicate that Plane Power's record has been worse than abysmal and that B&Cs well known reputation for reliability is completely justified.

Click to expand...

I'm not taking sides on the alternator discussion and the referenced thread was informative. However, the poll was definitely not scientific and the reader should not regard it as such. The poll might be useful as a single datapoint, but not as a definitive comparison of reliability.

+1 to Sam's comment. With auto alts, pedigree & installer's skills at adapting/installing can't be quantified.
Charlie

Sam Buchanan said:

I'm not taking sides on the alternator discussion and the referenced thread was informative. However, the poll was definitely not scientific and the reader should not regard it as such. The poll might be useful as a single datapoint, but not as a definitive comparison of reliability.

Click to expand...

What poll is "scientific". All of the "scientific" Presidential election polls unanimously showed that Clinton was ahead right up to the actual election.

In the case of the alternator poll there were responses from 87 auto alternator users, 110 Plane Power users and 83 B&C users. That's a pretty good base. And reading through the actual posts it is quite clear that the comments strongly reinforced the poll results.

Some VansAirforce polls are dodgy to say the least because they simply ask the wrong questions. But I personally believe that the alternator poll (and comments) really throws a lot of light on the reliability of the various options.

rv7charlie said:

+1 to Sam's comment. With auto alts, pedigree & installer's skills at adapting/installing can't be quantified.
Charlie

Click to expand...

It's true that the pedigree of many auto alternators cannot be quantified...but surely that's part of the reliability problem.

As for possible dodgy installation skills....well that applies to the installation of all alternators, not just auto alternators.

I don't believe the poll asked wether the alternator was routinely turned on after starting and turned off before shutdown. This procedure was discussed years ago and was the way I used to operate the alternator. Mine failed prematurely at about 200 hours. It was an automotive one that Vans used to sell. I replac d it with a Plane Power and operated it by ganging the alt field with the master. 1500 hrs of trouble free operation and the same with everyone in Cincinnati with Plane Powers, and we all operate them by "ganging" the field with the master switch.

I don't put my faith in polls!

Many auto alts could well be used, salvage yard pulls, etc, and/or improperly installed.

Purpose-built kits like the B&C have a higher probability of correct installation, due to clearly defined processes & pre-built 'pieces-parts'. Much like kit a/c having higher probability of completion that scratch-builts.

jthocker said:

I don't believe the poll asked wether the alternator was routinely turned on after starting and turned off before shutdown. This procedure was discussed years ago and was the way I used to operate the alternator. Mine failed prematurely at about 200 hours. It was an automotive one that Vans used to sell. I replac d it with a Plane Power and operated it by ganging the alt field with the master. 1500 hrs of trouble free operation and the same with everyone in Cincinnati with Plane Powers, and we all operate them by "ganging" the field with the master switch.

I don't put my faith in polls!

Click to expand...

Are you suggesting that the massive difference in failure rates (as shown in the poll) between the Plane Power alt and the B&C alt is solely due to the fact the Plane Power owners are switching their alternators off and on with the engine running (and that B&C owners never follow that procedure). Wouldn't it be logical to conclude that the percentage of owners (both Plane Power and B&C) who switch their alternators off and on with the engine running would be roughly the same.

In reality there are probably more B&C owners who switch their alternators off and on with the engine running because B&C have publicly stated that using that technique is not detrimental to their product.

If the PP alts were early versions of internally regulated auto alts, then operating them like traditional a/c alts could indeed cause problems. Internally regulated alts from that era were not designed to be shut down while functioning normally (under load), nor is there any need, outside of an emergency or the case of an already-failed alt. Doing so is an operational error, not unlike 'shock cooling' an air cooled engine; something that effectively can't be done with a liquid cooled engine.

Captain Avgas said:

What poll is "scientific". All of the "scientific" Presidential election polls unanimously showed that Clinton was ahead right up to the actual election.

In the case of the alternator poll there were responses from 87 auto alternator users, 110 Plane Power users and 83 B&C users. That's a pretty good base. And reading through the actual posts it is quite clear that the comments strongly reinforced the poll results.

Some VansAirforce polls are dodgy to say the least because they simply ask the wrong questions. But I personally believe that the alternator poll (and comments) really throws a lot of light on the reliability of the various options.

Click to expand...

Just because you have a fair number of respondents for each alternator does not make the poll scientifically accurate Bob. The respondents were not chosen randomly from the entire population of RV owners, or alternator users. The respondents were those who chose to look at the thread, and chose to respond. This is not a random sampling across the population.

My neighbor's sister had a dog in an internet voting "competition", and the neighbor sent out an email to all her friends asking people to vote for her sister's dog. It won, not becasue it was the best dog on the internet, but becasue the vote was manipulated.

It's very important to understand the difference between scientific and unscientific methods. Which doesn't make the data useless...it means that it has caveats that must be understood.

Ironflight said:

Just because you have a fair number of respondents for each alternator does not make the poll scientifically accurate Bob. The respondents were not chosen randomly from the entire population of RV owners, or alternator users. The respondents were those who chose to look at the thread, and chose to respond. This is not a random sampling across the population.

Click to expand...

All "polls" on VAF suffer from the same fatal flaw: self-selection bias. https://en.wikipedia.org/wiki/Self-selection_bias

From a mathematical perspective, they're pretty much what the acronym adequately describes: SLOP.

Ironflight said:

Just because you have a fair number of respondents for each alternator does not make the poll scientifically accurate Bob. The respondents were not chosen randomly from the entire population of RV owners, or alternator users. The respondents were those who chose to look at the thread, and chose to respond. This is not a random sampling across the population.

Click to expand...

Paul, I do understand what you are saying about the limitations of amateur surveys....and I agree. However the alternator survey in question was accompanied by a large number of comments about actual experiences involving the relevant alternators (98 comments to be precise). And those comments are very enlightening. The statistics from the survey may be a bit "wobbly" but the comments are generally supportive of the conclusion that B&C has a very high customer satisfaction rate and that both auto alternators and Plane Power units have proven to be more problematic (a LOT more problematic).

And to be honest, anyone who has been frequenting VansAirforce for a number of years and consistently reading the various threads on alternator problems would have already come to the same conclusion. It is surely no secret that Plane Power in particular has been beset with quality control problems....cracking cases, dodgy connectors, etc, etc. The archives tell the story for anyone interested in doing a little bit of research.

Captain Avgas said:

Paul, I do understand what you are saying about the limitations of amateur surveys....and I agree. However the alternator survey in question was accompanied by a large number of comments about actual experiences involving the relevant alternators (98 comments to be precise). And those comments are very enlightening. The statistics from the survey may be a bit "wobbly" but the comments are generally supportive of the conclusion that B&C has a very high customer satisfaction rate and that both auto alternators and Plane Power units have proven to be more problematic (a LOT more problematic).

And to be honest, anyone who has been frequenting VansAirforce for a number of years and consistently reading the various threads on alternator problems would have already come to the same conclusion. It is surely no secret that Plane Power in particular has been beset with quality control problems....cracking cases, dodgy connectors, etc, etc. The archives tell the story for anyone interested in doing a little bit of research.

Click to expand...

98 comments by people self-selecting to answer a survey does *not* make for a scientific, or even a statistically valid, poll.

The statistics aren't "wobbly"...they're *invalid* from a statistical standpoint, at least as far as deriving any conclusions.

Let's not get off in the weeds about unscientific and the statistics of the poll and PP failures.

1. Having spend many years in a design/production engineering environment with field units from hundreds to hundreds of thousands, you will NEVER get field failure information to meet some pure scientific poll as being discussed. And, it is not needed in a practical environment. A weibull is quite useful, and I dare say accurate (with confidence bands applied) from such data. It will, though, only show what is present at the time of the poll.

2. The PP units had several failure modes posted. It also had a failure prone group of the general population. The weibull plot showed that clearly. Failure rate and projection was not possible due to sample size. I looked at each posted failure with failure mode information, and contacted PP (Hartzell) to discuss. They DID have a production problem at that time. It was early in their problem resolution process, but did seem to have a very good handle on the issues.

3. Some alternators (automotive especially) cannot tolerate having the field turned off then back on when running. This failure mode was not identified as the prime issue with the PP failures at that time.

YMMV.

Disclosure: I have a PP EI60 alternator. It was made before the problem arose. If not there, they have warranty and seem to honor it. I might buy another brand if it fails, I might not. It depends.