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Back-Up Alternator

RViator60

Well Known Member
I’m considering installing the 30A PlanePower FS1-14 on the vacuum pump pad as a back-up alternator on my RV-14A. Has anyone had any issues installing the FS1-14 on their IO-390? My expectation is that both primary and back-up will be active but the back-up will kick-in to produce power if the bus voltage drops below 13.6V. PlanePower recommends a 30A ANL breaker on the B-lead, but it’s not clear to me under what circumstances I might have an over-current situation that justifies installing the ANL.
 
I’m considering installing the 30A PlanePower FS1-14 on the vacuum pump pad as a back-up alternator on my RV-14A. Has anyone had any issues installing the FS1-14 on their IO-390? My expectation is that both primary and back-up will be active but the back-up will kick-in to produce power if the bus voltage drops below 13.6V. PlanePower recommends a 30A ANL breaker on the B-lead, but it’s not clear to me under what circumstances I might have an over-current situation that justifies installing the ANL.

The breaker is to protect the wire in case of a short to ground.....you definitely want to install it.....a fat wire on fire is bad.
 
ANL, YES ... But make it a 40

I’m considering installing the 30A PlanePower FS1-14 on the vacuum pump pad as a back-up alternator on my RV-14A. Has anyone had any issues installing the FS1-14 on their IO-390? My expectation is that both primary and back-up will be active but the back-up will kick-in to produce power if the bus voltage drops below 13.6V. PlanePower recommends a 30A ANL breaker on the B-lead, but it’s not clear to me under what circumstances I might have an over-current situation that justifies installing the ANL.

You DEFINITELY want the "ANL Breaker" or some sort of protection.
(I would make it a 40A in this case though.)

I know for a FACT that when things go wrong, you can end up with SMOKE coming out from under your cowl. <This WILL get your attention.>

And if smoke is left long enough you get FIRE.

And if you have a FIRE, you will need to do some of that "Pilot Stuff" quick, fast, and in a hurry.

I plan to write an article about how this ALMOST happened to me. I have shared my insights with Plane Power and they witnessed (in my hangar) what is possible.
 
I was thinking of using the B and C BC410-H (20-40A) or BC462-H (35-60A) both of which also go on accessory pad. BC462-H is new.
 
Data

Note that the BC-462H is slightly larger in diameter than the 410...

It makes a difference if you intend on using the airwolf remote oil filter. Not quite enough room for both without modification. The 410 fits fine...
 
I’m considering installing the 30A PlanePower FS1-14 on the vacuum pump pad as a back-up alternator on my RV-14A. Has anyone had any issues installing the FS1-14 on their IO-390? My expectation is that both primary and back-up will be active but the back-up will kick-in to produce power if the bus voltage drops below 13.6V. PlanePower recommends a 30A ANL breaker on the B-lead, but it’s not clear to me under what circumstances I might have an over-current situation that justifies installing the ANL.

FWIW - 2 x experiences with the FS1 -14 -
1. A customers unit had bearings spinning in the rear housing therefore unserviceable. ~ 200 hrs.
2. My own unit had bearing problems = unserviceable. I only found that as I had to disassemble the engine for crankshaft replacement.
Ps - after replacing 8 of the 60amp units in various aircraft over 15 months, including my own , I made the decision to NEVER use them again. YMMV & they MAY have been improved, who knows ?
 
B Lead protection

PlanePower recommends a 30A ANL breaker on the B-lead, but it’s not clear to me under what circumstances I might have an over-current situation that justifies installing the ANL.

Plane Power calls it a “30-amp circuit protection device”.

The scenarios where B Lead protection is required is an internal short to ground in the alternator or the B Lead shorts to ground. The protection is located as close as possible to the battery which is the power source that opens the protective device.

IMO:
  • If it’s a CB, 30A is too small, 40 should be good and I wouldn’t argue against 50A (actually, I would use a 50 except I wouldn’t use a CB). I choose a 10 awg B Lead which melts at 330A (8 awg at 470A).
  • If it’s a CB, it kind of implies (because it’s resettable) running a high-current wire to the instrument panel which I choose not to do.
  • If it’s a Bussmann ANL current limiter, 35A is the smallest available and is kinda like a 90 A fuse which is appropriate.
  • A 60A Littelfuse MIDI/Bussmann AMI is a good alternative, physically smaller and opens with less energy. (my choice)
  • A fuselink wire 4 awg smaller than the B Lead can also be used but opens with the greatest energy of these choices (14 awg melts at 170 A).
 
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Plane Power calls it a “30-amp circuit protection device”.

The scenarios where B Lead protection is required is an internal short to ground in the alternator or the B Lead shorts to ground. The protection is located as close as possible to the battery which is the power source that opens the protective device.

IMO:
  • If it’s a CB, 30A is too small, 40 should be good and I wouldn’t argue against 50A (actually, I would use a 50 except I wouldn’t use a CB). I choose a 10 awg B Lead which melts at 330A (8 awg at 470A).
  • If it’s a CB, it kind of implies (because it’s resettable) running a high-current wire to the instrument panel which I choose not to do.
  • If it’s a Bussmann ANL current limiter, 35A is the smallest available and is kinda like a 90 A fuse which is appropriate.
  • A 60A Littlefuse MIDI/Bussmann AMI is a good alternative, physically smaller and opens with less energy. (my choice)
  • A fuselink wire 4 awg smaller than the B Lead can also be used but opens with the greatest energy of these choices (14 awg melts at 170 A).

Hi John, this is very helpful. Others I've spoken with also confirmed this to be the likely failure scenario, for example an alternator seizing up and shorting the battery to ground. I've decided to go with a 40A Bussman AML fuse. I won't venture into the debate b/w B&C, PP, or others, only to say that PlanePower has been extremely helpful and a great source of info.
 
To be perfectly honest, I am about to swap out my Plane Power 30a vacuum pad backup alternator for a B&C. I run the EFII system with the dual-alternator version of the Bus Manager. So both alternators are intended to be online at the same time in normal operations. For further reference, I run a Plane Power 60a primary alternator.

The voltage regulator in the standby alternator never quite failed, but the voltage crept up to 14.6+ volts over the course of the first 80 or so hours of life, enough to cause me to decide to replace the regulator. On advice from Tim at Hartzell at one Oshkosh, since both alternators would be normally on, I switched from the standard 13.8v regulator in the FS1-14 to the 14.2v regulator normally found in the FS1-14B. No problem, easy swap.

It has now been another 80 hours, and I'd say probably another 30 flight hours (another another Oshkosh) ago, /that/ regulator has also exhibited the same behavior. Tim is at a loss to explain, and I am also. I now, at startup and climb, keep the standby alternator on, only to charge battery 2. I get a high voltage warning at some point once the battery has charged, and then I turn off the alternator and leave it off.

Given what I've read in the past about Plane Power and their regulators, much less the bearings, I am probably going to be talking seriously with B&C this coming Oshkosh.

BTW, I run a 40a fuse also. I had a 30a fuse and blew it once during normal charging one time. I have EarthX batteries, which are more than happy to draw full amperage to charge.
 
fuse versus ANL current limiter

Don't confuse a fuse with a Bussmann ANL current limiter. A Bussmann ANL current limiter takes much more energy to blow and can be sized the same as alternator output capability. Other products may be called “current limiter” but are not the same.

These are the notes I put on my schematic re alternator B lead fuse/current limiter/fuselink:
  • Littelfuse MIDI (or, alternatively, Bussmann AMI, physically interchangeable with and sized the same as a MIDI) fuses are specified on this schematic for the alternator B leads versus legacy Bussmann ANL current limiters because they are physically smaller; 30 mm vs 61 mm bolt center to center.
  • Bussmann ANL (a Bussmann 61 mm center to center bolt down product, not to be confused with other bolt down products) current limiters with the same rating as the alternator could be used but Littelfuse MIDI fuses of a higher rating are chosen. It is assumed the alternator is capable of 120% of its rated output, this is divided first by 0.75 (nuisance blowing factor per Littelfuse "Fuseology" document) and then by 0.95 (temperature re-rating factor per Littelfuse MIDI fuse data sheet, a conservatively high 170F firewall temperature is assumed).
  • Main alternator: (60 * 1.2) / (0.75 * 0.95) = 101A, close enough to 100 to choose a 100A MIDI.
  • Vacuum pad alternator: (35 * 1.2) / (0.75 * 0.95) = 59A, a 60A MIDI is chosen.
  • MANLs aka Mini ANLs (which are not ANL current limiters but rather fuses similar to Littelfuse MIDIs) are physically interchangeable with Littelfuse MIDIs but are not specified on this schematic because manufacturers are unknown although Bob Nuckolls says MANLs such as KnuKonceptz are OK. If used, MANLs should be sized like Littelfuse MIDI fuses.
  • Alternate for alternator B leads is FLW (fuse link wire) 6" long and 4 awg smaller that the B lead, PICO brand is common; available from 10 to 20 awg.
  • FLW is a slightly cleaner installation; Bussmann ANL current limiters, and especially Littelfuse MIDI fuses, open with less energy.

You heard it from some guy on the internet.
.
 

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To be perfectly honest, I am about to swap out my Plane Power 30a vacuum pad backup alternator for a B&C. I run the EFII system with the dual-alternator version of the Bus Manager. So both alternators are intended to be online at the same time in normal operations. For further reference, I run a Plane Power 60a primary alternator.

The voltage regulator in the standby alternator never quite failed, but the voltage crept up to 14.6+ volts over the course of the first 80 or so hours of life, enough to cause me to decide to replace the regulator. On advice from Tim at Hartzell at one Oshkosh, since both alternators would be normally on, I switched from the standard 13.8v regulator in the FS1-14 to the 14.2v regulator normally found in the FS1-14B. No problem, easy swap.

It has now been another 80 hours, and I'd say probably another 30 flight hours (another another Oshkosh) ago, /that/ regulator has also exhibited the same behavior. Tim is at a loss to explain, and I am also. I now, at startup and climb, keep the standby alternator on, only to charge battery 2. I get a high voltage warning at some point once the battery has charged, and then I turn off the alternator and leave it off.

Given what I've read in the past about Plane Power and their regulators, much less the bearings, I am probably going to be talking seriously with B&C this coming Oshkosh.

BTW, I run a 40a fuse also. I had a 30a fuse and blew it once during normal charging one time. I have EarthX batteries, which are more than happy to draw full amperage to charge.

Did Hartzell express any concerns about overheating the standby alternator in it's location on the vacuum pump pad? I've never measured the temps between the engine and firewall, but imagine it can get pretty hot there. For that reason, each of my pMAGS is cooled with a hose through the rear engine baffle. For the typical installation where the standby only kicks-on when the primary fails, the service life may be longer. I may consider running some scat tubing to the standby alternator in any case when I install the FS1-14.
 
I added blast tubes to both the primary and standby alternators, pointed directly at the regulator heatsink air vents on the back of each unit, while I was replacing the standby's regulator the first time around. I did it during one winter's annual CI tasks. It didn't seem to do anything to the service life or apparent slow-failure behavior of the replacement regulator. And while talking with Tim at Oshkosh the first time, I mentioned the idea of adding blast tubes. He didn't really give an opinion one way or another, just a "it won't hurt, but it won't help as much as you may think" shrugs.
 
I added blast tubes to both the primary and standby alternators, pointed directly at the regulator heatsink air vents on the back of each unit, while I was replacing the standby's regulator the first time around. I did it during one winter's annual CI tasks. It didn't seem to do anything to the service life or apparent slow-failure behavior of the replacement regulator. And while talking with Tim at Oshkosh the first time, I mentioned the idea of adding blast tubes. He didn't really give an opinion one way or another, just a "it won't hurt, but it won't help as much as you may think" shrugs.

My recent input from Plane Power was that it is definitely good to have the blast tube pointed at the rear of the alternator and that it is MUCH BETTER to put the blast tube pointed directly at the regulator heatsink (JUST AS YOU DID).

Regarding temperatures, I have measured around 130-140 degrees near the firewall of an RV8 on a hot Carolina day. Of course when the plane is left in the sun after a really hot day, who knows what the temp might reach.
(I think the heat index is currently 110 degrees here today!!!)
 
Plane power FS-14b Failure

I don’t usually comment on choices of vendors but since I regard the backup alternator as a safety of flight item, I’ll chime in here. I chose PlanePower for my primary and backup alternators in good faith and used them for my transatlantic flights. While I had no issues during those flights, I’ve since replaced both of them due to quality control failures. The backup in particular suffered a spun bearing in the rear housing as others have encountered. After my calls to PlanePower went unanswered, I decided to dismantle the unit myself for a closer inspection and was unimpressed with both the design and quality of the unit. It is, in my opinion, unsuitable for a critical safety component. I replaced it with a B&C unit and external regulator and am more comfortable with that selection now, given my electrically dependent application.
 
I don’t usually comment on choices of vendors but since I regard the backup alternator as a safety of flight item, I’ll chime in here. I chose PlanePower for my primary and backup alternators in good faith and used them for my transatlantic flights. While I had no issues during those flights, I’ve since replaced both of them due to quality control failures. The backup in particular suffered a spun bearing in the rear housing as others have encountered. After my calls to PlanePower went unanswered, I decided to dismantle the unit myself for a closer inspection and was unimpressed with both the design and quality of the unit. It is, in my opinion, unsuitable for a critical safety component. I replaced it with a B&C unit and external regulator and am more comfortable with that selection now, given my electrically dependent application.

Just to be upfront, I have Plane Power AND B&C Alternators. Not picking vendors, just sharing some info.

When I had issues with my “older” Plane Power and reached out to “management” (including management of the company that acquired them, Hartzell), sharing design issues and concerns that I had, they stepped up and shared their findings of a similar nature with earlier product. They shared what they have done regarding bearings, regulators, vibration, heat, etc.

I suggested that they become more vocal here about the work that has been done since the acquisition by Hartzell.

I cannot say that their products have been rid of all issues of the past (don’t have enough history on the more recent product) but I was impressed with the engineering efforts that they (Hartzell) shared and I DO believe that the more recent products are FAR SUPERIOR to what was initially shipped when the company was formed and shipped for many years afterwards. They may look the same but Hartzell has made a lot of improvements. And to me, that is good.

I am hopeful that they will share more. I don’t want to misstate what was done so I will keep my comments general and encourage more specifics from them.

P.s. I started using PP many years ago on my 20 year old RV6.
 
Also throw my opinion in for the Monkworkz MZ-30. Much smaller than the B&C and PP units and does not require any goofy boxes to add the hands free, automatic switchover to backup power. Its all built in.
 
Quick update on my back-up alternator experience. I installed the Plane Power, FS1-14 on the vacuum pad and routed the output to the main bus. It does exactly what I wanted. As the buss voltage drops below about 13.8V when the A/C is running on the ground, the back-up kicks in to supply the needed extra amps.
 

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RViator60,

At the risk of thread drift, how difficult is it to get the oil filter off without making a mess? I'm getting ready to install the back-up alternator and have discovered that getting to the oil filter looks like a problem.
 
Oil mess

I’m assuming you meant how difficult with the backup alternator on the pad? I tried 4 or 5 different techniques all succeeded in getting oil down the leg fairing no matter how hard I tried to block it-catch it. Another builder/friend can do it on his 14 no mess. I’m not as talented it seems. Finally broke down and tried the Anti Splat blow air in the filter tool and worked perfectly. Not a drop of oil gets spilled. After changing the oil I do turn off the fuel pumps and ignitions to spin the oil up a little. About 5 seconds twice before turning on the fuel pumps and ignitions. Figured couldn’t hurt.
 
After trying several different gadgets to drain the filter, I finally tried the trick I read on this forum to use a piece of 11/2” PVC pipe cut in half lengthwise, placed under the slightly unscrewed oil filter, and directed into a bucket. Worked better than anything else I’ve tried. :cool:
 
I was pointed to "form a funnel"; a rubber strip 3" wide and 24" long that has foil sandwiched in between. It can be formed to fit up under the oil filter and catch the oil just like the large plastic split tubing. Nice not having to clean up spilt oil.
 
Removing and installing new filter is no problem...just have to do it from the below. I just changed my oil yesterday and took a series of pictures showing the sequence.
 

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... After changing the oil I do turn off the fuel pumps and ignitions to spin the oil up a little. About 5 seconds twice before turning on the fuel pumps and ignitions. Figured couldn’t hurt.

Couple of thougts on "cant hurt"...

First off, the camshaft and lifters are only lubricated with oil cast off the big ends of the rods. The cam is "splash lubed". Oil doesnt sling much unless the engine is running.

Assuming flat tappets, the realized load at the lobe/tappet interface is highest at rest and diminishes (somewhat) with increased RPM. This load is generated by the valve springs and is ever present, even with the engine sitting in the hangar.

Again, assuming flat tappets, the hydrodynamic oil wedge required to minimize metal to metal contact also requires a certain relative surface speed between the tappet and lobe. This means RPM, and grinding away on the starter does not generate that RPM.

The best thing for an engine is to pre lube with an external device, but short of that, get the engine up to idle as quickly as possible.
 
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Two things

Couple of thougts on "cant hurt"...

First off, the camshaft and lifters are only lubricated with oil cast off the big ends of the rods. The cam is "splash lubed". Oil doesnt sling much unless the engine is running.

Assuming flat tappets, the realized load at the lobe/tappet interface is highest at rest and diminishes (somewhat) with increased RPM. This load is generated by the valve springs and is ever present, even with the engine sitting in the hangar.

Again, assuming flat tappets, the hydrodynamic oil wedge required to minimize metal to metal contact also requires a certain relative surface speed between the tappet and lobe. This means RPM, and grinding away on the starter does not generate that RPM.

The best thing for an engine is to pre lube with an external device, but short of that, get the engine up to idle as quickly as possible.

As mentioned in the quote, I don't like blowing the oil out. Sure it is less mess, but that is just more air that has to work its way through during first engine start after oil change. I also tend to pre charge my filter with some oil; the more I can put in before installing, the less air I pump through the system.

Lastly, in your picture, it looks like those two power wires are running next to the hose clamp. If it is not just an optical delusion, I would check that for chaffing.
 
Removing and installing new filter is no problem...just have to do it from the below. I just changed my oil yesterday and took a series of pictures showing the sequence.

I’d take a look at this. It will probably produce some unwanted excitement imminently.

B9E32649-7A94-40A2-9AE9-0C5F85688F1A.jpeg
 
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