That looks identical to the BC410-H, which is widely used on the RV-10 – mostly with the D4A5 engine, which has a 1.3:1 gear ratio in the vacuum pump drive. I’ve read good reports on vansairforce and Matronics Aeroelectric-list to the effect that they provide an honest 30 amps at cruise speed but that’s at 12/14 volts.
Here is a link to the quick facts sheet that B&C provide for BC410-H customers. It includes a table showing output vs rpm at 24/28v but it looks as though 20 amps is pushing it. However, even if you pull an amp or 2 out of the battery, the range is probably still limited by the fuel available rather than the battery.
Reviewing my emails with B&C from 2013 it looks something like 15A should be achievable at 2400 crankshaft rpm (3120 alternator rpm).
The MM for the alternator also mentions an overhaul at 1700hrs which in 2013 cost $600+. This life limit is copied into the ICA section of the 337 used for the Field Approval.
I can reduce the aircraft power requirement to 15A, especially if pitot heat (5A) is not needed during most of the flight and I turn off a few other bits. The battery is 15Ah and drawing say 3A would give a 5hr endurance. In practice one would turn off everything not actually needed, until the battery current goes positive again.
And I can go to 2575 crankshaft rpm.
Peter wrote:
Did you contact B&C with your test data, Jesse?
Yes, they say return to USA for overhaul, they will not supply overhaul parts / data. Therefore maintenance is limited to their maintenance instructions, which are a bit of a joke (basically no maintenance, it doesn’t fail between TSO.
Michael wrote:
Why would this installation be any different than the Factory B&C installations on Mooney Ovations or any of the dozen or so STCs ?
I guess not, I just have come across one that meets spec. This could be because people only ask us to have a look at when they don’t trust it, and it has actually failed, or it could be that they are all under performing. This was why I was wondering if Peter performed a bench check on his, and what his results would be. Just to be sure, I ain’t saying that they are all bad, just that I never came across a good one, while we tested dozens.
You don’t need a regulator to test the output, output testing is done with maximum field, and controlling load and RPM to measure the output. You can never perform a good test using a regulator on these. While on a generator you would need the actual regulator to perform a good test.
Raiz wrote:
owever, even if you pull an amp or 2 out of the battery, the range is probably still limited by the fuel available rather than the battery.
While this is true, there are many cases where the main problem is that this goes undetected, so no load reduction is made. On Peters TB-20 there is a good low voltage warning system, on some other aircraft, for example older Cessna’s and some Pipers as well, this systems is quite poor or even simply very bad. On these aircraft there are quite some cases where the pilot found a low voltage when the radio failed during transmission for example. At that time, reducing load doesn’t have much effect anymore as the battery is drained.
Jesse wrote:
I guess not, I just have come across one that meets spec. This could be because people only ask us to have a look at when they don’t trust it, and it has actually failed, or it could be that they are all under performing. This was why I was wondering if Peter performed a bench check on his, and what his results would be. Just to be sure, I ain’t saying that they are all bad, just that I never came across a good one, while we tested dozens.
OK, now I understand, in other words, they do not, by-and-large, perform as advertised . That sucks.
Yes, they say return to USA for overhaul, they will not supply overhaul parts / data
What I meant was whether you asked them about the performance.
Also, what was the measured performance?
What was the test set-up? How was the alternator driven?
One could post the data on one of the US forums. One would soon get a response from the manufacturer! Europe is off the map…
No reply from Jesse to above…
The B&C alternator is also mentioned here
around 25:25. Mike Busch doesn’t mention that this product is substandard… also it appears to be installed on some Cirruses so if it was substandard one would think we would know about that, due to the size of that user base.
Peter wrote:
Also, what was the measured performance?What was the test set-up? How was the alternator driven?
You keep asking the same question over and over again. All alternators are checked the same way, with RPM input, variable load and measure the output at load.
They significantly underperformed. Without anything seemingly wrong with the internals.
Peter wrote:
One could post the data on one of the US forums. One would soon get a response from the manufacturer! Europe is off the map…
Not interrested in this, have had multiple contacts in the past with them on this. Also because it doesn’t make sense to send alternator or starters, or any other component back to the USA. They just don’t want to give spare parts, proper manuals etc. Just saying exchange isn’t service. Unfornately more and more manufacturers go this route, which is definedly not in the interest of the end customer.
All this doesn’t fail before engine overhaul without maintenance is rubbish, there might be a couple of products which well get there, most don’t.
Peter wrote:
Mike Busch doesn’t mention that this product is substandard…
So what does that say? The shop I worked before starting JP Avionics also performs electrical components repair and overhaul (alternators, generators, starters, and magneto’s). When it was busy and during holidays I used to help them out on these, as I was also licensed for theses components (pre-EASA). The guy in the shop is doing alternators, generators, starters and ignition systems only, full time for over 30 year).
When seeing so many components one learn to see the issues, and also see when an manufacturers changes something. A good example was one Slick magnetos, where there was no visible difference, same p/n distributor gear, yet a batch from over a year long, all had loose HV fingers.
Although they say nothing has changed, it definedly did, as you did see this issue on both new and previouse serviced Slick magneto’s.
Personally I have tested more then 10 of these alternators, none of which performed within specs. All these units where used, and tested as the performance was doubted (often after a main alternator failure).
So read carefully, I don’t say that all of these are bad, the ones I have tested where all bad, and that was why I was interested in your test results of a brand new unit. Although there seem nothing to be wrong with these used ones, it would be interesting to see if a new unit would perform within specs.
You can not perform a proper output check one the aircraft, it needs to be done at a bench. Often defective diodes on “normal” regulators aren’t reported / noticed at all, sometimes there a multiple defectives diodes, when it comes in for 500 hours, without any issues, on a test bench you will quickly see this.
Peter wrote:
also it appears to be installed on some Cirruses so if it was substandard one would think we would know about that, due to the size of that user base.
The electrical system on Cirrus is much better then that of Cessna and Piper for example, and while Socata has an quite ok electrical system design, the Cirrus design is much better. There is automatic load shedding, which is a good thing.
Many Cirruses are also equipped with two “real alternators” which is a better solution IMHO, not sure if that also fits on TB-20.
I don’t gain any benefit of you install this, or any other alternator or backup solution. So I am just saying to educate EuroGA readers on these kind of findings. Feel free to do with it what you want. I think it is a pitty to install equipment, which can not live up the expectations.
Jesse at what RPM did you get what output, versus the claimed mfg data?
@Aviathor
Is your (beautiful) aircraft apart ? 
