Alternator vs Generator?

[Lood]

I'm not sure if this has been discussed, but I would like some expert opinion, please. My Mooney still sports a generator and it hasn't really caused any problems - I just have that itch again. Is replacing the said generator with an alternator worth the money? I also see that the alternator option weighs substancially less than the current generator installation. So, which is better and what would you guys recommend?

[Ned Gravel]

If I understand it correctly there are four considerations affecting your decision;

1.  A dead battery will not allow an alternator to work. A generator does not care.

2.  A generator does not charge well below about 1000 rpm on an IO-360. An alternator does not care.

3.  The current set of alternator replacements almost all weigh less than the generators they are replacing.

4.  Alternator replacement kits can provide up to twice the charging current than most of the generators they are replacing.

I still have a generator in my Mooney and consideration number 2 notwithstanding, I do not see a real need to go for the change.  If I was upgrading the panel and needed more juice to run things like a G500, plus WrWx, plus speedbrakes, plus TKS, etc. I would consider it. 

Besides, I have already saved a good amount of weight forward of the cg with the change to the Skytec NL starter.

For me, the generator is still good enough.  Maybe.... if I win the lottery and have to consider the power drain of the L3 backup because I have removed my vacuum pump and the standby instrumentation for my G600 needs to be only electric........

[Ned Gravel]

And I posted a second time.

[Ned Gravel]

Doh!

[Ned Gravel]

Oops

[carusoam]

Ned has hit the reasons for changing right on the head.

From my recent experience.

[1] Although the generator can work from a dead battery.  Hand propping an 0-360 is not recommended.  I just picture my day going from bad to worse.  First a dead battery, then an injury from trying to hand prop such a large engine.  I have tried this twice.  Two occasions of dead batteries, unable to hand prop.  Jump starting a 12V battery though, is easy enough.

[2] The generator does not charge while taxiing on the ground (low rpm).  Apparently actual alternator installations are not so good at this either.  I got low voltage warnings recently while instrument training in a C172R.  There has been much generator bashing by the alternator crowd for this.  I was honestly surprised and dissapointed when the low voltage light came on with the alternator installation.

[3] Weight.  Generators are heavy and are pretty far forward of the CG

[4] The 50 amp generator in my 65C powered all of the antiquated analog equipment without any issues.  New digital equipment and LED lights could potentially lighten the electric load.

[5] For low cost upgrade and system improvement.  Consider replacing the old voltage regulator that is mounted on the engine side of the firewall with a new solid state one.  The output and voltage control is what you would expect of modern machinery. 

[6] For less than 1 AMU, you can purchase a rebuilt generator, solid state voltage regulator, and sealed battery all from aircraft spruce.  A qualified mechanic can probably change this out in an afternoon.  There is a credit for return of the old core.

I believe, A change to a generator set-up will require prop removal to change the drive belt size/style.

There is another post regarding voltage regulators and sealed batteries here somewhere.  I will append iIf I can find it.

[carusoam]

http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=2&threadid=250

This is the thread with information about the voltage regulators.

[Jerry 5TJ]

Another approach to Alternator conversion --

When the time came (engine ~ 2150 TT) in my 64 "E" I elected to buy a 0 SMOH engine from Lycoming.  I specified the alternator version of the engine, then I only had to buy a new alternator controller, circuit breaker and a few misc. items rather than the whole conversion kit.  The generator went back to Lycoming with the old engine core.

This approach was lots cheaper than doing a stand-alone alternator conversion. 

The 70A alternator on the new engine came on-line at about 1200 RPM versus about 1700 RPM for the original 50A generator with its mechanical "regulator." 

 

 

[Piloto]

If you do a lot of night flying the alternator is the way to go. With generators you have to keep the RPM up when taxing at night to maintain voltage due to landing and position lights added load.. Taxing at high RPM wears your brakes and heats the discs. With the alternator you can taxi at night at low RPM and still maintain voltage.

José

 

[scottfromiowa]

I have a generator in my plane.  Works fine.  DID have problems with old OEM light at low RPM.  Installed a HID landing light and operates on lower amp draw so while taxing I can see great.  Also installed new updated voltage regulator, 201 type plexi fairing mod and a electronics international amps/volts indicator with discharge light so I know condition of charging...The OEM indicator only deflected a "tad" off center to left and I lost all electrical (thankfully was day flight and had hand held for class C airspace).  Consider these upgrades vs. change from generator.

[Ned Gravel]

Yah!  I forgot to mention that my voltmeter is part of my JPI 700 and I also have the newer Zeftronics regulator.  Both of those significantly enhance the safer use of a generator, until a decision is made to change it out for an alternator.

 

[jamesm]

Generator vs. Alternator

Another advantage that the Generator's have over Alternator is the the Generator produces cleaner power. The Generator's armature is composed of multi segmented windings which helps clean up noise as well rectify ac voltage coming from the armature .  Sometimes from the  alternator you can get  alternator wine over the headsets. In about '68  when Mooney offered the alternator option they used a big capicator externally mounted and also RFI filter (inductor) to help alievate the Alternator wine problem. Newer Alternator like Plane power has the capicator inside and there is need for a big externally mounted Capicator.

I went the expen$ive route prior to plane power coming out with generator replacement kit and installed plane power alternator. Since all the parts  I used for my  alternator conversion where on the TCDS didn't require a  337 form and just needed A&P sign off in the logbook.

 

 

[rgaines]

The alternator is better than the generator.  My battery remains fully charged now where before I always had a problem keeping it charged enough for winter starts.

[scottfromiowa]

Jose,

My point with the HID light is that you get a super bright light at low taxi RPM due to the low power draw of the HID lighting systems vs. the old sealed beam quartz landing lights...and no filiment and super long life allowing the HID to be used as recognition while in flight.  No need to burn brakes taxing at high rpm with HID lighting system...and the quality of light is a huge safety advantage during landing/take-off.  The XEVision light (now at Aircraft Spruce) is WAY cheaper than the Boom-Beam light.  I purchased and installed for price of Boom-Beam and at that time got a higher lumen light.