over voltage protection

[Mike Ice]

Folks,

Wow, who would have thought a couple of questions could lead to so much GOOD information.

It wasn't that I didn't want to take the time or spend the money to install OV protection on a perfectly good IR alternator, it was just that I made up my own mind that it wasn't necessary (for me).

Any how, moot point (for me) I called Van's to make sure my new alternater that is shipping this week is the Plane Power unit. Now I will have the belt and suspenders approach.

I still find all of this very interesting and now that I know just a tiny bit about electricity I am sure I can make some great mistakes.

Anyhow if anyone does any experiments and blows up a battery (on the ground in a controlled experiment) please share it with us.

Mike Ice
still wiring but soon will be working on the canopy.

[Bob Brown]

George mentions above that the Icom A200 has no overvoltage protection, but when mine inadvertently got too much voltage for breakfast one morning and quit working, I discovered there is an internal fuse (old style glass with metal ends) inside the radio. It saved my radio's bacon...

[AlexPeterson]

I spoke with a technical person at the factory that makes Odyssey batteries today. I asked him how much current he thought it would take to drive the voltage of a PC680, for example, up to 17 or 18 volts. He wasn't sure, but he didn't think it was anywhere near as much as I alluded to in an earlier post in this thread. In fact, he thought a fully charged battery wouldn't take much current with 17 or 18 volts applied.

I'm afraid we will have to do the test to really find out.

[gmcjetpilot]

Originally Posted by Bob Brown

George mentions above that the Icom A200 has no overvoltage protection, but when mine inadvertently got too much voltage for breakfast one morning and quit working, I discovered there is an internal fuse (old style glass with metal ends) inside the radio. It saved my radio's bacon...

Yes sir that is good to know. What I meant was the regulated / surge protected power supplies the new stuff has. That is good to know the fuse blew.

Originally Posted by AlexPeterson

I spoke with a technical person at the factory that makes Odyssey batteries today. I asked him how much current he thought it would take to drive the voltage of a PC680, for example, up to 17 or 18 volts. He wasn't sure, but he didn't think it was anywhere near as much as I alluded to in an earlier post in this thread. In fact, he thought a fully charged battery wouldn't take much current with 17 or 18 volts applied.

I'm afraid we will have to do the test to really find out.

There was the one Odyssey that puff out from extended over voltage. The technical manual say 15 volts max for charge. I am sure it can take short times with high volts. Even if its not drawing much current it is doing damage I guess? Needless to say its not a great thing but not a explosion.

[uk_figs]

Interesting thread as I logged in to ask a question about this very subject, if I understand the thread correctly the alternator I will get as part of the firewall forward kit will be a Plane Power with internal regulator and overvoltage protection is this correct?
As I am also using the Z-11 drawing I assume that I connect the alternator field connection directly to the Battery/Alt Master Switch and I now put a CB between the main power distribution bus and the Battery/Alt Master Switch? If this is correct what amperage would be required?
Thanks

[gmcjetpilot]

Originally Posted by uk_figs

Interesting thread as I logged in to ask a question about this very subject, if I understand the thread correctly the alternator I will get as part of the firewall forward kit will be a Plane Power with internal regulator and over voltage protection is this correct?

No you get the plan vanilla Nippon Denso Clone with internal regulator. Does it say plane power and have a little external box hanging off the back? Good news, there is nothing wrong with a stock ND. 1000's fly, with 1000's of hours of reliable operation. You hear sales pitch with fear mongering, but ignore it. It's not based on facts. Your ND from Van's is fine.

Originally Posted by uk_figs

The Z-11 drawing I assume that I connect the alternator field connection directly to the Battery/Alt Master Switch and I now put a CB between the main power distribution bus and the Battery/Alt Master Switch? If this is correct what amperage would be required?
Thanks

Internal ND's do not have a FIELD wire. I am not being snarky, its very common misunderstanding and internally regulated (IR) and externally regulated (ER) are very different. They are installed and operated differently. I'm of the opinion that the Z drawings are not suited for IR alternators. Bob's (IR) alternators, his own words, is poor, but he has come a long way in the last year, but he still tries to fit EI alternators into his wiring like they are (ER) alternators.

See my post in this thread, there is a thumb nail sketch. It shows the wiring.
http://www.vansairforce.com/communit...85&postcount=6

The current draw on the IGN lead of a ND is milli-amps, not 5 or 7 amps as Bob thinks. Bob gets ER and IR mixed up, 1/2 or a 1 amp CB is plenty. Remember the IGN lead going to a ND is not a FIELD wire, its a LOGIC or SIGNAL WIRE. It tells the computer inside the alternator (yes the IR has a microprocessor) to come alive or go to sleep.

I can't say it enough NEVER turn the alternator ON or OFF while the engine is spinning.

The BIG disconnect (pun intended) between Bob's Z drawing is Bob loves a BIG fuse between the B-lead (output) of the alternator and battery. Bob loves to run that B-lead right to the battery with that big chassis fuse under the cowl. That's fine you can do that; that is what most cars do. This is the modification of above (click):


Bottom line follow the diagram posted for the IGN and L (light). The light is optional, but I'm a big fan of using it. Its an over-volt, low volt, lost belt, fault light. Install the alt Light at your option, if you have another low volt light. You should have a low volt light of some kind.

If you are going with a stock ND than go that way. You will be fine. Millions and millions of cars, trucks, industrial and farm vehicles going 24/7 world wide in extreme conditions can't be wrong. OV IS NOT A PROBLEM. Leave the OV relay for the ER-alternators, they do need it.

If you are really scared, may be you can return the unit you have or sell it and get a Plane Power unit. If you are flying IFR or have a electically depended engine that might be a reason. The Plane Power has consistent QC and the added on OV module is nice; it shuts the alternator down properly. It's totally different than the way Bob's OV relay crow bar works.


OVERVOLTAGE RELAY
MY opinion - Don't use the crow bar, OV relay, on a (IR) alternator out-put. Doing so will likely damage the alternator. Van agrees and will not warranty your alternator if you do this. Again (ER) verses (IR) are 180 degrees apart. The Nippondenso was designed to not need an OV relay. Disconnecting the alternator output from the battery, which is what the OV relay/crow bar does, while the alternator is powered, will damage any alternator. The technical data with any modern alternator says don't disconnect alternator from battery while its running. Why have something that can (will) damage a perfectly good alternator. The cure is worse than the ill.

[Jekyll]

Originally Posted by uk_figs

...if I understand the thread correctly the alternator I will get as part of the firewall forward kit will be a Plane Power with internal regulator and overvoltage protection is this correct?...

Dave: No, the FWF comes with the ND alt as pointed out by George however, Van's will be happy to delete the ND alternator and substitute the Plane Power for the difference in cost. I'm just a regular Joe but, I recommend the swap. The Plane Power has the correct fan rotation so they are actually moving cooling air through the unit plus it has positive overvoltage protection.

It's the only IR alternator that has Bob Nuckoll's approval (if that's important to you).

Are you buying the Van's wiring kit (in the FWF) or rolling your own?. Many builders who use the Z architectures delete the wiring kit from the FWF because it requires major modifications to use with a Z. It also comes with CBs which doesn't suit many Nuckollheads desiring fuses.

Jekyll

[uk_figs]

Thanks for the responses, I will probably do the switch to the PP alternator version. I already purchased the Vans wiring kit seperately so will be deleting that from the FWF kit and I plan on using the CB switches instead of fuses except for the avionics bus relay which has fuses.
At this point I am trying to reconcile the Vans electrical schematic and the Z-11 schematic to my desired panel layout which is all electric and figure out the correct CB values, busses, number and type of switches etc so I can plan and start the installation layout.
As I am not an electrical engineer the alternator section is giving me a headache, I checked the Plane Power site and they have a drawing that shows a 60A CB on the B side and a 5A and 1A CB on the switch and warning light side, if the 60A CB is in the cockpit do I have to run a big as**d wire from the starter solenoid to the panel? Do I need this?
If there is problem with the alternator voltage in flight what is the correct approach to shut down the alternator.

[Jekyll]

You can put an ANL-60 on the fw versus the CB; check Dan Chekoway's site. Just need the 5 amp cb in the panel.

Jekyll