Battery woes

[JamesMooney]

55 minutes ago, Ragsf15e said:

Definitely check the field voltage at the alternator with master on, engine off.  Should be just less than 12v.  While you’re there, check the connections to the alternator.  Wiggle them.

Field voltage is 0

My A&P thinks the VR is the problem, that its enough putting out enough to 'excite' the alternator

(Pardon my lack of electrical knowledge - definitely not my area of expertise!)

[PT20J]

1 hour ago, FlyingCanuck said:

Field voltage is 0

My A&P thinks the VR is the problem, that its enough putting out enough to 'excite' the alternator

(Pardon my lack of electrical knowledge - definitely not my area of expertise!)

If it is zero then it is either a broken connection somewhere or a bad regulator. I would next check the voltage at the field terminal of the regulator.

 

[Ragsf15e]

2 hours ago, FlyingCanuck said:

Field voltage is 0

My A&P thinks the VR is the problem, that its enough putting out enough to 'excite' the alternator

(Pardon my lack of electrical knowledge - definitely not my area of expertise!)

Exactly what Skip said. Measure field at the vr.  If 0 there, measure voltage coming into the vr sense line.  You’re looking at a broken connection somewhere…

[Kelpro999]

Start with field voltage check w/ master “on”. At alt. And breaker, if good move to output 

 It sounds like your A&P is doing diag. So telling you to physically pull and push the two breakers is moot as he’s most likely done that. 
 

[A64Pilot]

4 hours ago, Hank said:

Hmmm . . . . I get 6-7 years from my Concordes. And yes, it's capacity checked every annual. Methinks you speak without experience.

Often get 5 with a flooded battery, much longer with the Concordes, I’ve seen them go over 7 years before failing a cap check.

I’m a fan of LifePo4 batteries, when aircraft ones come down to lead acid prices I’ll think about buying one when the Concorde goes dead.

I just put four in my golf cart, because they were cheaper than Trojan lead acid cart batteries, the required charger made the total higher though.

The most likely reason why not to make the battery larger to at least equal the AH of the lead acid is most likely price, there are only a few actual battery manufacturers, almost all of them out there buy at least cells if not the whole battery, slap their label on it and sell it.

I bet Earth -X or whoever buys cells and puts them in a box and has someone else build the BMS, want to bet?

I’m astonished the FAA would grant an STC to a battery that didn’t at least meet the reserve capacity of the battery it was replacing.

 

[EricJ]

15 hours ago, FlyingCanuck said:

Field voltage is 0

My A&P thinks the VR is the problem, that its enough putting out enough to 'excite' the alternator

(Pardon my lack of electrical knowledge - definitely not my area of expertise!)

That sounds like maybe a short somewhere.   On my airplane the field wire is shielded, and I managed to catch a stray hair of the shield in the crimp when I did an AOG field repair away from home once, and didn't catch it.   That shorted the field and I had to fly home with no alternator.   The LED on my Zeftronics regulator properly diagnosed a field short, and once I found that and fixed it everything was fine.

If you have a shielded field wire there are several places where it can get shorted, including at the alternator and both sides of the firewall bulkhead connector.

[AndreiC]

In my plane the one time the system was not charging happened when the voltage regulator got itself tripped up over some overcurrent. The recommendation was to turn the master off and then after 15-20 seconds on again while the engine is running (obviously, you want all your electronics off). I don't believe this will fix your situation since I assume in your case you tried several times to turn things off and on again, hence resetting the VR, but since it's very easy to do may be worth a try once?