jbDC9

jbDC9

Well Known Member
Why? Because, well... I'm a dumba$$. I left the master switch on. Oops.

It was just a quick lunch run to Brenham this morning. Landed at 11:45 and saw lotsa cars and people in the parking lot headed inside to grab all the tables. Better hurry. Tied down, chocks in, head for the front door. The Big Red Light on the EIS was flashing and trying to tell me something, but in the bright sunlight and my haste, I never saw it. An hour later as I'm pushing it to the fuel pumps I found my boo boo... ruh roh, I hope it starts. Usual static voltage is around 12.2 and by now it was down to 11.9 volts.

But no worries; it cranked right up on the second blade! I couldn't even detect that it cranked any slower... granted, the master was only left on for an hour or so, but after so many years of being used to flying worn out, beater rental ships I expected the battery to be gone and needing a charge. I'm really quite amazed at how long this battery is lasting; bought in Oct. '04 (for $55!!), first flight Nov. '06 and still going strong with 654 hrs on the Hobbs. Nice.

As a side note, as I was dreading the thought of dragging my ship down to the mx hangar for a battery charge, I was certainly glad that I added a battery access hatch to the rear baggage bulkhead/shelf... had a charge been necessary, the access hatch would've been a huge time saver.
 
is static 12.2 V normal?

HI,
I really appreciate your post, because it addresses something I have wondered about.

Until recently, I was putting up with a Concorde battery with a shorted cell that would never hold static voltage higher than about 12.2. For this battery technology, I expect a static voltage of 13V or more. In flight, my voltage was always around 14.8 with a Plane Power 60A alternator.

So, I recently switched to an Odyssey PC680. I find that my static voltage is still around 12.2 V. In flight, I'm seeing 14.5 V or so, so I have been wondering if maybe it just has not gotten fully charged by several one-hour flights. I was expecting to see it also hold around 13V.

So, your post suggests that the 12.2V is 'normal' for the PC680....? so maybe my battery is fine? I was just thinking, "Jeez, what is it with me and batteries, anyway?":confused:
 
Steve,

I think your battery is fine (as long as it cranks the engine). Mine sits around 12.2-12.3 and goes up to 14.2-14.3 when charging. An hour in the air should more than charge your battery. I ran mine down a few weeks ago but had enough left to crank the engine over and fly. Was seeing ~20V initially but down to the normal 14.2 within a half hour (maybe less) and certainly was topped up by the time I was on the ground after another half hour.

greg
 
yakdriver said:
If you ever leave the master on and run the Odyssey completely down it will ruin it. Don
Click to expand...

I left my master on for 2-3 weeks during a bad weather period last fall. The next time I tried to go flying, the battery was as dead as a cinder block. Surprisingly, a couple of days on the charger and the PC-680 came right back. Even after that dumb mistake, I honestly can't tell a difference in cranking performance, which is a real surprise.

Not that everyone will be as lucky as I was (or dumb enough to leave the master on for several weeks)...
 
yakdriver said:
If you ever leave the master on and run the Odyssey completely down it will ruin it. Don
Click to expand...

Kyle Boatright said:
I left my master on for 2-3 weeks during a bad weather period last fall. The next time I tried to go flying, the battery was as dead as a cinder block. Surprisingly, a couple of days on the charger and the PC-680 came right back. Even after that dumb mistake, I honestly can't tell a difference in cranking performance, which is a real surprise.

Not that everyone will be as lucky as I was (or dumb enough to leave the master on for several weeks)...
Click to expand...

Same here, ten days with the master "on", PC680 as dead as a hammer. After an overnight charge with a two-amp charger, it came back and seems to be fine. Definitely not the way to make friends with a battery, but it seems to have survived the punishment.

There is now an audio transducer connected to the low oil pressure light. Don't think I can walk away from the plane with that thing screaming... ;)
 
scsmith said:
HI,
I really appreciate your post, because it addresses something I have wondered about.

Until recently, I was putting up with a Concorde battery with a shorted cell that would never hold static voltage higher than about 12.2. For this battery technology, I expect a static voltage of 13V or more. In flight, my voltage was always around 14.8 with a Plane Power 60A alternator.

So, I recently switched to an Odyssey PC680. I find that my static voltage is still around 12.2 V. In flight, I'm seeing 14.5 V or so, so I have been wondering if maybe it just has not gotten fully charged by several one-hour flights. I was expecting to see it also hold around 13V.

So, your post suggests that the 12.2V is 'normal' for the PC680....? so maybe my battery is fine? I was just thinking, "Jeez, what is it with me and batteries, anyway?":confused:
Click to expand...

12.8 volts is charged 100%. 12.2 volts is a charge of 50%. Measurements taken at the battery posts. Charge rate should be between 13.8 and 14.2. But never over 14.6 volts.

My 680 recovered just fine from DEAD:eek::eek: Just charge at a slow rate like 1/2 to 1 amp over a long period of time. If you prop and go, and let the alt. charge the battery, it might just kill it.
 
Charge the battery

gasman said:
If you prop and go, and let the alt. charge the battery, it might just kill it.
Click to expand...
Might not hurt the battery, but there is a real chance that you will kill the alternator.

John Clark
RV8 N18U "Sunshine"
KSBA
 
Ran mine down--two weeks w/the master on. Charged right back up on a charger. One thing that I think helps is that at some point the solenoid breaks the circuit when the voltage gets so low. That keeps from running the battery all the way down. Maybe that is why it isn't "ruined."

Bob Kelly
 
Last thing I do before climbing out of working plane or my 7 is to turn on strobe lights, powers is off, but if someone, or me hits the master, there is no dought about master switch being on or not.
 
videobobk said:
Ran mine down--two weeks w/the master on. Charged right back up on a charger. One thing that I think helps is that at some point the solenoid breaks the circuit when the voltage gets so low. That keeps from running the battery all the way down. Maybe that is why it isn't "ruined."

Bob Kelly
Click to expand...

Wouldn't the solenoid coil remaining on run the battery all the way down?
 
Left my master switch on my previous plane with a PC680 for 7.5 months while on deployment. It was so dead it was reading -12.8 volts (joking). Left the battery in my garage for 3.5 years used as a weight for gluing wood pieces together. Fast forward to my RV8 project. Plugged in a battery minder charger and a day later the battery holds 12.8 volts and cranks the engine as if it was new. I was/am amazed.
 
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