PC925L life

[kkmarshall]

I run a 925 in my 10 mounted on it's side and it seems to lose a bit of power after a couple of years,just wondered if side mounting affects life. They are cheap enough to replace that often but just wondering how long they are lasting in other people's 10's?

Keith

[Carl Froehlich]

Running two PC-625s mounted vertically in a modified mount. I replace one every three years so that no battery is more than six years old (same processed I did on the RV-8A). The pulled batteries go on to a second life in lawn tractors and such. I had my first pulled PC-625 go bad last year, but it was over 12 years old and I suspect the hard service in the lawn tractor did not help. I had one PC-625 go bad in the plane, but that was my fault - I left the master on and drained it. Once you abuse an Odyssey battery odds are it will never recover full capacity. The same thing happened in a buddies new RV-14. His 6 month old PC-680 got abused (ran the battery flat) and would not hold a charge. New battery is doing well and builder has a new understanding for care and feeding of Odyssey batteries.

I have concern about battery reserve capacity. Two ways to mitigate against a battery that is not up to snuff; test discharge or replace. The $100 every three years to replace is by far the simplest process.

Carl

[DanH]

6 years on a 925, side mounted, cranking a 390.

[kkmarshall]

Definitely still starts it but a noticeable difference on the first blade after 2 or so years. Not that expensive on an annual basis to replace every couple of years. Just curious as to others experiences.

Keith

[vic syracuse]

Originally Posted by kkmarshall

I run a 925 in my 10 mounted on it's side and it seems to lose a bit of power after a couple of years,just wondered if side mounting affects life. They are cheap enough to replace that often but just wondering how long they are lasting in other people's 10's?

Keith

Check your charging voltage. Keep it around 14.4-14.5 and the Odyseeys will last longer.

Vic

[kkmarshall]

The AFS display shows 14.1-14.2,I haven't checked at the bus.

Keith

[DanH]

Originally Posted by kkmarshall

The AFS display shows 14.1-14.2,I haven't checked at the bus.

Same voltage here, per the GRT EFIS display, but I'm told there is a small diode drop necessary to isolate the two power inputs.

Battery might not be the culprit here. For example dirty contact surfaces in the common start solenoid will generate the same symptoms. Not long ago I pulled a White Rogers from my friend Bill's Legend Cub, which was exhibiting similar symptoms, even after replacing a PC680. Bench wired it with a good Fluke across the big terminals. Powering the coil resulted in wildly different resistance each time. When amps are large, even a tiny resistance means a big voltage drop. Replaced the solenoid, and the Cub has been trouble free ever since.

[Machsandy]

Hello Keith

We have just replaced ours, again side mounted after 3 1/2 years as the prop was turning a wee bit more slowly on start.

[BobTurner]

PC925, mounted on its side in a -10. I've replaced it every 2 years, same symptom: it loses about 30% (?) of its capacity. Still starts just fine. Symptom: battery is at 12.7 or 12.8 volts. Turn on avionics, and the voltage drops within 1 minute to about 12.1-12.2 volts. After that it declines at a much slower rate. And, put it back on the charger, and it shows fully charged after about 2 minutes on the charger. I believe I have lost the top 30% capacity. Not sure why. Because of mounting it on its side? Buss voltage too low (14.2 volts from Plane Power internally regulated alternator)?

PS Anyone know for sure: Can I bump buss voltage up to 14.8 volts or so by putting a diode in series with the field line? Is this likely to be too high?

[kkmarshall]

Pretty much what I observe,still starts,just not as brisk on the first blade.
Same story on the voltages too.

Keith