I finally gave up on my PC680.....

After 12 years of faithful service, I replaced my PC680 with a new one. I took the old one and did a load test on it. It responded as if it was new. This battery is sitting on the shelf and continues to hold a charge of 12.84.

This battery did have a full discharge (left master on) about eight years ago. Recharged with a 1 amp charger. That was the only time a charger was used on this battery. I have no complaints with this battery.

The big question is are the new Odessey batteries built as good as the ones from yesteryear? I've had friends who bought them years ago and got many faithful years of service life from them, but recently there have been
too many reports of short service life and some cases of failures/leakage too.
I put a certificated Concorde sealed AGM battery in my old Cherokee and it lasted many years even after I sold the plane. My RV6 had a Concorde sealed battery in it when I bought it that was dead after sitting 3 years and it came back to life after a charge. Still, I asked the seller to put a new one in it when I bought the plane and he did. Now, only 3 years later that battery is showing signs of biting the dust and I've verified the alternator and regulator to be in good working order. I've thought about replacing the Concorde battery with an Odessey 925 since it's about the same physical dimensions as the Concorde but I'm worried that all the big name sealed AGM batteries are now manufactured to poor quality control and that perhaps if any of them are only going to last a couple years that perhaps I should instead just buy the cheapest Chinese battery that has the amp-hrs and physically fits and accept that I'll have to replace it every 2 or 3 years. Have all the sealed battery makers quality gone down the toilet lately?

Thoughts?

I am curious where your battery was mounted. The listed max temp is 122 degrees. I think a lot of the issues might be on firewall installs. I suspect the batteries are getting a lot hotter then many realize.
George

sailvi767 said:

I am curious where your battery was mounted. The listed max temp is 122 degrees. I think a lot of the issues might be on firewall installs. I suspect the batteries are getting a lot hotter then many realize.
George

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It is mounted on the firewall. I do have a temp probe mounted one inch from the case. The area usually runs 130 to 140*

gasman said:

It is mounted on the firewall. I do have a temp probe mounted one inch from the case. The area usually runs 130 to 140*

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After shutdown on a hot ramp in August?

Battery Forward of Firewall

I don't mean to be critical but, I simply don't understand why you'd ever mount your battery forward of the firewall. That seems like a very unfavorable thermal environment for any battery. Unless CG is an overriding consideration, why not put the battery in the cabin somewhere? Concerns about gassing, acid leakage, etc. seem to be largely mitigated by a properly maintained AGM / Lithium battery so I'd put that sucker in the reduced vibration, cooler environment where, hopefully, it will be more happy.

The other thing that AGM battery owners should consider is the charging voltage. The charging source for an AGM battery should be set to 14.5-14.7 volts. That's much lower than most folks probably have their regulators set for their standard lead acid batteries. Most Lithium batteries have their own charging circuit and will live happily with a wider range of input voltages. AGM batteries, with no integral circuitry, rely on the charging system in the airplane to supply the proper charging voltage. If you have an AGM battery like the PC680, you should check your regulator to ensure it is set for 14.5-14.7 volts.

As an aside, I also think that most of our aircraft electrical systems are ill suited for the proper maintenance of any AGM battery. In my motorhome, my charger uses a very different charging and maintenance process to maintain my AGM batteries. In my airplane, there is none of that level of sophistication. We just feed it voltage and current for the duration of the flight and hope for the best. That's not the best approach to battery charging / maintenance. AGM batteries like a fairly precise sequence of bulk, absorption, and then float charging. The lithium batteries that I maintain for my radio control aircraft also require a fairly sophisticated charger. Where is that level of battery maintenance sophistication in our airplanes? Maybe an opportunity for some aspiring entrepreneur!

My experience with firewall mounted 680

I have my PC 680 mounted on the engine side of the firewall in my RV-7A. Primarily because I did not want heavy 12v power cables in the cockpit. I am on my second battery in ten years. Changed it at 5 years just because. The old battery is on my bench and still takes a full charge. Debating if I should change again at the next annual. Never charge it between flights.

YMMV

Why Firewall forward

Another good reason besides C of G is how it is a wired. When I purchased my plane, there was no way to isolate the power between the battery, master and solinoid. In the event of a forced landing, if the fire wall got kicked into the main battery cable, there was an instant arc welder. In an Rv6, c of g is also a very good reason.

10:1 compression on a PC 680?

I am needing a new battery soon for a 10:1 Lyc. Have been using a wheelchair type battery for years but the quality of the new batterys significantly decreased and barely turns the engine over now. Anyone using a PC 680 to successfully turn a 10:1 Lyc. ? The PC925 won't fit the battery tray and weighs 26lbs

Steve

PC 680

The PC 680 cranks my 10-1 0 320 so fast one would think the spark plugs are not installed. The secret is a ground cable from the battery ground point to one of the starter fasteners. I am using a #4 welding cable for the ground.

Steve Barnes said:

I am needing a new battery soon for a 10:1 Lyc. Have been using a wheelchair type battery for years but the quality of the new batterys significantly decreased and barely turns the engine over now. Anyone using a PC 680 to successfully turn a 10:1 Lyc. ? The PC925 won't fit the battery tray and weighs 26lbs

Steve

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We have a IO360 with 10 to 1 Pistons. The 680 has no trouble spinning it. The other day I messed up a hot start and had to crank quite a bit. Battery was still going strong when I got it started.
G

f14av8r said:

I don't mean to be critical but, I simply don't understand why you'd ever mount your battery forward of the firewall. That seems like a very unfavorable thermal environment for any battery. Unless CG is an overriding consideration, why not put the battery in the cabin somewhere? Concerns about gassing, acid leakage, etc. seem to be largely mitigated by a properly maintained AGM / Lithium battery so I'd put that sucker in the reduced vibration, cooler environment where, hopefully, it will be more happy.

The other thing that AGM battery owners should consider is the charging voltage. The charging source for an AGM battery should be set to 14.5-14.7 volts. That's much lower than most folks probably have their regulators set for their standard lead acid batteries. Most Lithium batteries have their own charging circuit and will live happily with a wider range of input voltages. AGM batteries, with no integral circuitry, rely on the charging system in the airplane to supply the proper charging voltage. If you have an AGM battery like the PC680, you should check your regulator to ensure it is set for 14.5-14.7 volts.

As an aside, I also think that most of our aircraft electrical systems are ill suited for the proper maintenance of any AGM battery. In my motorhome, my charger uses a very different charging and maintenance process to maintain my AGM batteries. In my airplane, there is none of that level of sophistication. We just feed it voltage and current for the duration of the flight and hope for the best. That's not the best approach to battery charging / maintenance. AGM batteries like a fairly precise sequence of bulk, absorption, and then float charging. The lithium batteries that I maintain for my radio control aircraft also require a fairly sophisticated charger. Where is that level of battery maintenance sophistication in our airplanes? Maybe an opportunity for some aspiring entrepreneur!

Click to expand...

My PC680 spent 12 years on the firewall (RV7 location) in temps at least 120f. It was charged with a Toyota alternator for the first few years, then was switched to a Plane Power. Both alternators charged at a rate of 14.2 volts.

The PC680 ( AGM) battery has very well proven it's position on firewalls of thousands of RV's for thousands of hours.

Why did mine last for 12 years?

I mounted mine in it's metal case with no holes cut in it. I used welding cable for ground, charging and starting. I crimped AND soldered all ends and coated each connection with DE-OX. All starts and shutdowns are made with the ALT switch on.

The only time this battery didn't start my O320 with zest is when I left the master no at about year 5 and ran it down to totally dead. Not good. It recovered and has continued to work 100% to this day.

In my case, the 140* location and under charging it has not been a problem.