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Battery replacement recommendations & tips

wrongway john

Well Known Member
This is my present 25 amp B&C battery. Weighs 23.5 lbs. Dimensions are: 4.92" W x 6.5" L x 6.85" H . I've had this one for 7 1/2 years, it never once failed me, but feel like the cranks are getting a bit slower. It says unlike conventional gel cell batteries, these are not supposed to ever have catastrophic failure.

Sometimes, but not always, on occasionally I'd give it an hour charge or so if I haven't flown in a few weeks, but that was it, never kept it on a trickle charger. As much as I would like to go with this battery again, mainly due to how happy I've been with it and also because of the perfect fit of my battery box, but I would like to lose some weight, and haven't ruled out the lithium batteries.

This Odyssey battery is another 25 amp, but only weighs 13.2 lbs, and has choices close to the dimensions I was needing. They say it has a eight year design life according to the literature at Aircraft Spruce.



I like this Aerovoltz lithium battery
weighing only 2.44 lbs. Price isn't bad at $249.95. Evidently they haven't updated their site, because they have BMS balancers available for it now at about $114.85. I'm aware of the caveats of lithium batteries.

Any particular spacer you would recommend, or would you opt to build another battery box around new battery? What batteries have you been happy with or not?
 
Your battery looks like an overlabled Odyssey PC925. Batteries Plus nearby may have one for $187-ish.

There is also an "L" swapping poles, so don't get the wrong part number. In lithium LiFePO4 chemistry the EarthX folks advertise here.

https://www.batterymart.com/p-odyss...MI69WS_-zq3AIVxoWzCh1MMAVbEAQYAiABEgLpkPD_BwE

Which plane and battery location? I would try a vented EarthX in my 6 with the battery against pax side of firewall, but use a Deka SLA about the size of a Concorde RG-25XC. About same weight as your current battery.

If you try anything but a direct replacement, you may need to change cables.

Check your connections, every one you can get to, for corrosion if not voltage drops. It is quite common for that to drop starting oomph of an otherwise sound battery. In the case of 7+ years, I'd say replace with same and well done! If you have time and don't mind shipping, no reason not to reorder from B&C.

Sizes below show possibly not exact fit, close.

Product Specifications for Odyssey PC925 Battery
SPECIFICATIONS:
BM Part #: PC925
Made In: U.S.A.
Voltage: 12 Volt
Capacity: 28 Ah
Type: AGM
Length: 6.44"
Width: 6.75"
Height: 4.88"
Terminal Height: 4.43"
Cold Cranking Amps: 330 CCA
Shipping Weight: 26.00Lbs
 
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Thanks for the tip. Good catch, it does look like it is made from the same manufacturer. It is tempting to go with the B&C again, and be done with it, but gosh, it's such a heavyweight, and so is Odyssey PC 925 being just a few lbs heavier than my present one.

It's going in a RV-6, battery is located inside the cockpit in the middle by firewall.
 
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Why?

Why are you wanting to change if you got 7 1/2 years out of the B&C? That's all anyone could ask for. I fly with the same battery and it cranks the heck out of my high-compression engine. I change mine after about four years, though, just because.
 
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Odyssey bat specs

The PC625 isn't a 25AH battery. With, say 10A draw on it, you'll be lucky to get 12AH out of it. They are claiming 18AH...if you discharge it over the space of 20 hours. Lead acid batteries don't deliver nearly the same AH if you discharge at a higher rate.

Ed Holyoke

This is my present 25 amp B&C battery. Weighs 23.5 lbs. Dimensions are: 4.92" W x 6.5" L x 6.85" H . I've had this one for 7 1/2 years, it never once failed me, but feel like the cranks are getting a bit slower. It says unlike conventional gel cell batteries, these are not supposed to ever have catastrophic failure.

Sometimes, but not always, on occasionally I'd give it an hour charge or so if I haven't flown in a few weeks, but that was it, never kept it on a trickle charger. As much as I would like to go with this battery again, mainly due to how happy I've been with it and also because of the perfect fit of my battery box, but I would like to lose some weight, and haven't ruled out the lithium batteries.

This Odyssey battery is another 25 amp, but only weighs 13.2 lbs, and has choices close to the dimensions I was needing. They say it has a eight year design life according to the literature at Aircraft Spruce.



I like this Aerovoltz lithium battery
weighing only 2.44 lbs. Price isn't bad at $249.95. Evidently they haven't updated their site, because they have BMS balancers available for it now at about $114.85. I'm aware of the caveats of lithium batteries.

Any particular spacer you would recommend, or would you opt to build another battery box around new battery? What batteries have you been happy with or not?
 
I've been a fan of the Deka ETX series for years. They get marketed to the import tuner guys as Braille batteries. They tend to give similar performance to the Odessey batteries at a lower cost, and in a wider variety of sizes.
 
What you said at the start.

"This is my present 25 amp B&C battery." "I've had this one for 7 1/2 years, it never once failed me"

Very tough to improve on that.
 
The PC625 isn't a 25AH battery. With, say 10A draw on it, you'll be lucky to get 12AH out of it. They are claiming 18AH...if you discharge it over the space of 20 hours. Lead acid batteries don't deliver nearly the same AH if you discharge at a higher rate.

Ed Holyoke

Okay, Ed, thanks for that. This is why I run things by you guys first. This is my first battery change on a plane.

Why are you wanting to change if you got 7 1/2 years out of the B&C? That's all anyone could ask for. I fly with the same battery and it cranks the heck out of my high-compression engine. I change mine after about four years, though, just because.

Saving 21 lbs was a pretty good incentive for me if I went with one of the lithium batteries. Perhaps on my next battery change, which will hopefully be another 7 1/2 years, I'll be comfortable making the switch to lithium then, but for now, I've decided to go back with what I have.
 
7 1/2 years very impressive thanks for reference. I somehow forgot B&C has its own battery. Normally I change my PC680 every two years, they usually degrade noticeably after everyday cycling. My next battery will be B&C I am a big fan of their quality products. Have alternator and starter very happy customer :)
 
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