The consensus is spend about $50 more and get a Concord RG-25 AGM battery rather than a Gil G-25 lead acid battery.
What about spending $100 more over the Gill G-25 and getting the RG-25XC which is the same physical size as the RG-25 but has 150 more LPP (125 CCA)
Both the RG-25 and the RG-25XC are PMA'd replacement battery's for the 170
And on last question, I assume no one has had an issue with the Concord fitting their battery box? The G-25 is a tight fit and the Concord RG-25 is a pinch longer.
Concord RG-25 or RG25XC
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Concord RG-25 or RG25XC
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Bruce Fenstermacher, Past President, TIC170A
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Bruce Fenstermacher, Past President, TIC170A
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Re: Concord RG-25 or RG25XC
I have had the same Concord RG-25XC in my 170 since 2006 and it is still holding up very well. Voltage remains in the high 12s after a couple of weeks.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
2023 Best Original 170A at Sault Ste. Marie
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
2023 Best Original 170A at Sault Ste. Marie
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
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Re: Concord RG-25 or RG25XC
I've had the RG25XC in mine for 4 years now.
It fits in the box just fine.
The only real issue with them is they don't recover from being drained. Once dead, they don't hold a charge for crap.
Leaving your master switch on will most likely cost you a new battery.
BUT, since I bought my second one, it's never let me down.
It fits in the box just fine.
The only real issue with them is they don't recover from being drained. Once dead, they don't hold a charge for crap.
Leaving your master switch on will most likely cost you a new battery.
BUT, since I bought my second one, it's never let me down.

- Bruce Fenstermacher
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Re: Concord RG-25 or RG25XC
So I guess I should also ask if anyone has experience with the Gill G-25s which is a sealed battery but not sure if it is recombinant gas matt (AGM) or still a lead acid. Or alternately Gills 7025-20 which is recombinant gas matt (AGM) and a replacement for G-25s.
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Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
Bruce Fenstermacher, Past President, TIC170A
Email: brucefenster at gmail.com
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Re: Concord RG-25 or RG25XC
Bruce Fenstermacher wrote:So I guess I should also ask if anyone has experience with the Gill G-25s which is a sealed battery but not sure if it is recombinant gas matt (AGM) or still a lead acid. Or alternately Gills 7025-20 which is recombinant gas matt (AGM) and a replacement for G-25s.
Hi Bruce,
I bought an AGM Gill for my PA12 once. Within a few months I started having trouble with the battery running down. It was pretty random, so I just assumed I left something on but then it started going completely flat, and finally wouldn't take a charge. At this point it was only a year and a half old. I chucked it and bought a Concord AGM battery. After 6 years on that battery I sold the plane this summer and it was still cranking like the day I got it. I flew all last winter after lotsa cold soaks in below zero and single digit temps, and that battery never slowed one bit.
Put an Odyssey in my 170 due to space considerations with the Avcon conversion. I have mixed feelings. I love the small size and light weight, but when the temp drops below 30 it doesn't crank very hard. Now that I finally got my preheater installed we'll see if that helps.
DEM
- cessna170bdriver
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Re: Concord RG-25 or RG25XC
I think mine had a Gill AGM battery (wingnut can probably verify) that was new in the summer of 2011, but after 3 months of disuse last winter, it wouldn't even pull in the master relay. I took it out and put it on my 35 year-old automotive trickle charger on the "Maintenance-Free" setting for about a day, and never had any more trouble the rest of the spring and summer.
Del, if I haven't already requested it, when the time comes, please order a new one of whatever battery was in '98C when your guys picked her up.
Del, if I haven't already requested it, when the time comes, please order a new one of whatever battery was in '98C when your guys picked her up.
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
- GAHorn
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Re: Concord RG-25 or RG25XC
Prob'ly not the best place to add to the work-order.cessna170bdriver wrote:I think mine had a Gill AGM battery (wingnut can probably verify) that was new in the summer of 2011, but after 3 months of disuse last winter, it wouldn't even pull in the master relay. I took it out and put it on my 35 year-old automotive trickle charger on the "Maintenance-Free" setting for about a day, and never had any more trouble the rest of the spring and summer.
Del, if I haven't already requested it, when the time comes, please order a new one of whatever battery was in '98C when your guys picked her up.

'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.

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Re: Concord RG-25 or RG25XC
well I have been in the aircraft maintenance business since 1970 and seen many different battery installations over the years. the different claims by different battery manufacturer always raise a smile to me. the manufactures always say [accuracy in the claims are another laughing matter] what the battery can do when it is new. Not what it will do when after say 3 years ,being abused or left to run down. People have a tendency to forget the battery as it doesn't make a noise or move to make a aircraft fly. Vibration is another big battery killer. I always push clients to have a prop dynamic balance done. Every body gains. Batteries hate vibration and break down under vibration loads . Having a smooth running engine, Less wear and tear on the aircraft and less fatigue on you. BUT , the battery is your last line of defence so you can scream for help when the big fan stops. the best battery around and best value? I think the Concord RG25XC for the 170 taking into account its electrical loads and starter loads. NOTE... I have a pallet out the back of the hangar where all the dead batteries go before being sent to the recyclers and 65% are colored PINK.
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