Bill_Pyles Posted April 15, 2012 Report Share Posted April 15, 2012 I have a 1979 J model with a Gill G-35 12V battery. Best I can tell, this battery was installed in April of 2007, about 250 hrs ago. I have owned the plane since Sep 2011 and I live in AZ, but the battery hasn't seen a full, battery-life-shortening summer. I have flown the plane about 60 hrs and the battery has always started the engine---until today, when the battery gave up. How many years or hours can we expect our batteries to last? Thanks! Quote Link to comment Share on other sites More sharing options...
MooneyMitch Posted April 15, 2012 Report Share Posted April 15, 2012 Hi Bill. There seems to be some pretty interesting controversy over the two major manuf. of aircraft batteries. Check out the discussions on the below referenced MooneySpace thread. New battery time -- Gill or Concorde Quote Link to comment Share on other sites More sharing options...
KSMooniac Posted April 16, 2012 Report Share Posted April 16, 2012 you are lucky a Gill of that vintage lasted that long. Time for a Concorde. Quote Link to comment Share on other sites More sharing options...
Bill_Pyles Posted April 16, 2012 Author Report Share Posted April 16, 2012 I read the Gill vs Concorde thread. A) it looks like I am due for a new battery and it aint gonna be a Gill just based on the overwhelming endorsement for the Concorde. Thanks! Quote Link to comment Share on other sites More sharing options...
danb35 Posted April 16, 2012 Report Share Posted April 16, 2012 Battery life seems to be highly variable. Unfortunately, if we just wait until it won't start the engine any more, it's already been mostly gone for quite some time. Concorde calls for periodic battery capacity tests, and for discarding the battery when its capacity falls below 85% of spec. Few shops have the appropriate equipment to do the test, though (and Concorde's recommendation isn't mandatory), so it doesn't happen. The tester could be approximated with something like a couple of landing lights hooked together, but it'd be a rough approximation at best. Quote Link to comment Share on other sites More sharing options...
rbridges Posted April 16, 2012 Report Share Posted April 16, 2012 I use a float charger on my battery. I think boat and plane batteries have the worst situation--long periods of inactivity. Batteries will naturally discharge slowly with time, and the lead plates will sulfate. After a while, this becomes irreversible, and your battery is toast. A trickle charger should extend your battery life since it should counter the discharge. 1 Quote Link to comment Share on other sites More sharing options...
Bill_Pyles Posted April 16, 2012 Author Report Share Posted April 16, 2012 Do you need some sort of trick, aviation charger, or will an ordinary charger like you get at the auto parts store do the job? Also, what is a "battery minder?" Quote Link to comment Share on other sites More sharing options...
rbridges Posted April 16, 2012 Report Share Posted April 16, 2012 I know some people recommend specific chargers geared toward our batteries, but I use a plain jane float charger that cost $25 from lowes. It's works fine for me and other people, but I'd read up on it before you take my advice. You need to make sure it has a "float" charging ability. If you get one that is a continuous trickle charger, it can overcharge your battery. A float charger will shut off automatically when the battery reaches a certain voltage and kick back on when it dips below a certain level. Quote Link to comment Share on other sites More sharing options...
Bill_Pyles Posted April 16, 2012 Author Report Share Posted April 16, 2012 Thanks Rob. I will look at my charger to determine if it has float-charging capability. Quote Link to comment Share on other sites More sharing options...
danb35 Posted April 16, 2012 Report Share Posted April 16, 2012 ...and a Battery Minder is a particular brand of (moderately high-tech, but fairly expensive) battery charger. It does have a good float-charging mode, as well as a regular charge at up to 8 amps. It gets good reviews, but some folks figure that they can do the same job with a much cheaper device. I use one and am happy with it. Quote Link to comment Share on other sites More sharing options...
MooneyMitch Posted April 16, 2012 Report Share Posted April 16, 2012 Thoughts have been previously discussed on auto battery life compared to aircraft battery life. One being aircraft battery life is much shorter than auto battery life due to the certification process which creates a battery built to minimum standards. Another thought was because the aircraft battery had to be smaller/lighter weight than the auto battery, therefore making its life shorter. I think my car batteries are of pretty equal weight to my Ovation Concords, although I have not specifically compared the two. One more thought could be planned obsolescence. I would venture to say the auto battery market is greater than the aircraft battery market. That being so, maybe less marketability produces a higher priced widget, not lasting as long in order to keep the manufacturer in business by selling widgets more frequently? Someone else mentioned aircraft batteries sit for long periods of time , consequently degrading the battery life rapidly. That is absolutely true. I have an auto I bought new in 1997. It's been sitting covered in my garage most of its life. I recently replaced the battery after 15 years. I joked about what a piece of junk that Delco battery was, only lasting 15 years! Imagine your airplane battery lasting that long! At aircraft trade shows, I've never asked Gill or Concorde reps. this "life" question. I'm not questioning anyone's thoughts on MooneySpace, I'm just curious if maybe all theses theories contribute to a shorter battery life for us. Quote Link to comment Share on other sites More sharing options...
Seth Posted April 16, 2012 Report Share Posted April 16, 2012 I have a battery minder and currently would buy it and again and do endorse it. I have had no issues with power at startup in my Mooney Missile. I currently have two Gill batteries on the special rack in the tailcone. I replaced my Gill in the 1967 Mooney M20F with a Concord with extra crankingpower after two and a half years of ownership when it woundn't hold enough charge to start the engine. -Seth Quote Link to comment Share on other sites More sharing options...
KSMooniac Posted April 16, 2012 Report Share Posted April 16, 2012 I use a Battery MINDer Aircraft version with my Mooney (and Concorde RG-35AXC) and am pleased with both. I have Odyssey drycell batteries in my motorcycle and truck, neither of which are daily drivers. Recently my truck battery was completely discharged and my non-drycell specific charger (multi-function charger/starter/desulphator whizz-bang unit) could not revive the Odyssey. I took it back to the vendor (it was 6 months old) and they were able to re-charge it with a better charger, so I purchased another Battery MINDer for my vehicles from Amazon. I previously used a Battery Tender Jr but after a few years it self-discharged the magic smoke and no longer functioned. I believe the Battery MINDer is a much better unit. Quote Link to comment Share on other sites More sharing options...
rbridges Posted April 16, 2012 Report Share Posted April 16, 2012 they say the more expensive ones have a desulfating mechanism, but some reviews seemed iffy. I may get around to a nicer charger, but I want to see how long my new (6 months old) battery works with the current charger. Quote Link to comment Share on other sites More sharing options...
231flyer Posted April 16, 2012 Report Share Posted April 16, 2012 Under "normal" operating conditions you should expect your Gill G35 to last 3-4 years in service. The biggest variable to battery life is condition when asked to deliver cranking power and subsquent charge condition following startup. If your battery is fully charged before a start it will deliver a strong start (usually lasting less than 20 seconds) and need very little topping off by the ship's charging system (2-4 Amps) after startup. If the battery is not fully charged, it will have to work harder to deliver the cranking power required. After startup the battery will be relatively more depleted and will suck more Amps from the ship's charging system (could be 10 Amps if sufficiently discharged). Large current draws tend to further heat up an already heated battery (normal chemical reaction when discharging or charging) and can result in warped plates and boiled off electrolyte. A few cycles of this and you are assured premature battery death. Its best to keep your battery "top off" charged with a float charger (max 2 amp rating if you are using an automotive type rather than one of the more expensive aircraft types which sense battery temperatures and can automatically vary the max current). Flooded lead-acid batteries (G35 type) tend to be very hardy if maintained carefully. In addition the electrolyte levels need to be monitored closely. Each cell (6 in the G35) needs to be filled to the bottom of the filler split ring with distilled water on a regular basis. In Texas my G35 will need a bit of water every 3-4 weeks. If the electrolyte level is too low the top of the plates will be exposed to air and will oxidize rapidly. Extreme temperatures do have an adverse effect on battery condition but can be minimized by pre-heating at temps below 40 degrees or parking the airplane in the shade in temps above 100 degrees. I use a battery minder and top-off charge my battery the night before a flight. Quote Link to comment Share on other sites More sharing options...
231flyer Posted April 16, 2012 Report Share Posted April 16, 2012 Rob: Your current charger should work fine if it can maintain currents at or below 2 Amps. Just don't leave it plugged in for days on end. The cheaper float-types shut-off circuits have been known to malfunction ($4 Harbor Freight comes to mind). The float circuitry is very simple and highly dependent on the quality of electronics used. Its best to charge right before a flight so as to avoid any surprises. I remember having to get a ground cart in SLC and the fbo guy forgot to switch to 12 Volts even after my continued reminders. The 24 Volt Charge fried my battery and one of my radios. Now I check my battery condition before I get in at any away airport. I have an automotive 3 LED "idiot" volt-meter wired to my battery. Quote Link to comment Share on other sites More sharing options...
steelerp Posted November 25, 2013 Report Share Posted November 25, 2013 This forum is great for stuff like this! After researching comments here and on other websites, I replaced the G35 Gill with the Concorde RG35-AXC. Could not be happier. Was a cold day here in Houston....ok, not as cold as you guys up north...but, 40...ish. The 440 CCA of the battery was very welcome over the 250 cold cranking amps of the Gill. Let's see how it holds up. For the record, the G35 Gill was done in 2years 4 mos. Quote Link to comment Share on other sites More sharing options...
jetdriven Posted November 25, 2013 Report Share Posted November 25, 2013 Remember to update the W+B for the RG-35AXC. Our Gill G-35 bit the dust after two years and it left plenty of corrosion in the battery box. The Concorde solves this problem, and reports of 7 years on a Concorde are pretty common. Quote Link to comment Share on other sites More sharing options...
VetRepp Posted November 25, 2013 Report Share Posted November 25, 2013 I use a battery Minder with my Ovation Concords and I am very happy with both. Mine is hardwired with the plugs tucked inside the external electrical plug door (?.. I'm spacing on that part name right now). BTW Concord recommends slightly different settings (Maintenance float or such) and Battery minder makes a specific unit for Concords specifications. Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 26, 2013 Report Share Posted November 26, 2013 VetRepp, Ever mix a Gil with a Concord? Or did you swap both out at one time? Best regards, -a- Quote Link to comment Share on other sites More sharing options...
VetRepp Posted November 26, 2013 Report Share Posted November 26, 2013 Carusoam When I bought the Ovation 2 yrs ago it had the Concordes. - Looking in the log book they were installed 4.5 years ago by prior Owner about 1 mo apart - no mention what the prior batteries were, (but that means the originals only lasted ~2.5yrs.) I assumed they were always Concordes, but maybe he replaced Gils?? (BTW -I checked BatteryMinder website and they no longer differentiate Gil from Concorde units - but they did 2 yrs ago when I bought mine. Also Concordes website still states that they worked closely with BatteryMinder on specs for their batteries - So I wonder if Battery Minder adapted those specs for all units?) But anyway, Mine are going strong and happy with the setup 1 Quote Link to comment Share on other sites More sharing options...
Hank Posted November 27, 2013 Report Share Posted November 27, 2013 I just looked at my Concorde the other day. When I needed one, I bought the one with extra CCAs to handle winters here in West-by-God Virginny. My A&P wrote on it, New 12/10. Still strong, I feel like I could taxi using the starter. Quote Link to comment Share on other sites More sharing options...
carusoam Posted November 27, 2013 Report Share Posted November 27, 2013 Thereby defining the hybrid version of the M20C... Or M20hC. My firebird has used this option in the past, and probably will again in the future. Nice thinking Hank, -a- Quote Link to comment Share on other sites More sharing options...
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