The International Cessna 170 Association

Its been a while since this subject came up so I am wondering if there are any updates on suggestions for replacing my Gill G-25 with some type/brand of sealed battery. Although I am going to give George's earlier suggestion of putting baking soda in my battery box for the immediate future, I am tired of having to pull the battery, dig out/clean up corrosion out of my battery box every few months and repainting it. I don't know if I am putting too much water in each cell or what. I usually bring the level up to the bottom of the plastic dingy that sticks down inside each cell. I want to get a sealed battery and don't really know which brand or model number to look for. I would even consider going to one of those Odyssey PC625's that were discussed some time back. I haven't asked my AI if he would do the paperwork or not, but I want to stop the continuous problems I am having. Suggestions?

Make sure the battery is fully charged before adding distilled water. Just make sure the electrolyte covers the lead plates before charging. Otherwise, the electrolyte will expand during the charge and there will be too much electrolyte in the battery.

Yep, Frank. YOu don't want the electrolyte to touch the "thingy" ...if by "thingy" you mean that screw-in cap. The level should be below the inner ring of the pink battery... or as previously said....just covering the plates.
If your battery is boiling over even when not overserviced...then your charging system is likely adjusted to "high", and is overcharging your battery (which will also render it a short life.)

I just charged and installed a new Gill battery this past Friday per the instructions that came with the battery:

1) Filled each cell with acid to just covering the plates
2) Let it sit for about 30 minutes and rocked it occasionally to free up any air bubbles
3) Charged it at a constant 3 amps for 1 hour
4) Filled acid to the bottom of the plastic split ring in each cell
5) Continued 3-amp constant current charge until a specific gravity of 1.275-1.295 in each cell

The whole process took about 5 hours.

Miles

Thanks for the response regarding how to service the battery. That is what I do, I fill the cells with distilled water until it comes up to the bottom of the split ring (thingy). Maybe I need to not fill them quite so much, just make sure the top of the plates are covered. I have had this "problem" for a number of years. I think my battery is about 3 or more yrs old. I don't know how one would adjust the alternator output. I have one of those solid state regulators, but until I replace the battery I will keep the level a bit lower and see if that helps.

I'm not positive, but I think the reason they have you charge the battery for an hour before topping off the elecrolyte is that the electrolyte expands as it warms. Charging (on the bench or in the airplane) warms the electrolyte and puts it at the level it will normally see in operation. Then you can fill to the bottom of the rings. If the cells were filled to the split ring while cold and then charged, the level would rise, causing the cells to be overfilled.

Miles

My comments regarding filling the cells w/ distilled water is after having the battery in the plane for months/years. I still need to keep the level of the electrolite lower and that might reduce my problem, but sooner or later I am going to go to a sealed battery.

Your question was about a replacement!!! I converted to a Gel cell sealed battery in 1994 and I am using the same battery to this day. I will give you the paper work if your interested. Thats about 700 flight hours. The battery is 12V and 26 AMP HR Gell Cell. I also converted to a Flight Lite starter which saved 7 pounds. The Advantages are more amperage, no fluid to mess with, no spills, and no vent required. I also moved the battery from the firewall to under the right front seat. Is that what you had in mind?

I installed a Concorde sealed battery about 5 years ago. It was the same length and width but not quite as tall so I made a thicker filler for the cover. I did no paperwork and no IA has questioned the change. No more acid, no more mess. I do keep an automatic trickle charger on it during periods of inactivity.

Thanks Green Bean, and others, for your input. While I will always take advantage of reducing weight, my main reason for wanting a gel cell battery is to stop the clean up problems that seem to be in my battery box constantly. I will continue to use my existing battery box, but with a different battery.

If you want to avoid the paperwork hassles, go with either the Gill G-25S or the Concorde RG-25 (or RG-25XC). All are STCed for the 170. These are sealed cell batteries which supposedly have no spillage in any position. The Odyssey is not approved for the 170 and requires a 337 approval. I don't believe any of the gell cell type batteries are approved.

In a somewhat dated article at http://www.aeroelectric.com/articles/battery.pdf Bob Nuckolls sings the praises of the RG battery, "I recommend switching to an RG battery at the next opportunity; there's nothing to maintain on this truly sealed battery, just keep an eye on charging voltage. Converting to leak-free, fume-free devices will reduce battery box maintenance to zero as well (homebuilt aircraft don't use battery boxes; RG batteries may be operated in any position by simply strapping them down to the airframe."

Concorde always seems to have a rep. at IA renewal clinics. They've gone to a lot of work obtaining STCs to install their batteries in every aircraft under the sun and teaching A&Ps about the maintenance requirements of these sealed batteries. STC SA01118WI applies to the 170 series. See: http://www.concordebattery.com/ While it is not specifically STCed for the 170, Gill's sealed battery is on the FAA-PMA Eligible Installation list. http://www.gillbatteries.com/battery_pdf/pma.pdf . Correct me if I'm wrong but I don't think an STC or field approval is necessary for the Gill G-25S.

Gary wrote:Correct me if I'm wrong but I don't think an STC or field approval is necessary for the Gill G-25S.

Gary, that's the way I read it. The 170 is on the FAA-PMA list and it states on their site:

Installations NOT shown on D.O.T. FAA/PMA listings will require field approval using FAA form 337 or FAA approved STC.

n2582d wrote: ...Bob Nuckolls sings the praises of the RG battery, ... (homebuilt aircraft don't use battery boxes; RG batteries may be operated in any position by simply strapping them down to the airframe."...

That's not exactly apples to apples, tho'. Homebuilts don't meet a LOT of requirements of certificated aircraft. They can use lawn-tractor batteries from Pep Boys! (of course I hear there's a 170 in California that does as well.)

That's not exactly apples to apples, tho'. Homebuilts don't meet a LOT of requirements of certificated aircraft. They can use lawn-tractor batteries from Pep Boys! (of course I hear there's a 170 in California that does as well.)

Years ago I annualled a J-3 that had a field approval for a motorcycle battery. Might be a little tough getting that sort of approval these days.

Nah George, I figure that by the time I get my kids through college (and have money for my C-170 project) battery technology will have advanced so far that I'll be able to put a LiPo (Lithium Polymer) battery in place of the G-25 and have it drive a 180 h.p. electric motor in place of the O-300 http://www.plantraco.com/hobbies/product-lpcells.html

Either that or maybe Zoche http://www.zoche.de/ will get his act together and I can make a mini C-195 diesel out of the 170. As long as I'm dreaming, might as well power it with recycled veggie oil. My brother Ken recently went across the country in a Jetta diesel he converted to burn the stuff. http://courses.fresno.edu/ken.martens.f ... 0Today.mov

I better quit. The FAA might read this and pull my medical.