Oh, man, I sure wouldn't move that battery aft. The battery on the firewall ensures that your battery is always warm in cold weather, so you preheat only the engine compartment.

With cables long enough to reach aft, you gain a good five to ten pounds of unnecessary weight, and you lose probably 20 to 30 % or more of your cranking power to cable loss.

These airplanes load aft. Putting weight back there means your CG will start out aft. You will always be fighting to stay forward. A forward airplane is always better than an aft one.

I have an Odyssey 680 battery in the stock box on the firewall. Ten pounds lighter than the Gill or other "standard" battery. NEver a problem, and it's worked great for years.

Consider this: There are STC'd conversions for the Cessna 180, 185, the Beaver, and probably a half dozen other airplanes to move the battery from back aft to the firewall. I've never heard of an stc to move one from the firewall to the aft baggage.

Wonder why?

MTV

Lance,

If you are interested in the Odyssey 680 battery, and can get it approved in your area, there are several outfits who sell very nice and very compact brackets for that battery, that fit nicely on the firewall almost anywhere on a 170. I simply put mine in the stock box, because there wasn't any of this stuff around then, but now, I'd consider one of the brackets. Atlee Dodge in Anchorage makes a very nice one.

Taking ten pounds off the weight of these planes by installing a better battery is a good deal, in my opinion. Helps offset the 10 pound harmonic damper for the 80 inch prop.

MTV

Hey Jr,

Keep the posts and pics coming. I love to see/hear how others go about the process.

Our battery is aft of the baggage area. We also did the extended baggage kit. The battery box is just barely below the floorboard of the Selkirk metal kit and did not interfere with the extended baggage kit at all. In fact we got rid of the fiberglass battery cover and built a hinged aluminum access hatch right over the top of it. Works great.

You're right about removing the rear seat... It really helps. With the stock rear seat installed, we are right at the forward CG limit with two 170# people up front and no fuel on board. We haven't had any major loading/CG issues, as you aren't supposed to put more than 50# in the extended area anyway.

I haven't experienced any starting problems in cold weather yet. My hangar is not heated, and my battery cranks with authority on 20F mornings. (Granted, I am not operating in AK, but neither are you!) My Concord battery is 4 years old. Knock on wood!

Our conversion is the Franklin 220, but I have a million pics of our conversion process if any specific areas would help. Lemme know...

Matt

Congratulations on getting it airborne!! I'm sure that first flight was like Christmas and seven or eight birthdays all wrapped up in one.

Once you get some time on that engine, try running it oversquare for the ultimate in cruise performance and economy. Try running 1900 rpm and 21 inches or 185 and 21. You'll get the fuel flows down even more and speed may actually pick up a bit. Don't do this till the engine is fully broken in though, since Lycoming recommends high power settings for break in, and this is apretty low power setting.

Again, congratulations, it sounds like you done good.

MTV