Battery question

[Dream to fly]

Finishing the plane and was doing gear extension/retract test and the battery which is 5 years old is starting to show signs of age.  Instead of tempting fate I am going to replace it.  Is the Concorde 35AXC or 35A the replacement battery of choice? 

[RLCarter]

I like maintenance free, acid seepage and aluminum don't mix

[Vance Harral]

As a fellow M20F owner, I'd suggest there's little reason to pay the extra cost and weight penalty for the 35AXC.  We've been running the 35A model for over a decade with zero problems.  First one lasted 8.5 years and was still "usable" when we replaced it, just starting to show very early signs of reduced total capacity.  Bought another which has been running strong for 3.5 years.  Aircraft lives in Colorado, near Denver, and sees occasional days above 100 and below 0.  We don't use a battery minder or anything similar.  We do fly frequently, but the airplane occasionally sits for several weeks, and has always fired right up.  Finally, some people report having to modify the top of the battery box to fit a Concorde battery, but we didn't need to do so for the 35A.

Based on my experience, the extra cold-cranking capacity of the AXC is irrelevant for an IO-360-AIA engine.  The AXC does give you 17% more total capacity, which theoretically gives you 17% more time with electrical power if your alternator gives up the ghost.  But the scenarios where that would matter are pretty far into the corner cases.

 

[N6758N]

29 minutes ago, Vance Harral said:

As a fellow M20F owner, I'd suggest there's little reason to pay the extra cost and weight penalty for the 35AXC.  We've been running the 35A model for over a decade with zero problems.  First one lasted 8.5 years and was still "usable" when we replaced it, just starting to show very early signs of reduced total capacity.  Bought another which has been running strong for 3.5 years.  Aircraft lives in Colorado, near Denver, and sees occasional days above 100 and below 0.  We don't use a battery minder or anything similar.  We do fly frequently, but the airplane occasionally sits for several weeks, and has always fired right up.  Finally, some people report having to modify the top of the battery box to fit a Concorde battery, but we didn't need to do so for the 35A.

Based on my experience, the extra cold-cranking capacity of the AXC is irrelevant for an IO-360-AIA engine.  The AXC does give you 17% more total capacity, which theoretically gives you 17% more time with electrical power if your alternator gives up the ghost.  But the scenarios where that would matter are pretty far into the corner cases.

 

Agreed, the 35A is more than enough to handle any short body demands. 

[Raptor05121]

I bought the AXC simply because SnF show specials had it for cheaper than the 35A retails normally.

As long as you go Concorde, you'll be okay.

[M20F]

I have an AXC.  The weight is minimal and aft CG makes you go fast.  The real reason though is you can never have a big enough battery or too much gas. 

[Raptor05121]

Some of us get nose CG

[M20F]

4 minutes ago, Raptor05121 said:

Some of us get nose CG

I don't count letters less then F :-)