I have seen a few T303 owners on this group. Do you have any ideas what to use for a ships battery?

The airplane I have in the shop originally had the larger 28 amp hr Cessna battery but sizing has not really worked out to match up with an existing production manifold type mount sealed battery.

The battery box tray is about 8 1/2” X 10 1/2” The Concord RG24-20 is close but not manifold lid for hold down mounting or to connect to existing vents (not needed with sealed battery)

It did have a Gill 7243-15 which says T303 on the applicability list but it’s very small especially for IFR twin with air conditioning and electric hydraulic gear. The 7243-15 does not fit the factory tray or hold down bolt/stud which are for a much larger factory optional battery. P/N was a Cessna C614001-201 which does not show up on any cross reference lists.

T303 IPC calls out either of these batteries:

C614002-0102 (Gill G-243) 10 A/H @ C1

C614002-0201 (Gill G-247) 19 A/H @ C1

I'm getting the source of supply because I'm looking at the C614002 spec drawing.

SkyGeek claims to have 2x G-247 in stock, or more likely that they can source, for $773.32.

Note that the -0201 is only applicable to S/N T30300118 and on.

Sorry I forgot in the first post looking for a sealed battery. Similar size and mounting to the G-247. Interesting my parts book calls it a 28 amp hour battery but Gill uses a smaller rating.

This airplane is S/N T303-00301 and has the larger size battery tray. The smaller G-243 won’t work.

The old Cessna spec document lists the -0201 as a 28 AH battery at "5 Hour Rate." No one uses that specification for anything these days. That means it will yield 28 AH of capacity if discharged at such a low rate that it reaches EPV after 5 hours.

Typical spec is the C1 rate, which means for the -0201 it will reach end point Voltage after discharging it at 19 Amps for 1 Hour.

It might be possible to find a sealed battery that can be adapted to fit, but you would likely need a STC for it. Cessna out of production engineering isn't going to tackle that as long as the G-247 is still available.

Thanks Matt. Might be time to give the field approval process a try again. Maybe...