ALERT: Gear-up light comes on with doors open!

[Ernie Martin]

I "recondition" the battery every 6 - 9 months by adding distilled water and trickle charging at a constant 28.4 Volts. For the first 2 - 3 months after that, the gear breaker never pops. It also never pops if the aircraft is used regularly, even if reconditioning hasn't been done for a while. And it never pops at the end of a flight. In short, it pops only on retraction on the first flight after the aircraft has been unused for weeks and if the battery has not had reconditioning for a while. So, yes, I think it's the battery.

Ernie

[edasmus]

For Christmas I just received two "smart" aviation battery minders designed specifically for the the Gill batteries I use (12 volt in a PA24 Comanche that I also fly and 24 volt for my C337). I purchased them from batteryminders.com, MODEL: BatteryMINDer 24041-AA-S2 for our C337's using Gill batteries. They have other models specifically for the battery you use so read the fine print if using Concord or other sealed batteries. One should be able to find what they need for whatever battery they prefer to use. These units are designed to charge and then maintain the battery and should be left on continuously when not flying the aircraft. They contain a microprocessor and provide the battery with exactly what it needs to stay properly charged (this is the claim anyway). The units were $200 and if they double the life of the battery (which sounds likely), they would pay for themselves easily. More importantly however is flying with the confidence that the battery is as it should be and starting performance would be top notch.

I hope they work as advertised. Mike Busch speaks high of these units as well if any of you folks agree with what he preaches.

Good Luck,

Ed

[Ernie Martin]

Thanks, Ed, but I tie down on the ramp, far from any outlet.

Ernie

[edasmus]

The batteryMINDer folks do not permit these units being exposed to the elements however it's probably less than 10 minutes to remove battery and take it home and then reinstall on preflight. An inconvenience for sure but not completely out of the question especially if you know the airplane is likely to sit idle for a month.

Just a thought.

Ed

[louis@52f]

Ernie
I had a similar problem on my '69 T337 some years back. I have these comments relating to this;
1. On my a/c, the gear up light indicates only that the up position switches, which are in series, are all closed. The position of the doors is not part of that circuit, so with certain failures, the doors could be open in either the up and locked or down and locked condition. The gear position light SHOULD reflect the door are closed, but not with a failure of various types.
2. I'm no electrical engineer, but I can't imagine a weak battery is the source of your problem. If the charging system can not charge the battery and supply full aircraft electric load, thus allowing the system voltage to drop too low, this might lead to your gear door problem. However, then you have in my opinion a bigger problem, weak charging system and weak battery, not a good combination.
3. I found my problem was a high resistance in a wire terminal on one of the up position switches. The up light would come on, but the current was not enough to keep the door solenoid closed. (Engine driven hydraulic pumps, but I think the door control on yours is similar.) The gear would come up and lock, doors would close, then open, maybe close again, but then open and stay open. I replaced all the wire terminals in the gear position indicator circuits, never had another similar problem.

Lou