Thorp Air Command - T18.net

So I got bored yesterday and decided I was going to build my airplane's battery box out of material I had on hand. That included some angle and .090 sheet alclad. She weighs in at just under 10 lbs! Not sure what Im going to do with this monster now. Maybe a lunch box for giants, or a tiny tool box.

I have been operating with a deep cycle amg battery without a battery box for thirty-six years and 3000 hours and note no corrosion.

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Bob Highley
N711SH
SN 835
KLAL

I just went online and bought a premade lightweight battery box for my AGM and bolted it to the firewall . BADA BING , BADA BOOM

RB

What capacity AMG batteries are you fellas using. Was thinking of buying a EarthX lithium for a huge weight saving but $700.00 ouch!

well, I went back and used .025 instead of the .09 sheet, and I removed all the decorative angle. She weighs 2 lbs now. I can live with that. I thought about no battery box at all, but since I have this one made now, I may use it. Still undecided...

You do need something to hold the battery. Mine sits in a tray with a stainless strap over the top.

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Bob Highley
N711SH
SN 835
KLAL

I used the PC 680 for many years , but found that about the 2 year mark they would no longer hold hold a full charge ? I discovered the FULL THROTTLE P/N 230 AGM battery that replaces the PC 680 . The PC 680 states it has 170 CCA . The Full Throttle has 230 CCA for about the same price . I'll have to look , but I should be at about the 1 1/2 year mark with the FT 230 .

RB

Rich, you may want to check your charging system voltage. 14-14.2 volts is all that is wanted. The “book” range is 13.9-14.6 but this is a case where I have found less to be more. Some automotive trickle chargers put out more than that. My PC680 is 10 years old and has been discharged at least twice. I ordered a spare the time I left the switch on about 4 years ago. The spare sits on the shelf and gets used to start the Pawnee (O-540) to circulate the preservative oil from time to time.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

First thing that I did . Voltage right at 14-14.2 volts . Had the Odyssey PC 680 checked out at an Odyssey battery dealer . They found a bad cell or whatever you call the innards of an AGM battery . >:( The charger/maintainer is "specifically made" for Odyssey batteries ! The other thing that changed my mind was the fact that the Odyssey battery originally had 220 CCA on the battery , now it sez 170 CCA ? Coming up on the 2 year mark for the Full Throttle battery . We'll see how it works out !

RB

That looks like about 8 lbs of clecos.

About batteries: I also have the Odysey PC680 and it’s been great turning a Skytec starter on an O-320. Had it 5 years now going strong. Barely as well with the original Bendix starter. Box is .025” Alclad. Alternator is Denso automotive. Fully discharged The battery with a switch left on on once. My 10A automotive trickle charger couldn’t give it enough to get started again until I bumped it up with another heavy duty supply. After that the trickle charger did the job again. Maybe I should leave a maintenance charger on it but never do. I’ve had the plane sit for a month (shame on me) but it always starts right up by the 3rd turn.

Les Krumel
Albuquerque

That's funny Les, but true. I did weigh the first box with the clecos installed.

Rich, do you have anything drawing power with the master switch off (Radio memory, clock...)? Running the maintainer should keep that from being an issue but I am wondering if it was getting too long of a high amp charge from the alternator. I think yours is the first negative review I have seen of the PC680.

I don’t run a maintainer and I charge with a charger from NAPA or Walmart when needed but I have nothing drawing power when the master is off. Too soon to tell but I may have shortened the life of my battery by mounting it in the engine compartment. Batteries don’t like heat.

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Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

N18LK also has it on firewall. Still there 5 yrs... Les

27DW also has a PC 680 mounted on the firewall. I had noticed it was starting to get a little weak last summer but still started the engine without much trouble. After the engine was overhauled with higher compression pistons and the battery had set for a year with no maintenance it just wouldn’t do it anymore. When I replaced it much to my surprise the manufacture date of the battery was Sep 2010! Needless to say I think it had served it’s time!

Hello Fella's,

Bought a Full Throttle FT230 that Rich recommended for my T-18. Works fine, but I'm really interested in LiFePO4 batteries for their performance and light weight. For an experiment I bought a Antigravity YTX12-16 with 480 cranking amps and 3.4 lbs. a 1 volt higher resting voltage. Wow!!! This thing cranks over my O-320 way faster than the FT230. Did 4- 5 second cranks cold and still had a lot of battery left. The amp hours is lower than the FT230 of course, but its rated at 192 Watt hours so you should be able to pull 15 amps for an hour if needed. Putting N2WB on a diet losing 12.6 lbs. for under $200 bucks seems like a no brainer to me. Also this battery technology only loses 1% of charge per month without a parasitic draw verses up to 1% day with AGM technology. So no more battery tender i hope! Bought a LiFePO4 maintainer just in case. Yes! they are a different charger due to the voltage is a volt higher. Anyway- just thought I would share, and of course any input would be appreciated. I got a new FT230 battery for sale if interested $60.00 shipped to lower 48