RV-9A on diet

PerfTech · #1 01-21-2014, 02:05 PM

.... I just shed 25.5 lbs. in my 9A in one quick move! I removed the Odyssey 925 battery that is 26 lbs, 28 amp hr, 330 CCA. This battery is the equivalent of two 680 Odyssey's. I replaced this with one SHORAI LFX Lithium-Iron Powersports battery, 36Ah, 540 CCA, 12V that weighs in at a whopping 4.9 lbs. With the cables and battery box mods we did we saved over 25 lbs. This new battery actually starts or cranks the engine faster than the over-kill 925 ever did. I am happy with this so far (35 hrs) and will keep you informed if things should change. Thanks, Allan...

bret · #2 01-21-2014, 04:32 PM

Currious, do these self discharge over time, like 30 days or so, and is the resting voltage higher than 12.6 V I remember reading somewhere about trickle chargers kicking out with the higher voltage? All that said, I do like the light weight!

Bevan · #3 01-21-2014, 07:19 PM

Quite the opposite. These LiFePo bateries hold a charge for a very long time (think 1 year) with non-use compared to a Pb battery. The possible negatives that I see are that they don't work as well in extreme cold weather (but there is a work-around for that) and, they require a balancing charger once in a while to maximize charge to all the cells. I suppose another negative is determining when they are getting discharged as they hold voltage very well right to the end then drop off sharply. Also initial cost is quite a bit more, and ratings are a little tricky to understand. But there isn't a less costly and simpler way to lose 12 lbs on an RVx with a PC680 battery.

Bevan

ChiefPilot · #4 01-21-2014, 07:59 PM

Quote:

Originally Posted by Bevan

Quite the opposite. These LiFePo bateries hold a charge for a very long time (think 1 year) with non-use compared to a Pb battery. The possible negatives that I see are that they don't work as well in extreme cold weather (but there is a work-around for that) and, they require a balancing charger once in a while to maximize charge to all the cells.

I've had mine in -5? F weather and it still started the IO-360 like a champ. Full details of my installation here.

N941WR · #5 01-21-2014, 08:29 PM

Now, if you really wanted to put your -9A on a diet, you would turn it into a Tailwheel tip-up. The only problem there is you kind of hurt your marketing tool.

Steve Melton · #6 01-22-2014, 05:55 AM

that's a huge weight reduction per dollar. I'm beginning to think lead doesn't belong in aircraft. my concorde battery weight = 26 lb. I can add a micro turbine for this weight reduction.