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Battery Decision

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drone_pilot

Well Known Member
Hello All,

I know there is a lot of talk on battery technologies out there. I'm still confused about it all.

I am at the point where I need to select the battery arrangement for my 7A. I've got an IO-360 Angle Valve engine but will be swinging the new Catto 3 bladed propellor. Going all Dynon Skyview in the panel. I'm also going with the B&C 60 Amp Alternator and LR3C (?) external regulator.

If you were me, would you continue to move on with the Odyssey PC680 battery or would you go LiFePo? Are there any electrical changes or considerations that I would need to make if I went to the LiFePo?

I'm already expecting to be light on the nose of the airplane so I'm also wondering how the CG would be affected with a light weight battery.

Your opinions are appreciated!!!
 
PC680

I researched this quite thoroughly for my RV-9A and decided to go with the Odyssey PC680. In my opinion other battery chemistries are not yet ready for small aircraft use. Even Boeing got in (and may still be in) a lot of trouble with lithium based batteries. They essentially had to build a fireproof structure around the batteries to contain any explosions or fires. I wonder if after doing that whether there was a net weight saving.
 
Another vote for the PC680... it's a proven battery technology. My personal opinion is that lithium batteries are still a bit too risky to use in close proximity to fuel tanks, valves, lines, etc, in a small single-engine aircraft.
 
I like the PC680 a lot, and in fact, their weight is perfect for the CG in a couple of our airplanes, so as much as have wanted to try a LiFePo, I haven't made the move becasue it woudl screw up the balance.

The problem with these discussions (and I know most will ignore this, and the thread will go for many pages) is that saying "Lithium" is like saying "Fruit". There are many different types of Lithium-based batteries, and they have radically different properties. Boeing did not get into trouble with LiFePo (if I recall correctly), it was ANOTHER Lithium technology. So if you are going to talk about these batteries, you need to be very specific, and not lump them all together. Or....you're just talking apples and oranges. And that's just noise.

I know of a number of builders/pilots who are flying LiFePo batteries quite successfully and have not had a lick of trouble BTW.
 
If weight is not a problem (I need the weight on my -6) consider the PowerSonic PS-12350.
It's a 35 AH sealed lead acid battery that costs in the neighborhood of $80 and mine have typically lasted between 4 and 7 years. Been using this model since 1993 and have been very happy with it.
 
drone_pilot said:
Hello All,

I'm already expecting to be light on the nose of the airplane so I'm also wondering how the CG would be affected with a light weight battery.

Your opinions are appreciated!!!
Click to expand...

I don't think you're going to be light on the nose with that angle valve up front :eek:
 
I agree with Paul. "Lithium" isn't enough of a descriptor to make a decision or offer advice. LiFePo is the current formulation of Lithium that has promise. It probably needs to have REAL "balancing" charge circuitry built into the battery assembly for the aircraft application. If you're concerned about thermal runaway (fire), do a search on Youtube and you will see all kinds of abuse such as dead shorts, axe chopping, stabbing, skewering, burning, shooting with a shot gun etc. Sometimes you get a little smoke but that's about it. People are trying to get dramatic results but fail everytime. Almost looks like they are all using dead battery cells.

Bevan
 
I replaced my 680 with two EarthX EXT36C's. I also had a 9AH sealed battery for my backup that weighed about 5 lbs. My 680 weighed 17 lbs or so and together my two EarthX's weigh in at 7.5 lbs. They spin my ECI Stroker 370 noticably faster than the 680 did for start.

I'm using my normal alternator setup to charge both, one is thru a diode for the standby bus. I have a temp probe between the two batteries to alert me of any heat issues.

I know there are a lot of folks that wouldn't touch these, but there are a lot of us using them successfully.

I had an angle valve on the front of my 8 before i got my ECI engine and I don't think you are going to have to worry about a light nose.

Your mileage may vary, but I'm happy with my setup and I doubled my battery capacity and saved 15lbs of weight.
 
Walt said:
I don't think you're going to be light on the nose with that angle valve up front :eek:
Click to expand...

I agree with Walt. If you have a C/S prop with that, you will likely bust the max nose gear load limit. Think ahead and mount stuff in the tail.

my vote is PC680. Not ready to power my chariot with fruit. :)
 
Boeing 787 Lithium Ion Batteries

Yes, Paul is right, Boeing uses lithium ion batteries in the 787. And here's how to fight the fire if the battery has an "event".

http://www.boeing.com/assets/pdf/commercial/airports/faqs/787batteryprocedures.pdf

Of course LiFePo is a different chemistry and the characteristics are different. But I would have thought that Boeing considered all alternatives to batteries when they designed the 787 and chose the lightest and safest one available.

When a battery has to have an internal electronics sensor/circuit to prevent overvoltage/thermal runaway "events" (read explosion/fire) they are too complex for my airplane.
 
PC680

I had 200hp IO-360 in my Starduster Too. The PC680 spun the prop well. Even my injected engine, which was sometimes hard to start wouldn't kill the Odyssey PC680. I'll be putting one in my RV-4 when the Excide goes bad.
 
Decision Made!!

Thanks for everyone's input! This forum is an awesome source of information.

I just wanted to make sure that I wasn't overlooking something that I needed to consider. If you go back six years or so in the posts, its amazing to see how much aviation technology in general has changed in that amount of time. I am sure that the Lithium type batteries will be in the mainstream of aviation at some point in the near future.

So here is my thought process.

1) The PC680 is an older but proven technology and appears to be in the vast majority of RV's. Lithium is still a newer technology and there may be more revisions before the technology in aviation is considered mature.

2) This is my first home built project (hopefully not the last) and there is more that I don't know than what I do know. When considering Lithium batteries, I would like more confidence in knowing how things are affected, like safety, weight & balance, and electrical/mechanical modifications. This spells more delays in completing my project.

3) The Lithium batteries have a "cool" factor but appear to be at least double the cost of the PC680 and the lightweight of Lithium batteries seems to be the biggest selling point. If I can save about 10lbs of weight with a Lithium battery, it would be more advantageous to me to lose at least that much from my waist line. :eek:)

4) Saving space on the firewall would be nice but.........the PC680 has a home under many cowlings.

5) I live in a very warm climate, so my cold starts would be more of a cool start for the majority of my friends up North. The PC680 seems to have enough cranking Amps for the majority of my starts.

6) I'm using Dynon backup batteries on my SkyView displays (mainly to prevent them from rebooting during engine starts) which will buy an hours worth of instruments in the case of an electrical failure. My handheld radio should cover the Coms. At that, I'd still have to lose my main battery and alternator/regulator.

7) After all of that I ask myself, "What does a Lithium battery buy me for double the cost?" All that I can come up with is about 10lbs. While important, I've already removed a lot of weight in prop governors/CS Props and going with the Catto.

Decision: PC680 for now and I can always modify later as I get more familiar with my airplane. Thanks everyone!
 
I am watching the various lithium developments with interest, but won't decide until my existing PC-680 wears out. It has been perfect so far after 3 years / 180 hours and no special charging.

I don't think you will have a CG problem with your angle valve. I have a similar plane with lighter engine. (7-A, tip-up, painted, single Skyview, Catto prop, PC-680, and parallel valve IO-360). My CG is in the middle of the range for local cruising with a passenger, and at the rear of the allowable range with passenger, full baggage, and low fuel. (End of long cross country flight).

Jay
C-FXPT
 
I've been running a Lithium nanaphosphate battery on my Pitts Special for 2 1/2 years now.

In my opinion its the cheapest way there is to get weight off an aeroplane (or address CG problems) ..... apart from eating salad maybe :D

By my calculation it saved 14.1 lb over the PC680 it replaced.

It has worked perfectly, but it's not without some issues - mainly voltage drop and not firing pmags when cranking.

Here's the thread I started when I first fitted it - there's been lots of discussion

My final comment is that I've fitted a PC680 to my new RV, but I'd still go with the lithium for an acro machine (where weight is more critical)

http://www.biplaneforum.com/showthread.php?t=6119
 
I think dropping 10lbs for an extra $230 is a bargain compared to the price of the plane. And if you're willing to drop 10lbs of personal weight, there's 20lbs. :)
 
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