Page 2 of 4 FirstFirst 1234 LastLast
Results 11 to 20 of 33

Thread: Best battery replacement advice from Cubcrafters?

  1. #11
    Senior Member
    Join Date
    Jan 2010
    Location
    Palm Beach, FL
    Posts
    205

    Default Re: Best battery replacement advice from Cubcrafters?

    Its the X2 Power Extreme X2-14 and is widely available at Batterie plus either local store chain or online is $95 and exact same dimensions as original battery so fits pefectly. Here is a link http://www.batteriesplus.com/product...nt-X2--14.aspx

  2. #12
    Senior Member Dan L's Avatar
    Join Date
    Jul 2010
    Location
    Montana
    Posts
    766

    Default Re: Best battery replacement advice from Cubcrafters?

    Thanks much. I've got one coming and as a bonus it looks like it is about 3 1/2 pounds lighter than the Power Sport battery too.

    Hopefully the terminals are in the identical position as I don't have much wire wiggle room.
    Flying Carbon Cub EX #11 since 2011

  3. #13
    Senior Member randylervold's Avatar
    Join Date
    Jan 2010
    Location
    Yakima, WA
    Posts
    1,378

    Default Re: Best battery replacement advice from Cubcrafters?

    Good discussion, and thanks to all of you who are trying different batteries and reporting your experience. As Pete indicated we have been evaluating the Shorai Power LFX 18 LiFe (lithium iron phosphate) for nearly a year now. We are VERY attracted to the weight savings which is over 5 lbs, in our world that is very significant, as well as the apparent improvement in starting performance.

    On our company planes they have worked perfectly, both saving weight and in improved starting performance. Sounds like both Gary and Royce have not found them suitable however, I have no explanation for that. Our original Carbon Cub SS, N155PC, failed to start on me twice while hot over the years and stranded me when my attempts at hand propping then failed. It got so bad that when taking that plane cross country by myself I started carrying a little rechargeable jumper battery Pete bought for the shop. I can hand prop a CC340 by myself maybe 40% of the time, the other 60% I am stranded. Since installing the LiFe it has always started perfectly cold or hot to the point that I no longer carry the jumper when taking trips in it.

    Bottom line: we would have already switched to it if we could find better test data on failure modes. As the aircraft manufacturer we simply can't have batteries exploding under the pilot's butt and we can't find enough empirical test data yet to have that level of confidence. Performancewise we are convinced, Gary and Royce's experience notwithstanding.

    All that said, let's look at the big picture. In the interest of saving weight, and since batteries are notoriously heavy (most of them contain LEAD for heaven's sake!) and therefore an opportunity to save some easy weight, we are using the smallest battery we can to get the job done. Starting a 340 cubic inch engine with a motorcycle battery pushes these powersports batteries to their limit. For several aircraft we switched to an AGM battery and found out it wasn't up to the task so we replaced them all and went back to the sealed lead acid. Because of the strain we put these batteries under their life is shortened. Personally, I recommend replacing your main battery every other year at annual regardless of how it is performing just because of the stress they are under.

    Things you can do to improve starting performance
    Let's look at some things you can do to optimize starting performance. Since our starting systems need every fraction of an amp our batteries can deliver we need to make sure the current makes its way as efficiently as possible to the starter. To accomplish this go to any auto parts store and get some dielectric grease, here is an example. Then find yourself a maroon Scotchbrite pad which can be found in the aviation department of Home Depot. Now, wait for a Saturday when it is IFR and you can't fly and spend the rest of the day in the hangar. Starting from the battery, dissasemble each connection in the fat wires, both positive and negative, from the battery to the starter. Take a scotchbrite pad and buff the mating surfaces so there is no corrosion or contaminates, just fresh metal, and smear a very small amount of dielectric grease on the mating surfaces. Reattach the connection with the appropriate torque. This is like a chain, if you miss one connection (link) your path is still weak. Remember to include both the positive path all the way to the starter and the negative path all the way to ground. Don't forget the starter ground and the engine ground strap. Now you have optimized the electrical path and will get nearly 100% of the available battery current with minimal loss. Gary, you live in a moist environment, you might have the most to gain from this drill.

    Hope this helps shed some additional light on the issue, and we will keep everyone posted in our quest for improved battery performance, we appreciate you doing the same.
    Randy Lervold

  4. #14
    Senior Member turbopilot's Avatar
    Join Date
    Feb 2010
    Location
    La Quinta, CA
    Posts
    536

    Default Re: Best battery replacement advice from Cubcrafters?

    Quote Originally Posted by randylervold View Post
    Our original Carbon Cub SS, N155PC, failed to start on me twice while hot over the years and stranded me when my attempts at hand propping then failed. It got so bad that when taking that plane cross country by myself I started carrying a little rechargeable jumper battery Pete bought for the shop. I can hand prop a CC340 by myself maybe 40% of the time, the other 60% I am stranded. Since installing the LiFe it has always started perfectly cold or hot to the point that I no longer carry the jumper when using it when taking trips in it.

    Bottom line: we would have already switched to it if we could find better test data on failure modes. As the aircraft .
    Great write up. I have not had a hot start problem. What is the theory on this. Is this because it takes more cranking time when hot or is something else going on? Given hot oil it would seem a hot start should be easier than a cold start on the battery.
    Bob Anderson, CC11-00435, N94RA

  5. #15
    Senior Member randylervold's Avatar
    Join Date
    Jan 2010
    Location
    Yakima, WA
    Posts
    1,378

    Default Re: Best battery replacement advice from Cubcrafters?

    Quote Originally Posted by turbopilot View Post
    I have not had a hot start problem. What is the theory on this. Is this because it takes more cranking time when hot or is something else going on? Given hot oil it would seem a hot start should be easier than a cold start on the battery.
    My theory is that compression is higher when the engine is hot because the piston has expanded and tolerances go down. When cold there is blow-by which is one of the things that pollutes your oil. When doing compression checks at annual a warm/hot engine will always yield higher compression numbers than when cold.
    Randy Lervold

  6. #16
    Senior Member turbopilot's Avatar
    Join Date
    Feb 2010
    Location
    La Quinta, CA
    Posts
    536

    Default Re: Best battery replacement advice from Cubcrafters?

    I wonder about the gauge of the wire running from the + battery lug to the starter. Might it help to run another smaller wire parallel from the + battery to the starter?
    Bob Anderson, CC11-00435, N94RA

  7. #17
    Senior Member randylervold's Avatar
    Join Date
    Jan 2010
    Location
    Yakima, WA
    Posts
    1,378

    Default Re: Best battery replacement advice from Cubcrafters?

    Quote Originally Posted by turbopilot View Post
    I wonder about the gauge of the wire running from the + battery lug to the starter. Might it help to run another smaller wire parallel from the + battery to the starter?
    I don't think I'd run another wire, but a heavier gauge wire would have less resistance and pass the current better. But it would also be HEAVIER... light is right!
    Randy Lervold

  8. #18
    Senior Member
    Join Date
    Feb 2010
    Location
    Indianapolis
    Posts
    283

    Question Re: Best battery replacement advice from Cubcrafters?

    Increasing the starter wire gauge is an interesting Idea.
    Does anyone at CubCrafters know how much current the starter on a CC draws? Has it been measured?
    I would guess 200-250 amps.
    What is the starter wire size and how long is it?
    I can calculate the voltage drop if I know the amp draw and the wire size and length and the improvement with a larger wire size.
    I know lighter is better but getting stranded in some remote location is not acceptable.

    Carbon Cubs are for going places no other airplane can go and getting back.
    I would much rather carry a few grams more wire than a backup jumper battery.
    Until we have a better battery technology a larger wire size might be helpful.
    Bill

  9. #19
    Senior Member turbopilot's Avatar
    Join Date
    Feb 2010
    Location
    La Quinta, CA
    Posts
    536

    Default Re: Best battery replacement advice from Cubcrafters?

    Quote Originally Posted by seastar View Post
    Carbon Cubs are for going places no other airplane can go and getting back.
    Agree. Moving the battery to the firewall would decrease the cable run which is another solution to decrease resistance without additional weight. I never really liked the idea of sitting on the battery. There would be a CG issue, however. CG is all ready far forward single pilot.
    Bob Anderson, CC11-00435, N94RA

  10. #20
    Senior Member
    Join Date
    Feb 2010
    Location
    Indianapolis
    Posts
    283

    Default Re: Best battery replacement advice from Cubcrafters?

    Here is a website that orovides some guidance---
    http://www.skytecair.com/Wire.htm
    Bill

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •