Starting performance with the CC340

[randylervold]

About the batteries in CubCrafters CC11 family aircraft (Carbon Cub and Sport Cub)
In the interest of saving weight, and since batteries are notoriously heavy (most of them contain LEAD for heaven's sake!), batteries are an opportunity to save some easy weight. In our quest for light weight we are therefore using the smallest battery we can to get the job done -- a motorcycle battery. Starting a 340 cubic inch engine with a motorcycle battery pushes these powersports batteries to their limit. For a short time 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.

In our quest for both improved starting performance and weight reduction we have been evaluating the Shorai Power LFX18 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. 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. 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. A couple of our owners have also tried them and not had good luck, I have no explanation for that.

Bottom line: we would have already switched to LiFe 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, some contrary owner experience notwithstanding, and we are continuing research in this area.

Things you can do to improve starting performance
If you are experiencing difficult starts, hot or cold, there are 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.

[carlconti]

Have you considered the Shorai LFX21A6-BS12? It's only about one pound heavier an they list at at 315 CCA. Looks like it will also fit.

[t.c.williams]

I posted the other day about the Aerovoltz 12 cell Lithium ferrous battery. Weight is 2.5 lbs. 410 CCA. It will fit in the CC. A friend has it in his PA 12 and says it turns it over twice as fast. How about it.

[glickle]

Several members of this forum have been privately emailing me asking where this post is and it was under another section regarding Life04 batterys so I am reposting here: Its now July and the Aerolithium Battery has worked well for me, no issues since I installed it in April.

Here is the post from April :



Hi All, I spent some time with Andy of Aerolithium Batteries at Sun & Fun. ( www.aerolithium.com check it ut as there are you tube videos of some comparison motors/batteries) He says he has been developing electric cars for 6 years which led to his building these batteries: Here is what I found out about his batteries.

First and most important he states and also on his website his batteries are lithium IRON "high rate" cells not lithium ION.
He had split open three manufacturers batteries on display the Shorai, the Aerovolts and his. I must confess to my eye, the Shorai looked very cheesy as to the guts but looks great on the outside for finish, Andy claimed their flat cells are not high rate cells like his which are more costly. ( I treid 2 Shorai batteries one failed immediatley and shorted out the other was not as powwerful as the Extreme x2-14 so I sent it back.) Aerolithium batteries look just the opposite. The insides look more subsatntial but his case looks ameturerish.

Andy loaned me a 330 amp 2.5 lb battery to try on my CC and unfortunatley the power of that battery was about the same as the X2-14 Extreme Battery I have been using, so I took a pass. That said Andy was very accomodative and he was not giving up. I noticed the 330 amp battery was so small ( about half the size of ours) that there was plenty of room for a larger one. I gave Andy the measurements of our battery box and he then built a 16 cell 430 AMP 3.8 lb battery and sent one to me to test and ............................... IT WORKS! Much faster turn over and good starts when hot. I have stopped and started the hot engine 4 times in a row and still plenty of power . I only have a few hours and starts on it but will report what I find over the longer term.

Also here is some info regarding Lithium Batteries that I learned at the show from a few dealers:

1) Its critical that they not go below 12 Volts ( like leaving the master on or playing with your avionics without the engine) If they do drop below 12V then you need a special balancing charger to get them going again properly. If you run the lithium battery totally down it may not come back at all. A regular charger or letting the alternator do the job will probably ruin the battery. It makes a case for having a spare lithium with you just in case as the shelf life is well over a year without charging and they are so light weight just swap it out ( only draw back here is the cost as they are much more expensive that the lead acid, about 2.5x )

2) You can buy a cut off switch for those who are in the habit of leaving their masters on which will disconnect the battery if voltage goes below 12V in order to save it

3) Unless in an emergency you should never jump start a lithium battery as having all that amperage from the alternator hit the battery without a balanced charge will probably destroy the battery.

I suspect others on this forum know more about this and batteries in general and I am not endorsing or representing anything here other than passing on what I learned from three lithium reps ( Shorai, Aircraft Spruce re the Aero Volts and Aerolithium) while at the show. Clearly this line of batteies is developing quickly so would love to hear from anyone who knows more about these batteries and the technology. Best Gary

Here is a link to more than you might want to knwo about Lithium ION vs Lithium IRON http://en.wikipedia.org/wiki/Lithium...sphate_battery


Later answer to Pete Dougherty question about the various designs:


Hi Pete yes, the Shorai was flat plates and the Aerovoltz cylinders similar to the Aero Lithium, but was told the Aerovoltz are using non high rate cells. I have no verification of the high rate vs lower rate cells though. Below also is a chart and commentary from a website on Lithium Batterys ad the differences and Aerolithium says his are Lifepo4 Hope this helps Gary



Lithium iron phosphate cells have the best safety characteristics—long cycle life (up to 2000 cycles) and good availability. They are very suitable for high discharge rate occasions such as EV (including e-bike, electric scooter, and electric car), power tools, UPS and solar energy system.

COMPARISON DATA AMONG VARIOUS LITHIUM BASE BATTERIES:

Battery	LiFePO4	LiCoO2	LiMn2O4	Li(NiCo)O2
Safety	Safest	Not Stable	Acceptable	Not Stable
Environmental Concern	Most Enviro-friendly	Very Dangerous		Very Dangerous
Cycle Life	Best/ Excellent	Acceptable	Acceptable	Acceptable
Power/Weight Density	Acceptable	Good	Acceptable	Best
Long Term Cost	Most Economic/ Excellent	High	Acceptable	High
Temperature Range	Excellent (-20C to 70C)	Decay Beyond (-20C to 55C)	Decay Extremely Fast over 50 C	-20C to 55C

[glickle]

As a follow up I noted that Andy from Aerolithium is presenting at KOSH next week Thursday regarding Lithium Batteries. If anyone is there can attend and report back on the forum what thyelearn might help all of us. Best Gary

7/26/2012 - 1:00 PM - 2:15 PM - Forum Pavilion 06 JP Instruments - Map
Lithium Batteries as Replacement for SLA in Starti - Describing the benefits of Lithium batterieies over lead acid. Answering questions all pilots have about all the misinformation they have heard. Information on the different types of lithium batteries and the cell specs.
Presented by: Andy Reich

[Scott c]

Can I get some comments on the success of hand proping the CC? Can they be hand proped easily?

[Pete D]

Can I get some comments on the success of hand proping the CC? Can they be hand proped easily?

I have seen it done. I have tried it several times with out success. With the thin composite prop and the electronic ignition combined with the high compression it isn't a very good idea. When (if) it fires off it fires a lot harder than with magnetos. It is easy for it to kick back if it does fire. Also, because of the electronic ignition you need battery juice to power the electronic ignition boxes.

The other thing to think about is the battery-if it is low enough to hand prop and you are able to get it started then the alternator will be pumping a lot of amps into the battery trying to charge it up, potentially damaging the battery and setting yourself up for problems later. A low battery should be charged up on a 1 or 2 amp charger, not 20-30 amps the alternator potentially could be pushing to it.

In short, not recommended.

[Scott c]

I have seen it done. I have tried it several times with out success. With the thin composite prop and the electronic ignition combined with the high compression it isn't a very good idea. When (if) it fires off it fires a lot harder than with magnetos. It is easy for it to kick back if it does fire. Also, because of the electronic ignition you need battery juice to power the electronic ignition boxes.

The other thing to think about is the battery-if it is low enough to hand prop and you are able to get it started then the alternator will be pumping a lot of amps into the battery trying to charge it up, potentially damaging the battery and setting yourself up for problems later. A low battery should be charged up on a 1 or 2 amp charger, not 20-30 amps the alternator potentially could be pushing to it.

In short, not recommended.

Thanks for the comments Pete. So what is the answer? Mine is a Canadian EX so I have some flexibility with weight. Is there a bigger battery that I can put in or am I concerned about nothing? I am having a electric blanket installed on the battery. Is a tender recommended?

[Pete D]

The newer aircraft from the 2012 model year change and on have a Hartzel starter that turns over much better than the older aircraft with the Skytec starter. If you have new new style cowling it will have a small bump in it to clear the Hartzel starter. Older aircraft can be retrofitted but need a bump added to the cowling there. Somewhere on the forum was someone selling the bump as a pre-made screw on part.

If you leave something on and end up with a dead battery I would say swap in a charged battery. They are pretty cheap, would be pretty easy to keep one handy in the shop or hanger.

The newer seat bases and older ones with a retrofit kit can take up to an Odyssey sized battery. It is the heaviest option however. Even with the big battery the older aircraft with the Skytec starter don't turn over as well as a newer plane with the smaller battery and the Hartzel starter.

[Scott c]

The newer aircraft from the 2012 model year change and on have a Hartzel starter that turns over much better than the older aircraft with the Skytec starter. If you have new new style cowling it will have a small bump in it to clear the Hartzel starter. Older aircraft can be retrofitted but need a bump added to the cowling there. Somewhere on the forum was someone selling the bump as a pre-made screw on part.

If you leave something on and end up with a dead battery I would say swap in a charged battery. They are pretty cheap, would be pretty easy to keep one handy in the shop or hanger.

The newer seat bases and older ones with a retrofit kit can take up to an Odyssey sized battery. It is the heaviest option however. Even with the big battery the older aircraft with the Skytec starter don't turn over as well as a newer plane with the smaller battery and the Hartzel starter.

Thank you Pete