Poor cranking - my problem resolved.

[quentas]

I have a J230 which is a stubborn machine to start in the cold and I am VERY interested in this battery. My only concern would be the lightness of this battery for CofG purposes as I think I need more weight in the front than the back. I have noticed it flies slower when loaded up with luggage in the back. I think it may have something to do with gettin`on the step` with less AoA. Do factory J230 aircraft have weight in the tail that can be compensated for by a lighter battery? (I know this is engineer territory)

 

P.S. a starter spray like `start yer barsard` does wonders first up on a cold day.

 

 

[Guest lithbattboss]

Quentas if you are concerned about the light weight of the battery there is a simple solution. So long as it is in your budget there is nothing to stop you from putting in the next size up in this battery range (SB1220-C). This battery weighs 4.2kg and has twice the cranking ability/power of the smaller one. Of course it is almost twice the size so this is a consideration also. But look at the benefits. A heavier battery with less CofG problems combined with unsurpassed cranking power to spin that prop on cold mornings! You will soon see the power of these batteries as it cranks that engine over and that prop turns on the starter motor like there is no tomowrrow.

 

This battery will ensure reliable starting for many years to come (of course assuming your engine and ignition components are in good working order).

 

 

[quentas]

Thanks for the info. Now the big question....How much? Even RRP for now will do for an idea.

 

 

[Guest Andys@coffs]

The Odyssey Battery that powers the J230 is the PC625. From the Odyssey website the specifications for that battery are as follows:-

 

PC 625 Specs:

 

• 625 cranking amps for 5 seconds
   
   
  
• 545 cranking amps for 10 seconds
   
   
  
• 480 cranking amps for 20 seconds
   
   
  
• Short circuit current over 1800A
   
   
  
• 27 minute reserve capacity with 25amp load
   
   
  
• Length 6.7"
   
   
  
• Width 3.90"
   
   
  
• Height 6.89"
   
   
  
• Weight 13.2 lbs
   
   
  

 

 

The point of interest and complete relevance are the H x W x D and the weight (converted lb's to Kg's = 6Kg

 

So Armin, in our configuration W and D are important, H less so, providing its not a huge delta. As youve already understood weight is important, but 1-3Kg's probably wont be an issue, though someone would need to do a Weight and Balance to ensure that is correct.

 

Are you able to publish the physical dimmensions and weight for the batteries you are selling.

 

Andy

 

 

[Guest lithbattboss]

Andy, I would suggest you would require a 20Ah capacity LiFePO4 battery which would give you closer to the perfomance specifications of the Odyssey battery.

 

The standard 20Ah battery (SB1220-C) might be a bit too large (not sure?) for your aircraft since its dimensions and weight are 7.17x7.17x4.57inches and weight is 9.2lbs.

 

Alternatively you might be able to fit two of the smaller 10Ah batteries together in parallel side by side (SB1210-C) since this is a much narrower shape with dimensions 7.17x7.17x2.78inches and weight is 5.1lbs.

 

I have checked my earlier emails from Jabiru and it appears they have given me two different batteries which they supply with their aircraft. As you mentioned one is the Odyssey PC625 and they also supply the Yuasa YTX12BS which they say they supply for weight critical aircraft and appears to be the battery they were comparing with my smaller lithium battery. The larger lithium battery is closer to the specifications to the Odyssey battery.

 

I would like to ask one question of Jabiru owners. With such a high reported cranking current specification for the Odyssey PC625 why do so many Jabiru owners have trouble starting their engines in cold weather? I would like to bet that the specification quoted by Odyssey is for a warm (or even hot) battery since it appears the cranking ability is greatly reduced in cold ambient conditions.

 

Jabiru tell me that their engine draws less than 100 amps while cranking.

 

The Odyssey specification says that their battery will supply 480 amps for 20 seconds.

 

So why then won't the Odyssey battery start an engine in cold weather if the reported specification is correct and their battery can supply 4 times the required current to turn over the Jabiru engine?:confused:

 

Does anyone have any answer's here???

 

 

[Guest lithbattboss]

Thanks for the info. Now the big question....How much? Even RRP for now will do for an idea.

I am waiting for Ian to set the prices which should be available in the next few days.

 

 

[Guest Andys@coffs]

I dont know.

 

In summer the battery starts the aircraft every time without issue ever. In winter, if it doesnt go in the first 5-10 secs (Ether based Start Ya Bastard is a good help here) then it wont go until it warms up, or you jump it with a running vehicle. WIth the jump it will start as though it were summer.

 

Its almost as though the cold negatively impacts on the starter load (harder to turn over), perhaps the ease of ignition and the battery itself.

 

Theres one thing for absolute sure though. If one of these batteries works as well as is suggested, doesnt have an outlandish costs associated with it (PC625 from memory is between $200 and $300 as a replacement) and someone here posts their experiences I suspect that the market for these will skyrocket. I cant think of a single J230 owner who hasnt had this issue at some stage. Some have gone to the trouble of setting up jump start points so that you dont have to remove the cowls to do it.

 

So.... Who's to be first.... Jabiru, in Bundaberg are probably aware of the issue but I suspect rarely if ever would experience it for themselves, I imagine its a definite "south of the border" issue.

 

Armin, Is it possible, against the specs I identified above for the odyssey, to put your corresponding battery specification for one or both batteries so an exact comparison can be made one to the other. I understand that comparing one chemical composition against the other may mean that there are differences and therefore don't exactly expect every number to be equal or better, but there are some that must be equal or better. From the manufacturers specifications (load graphs) please quote the duration that the battery(s) can supply a 25A load for. I haven't worked professionally with electronics for some time but seem to recall that a 20Ahr rating = 20 Amp load can be fed for 1hr before the voltage falls off. At 25Amps that may be significantly shorter time frame . Also, from memory,the voltage fall off in a lead acid battery is progressive and as such the radio or intercom may give an indication of a discharging battery long before the ignition system fails. (distortion in the audio, or unexpected panel behaviour etc) I seem to recall (but may be wrong) however that Lithium based batteries have a fairly flat voltage discharge curve up to the point where an almost square wave fall off in voltage occurs. Is my recollection correct? If so no indication of approaching flat would be noticed until you fall over the discharge edge. If that is true, in my opinion its not an insermountable issue, just means that a circuit capable of identifying a working battery charging circuit would be needed so you can immediately plan for landing as soon as something goes wrong.

 

Andy

 

 

[Guest lithbattboss]

It is a bit difficult to compare the specifications of the Odyssey battery and the LiFePO4 battery since we are not comparing apples with apples. Lead acid and lithium batteries are not judged by the same specification criteria. This is especially the case with engine start batteries since lead acid starting batteries are rated in CCA (cold cranking amps). CCA does not apply to lithium batteries due to the slightly different fully charged and fully discharged voltages between the two different battery chemistries.

 

For those who are interested I have attached (below) the technical specification of the 40138F1 cells which are the building blocks that make up the batteries.

 

As you can see from the specification the cells are rated to operate as low as minus 10 degrees celcius. I have no hesitation that this is an accurate figure after my own personal experience of starting my car last weekend (Toyota Camry 3 litre six cylinder engine) in near freezing temperatures.

 

I would be interested to hear from any Jabiru owners in the Sydney region who would be happy for me to try one of the batteries out early one morning when it is close to zero degrees to jump start their aircraft. Let me know if anyone would like to try this out and then the results can be posted on the forum.

 

Any interested parties can either give me a call on 0420948757 or email me directly at [email protected]

 

BMI 40138F1 Cell Specification

 

Nominal Capacity - 10000 mAh

 

Minimum Capacity - 9000 mAh

 

Charging Voltage - 3.65V

 

Typical Voltage - 3.30V

 

Cut-off Discharge Voltage - 2.10V

 

Charging Method - CC/CV

 

Maximum Discharge Current - 120A (12C Continuous)

 

Maximum Discharge Current – 140A (14C for 18 second pulse)

 

Peak Discharge Current- 200A

 

Maximum Charge Current - 30A (3C)

 

Cycle Life - 3,000 cycles (minimum)

 

Charge Temperature Range - 0 ~ 45 (degrees centigrade)

 

Discharge Temperature Range - -10~55 (degrees centigrade)

 

Short Period Storage Temperature - -10~45 (1 month)

 

Long Period Storage Temperature - 0~35 (6 month)

 

Gravimetric - >80 Wh/Kg

 

Volumetric - >170Wh/L

 

Power Density - (100% SOC, 18s peak)

 

Gravimetric - >600 W/Kg

 

Volumetric - >1230 W/L

 

Initial Internal Impedance -

 

<6 mOhm

 

 

 

 

 

[Guest lithbattboss]

Andy, I don't have a cell discharge curve for 25amps but I do have one at 40amps.

 

This test was done in Perth a few months ago.

 

You are absolutely correct about the different discharge characteristics of the two battery types. The lead acid battery voltage will gradually but steadily decrease as the battery discharges. As you rightly mentioned you might notice the battery slowly becoming flat by factors such as distortion in the audio etc. As you can see in the attached lithium discharge curve by the blue current and white voltage curves both are close to linear for approximately 90% of the cells capacity. During the last 10% of capacity is when the voltage and current decay quite rapidly. This means that the battery will appear to be providing close to full power even when it is almost fully dicharged and then the battery will go flat and lose power very suddenly.

 

This is why in the u-tube video of the guy starting the motorbike engine, the engine cranks over without slowing down at all, right to the point of the battery becoming flat and then all of a sudden it dies. This is in stark contrast to what most people are familiar with a lead acid battery whereby as the voltage slowly drops during discharge, the cranking becomes more and more sluggish until the battery doesn't have enough power to turn the engine over anymore.

 

 

 

[jetjr]

Battery characteristics

 

The high output then stop would be of great benefit to Jabirus

 

The require very high crank speed for start and the Odyssey falls below this quite quickly

 

Id suggest maybe Jabs require close to full chatged battery for effective start.

 

When cold, battery old, slightly crook connection then it cant deliver max volts and you only get a few seconds of max crank speed

 

Incidently Ive got a 550hr J200 and fitted new batt last winter and havent had an issue since then. I just turn over by hand maybe 10 times before a cold start ~ 2 deg C

 

If these new batts work then scratch another kilo or 2 for jump leads??

 

In regards to COG, Jabiru are going to great length to move weight off the nose - theres a reason why fuel header tank moved to behind rear curtain from under LH seat

 

Some J200's have lead shot in the tail to help fix COG issues

 

Bundy should be able to calc COG with correct weights and aircraft info

 

JR

 

 

[quentas]

If Jabiru could make an ignition system that will fire the plugs at 200rpm on the starter on a cold day then I would be happy. It seems everything has to be absolutely perfect for a successful Jab start on a cold morning and attaining the magical 270rpm with a combustable mixture in the cylinders seems more like a dream for me. It seems most Jab owners are quite content with pouring hot water/heating/jumpstarting etc and accept it. I love the 230 when its running but many times Ive been standing next to it on a cold morning with cowls off jumpstarting it whilst `other` aircraft taxi by. I feel the best fix would be a better ignition system full stop then forget about the plug gaps/oil type/starter sprays/jumpstarts/external power receptacles /lith batts etc...PLEASE Rod, make this happen.

 

 

[jetboy]

If youre desperate you have some choices: in UK website there is mention of adding a 3rd system for starting, with a changeover switch and retarded (no pun intended),

 

or you could fit an entire Rotax setup - pickups, 4 coils, no distributors, may need different alternator windings - huge $ certainly more than the $150 for the lawnmower coil

 

or I read in the USA one of the first 701s with a 2200 runs 2x 12 AH batteries in parallel for 12V running and switched in series to the starter motor (24V)

 

The last method is the only one I'd consider - but I already have a PC 925 battery there, apart from one time it was low and wouldnt fire up (yes it was annoying) that size battery is adequate (mild winters here too)

 

Ralph

 

 

[motzartmerv]

I can't believe i only just found this thread..We have 4 jabs, 3 of which never start on cold morning's.. It came to a head the other day when 2 students left because they couldn't wait around for us to charge batteries.. The engineer looked at the problem and said it was the starter..so, the owner (who ownes like 15 jabs) organised a starter to be taken off a a jab at bankstown.. so i jumped in the VH jab and whizzed over to bankstown..taxied around for 25 mins before finding the right shed, picked up the part and back to camden.. The engineers fitted the new starter and all was good...but, all wasn't good, it STILL wouldn't start...gggrrrllll....so i was there till last light charging and starting on pack power...i did a couple of circuits to charge her up...next morning....NO GO, the thing still wouldn't start.....

 

Next week we are taking the 230 up to bundy, jabiru want us to trial a new ignition system in the cold for them... if it works out, they'll be issuing some sort of mod for all jab engines..

 

so hear's hopeing

 

 

[quentas]

hoorah!! maybe some light at the end of the tunnel. I have been trying to press this problem home to Jabiru but their tech people tell me its `maintenance` issues. I have a 46 yo cessna that has NEVER let me down yet my 8 mo J230 has let me down EVERY time since the cold kicked in. Having said that, the J230 is a fantastic aircraft once it has been started in the morning and I think Jabiru would sell bucket loads more of them IF they sort out this ANNOYING start problem. I know they dont want people hand starting them but a slower firing coil would fix all.

 

 

[Jabiru Phil]

Poor cranking

 

Hi all interested in this forum,

 

I cant help wondering that we may be on the wrong track with this cold starting problem. We have two Jabs and they both start on cold days ONLY if we pour hot water over the carbie. To me that sounds like fuel not battery.

 

Any comments?

 

Phil.

 

 

[jetjr]

I reckon it could be to do with very lean settings of carb and weak ignition setup

 

Hot water on the carb, id guess would make fuel a bit more availiable - richen mix just a bit

 

Mines a J200, running old linear needle in carb and starts no problem - uses a bit more fuel than maybe it could but who cares if it avoids these start problems. It does spend nights in a hanger.

 

It says to me this shouldnt be that hard to fix. Interested to see what Jab comes up with

 

JR

 

 

[motzartmerv]

Hmm...can't see how carbie is going to affect poor cranking.. Sure if it wound away, turning over but not starting then fuel would be susupected...but our probs have been no cranking..just a clicking sound and the prop sits there like a stale bottle of proverbiale.

 

cheers

 

 

[Derby]

Maybe it's an earth problem.

 

 

[jetjr]

Thats a different issue - normally they wind over OK just wont fire.

 

Id be checking for basic electrical problem, Power isnt getting to the starter OR dodgy earth, or restriction in engine.

 

Check volts in Bat then, volts on bat when starter pressed, check volts at solonoid (both sides), then volts at starter - all should be similar, wherever you see less volts is where the blockage is.

 

Solonoids do fail - theres another topic here about it somewhere

 

And watch the prop!!!!! in case it does turn over.

 

I recently had a system - not an AC - replaced battery, starter, cables. Did these tests above and found brand new battery, very expensive AGM, was faulty, charged to 12.5, soon as it was loaded dropped to 9V

 

JR

 

 

[Guest brentc]

All solved with electronic ignition. I read recently someone who fitted a small electronic unit to assist with cold starting / ignition strength that overcame the 285 RPM issue. If anyone else saw it and knows where it is, please let me know!

 

 

[Guest Nelson Smith]

Hi Brent,

 

Maybe the unit you are referring to is Geoff Hennig's starting system.It was published in RAUS mag.some years ago. I will try to look it up.

 

Nelson

 

 

[Jabiru Phil]

Ahh. Thats a different problem, ours cranks OK and if temp is below around 10 deg no fire at all, just tip HOT water through funnel onto top of carbie and it fires straight away, never failed yet. A pain to do as we have no power at the airport and use a gas burner and kettle. Muat keep the choke on until start.

 

Phil.

 

 

[quentas]

Wouldnt it be nice to jump in, turn the key, and press the button and hey presto...it starts!! (Just like my 1962 172 Cessna)

 

 

[Guest brentc]

I was having some starting issues a while back and found when I looked closely that my choke wasn't pulling on fully. It was very close, but just not quite there. I remember on one occasion I just couldn't get it going even with a jump start. My mechanical assistant took the cowls off with me and pushed the choke that little bit further and away it went instantly.

 

Make sure the throttle is COMPLETELY off and the choke FULLY on and that might discount the carby as being the problem.

 

 

[quentas]

I have just recieved a jumper kit from Jabiru with a letter stating Jabiru is working on the `cold start` problem. I am please this has been acknowledged by Jabiru. I feel they will conquer all when this problem is fixed, they are as I have said before, a sensational airplane to fly.