I have a 205ccc, 10.5:1, 117 engine, with manual comp. releases in a 2010 softail deluxe. Stock starter (1.2kW, I presume = 100A locked rotor current draw). 

The stock (original) battery just manages to start the engine on a good day, most of the time. Turns over really nicely with a 480CCA car battery (eg in jump start situation). 

In cold weather or not riding for a couple of weeks (due to a temporary situation), I only get a few seconds of crank before battery is too flat.

So I decided to try out the latest and greatest LiFePo batteries - www.ultrabatt.com

These are supposed to be able to deliver a massive starting current. These little battery units can be joined up to make a bigger battery. I bought 4 of these to make up a 360PCA battery (480PCA). This should have had way more starting grunt than the original battery - comparable to a small car battery. 

Wouldn't turn over the engine - cranks way too slow to fire, like a flat battery.

I've tested/tried/ruled out the obvious things including the following - battery faulty, not charged, excessive draw before starting, starter motor wiring, alternator, voltage regulator, lithium cell warm-up.

Dealer tested battery units with carbon pile load tester - perform as rated. 

The stock HD AGM Pb acid battery (P/N 65989-97C) apparently should be 270-280CCA. I've had the original battery since 2009 when I bought the bike.

Fully charged, with headlight fuse out, only 2A draw with ignition on (normal 10A), 13.35V across battery. On starting voltage drops to under 6V on starting, and engine doesn't fire. I've tried several consecutive starts to warm up the Li cells, and a number of other variations.

The old Pb battery is probably nearing the end of its expected lifetime, and that starts the engine just fine partially charged reading 12.4V.

None of this makes sense. The Li battery should be able to deliver a massive amount of current - they have to be fused for safety. (Fuses not blown, checked that).

I saw somewhere, a 310CCa battery from a HD OEM actually delivered 360CCA, could it be my stock Pb can deliver way more CCA than rated? Even then that doesn't explain my problem, since the Li battery should still be able to deliver more current.

Anybody else tried a LiFePo battery on a big high comp harley engine and found it no good?

Maybe I just need even more grunt, could probably fit another 2 or 3 units to give me 630CCA? That would be expensive.

Would a bigger starter motor help? Or would that make it worse?

Dealer has agreed to refund, he is stumped, the manufacturer is stumped too. Taking the bike to him to run some more tests this weekend.  Going to try more and less CCA, test the actual CCA of the lead acid battery.

Very frustrating.

Anybody else been here?

Have you got access to somebody else's starter motor to swap n try, least then it will confirm or totally rule that out

Save yourself the headache and return the LiPo's and spend ~$150 on a new HD or Deka battery.
I've heard too many bad reports on the newer battery technology to bother.
If it measures down to 6v you have no chance.

 as speedzter says look into a new harley battery ,  also i would be looking @ cam choice & comp ratio 

Might pay to double check your earth leads at each end for tightness and contact cleanliness. Looks can be deceptive.

just wondering how many pound of cranking pressure you have?

 

Lurker, i think you miss the obvious.
A 4 year old stock HD battery will start the bike most times, and the
New LiPo's won't.
Answer = buy new lead acid battery.

You might have missed this part further down in his post:

"The old Pb battery is probably nearing the end of its expected lifetime, and that starts the engine just fine partially charged reading 12.4V."

I am only going by the information he supplied to us. Which would have me believe his starting system is doing it's job.

Regardless, i will be interested to see the outcome of further testing
With the battery supplier.

Email the company that makes the battery (-ies) and ask...

Thanks for very helpful info - sorry I contradicted myself there and started an argument..... when I said started the engine just fine, I mean started the engine with the usual "just-barely-cranks the engine", rather than failing to start the engine.

Anyway, went up and got it tested today - lurker501 had it right - starter motor is drawing way too much current for the lithium batteries - 500amps. Thats warmed up, with comp releases in. His 3.0L diesel van only draws 380A.

So that harley lead acid battery must be way way underspecced at 270cca. I'd seen that comment before somewhere, but not to that extent.

Guy reckoned I'd need 6 of those lithium battery units (from their specs 520CCA, 600pca) to comfortably start the motor.

Going to stick with lead acid for now, maybe get a bigger starter motor...

Lesson learned, stay away from new technology.

Let us know how a new Lead acid battery works.
I'm interested to know how he measured the starter current draw ?
What battery was used, and what was the cranking voltage ?

As a matter of interest, i just did a 95 cube freshen up, and with the 4 year old battery the cranking compression
was around 180psi, and with a new battery it's over 190psi, which is where it should be.

cheers

I had a very similar problem to the OP. Bought a new Deka battery and solved the problem for the first week only, started again. I thought it was a faulty (new) battery so took it back and tested. It was rated at 310CCA and actually had 400CCA with 25Ah storage. In the meantime I bought a lipo battery, 700CCA, did exactly the same. The starter motor was drawing so much out of the battery it failed to start 90% of the time. I ended up getting a new starter, totally solved, been starting perfectly for the last 6 weeks with either the Deka or the lipo.
BTW, the new starter came with a dyno sheet LOL. It was a 1.4kw starter but the dyno sheet showed 1.75kw with a current draw of 475 amps! Still the Deka 400CCA started it ok but the lipo cranks it over quite a bit quicker.

Big T , what brand of LiPO ?
The new HD battery I bought had a test report of 458 CCA

I reckon well done to CF for nailing it on the first reply, but no thanks there........

10.5:1 is not that much comp, cubic inches mean nothing.
If the engine turns over slow with manual comps in. I'd say starter and cables for sure.
I bet you havnt swapped starter out and tried another yet?

Update - have installed one of these starter motors. 

With the half charged stock battery, turns over like a stock engine.  When I get a chance I'll find an auto electrician or someone with a clamp meter and measure the draw with the new starter, and quantify the difference. 

Will also take apart the old starter motor and run the usual tests on it too, see if anything was wrong with it or just underpowered.

 

Final update:

Measured starting amps with new starter (above) - 330A vs 500A.

Dealer measured the HD battery at 258CCA. Not sure how we got 500A out of it, must be bloody good battery.

Was still going flat if left for a week and only doing short rides. Gave up and getting a battery conditioner.

Thanks all for help and suggestions. Much appreciated.