Technology Marches On

Your right RMD, this is a maintenance issue I haven't heard of but makes sense.

Cheers

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Also worth considering is that most starters get dunked at every creek crossing. They are not thoroughly waterproof.

It is not only starters that need maintenance lubing, alternators are spinning at 6,000rpm the whole time your'e driving, and in a hot engine bay. Who ever thinks to pull them out for a service job?
And if the alternator fails, you may be in a very difficult situation.

"And if the alternator fails, you may be in a very difficult situation."

I had this happen to me. The 120 Prado CR diesel dew 15 amps just to keep the engine runnin. Add lights, aircon (for demisting, not comfort in this circumstance), wipers, etc and the load goes right up.

Fortunately I was towing my Karavan with its 360Ah of lithium batteries. I adjusted a few switches and fed power forward from the van to the car. The van was supported by its rooftop solar when the sun shone. The plan for night driving or depleted battery, if it came to that, was to strap the generator onto the van's fire wood rack, run a cable to the 240V charger and proceed from there. We didn't drive at night, but it would have been novel :-)

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Novel indeed Frank.
My innovation was back in the 60's when driving overnight from Melbourne to Adelaide in a Morris Minor. The generator failed. It was clear moonlight and very little traffic so I turned off the headlights and only switched them on for approaching traffic. The battery carried the ignition coil load for the remaining 5 or 6 hours of the trip. Fortunately, the cops didn't work at night in those days.

The modern designed AGM's provided today seems to be dispelling the the view that AGMs fail or have a much shorter life due to under bonnet location. Provided, they are installed east - west with full airflow cooling. Also my much used AGM second battery has been trouble free. Admittedly I don't travel out west in the middle of summer.

Good to here from members that have used Optima batteries with good long term results.

Thank you.

Cheers

Hi Malcom,

My OME Panosonic has been good for cranking the V6 petrol but is getting tired from winching thus the interest in an AGM that can crank. Wet Cell batteries have issues with heavy winching, 30 seconds on 30 seconds off or not.

Cheers

Michael, the Yellow Tops are optimised for duty stuff like winching.
I certainly don't muck about with 30 secs on/off. I run the winch with the engine running as well. I'd only do stop start stuff if I felt the winch was suffering.

I also don' t go for this 30 on off stuff if you know it's going to be a heavy or a long winch use a snatch block or 2 where possible they will reduce both mechanical, electrical load. Idle up engine turn of items that are not needed to reduce power drain stereo, A/C, spotlights, fridge if necessary. If you go out looking do lots of winching look at getting a bigger alternator, set up dual starter batteries.

I've had 4.0L / 4.5L Diesels mostly so I understand cranking needs. The current one is a 4.0L V6 petrol. Winching when I'm silly enough to get caught and too lazy to take off the Maxtrax but thankfully not often with Lockers etc.

Cheers

Macca , everything depends on the CCA of the battery [Cold Cranking Amps] which a Optima Red Top R34 has a figure of 800 , even a D34 Yellow top has 750 CCA .....have a look at your average battery in a 200 series diesel or petrol V8 , a standard N70 ?? CCA is the same .....

Michael M34 , When the factory 'Panasonic' battery gave up the ghost in the FJ Cruiser 4.0lt V6 at 3 years I replaced it with an Optima Red Top ..3years on no drama , Have a D34 Yellow top in same vehicle as Aux ,that Batt now 6 years old ...no dramas .

Hi Alloy,
That's encouraging to hear re Optima's.
My Panasonic in the FJ is still going strong after 5 years but with a seriously remote trip soon I'm buying some battery insurance.

Cheers

Michael M34 , No cable mods needed with the R34 Red Top to fit straight into the FJ , But the riser plate to lift the battery 1/2 inch [comes with battery] has to be used otherwise the battery tie down runs out of thread before being tight ...

A 2.8 diesel has a cylinder of 700cc to crank at each compression. A 5.6lL v8 the same size. A 4.5L diesel is less cylinder to compress at around 560cc. Therefore apart from the additional cylinder drag the battery requirements may not be so different after all.
Anyone kick starting a 500cc twin cyl bike finds it far easier than a 500cc single.
Battery load, starter gearing, ring gear/pinion ratio all has a bearing on it. Just because the engine sounds big doesn't mean far more battery ability is needed. Just food for thought.

No it dosn't quite work like that Michael as diesels usually run more compression than petrol for eg; GQPatrols I know their old school but this is from my Gregory's repair manuals the stndard compression ratio is as below you may be surprised at how large a battery a diesel needs.

Petrol 4.2 ltr = 170 psi

Petrol 3.0 ltr = 172 psi

Diesel 4.2 ltr = 426 psi

Diesel 2.8 ltr = 440 psi

Well then Batts , even your own figures show that by rights a diesel 2.8 would need more 'grunt' [for want of a better term] than a diesel 4.2 .....as I stated earlier .its NOT the size of the battery its everything about CCA....how much actual 'GRUNT' the battery can provide for starting .....

Batts
A conventional diesel is different to a CRD engine. Most old ones are indirect injection, high compression ratio and higher peak compression. Around 22:1 comp ratio. Nearly all if not all CRD engines are around 16:1 comp ration and so far less initial cylinder pressure to overcome. Most high comp modern petrol engines are high compression by design and not much lower than a CRD diesel. Each engine design has a starter which is made to perform for that engine, petrol or diesel, and that is done with battery ability in mind. Nothing we see today is anything like an old Perkins direct drive starter which would draw double the amps of today’s starters. On a multi cylinder engine, a cylinder once compressed returns some of that energy by applying the pressure to the pistons downward movement which in turn assists to rotate the crank. This is not available on a 4 cylinder engine of same cylinder volume, so battery load can be as high with a 4 as it is with a multi cylinder of smaller piston dia.

PS, a turbo diesel increases/varies it’s compression ratio by using a turbo to force air into the cylinder and so doesn’t require initial high compression. It’s compression ratio is dynamic.

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Way, way back (1950's) on the Woomera Range we had a number of diesel alternators. Many of them were hand-cranked 3 cylinder Listers(?) with an extended crank handle to allow two persons to contribute. But often, I was alone in swinging the handle. They had decompressors of course and the technique was to crank with increasing speed until you figured the moment was right to slap the decompressor lever down. If it did not fire you then had to repeat the exercise and it was twice as hard the second time. You soon learned not to cut corners on the first crank. Also, sometimes if you hit the lever down too soon, the crank would bounce back off the compression and threaten to cause you an injury!
I did learn a little about diesel compression and flywheels at those times.
Fortunately, technology does "march on". lol

Thanks RMD I realise things change over the yrs that's why I mentioned what I put up is old school in my reply all good.