Engine starters.

I reckon the most reliable jump start battery is the one installed in a dual battery system. ie for the cost a battery and associated switches etc you get the alternativve start battery which hopefully is always ready. In fact should be tested as a stand alone start battery frequently. A portable booster is by nature low powered and also likely to die while not being used. Of course this doese not help you at home. I have a 12v deep cycle 100AH battery on solar panels at home that operate outside security lights every night. Means I always have a 12v jump start battery available even if it is a bit heavy. ol'will
 
Those car starter things won't usually work unless there are between 11 and 12 volts on the battery; they're meant to supplement a low battery, not replace a dead one. If a car starter would work, there's another trick that works very well for engines with a decompressor. Operate the decompressor and get the engine turning over with the starter. Because there's no compression, it will turn quickly even with a low battery. Then drop the compressor while the engine is turning quickly, and the engine will be turning fast enough to start. Had to do that once on mine; it works a treat. Of course, that won't work if the battery is completely an ex-battery, one that is no longer with us, but it will work if the battery will turn the engine, but not fast enough to start it.
 
Those car starter things won't usually work unless there are between 11 and 12 volts on the battery; they're meant to supplement a low battery, not replace a dead one. If a car starter would work, there's another trick that works very well for engines with a decompressor. Operate the decompressor and get the engine turning over with the starter. Because there's no compression, it will turn quickly even with a low battery. Then drop the compressor while the engine is turning quickly, and the engine will be turning fast enough to start. Had to do that once on mine; it works a treat. Of course, that won't work if the battery is completely an ex-battery, one that is no longer with us, but it will work if the battery will turn the engine, but not fast enough to start it.
Had to do that when collecting a boat that got marooned by lockdown. 1GM10 and there was a sniff of rptten eggs about the battery. When we arrived at La Rochelle, just managed to do it again, but only just.
 
Those car starter things won't usually work unless there are between 11 and 12 volts on the battery; they're meant to supplement a low battery, not replace a dead one. If a car starter would work, there's another trick that works very well for engines with a decompressor. Operate the decompressor and get the engine turning over with the starter. Because there's no compression, it will turn quickly even with a low battery. Then drop the compressor while the engine is turning quickly, and the engine will be turning fast enough to start. Had to do that once on mine; it works a treat. Of course, that won't work if the battery is completely an ex-battery, one that is no longer with us, but it will work if the battery will turn the engine, but not fast enough to start it.

That's fine as long as the solenoid relay actions on a low battery. Some fail to close on a low battery .....

On Decomp levers ..... my 4-107 and its previous 4-99 I had - no decomp lever ....
 
I’d have thought that’s a good thing though as it will avoid burning out the starter motor with low voltage and adding to the problems.
 
That's fine as long as the solenoid relay actions on a low battery. Some fail to close on a low battery .....

On Decomp levers ..... my 4-107 and its previous 4-99 I had - no decomp lever ....
I've never been able to start any diesel using decompression levers.

I had a Volvo 2000 series engine that came with a starting handle but I could never generate enough speed. I later learned that the starting handle was never intended to start the engine.

I remember a diesel club launch that did not require a battery to start it. It had cranks and a bicycle chain affair and used hand an arm power . Worked well.
 
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I've never been able to start a diesel using decompression levers. I had a Volvo 2000 series engine that came with a starting handle but I could never generate enough speed. I remember a diesel club launch that did not require a battery to start it. It had cranks and a bicycle chain affair. Worked well.

When as Junior Officer on ships - Lifeboats were my responsibility ... and once a month - had to be with Junior Engineer to test the motor in L/B #1 ...... often a lister with decomp levers.
I got to hate Listers !!
 
Those car starter things won't usually work unless there are between 11 and 12 volts on the battery; they're meant to supplement a low battery, not replace a dead one. If a car starter would work, there's another trick that works very well for engines with a decompressor. Operate the decompressor and get the engine turning over with the starter. Because there's no compression, it will turn quickly even with a low battery. Then drop the compressor while the engine is turning quickly, and the engine will be turning fast enough to start. Had to do that once on mine; it works a treat. Of course, that won't work if the battery is completely an ex-battery, one that is no longer with us, but it will work if the battery will turn the engine, but not fast enough to start it.
The NOCO GB40 I have has a button on it that bypasses the minimum voltage check so it will work with a dead flat battery
 
It is one thing turning with grips, another fast enough to get over a compression to fire. I had a 4-108.
Don't you believe it!

Son's KTA19 had a seized on clutch. There is no gearbox, just a clutch and a variable pitch propeller (around 5' in diameter!).
The clutch had a "get you home" arrangement such that, if it failed to engage hydraulically, the plates could be forced together by tightening 12 external screws on the casing. Checking that the problem was not due to one or some of these screwed in, I needed to inch the crankshaft around one twelve at a time. Using a crowbar, on the third such part rotation the engine fired.

As son had removed the turbo, the oil gauge and the stop solenoid, the next half hour was interesting trying to stop a 19 litre engine with a jet of oil squirting across a smoke filled engine room, no obvious method of stopping it and the boat surging against its moorings.
 
I think the battery voltage detection is a safety feature.

The unit wants to be happy you haven't got the croc clips flapping freely about, ready to accidentally touch, sparking and melting things.

So if the unit detects at least a couple of volts it assumes you've connected the leads safely to the battery, and will allow full power.

That's my understanding anyway, from reading the NOCO GB50 manual (online). It's functionality that has had me puzzled up to now.
 
I've never been able to start any diesel using decompression levers.

I had a Volvo 2000 series engine that came with a starting handle but I could never generate enough speed. I later learned that the starting handle was never intended to start the engine.

I remember a diesel club launch that did not require a battery to start it. It had cranks and a bicycle chain affair and used hand an arm power . Worked well.
I agree that starting a 200x series engine manually would be difficult for anything less than a gorilla; no flywheel so no way to store energy! But we regularly hand started an 8hp Sabb diesel, and I suspect that the technique that worked on that would work on other engines that have a large flywheel. Basically, you opened the decompressor, turned the engine with the crank handle as fast as you could to get the flywheel turning fast and then closed the decompressor. The flywheel would then take it through a couple of compression strokes, which was usually enough to get it started. I don't see why that technique wouldn't work with a bigger engine; the person cranking isn't trying to get it over TDC, it's the stored energy in the flywheel that does that.
 
My T6.354 is 24V electrics... I bought an Arteck 2000A 12V Lithium pack (from Amazon), but it didn't work when needed and I ended up calling Sea Start who had the exact same model of pack...which also didn't work.
I later discovered that the reason it wouldn't work (even on a petrol car) was that the battery needed to be below a certain voltage to trigger the pack to provide a boost!

I still have it as a car starter (now that I know how it works), but invested in a Clarke 24V/12V Lithium starter: Clarke JS1224Li 12/24V Lithium-Ion Jumpstarter - Clarke Tools
Not cheap, but works really well...

I also have a set of jump leads on board so I can also use the Leisure battery in an emergency
 
A standard car booster won't be enough to turn a higher compression deisel engine but if you buy a heavy duty boster it will work. I have had this one a couple of years SUAOKI E15 1500A Peak 2000mAh Jump Starter (for ALL Gas or 6.5L Diesel Engines) Portable Car Battery Booster with Type-C & USB 3.0 Quick Charge, Smart Clamps, LED Flashlight : Amazon.co.uk: Automotive and great peace of mind. Yes it has started cars and boat engines (Yanmar 240HP)

Again an inaccurate Amazon ad. States both 700 Amps and 1500A (no definition of peak), 2.000 and 20.000 mAh capacity ❓
booster.jpg
 
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The big give-away with these units is the physical size.

To supply 12V and have 20000 mAh capacity means a 3S pack and substantial size ...... far larger than shown ! I believe an extra 0 has crept in there .. so lets take the 2000mAh as the correct figure.

To be able to deliver 700A from a 3S 2000mAh pack means that the C rating must be incredibly high ... lets say constant max discharge rate of 300A and 700A burst for max 10secs ... would need a C rating of at least 150+. The advert says in title 1500A .... that puts C rating at 750 !!!!
It is generally known that LiPo C ratings over ~50C are usually optimistic at the least.
 
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