Power pack to start boat engine ?

[Neil]

Rather amazed at the specs above. Can start an engine 20 times but only charge a phone 8 times?

Something funny there..

To be sure I don't think my phone stands any chance of starting an engine a couple of times!

Maybe I've misread it?

Have the bigger Halfords one for up too 3lt diesels. Now I no longer have the Sadler or the Landrover, I don't need it, but I do use it to charge the iPhone away from the grid. It does seem to use half its charge to get the iPhone back up to 100% - it always surprises me. The other thin is that it need about 3 or 4 volts left in the battery to trigger the failsafe, so if it's completely flat you're cattle trucked.

 

[RobWard]

I've got a Noco; as far as I'm concerned it's a 'get out of jail card' , much more convenient than a 'spare' conventional battery, highly portable and unobtrusive. When my cranking battery was (over)due for replacement, it got me out of bother approaching Cardiff barrage before I could arrange it.

 

[Farmer Piles]

Exactly, why not just buy a suitable battery and jump leads, and keep for emergencies?

I'm with Colin - why buy a battery and jump leads? Expensive and restrictive, heavy and cumbersome. I would say why not buy something that is proven to be effective, small and light, easy to charge and carry and versatile. You can charge phones, run refrigerated cool boxes, etc.. all with something not much more than pocket sized. a great belt and braces to have onboard.
With regard to being caught out: it's not that rare for even a fairly new battery to fail - sometimes a cell gives out and the whole battery is shot.

Also, Auto Express did a review of these chargers online. Best mini jump starter packs 2022 | Auto Express

It makes useful reading.

 

[DoubleEnder]

Interesting thread. I’ve been talking to a friend who has a small boat, 10hp diesel and a single large-ish 12v battery. His domestic demand for electricity is low, a few cabin lights, Nav lights, VHF, depth sounder. Bilge pump & USB socket.
We have been discussing adding a dedicated engine start battery, but it’s a surprising amount of work and £. Got to modify the battery compartment, extra wiring, some sort of switching arrangement and charging arrangement. I think I’m going to suggest he just carries one of these jump start packs. Much cheaper, quicker, and in a small boat the space is really valuable.

 

[jwilson]

As soon as you have a non-hand-crankable engine you need a proper two-battery setup (not a 0-1-2 switch). Not to have this is silly. As is persisting with a known dodgy battery.

 

[Stemar]

There's nothing wrong with a 0-1-2-both switch arrangement if its done right. My old boat was wired up with the starter to common, a dedicated engine battery to 1 and the domestic battery to 2. I also had a cheap cube relay energised by the charge warning light terminal to put both batteries in parallel for charging. It served me well for not far off 20 years.

Off isolates the engine battery, 1 is for normal use, 2 allows me to use the domestic battery to start and B puts the two in parallel.
If I were setting up a similar boat now the only thing I'd change would be to use a VSR instead of the headlamp relay.

 

[jwilson]

Stemar is correct, but only if you never make a mistake operating it. Two separate batteries or banks with a VSR or diode arrangement is as close to foolproof as you can get. Then the only other likely starting problem is a dead starter motor. Or various other bad maintenance things like very dirty fuel or mechanical problems with the engine, and small diesels with no ECU type electronics really are pretty long-lived and reliable given basic maintenance.

 

[AngusMcDoon]

Rather amazed at the specs above. Can start an engine 20 times but only charge a phone 8 times?

Something funny there..

To be sure I don't think my phone stands any chance of starting an engine a couple of times!

Maybe I've misread it?

A nerd like me can't let this one go Here are the sums (ignoring all inefficiencies)...

Engine starting an engine 20 times taking 250 A at 12 V for 5 s of cranking...

12 V * 250 A = 3 kW = 3 kJ/s
Assume 5 s of cranking
Total energy used per start = 15 kJ
20 starts energy used = 300 kJ

Charging 8 times my phone's 10.6 Wh battery...

Energy contained = 10.6 * 60 * 60 = 38.2 kJ
Energy needed for 8 charges = 8 * 38.2 = 305 kJ

So almost the same. Engine starting takes a lot of power but little energy. Conversely phone charging takes little power but a lot of energy. Your phone battery has sufficient energy in it to start an engine but not the available power output.

 

[black mercury]

A nerd like me can't let this one go Here are the sums (ignoring all inefficiencies)...

Engine starting an engine 20 times taking 250 A at 12 V for 5 s of cranking...

12 V * 250 A = 3 kW = 3 kJ/s
Assume 5 s of cranking
Total energy used per start = 15 kJ
20 starts energy used = 300 kJ

Phone charging 8 times my phone's 10.6 Wh battery...

Energy contained = 10.6 * 60 * 60 = 38.2 kJ
Energy needed for 8 charges = 8 * 38.2 = 305 kJ

So almost the same. Engine starting takes a lot of power but little energy. Conversely phone charging takes little power but a lot of energy. Your phone battery has sufficient energy in it to start an engine but not the available power output.

This explains why the small lithium booster packs have capacitors. When you connect the leads to the battery being jumped you will hear a click after a few seconds and a red light turning to green. The capacitors inside the jump pack use the power left in the battery being jumped to charge themselves. When the light turns green you are ready to try to start the engine. The lithium battery inside doesn't have the power to turn the engine over by itself but combined with the quick release of stored electricity from the capacitors it does.

 

[Biggles Wader]

I have a standard 1 2 Both Off switch with just the two battery set up. The domestic battery also has its own isolator on the positive terminal. All works well providing you remember to ensure the isolator is "on" when charging the domestic battery and you dont ever leave it in the "both" position when not deliberately using both.
I tend to take a spare fully charged battery and jump leads from home with me just in case anything has gone flat and leave it in the car unless there is a problem. Never needed it but Im sure I will when I forget to bring it.

 

[Tranona]

Interesting thread. I’ve been talking to a friend who has a small boat, 10hp diesel and a single large-ish 12v battery. His domestic demand for electricity is low, a few cabin lights, Nav lights, VHF, depth sounder. Bilge pump & USB socket.
We have been discussing adding a dedicated engine start battery, but it’s a surprising amount of work and £. Got to modify the battery compartment, extra wiring, some sort of switching arrangement and charging arrangement. I think I’m going to suggest he just carries one of these jump start packs. Much cheaper, quicker, and in a small boat the space is really valuable.

That is how things were done 40+ years ago - just one battery does everything. Whether that is valid now depends on how you use the boat. If you just day sail and have a means of fully recharging the battery in between trips it is probably still fine. The danger is when you use the domestic side more extensively like an overnight or sailing at night you can quickly drain the battery to the point where it can't start the engine. A jump pack might well be an emergency solution, but it really is not too difficult or expensive to add a dedicated start battery and a split charging system.

Either this
force4.co.uk/item/Blue-Sea/Add-A-Battery/T4P?utm_source=google&utm_medium=base&utm_campaign=base&stock=11924&gclid=EAIaIQobChMI6umwqL38_wIVOIBQBh0saQXLEAQYByABEgJMq_D_BwE

Or in my view even better this which uses a vSR and gives 2 independent banks and a parallel
marine-electricals.co.uk/product/square-battery-distribution-cluster-for-single-engine-with-two-battery-banks-bep/?utm_source=google&utm_campaign=pmax&utm_medium=cpc&utm_term=8220&gad=1&gclid=EAIaIQobChMI4I6U-b38_wIV04BQBh1LTwBLEAQYASABEgI1A_D_BwE

Plus a simple car battery of around 50Ah suitable for a small diesel car like a Citroen is fine for a 10hp diesel and costs £50-60
Bosch car battery S4001 544 402 044 12V 44Ah 440A/EN

and some cabling adds up to roughly £250 plus the cost of creating a new battery box.

I used exactly that set up for years with a Yanmar 1GM with a 105Ah house battery. Never used the parallel as the start battery has an easy life and is quickly recharged even by the modest 35A alternator. For more extended cruising or if the boat is kept on a mooring a solar panel will help keep the house battery recharged.

 

[DoubleEnder]

That is how things were done 40+ years ago - just one battery does everything. Whether that is valid now depends on how you use the boat. If you just day sail and have a means of fully recharging the battery in between trips it is probably still fine. The danger is when you use the domestic side more extensively like an overnight or sailing at night you can quickly drain the battery to the point where it can't start the engine. A jump pack might well be an emergency solution, but it really is not too difficult or expensive to add a dedicated start battery and a split charging system.

Either this
force4.co.uk/item/Blue-Sea/Add-A-Battery/T4P?utm_source=google&utm_medium=base&utm_campaign=base&stock=11924&gclid=EAIaIQobChMI6umwqL38_wIVOIBQBh0saQXLEAQYByABEgJMq_D_BwE

Or in my view even better this which uses a vSR and gives 2 independent banks and a parallel
marine-electricals.co.uk/product/square-battery-distribution-cluster-for-single-engine-with-two-battery-banks-bep/?utm_source=google&utm_campaign=pmax&utm_medium=cpc&utm_term=8220&gad=1&gclid=EAIaIQobChMI4I6U-b38_wIV04BQBh1LTwBLEAQYASABEgI1A_D_BwE

Plus a simple car battery of around 50Ah suitable for a small diesel car like a Citroen is fine for a 10hp diesel and costs £50-60
Bosch car battery S4001 544 402 044 12V 44Ah 440A/EN

and some cabling adds up to roughly £250 plus the cost of creating a new battery box.

I used exactly that set up for years with a Yanmar 1GM with a 105Ah house battery. Never used the parallel as the start battery has an easy life and is quickly recharged even by the modest 35A alternator. For more extended cruising or if the boat is kept on a mooring a solar panel will help keep the house battery recharged.

Should have said the the boat is really quite lightly used and he’s never had a problem yet, but was thinking he should probably upgrade. Thank you for the links. I think the biggest issue is where does the enlarged battery bank go? But this is useful and appreciated

 

[Tranona]

The batteries don't have to be in the same location although it helps reduce the wiring runs if they are.

 

[derod]

Another vote for Noco from me. I have a couple of GBX55's, one in the Landrover and one in the workshop. They start my 4 ltr tractors and the 2.5 TD5 L/R easily and are much lighter than my old "battery and jump lead set-up". I had one fail when it was plugged into the wrong charger (operator error, DOH!!) and although it was 3 months out of guarantee, Noco sent a free replacement when I enquired about possible repair. ps, I have no connection to Noco other than as a happy customer.

 

[mullet]

Would a Noco-type battery pack be suitable for running a 12v air pump? I’m tempted by one as backup for engine starting in case someone messes up with the 1-2-both switch (yes, I know a VSR would be better…). But I could *definitely* justify it if it would run the Rule pump I use to inflate a tender too. Bit hard to figure out if it would work for that or whether it is geared to charge capacitors to give a huge jolt for engine starting rather than a lower, longer duration current.

 

[mullet]

Would a Noco-type battery pack be suitable for running a 12v air pump? I’m tempted by one as backup for engine starting in case someone messes up with the 1-2-both switch (yes, I know a VSR would be better…). But I could *definitely* justify it if it would run the Rule pump I use to inflate a tender too. Bit hard to figure out if it would work for that or whether it is geared to charge capacitors to give a huge jolt for engine starting rather than a lower, longer duration current.

Answer to this question is "yes". The Noco won't put out any current to a pump on its standard settings (it will only output power if it detects a battery is connected) BUT it has an override "try to start a totally dead battery" setting which does the trick for running the Rule pump. Filling and deflating a 2.6m SIB seems to use about 1/4 - 1/3 of the capacity of a GB40 unit.

 

[B27]

Every used car dealer has one of these packs these days.
On your own boat, you need a two battery set up.

Another option is a lithium battery intended for a motorbike. This may have more capacity.
The people you see at the slipway failing to start grumpy outboards seem to need a lot more cranking minutes than you will get from a 'boost pack'.
A boost pack is a good tool when the problem is simply a low battery.
It is no good for more complex problems like say a dodgy carb making an outboard reliuctant to start, or a diesel that won't bleed, or your battery went flat because your alternator is sick etc etc.
Maybe it would run the plotter and the sounder while you sail into harbour, other than that, it's a one-trick pony for starting good engines.

 

[Tinto]

I have one and it’s great. Will also charge from its USB as well has a torch. I have used it and it worked perfectly

 

[Whaup367]

Answer to this question is "yes". The Noco won't put out any current to a pump on its standard settings (it will only output power if it detects a battery is connected) BUT it has an override "try to start a totally dead battery" setting which does the trick for running the Rule pump. Filling and deflating a 2.6m SIB seems to use about 1/4 - 1/3 of the capacity of a GB40 unit.

Hmm, very interesting: would that allow it to run a trolling motor, do you think?

 

[mullet]

Not for long. They don’t publish the battery capacity but it isn’t especially large. Charging an iPhone off it a couple of times pretty much empties it. I wouldn’t expect to get more than a few minutes running time on a trolling motor for the size I’ve got. And if you want a larger capacity battery there are much economical options than one of these packs. I think I remember seeing someone on YouTube who put this to the test - if you search I’m sure you’ll turn it up.