Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm20

[rardiH36]

On this forum several days ago was a thread about pocket jump starters. I had first noticed these about a year ago. The thread prompted me to take advantage of a Black Friday weekend offering at a well-known brick-and-mortar boater's supply store.

The unit I bought totally failed to turn over my Yanmar 2QM20 in my simulated dead battery test.

The product itself looks very well designed and made. And it did easily start my 1.5 liter Toyota in the same dead battery test. Because it capably did what was specified (start a car) I don't want to degrade the product name by mentioning it.

However I thought to at least post my experience that maybe not all of these units have enough oomph to turn over every sailboat diesel engine in a severely depleted battery situation.

Details of my test:

1st Phase - My Car:

- Charged the pocket charger per instructions until it's LED's showed fully charged.
- I have an old 12ah 12v gel-cell at home which I occasionally use as a 12v power supply. I disconnected the 12V+ harness from my Toyota's battery and connected the gel cell as it's substitute. I then turned on the lights, heater, etc to drain the battery until the all car's systems were totally dead.
- I then connected the pocket jumper per the instructions.
- The engine started almost as quickly as with it's normal fully charged 12V battery.
- I disconnected the pocket jumper and went about re-charging it again.

2nd Phase - My Boat's Yanmar 2QM20

- Essentially the same process as the car.
- Disconnected my group 27 deep cycle #1 and #2 batteries from the circuit.
- Connected in their place the same gel-cell I used as the simulated dead battery in the car start experiment.
- Connected the pocket jump starter as per the instructions.
- Upon turning the start key, the starter did engage, but could not crank the engine. Not even close.
- I tried several times.
- Just in case the pocket starter needed some less resistance between its clamps and the starter, I even ran a second starter motor wire. Still wouldn't turn over.
- Reconnected the dedicated G27 batteries. Battery #1 started the engine in 1-2 seconds.

Granted, using a totally depleted rather small gel-cell as the dummy battery is a worse-case rather extreme scenario. But I would want to have fully able back-up in the case some mistake was made and my house batteries did become virtually depleted. I have a very basic set-up. No low battery alarms or auto shut-off when the voltage drops. So maybe this level of extreme may not be common for most owners.

 

[Maine Sail]

On this forum several days ago was a thread about pocket jump starters. I had first noticed these about a year ago. The thread prompted me to take advantage of a Black Friday weekend offering at a well-known brick-and-mortar boater's supply store.

The unit I bought totally failed to turn over my Yanmar 2QM20 in my simulated dead battery test.

The product itself looks very well designed and made. And it did easily start my 1.5 liter Toyota in the same dead battery test. Because it capably did what was specified (start a car) I don't want to degrade the product name by mentioning it.

However I thought to at least post my experience that maybe not all of these units have enough oomph to turn over every sailboat diesel engine in a severely depleted battery situation.

Details of my test:

1st Phase - My Car:

- Charged the pocket charger per instructions until it's LED's showed fully charged.
- I have an old 12ah 12v gel-cell at home which I occasionally use as a 12v power supply. I disconnected the 12V+ harness from my Toyota's battery and connected the gel cell as it's substitute. I then turned on the lights, heater, etc to drain the battery until the all car's systems were totally dead.
- I then connected the pocket jumper per the instructions.
- The engine started almost as quickly as with it's normal fully charged 12V battery.
- I disconnected the pocket jumper and went about re-charging it again.

2nd Phase - My Boat's Yanmar 2QM20

- Essentially the same process as the car.
- Disconnected my group 27 deep cycle #1 and #2 batteries from the circuit.
- Connected in their place the same gel-cell I used as the simulated dead battery in the car start experiment.
- Connected the pocket jump starter as per the instructions.
- Upon turning the start key, the starter did engage, but could not crank the engine. Not even close.
- I tried several times.
- Just in case the pocket starter needed some less resistance between its clamps and the starter, I even ran a second starter motor wire. Still wouldn't turn over.
- Reconnected the dedicated G27 batteries. Battery #1 started the engine in 1-2 seconds.

Granted, using a totally depleted rather small gel-cell as the dummy battery is a worse-case rather extreme scenario. But I would want to have fully able back-up in the case some mistake was made and my house batteries did become virtually depleted. I have a very basic set-up. No low battery alarms or auto shut-off when the voltage drops. So maybe this level of extreme may not be common for most owners.

Good test and not at all surprising. Diesels have a very high in-rush demand and I would suspect most of these are simply too small for most diesels.. I have a hefty AGM based jump pack and it too gets wiped out on some diesels...

 

[Stu Jackson]

Re: Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm2

Thanks for that real-world test rardi. Many of us have been suggesting that if folks were even considering those things, they would be better served by adding a true reserve battery bank, and just wiring and fusing it properly. For about the same cost. And it would work.

The ONLY considerations I've EVER heard that makes any sense to me is where someone made good use of it elsewhere in their lives, like for their cars. But then one has to schlep the thing back and forth anyway and make sure it's charged.

Great report, thanks again.

 

[Johnb]

Re: Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm2

I have successfully started the diesel on weak batteries by relieving the compression, starting it cranking and then restoring the compression. It may be interesting to try that if you are willing to take the trouble.


JEB

 

[rardiH36]

I have a hefty AGM based jump pack and it too gets wiped out on some diesels...

would be better served by adding a true reserve battery bank, and just wiring and fusing it properly. For about the same cost. And it would work.

Until I found a more advantageous use for it at home, I did have a 35AH AGM reserve battery on my boat. When I remembered, I would flip a shunt switch from my maintenance charger solar panel to keep it topped up. It's own A/B/Both switch kept it isolated from the starter and the house circuits unless needed. This small battery did start the 2QM20 quite well. As you both suggested above, when the pocket charger didn't work as hoped (but frankly I had my doubts anyway) it did occur that wiring up a basic starter battery, fuse and a low watt solar maintainer like this one (http://www.batterymart.com/p-blsola...campaign=PLA&gclid=CJHRk9bqo8ICFcvm7AodBRYAoQ) wouldn't cost much more in total than a pocket starter but would be very adequate. The solar trickle charge, cycling every date/night, would likely mean the never deeply drained battery would stay in prime condition for years!

 

[Benny17441]

Re: Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm2

Thank for your report, I was starting to get interested in these but I guess I'll pass and continue to use my bulky battery pack.

 

[centerline]

not saying anything you did was wrong, or that the jump-pak would ever start it, but some of these little jump starter packs have so much energy stored in them that it cant transfer out of the small cables fast enough to the other battery/starter.

as with jump starting the conventional way with jumper cables hooked to another battery, it will ALWAYS give the best results if you wait 5-10 minutes after connecting them before attempting to start the engine.

I have used my "Rescue 900" jump pak to start a caterpillar D-6 dozer with (4) G31 batteries that was too dead to crank over.... hooked the jump pak up to it and waited 15 minutes... and it cranked over and started, and thats saying quite a bit, because the ECM needs to see enough juice after the starter kicks in, or it will still crank without starting...

 

[Brian D]

Re: Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm2

So in essence centerline, you are basically allowing the jump pack to charge your batteries enough to give it a kick? Interesting. As I was reading other comments I thought about that. But can the jump pack actually transfer to the dead battery enough juice to allow it to kick over a diesel?

 

[Chief RA]

Re: Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm2

Centerline: careful with that approach as you can wind up with your jumpstarter battery not able to start anything either after equalizing the voltage level with the low battery bank.
My best results have been to disconnect the primary batteries and start the motor with just the jumper battery. Chief

 

[buzzerk]

Re: Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm2

I gather the focus of this thread is starting the Yanmar 2QM20 with less than full battery capacity. My Yanmar 2QM20 still has the manual start hand crank. I mention this because the hand crank is useless without releasing the engine's compression. Hand crank starting is another story.

A 'dead' battery will crank any engine with no compression as long as the battery is not dead flat from being drained by a high resistance short somewhere in the circuit or other reasons too numerous to include here.

If the battery can engage the start motor with compression it will turn the engine with good speed to get the first 'bump' to start the engine. (it helps to have a remote start button near the compression release at the engine, as my installation does not have a compression release at the engine panel in the cockpit)

I have done this with my Yanmar 2QM20 as an experiment. It was successful.

use the factory compression release

 

[centerline]

Centerline: careful with that approach as you can wind up with your jumpstarter battery not able to start anything either after equalizing the voltage level with the low battery bank.
My best results have been to disconnect the primary batteries and start the motor with just the jumper battery. Chief

there are always risks when jump starting.

my business includes jump starting equipment.. LOTS of equipment that is hard to get to and have large batteries or a bank of batteries..... if it was easy they wouldnt call me.

the jump pak does lose its charge, but it can be recharged... or as in the one i have, the batteries can be replaced for about 25% of the cost of the unit. so i am more concerned with getting done what the man is paying me for.
but there IS a lot of common sense being used in the process of it all.

all these newer jump paks carry a lot of potential energy.. and so does the single bank of 4 g31 batteries in my truck, but if the energy cant transfer out quick enough, it does no good at all.

here is a scenario that i run across quite often, but is a bit more extreme than many will ever have to experience... it is an attempt to explain the process of what I meant in my earlier post.

I have a set of jumper cables made out of #2/0 welding lead. they have SMH connectors so that I can insert extensions (or so I can hook to the welder for when we need some REAL amps), and I have extension enough to reach 75 ft from my truck..... but even with all that potential energy I have in my truck batts, it takes a while to transfer out to a battery that is 75 ft away.
and taking the dead battery OUT of the system and only trying to use the jumpers is detrimental to the process. it NEEDS to be there for an energy sink next to the starter, someplace for the stored energy to expand into... and be realized when the start button is pressed.

as much as this particular type of jump start never works for an immediate start, it is ALWAYS 100% effective if you have patience....

and procedure with the small jump pak may be no different, but everything is just on a much smaller scale. give it time to do its thing and you may be surprised with the results.


and I think most people that need a jump start are more concerned with the results than they are with the methods... nor do they even realize or understand that it may not be a dead battery at all, but a failed connection....

when jump starting, there are many risks being taken, and if the fear of damage to life, limb or equipment is too great to get the job done, then either more education is needed or someone else with more education is needed to complete the task... in most cases, experience = education... but not always

 

[Bgjj]

You need to have a poweful enough jump pack, mine will start a dead diesel in 20 degree below in winter will also run my home furnace in power outage for a day

 

[centerline]

You need to have a poweful enough jump pack, mine will start a dead diesel in 20 degree below in winter will also run my home furnace in power outage for a day

I would never say bigger isnt better in this case, but sometimes when you dont have bigger to use, you have to use what you do have to its best advantage...

no matter what it is, some of us buy the biggest, baddest and the best (according to the advertising)... some of us buy what we know will work for us.. and others try to get by with the budget unit.
but knowing how to get the most from what we have is sometimes more important than thinking, after the fact, that we should have bought the biggest unit available...

 

[Charlie Jones s/v Tehani]

I have successfully started the diesel on weak batteries by relieving the compression, starting it cranking and then restoring the compression. It may be interesting to try that if you are willing to take the trouble.


JEB

Yep- my old 2QM20 had a decompression lever. You could spin it with a virtually dead battery (or hand crank it), but not all small diesels have that set up. A friend of mine has a Beta Diesel ( 20 HP) and it doesn't.

 

[rardiH36]

I have successfully started the diesel on weak batteries by relieving the compression, starting it cranking and then restoring the compression. It may be interesting to try that if you are willing to take the trouble.JEB

John and TSSB:

Yes thanks for the suggestion about the decompression method. On my boat however, the engine is mounted such that the hand crank bumps up against the framing behind the companionway stairs. Can't really get much of a spin. I sail mostly solo -- or with people who I wouldn't feel confident about assisting with much. So to use the decompression levers to assist electrical jump starting (or maybe getting the engine started with run-down batteries), I would really need to run a push-pull control cable from the compression lever fitting on the engine into the cockpit. This way I could attach a jump starter, open the decompression lever, push the engine start button and while still pushing it close the compression lever.

 

[Charlie Jones s/v Tehani]

Re: Pocket Jump Starter Outcome: Would Not Crank Yanmar 2Qm2

Yep- sometimes the engine is installed for triple jointed folks with nine foot arms . Sorry.

 

[rardiH36]

We All Gotta Learn about Li-ion Technology

Reflecting more on my opening post describing the disappointing experience with a Li-Ion pocket starter, and re-reading some of the responses, I thought maybe to pass on what I have learned about Li-ion (and also the LiPo variant). It's raining outside so I've got the time today.

This is a technology that going forward we should know as much about (or more actually) than lead-acid batteries. Besides my attempt here, I've included way down below the urls to a couple of very good primers about Li-ion and LiPo batteries.

I am not an engineer. The following is just some of what I have observed and learned over the years from RC model airplane experiences, a few DIY LiPo projects, and just reading stuff. This started about seven/eight years ago when I decided to try my hand at remote control model airplanes. Just a few years before then, two technologies converged which overnight virtually put the old gas/glow plug engines we knew as youngsters into pasture. The new kids on the block were Lithium Polymer batteries (LiPo's) and Brush-Less motors. These two advances are the basis for the power plant in every helicopter type drone you guys are using to take areal videos of your boats.

Brush-less motors are much more efficient than brush/armature motors at converting electricity into useful power. Recently on this forum was a discussion about their adaptation for cordless power tools.

Li-ion batteries are what enables our smart phones, laptops, notebooks, GPS's, etc to work so well. They hold many many times the amp hours for a given size and weight compared to Pb, NiMh and NiCd batteries.

But Li-ion have limits for high amp draw applications.

So step over to Lithium Polymer (LiPo) batteries. They have the same basic chemistry as Li-ion, but variations in electrolytes and construction permit incredible discharge rates. LiPo's that one can buy at any hobby shop have a "C" rating. Multiplying a LiPo's milliamp (maH) hour rating times C = the sustainable amp draw. When I first started RC airplanes 10C was common. Now 30C is middle of the road. And I've seen up to 65C. This are the continuous ratings. Usually C is twice that for burst mode. Example: say a LiPo is rated 3000 mah = 3 amp hours. Times 65C = 195 amps continuous draw rate. Incredible. But the downside is that 3 amps/195 = .015 hrs. This battery will be depleted in about one minute. And three amp capacity won't do much to top up a depleted 12v starting battery.

From the website of the Pocket Jump Starter that I bought (now returned), 24 watt hours is its capacity at ~ 12V. This would imply approximately 2000 mah = 2amp capacity. Instantaneous cranking power is amazing. But the engine better start quickly.

I expect that pocket jump starters generally have three lipos wired in series (and I have encountered a report or two on-line where people say they have taken one apart and found three cells inside). The nominal voltage for a Li-ion or LiPo cell is 3.7v. This represents approximately 20% charged state. Fully charged voltage is 4.2. So for three in series its 12.6V. (But a 3S Lipo cell is usually referred to as 11.v)

A downside of Li-ion and LiPo batteries is they require sophisticated and sometimes expensive circuits to prevent over-charging resulting in potential explosion and fire. And they prevent over depletion below a certain threshold which would otherwise totally ruin the battery or greatly reduce its function in subsequent recharging attempts. Here is a link to a Protection Circuit Board example that at 80amps would be presumably be suitable for a DIY power tool conversion (from NiCad) that one could charge from a boat's 12V battery. http://www.ebay.com/itm/Battery-Pro...300?pt=LH_DefaultDomain_0&hash=item3a9c2ee984

For LiPo's wired in series, each cell has a tap which is wired into the control circuit thus allowing the circuit “to see” each cell individually. Every application must have circuitry that controls and cuts off charging, cuts of the battery pack when cell voltage reaches a set minimum, monitors current draw and the like. 4.2 volts is the upper charge limit for each cell, although 4.35v can be the absolute charge termination threshold. Beyond this limit, LiPo's will over-heat and are subject to spontaneously igniting. If a LiPo cell is over-discharged, its ruined for good. No recovery. I haven't seen any hard and fast rules, but discharging not more than about 20% capacity (~3.7v per cell resting) supposedly will ensure hundreds or even a thousand recharges. Down to 1.5 volts is recoverable, but with loss of function. Below 1.5v, toss the battery. Each cell's tap enables it to be charged individually to the 4.2v max. And the control circuit will cut off the entire pack if any cell falls below the minimum voltage threshold. Or if the amp draw exceeds the designed rating. And example of this is Li-ion power tools. They go from working strongly to completely stopped when the monitoring circuit detects that the voltage in one of the cells falls below the threshold at which point the circuit cuts the power totally. You can see details of this in the specification info contained in the above url example. Because power tools can have very high amp demand, the circuits (which are inside each battery pack) are very robust with heat sinks and large solid state components. Our mobile hi-tech devices have circuits that do exactly the same. But the circuit boards can be diminutive in comparison.

LiPo's and Li-ion batteries now are available in many different shapes and capacities. Although the shapes are designed so they will not fit in AA, AAA, C and D devices. Some new consumer devices are being marketed just for these cells. Hi lumen LED Flashlights are one example. Electric cigarettes are another. I recently bought “9V” rechargeables which in the Li-ion variety charge actually to 8.4v max. A special charger is required. Each “9V” battery has on board a PCB which will cut off the power if one of its two cells is discharged to the trigger threshold. Rated at 650mah, these 9V's are hi-capacity compared to alkaline.

A very strong plus for Li-ion and Lipo is self-discharge is extremely low. Can be stored for a year or longer. Although for best life an unused Li-ion should be discharged to 3.7v rather than stored after charging to 4.2v. The special chargers that RC enthusiasts use have a function to discharge batteries to this voltage.

I hope someone has read this far. And for those that hadn't really given Li-ion or LiPo a thought before, maybe some background why on this battery type is a completely different animal from what we have previously known like alkaline, NiMh, NiCd and Lead acid. Below are links to a couple of very understandable primers which do a much better job than I have.


http://www.rchelicopterfun.com/rc-lipo-batteries.html

https://www.electricbike.com/lithium-battery/

 

[Maine Sail]

Some of us are actually using Lithium batteries for our house bank. No problems cranking with 400 Ah's of LiFePO4..

 

[Chris Patterson]

Man, I can't wait for this technology to become more mainstream in application, ie: boats. When Maine described how the glow plugs burned out so quickly was my selling point..