Garden tractor battery update

[bigdee]

Because of potential marine battery theft I chose to try a small garden tractor battery ($29) in my 'toon. After almost a full summer of boating it has worked great and the thieves don't seem interested in it. Cranks my 85hp Yamaha easily and runs the navigation lights while anchored for hours while fishing. I know it sounds crazy but it works. My tilt also slowly drifts down ( I raise it out of water when docked) so I routinely go down to dock to raise motor without charging battery.

 

[alldodge]

Great follow up, I don't plan to do the same, but would be great if one of those would crank up and BBC

 

[bigdee]

I'm not recommending everyone do this but I was surprised it worked so well on a 85hp 2 stroke. Just had to share!

 

[alldodge]

Not to side track your thread (read the original) but this idea is great for the smaller OB,

Wonder if someone installed a battery under something non-discript and left bare ghost cables out in the open for looky lues, (theives). So it looks like the boat owner took the bat with them, but actually its under something else hidden. In any case glad it worked out

 

[Scott Danforth]

I had used two of the AGM batteries that you find in a jump pack or emergency lighting for my wooster as it didnt take much to turn over the 9.8 also using them on the fishing boat as that is only a depthfinder and lights (pull start)

 

[HotTommy]

On the topic of lightweight but powerful batteries, has anyone here used a Lithium battery? I know they are pricey, but I'm curious if anyone has real world experience with one.

 

[alldodge]

Have not seen a 12V lithium (not rechargeable) battery, but to use as a start bat, it would need to be Lithium Ion (rechargeable)

 

[bigdee]

On the topic of lightweight but powerful batteries, has anyone here used a Lithium battery? I know they are pricey, but I'm curious if anyone has real world experience with one.

No not really BUT I do have a lithium power pack about the size of 3 cigarette packs ( roughly 3.5x 6 x 1" thick) and have jump started numerous engines including 5.7 V8. It is so small I carry it every time I go boating. It has helped a number of times at marina getting people with dead batteries going. Out performs my BIG heavy Stanly Fatmax jump starter.

 

[ahicks]

Re: lithium batteries, they don't care much for being overcharged. Leaving them on a small trickle charge a definite no-no. Their chargers need to shut off completely when the correct voltage is reached. Same thing on the discharge side. If you run one down down completely, you've likely ruined it (like leaving a light on for instance). Bottom line is the batteries need to be managed carefully, or combined with electronics that will do that for you automatically. Those are known as BMS's, as in Battery Management System which usually make the package quite a bit bigger than just the battery. At least that's the way it is today. Tomorrow, who knows.......technology like this advancing at an incredible rate!

Upside is that they hold their charges at near 100% for months on end, so they're ready to go when you need them. Too, they have incredible output when it comes to amperage. You don't need a lithium battery anywhere near the size (or weight!) of a lead acid for instance.....

 

[Scott Danforth]

On the topic of lightweight but powerful batteries, has anyone here used a Lithium battery? I know they are pricey, but I'm curious if anyone has real world experience with one.

guy at work has LI's in his boat to run his trolling motors but not the outboard. he fishes tournaments and gets more time fishing. think he said he spent $3600 for the batteries and charger.

 

[clemsonfor]

That's the downside. They cost 3x what normal LA batteries cost

 

[Cat nip]

The battery from a honda civic is a group 51 and is less than half the size and weight of a typical group 27 and has plenty of power to start a 1.8 litter 4cyl engine in sub zero temps. If all you need is a cranking battery for an outboard under 150hp it would certainly have enough power

 

[ahicks]

Let's keep in mind that not all starter motors are created equal. Some are equipped with a gear reduction, which not only draws less amperage, the starter motor itself can be smaller/lighter.

 

[icwingman]

buy a big jump box and take it home when leaving the boat.

 

[bigdee]

buy a big jump box and take it home when leaving the boat.

My days of the big jump box is over. The little lithium jump boxes that will fit in your pocket (cargo pants) are the way to go.

 

[bigdee]

Update: Now the garden tractor battery has been moved from pontoon to a Chevy Malibu that needed to be moved!. Cranks just fine......temporary of course. Kinda funny lawn mower to pontoon to car.

 

[gm280]

Interesting read for this thread. If you would like to install a LI pack, you can either buy or build a charger setup the would work off the engine (while running of course) and be safe to charge and disconnect or shut off after it is recharged.The circuits are out there, and can be built if that is your hobby. JMHO

 

[H20Rat]

Interesting read for this thread. If you would like to install a LI pack, you can either buy or build a charger setup the would work off the engine (while running of course) and be safe to charge and disconnect or shut off after it is recharged.The circuits are out there, and can be built if that is your hobby. JMHO

There are lithium iron batteries that are meant to be used as starting batteries. Doing what you propose would fry the electronics in most engines without more modifications. Modern engines need a battery connected to help regulate voltage. Disconnect the battery, and voltage will go sky-high, frying everything in the path.

Something like this... Price isn't even too bad.
https://earthxbatteries.com/shop/etx12a

or
https://earthxbatteries.com/shop/etx680