Battery Pack/Jump Starter Help

I'm hoping some of you guys can provide some guidance on a battery pack/jump starter. Recently, I've run into some sort of electrical problem that's draining my cranking battery. I have a 115hp Optimax.

The problem is quite intermittent and I never know when I might have a problem. Fortunately it has sprung up when I'm pretty close to home or the ramp. While I'll be working to figure out what my problem is, I thought it would be a good idea to add one of those small battery packs/jump starters on the boat. Do any of you guys have experience with a certain size/brand that you might recommend I purchase or maybe steer clear of?

My plan would be to keep this thing on the boat permanently and only have to charge once or twice a year (to make sure it is always ready to go) or maybe after it has been used. I'm guessing there are some lithium versions that would be the way to go.

Thanks for any input.

TW

Is the alternator on motor charging ?

With the motor running check the voltage at the battery. Should read 13-15 VDC
Check all battery connections to be sure they are squeaky clean and tight. Look for signs of corrosion at the base of the lugs. They can corrode inside and cause intermittent problems. A voltage drop test is the cadillac of electrical tests.

You really need to get that fixed. The optimax will not live long with low battery voltage. I know from very costly and painful experience. It'll quit pumping oil and seize a piston during a low voltage episode. Powerheads are like $6k each. Not good.

Okay, here's some more info. Thanks for the comments so far. I bought a Mako 18LTS from BPS in Myrtle Beach in 2015. Overall, the boat has been very good. When I first got the boat, it seemed odd that every time I took the boat out of the water, there was always a fair amount of water to drain out..... at least a gallon or two (maybe more than that). I'd never had a newer boat like this and just assumed this was normal. I often have my boat tied up to my pier at lake norman overnight. Here over the past couple of years, there's many times that as soon as I step in the boat, the bilge way down in the bottom comes on. I have no idea where it is pumping the water, but it will pump for a while, even to the point I hear air getting into the line...... but it keeps pumping and won't shut off. It may run 15 minutes before shutting off. Here over the last month, it seems to have gotten worse. What I don't know is if the bilge float switch is getting hung up, or is it possible there's just more water coming in from wherever it is getting in at. I will say that I still hear, and see, air in the line as it runs for a long time. I also recently found that if I stick my hand down to the bottom (very difficult), I can sometimes wiggle or hit the bilge and it will go off. My wife has also mentioned that she has heard the bilge running when she was outside and really, there was nothing happening with the boat - it was just more or less sitting there still. I'm thinking that the bilge may be running for such a long time, that it may be draining the battery - the boat may sit for maybe 18 hours between uses. If the bilge ran for 6 hours or so, would that be enough to drain the battery (5 years old but recently tested out good). So, It seems I should do a couple of things - first just get a new Bilge pump and see if that fixes the problem - if the bilge shuts off once it is complete, it would run way way less. Next, see where the water is getting in at. This could be quite difficult as I guess there are many, many places - cracked hull, leak where the plug goes, bad plug, leak where the bait tank pulls water, cut hoses, loose fittings, etc, etc, etc.

My reason for getting a battery pack is 2 fold - I'd rather figure this out myself than take it to BPS and waits weeks or months as I want to keep using the boat over the next few months. Also, it just seems like a good thing to have on board - for me or the other stranded boater.

More comments and suggestions are welcome.

TW

I have one of the lithium battery packs from Walmart,It works great,I had one I bought off Ebay,Volt power was the brand,It worked great also just got hooked up backwards and fryed it.

If you don't have a dual battery setup.... you should always carry a battery backup. Here is one I recently purchased ... just in case. Works well. Good reviews and cheap.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

You should also have an onboard battery charger that keeps you batteries at full charge when not in use. It will save a world of aggrevation and trouble. Most people don't run their outboard enough to keep the battery charged.

OK, SO there seems to be quite a lot going on here lol.
For a jump starter, I'd recommend going to Amazon, getting one of the ~$60 Lithium ion jump starters. They are compact and work well when the power goes out for charging things.
For the true issue at hand, those automatic bilge pumps have a bad habit of malfunction. They seem nice, but they malfunction at the worst time, either not coming on or coming on all the time.
First thing I would do is pull the boat and find the leak. That's more of an issue than the bilge draining the battery. Put it on a trailer and run some water inside from a hose, and see if you can locate the leak. It could be a thru hull or something more serious. Once that's fixed replace the pump and you should be good to go.
Moisture in a bilge will eventually cause some horrible problems.

I agree try to fix the issue first but look at the NOCO genius GB40 to take with you incase your main battery drains.

I recommend an isolation switch at the battery. if you are draining the battery while it is on the trailer that will solve that problem. If you only have the problem after it has besetting for a few days I don't think it would be the alternator but I could be wrong. My boat has a run/auto switch for the bilge pump. I never turn it to auto unless it is in an open slip and expecting heavy rain. I learned that lesson the hard way..