Battery boost starter.

[Walter Hobbs]

Greetings all,

Anyone carry one of those battery boost devices on board. In theory you could run down your battery banks and then start your engine if you had one of these on board. I see them available for less than $100. Seen demos of lithium batteries catching fire. But checking on google says they are safe.
Thoughts? Thanks.

[sgbernd]

My thinking is as follows;

1) How long do they last before they don't work enough to start a diesel? 3yrs? 5yrs? 9yrs? If you have experience, I'd like to know. If the number is on the order of the lifetime for lead acid, why not just keep fresh house batteries?
2) What is the fire danger? I know of boats burnt up due to Li batteries in portable laptops, etc., including a local dive boat with loss of many lives a few years ago blamed on a fire during recharging. Lead acid is pretty good in that it does not tend to burn.
3) This is why we use dual batteries and a combiner switch, one for the house and one for the engine. Having never had any trouble with that arrangement, what probability is there that you will need the backup?

My old MD7 engine could be hand cranked which made me happy to have a backup. Unfortunately, the current engine (a Beta) cannot. In the 22 odd years I've owned this boat, the diesel never failed to start without hesitation. So I have decided not to worry about it anymore.

-steve

[gonesail]

i just bought one for 60.00 and carry in my truck but will carry in the boat too. it is rated to start a 3.5 liter diesel and 7 liter gasoline.

[John Stone]

When I was installing the diesel in the Far Reach and soliciting input on the battery system one of the forum members recommended I car a small portable jump battery kit as insurance. I don't remember if it was Fred, Paul D, Jim, Chris, or Tim. Anyway, I did some research and we purchased one called Track Life T8 Pro. Comes with all kinds of adapters as well as small jumper cables. What a capable little unit. We carry it with us Overlanding in our Jeep but I have it with me on the boat. I just checked its SOC. Still 100 percent. You can charge it from a 12v USB or 110v. It has adapter to run your phone, laptop, or start the engine. Though I have never had to use it, seems like a good piece of equipment to me.

[fmueller]

Hey Walter

I have one from Noco ( 4 years ) ... I'd say similar quality (high) to John's example. Holds a charge seemingly indefinitely.

https://no.co/gb40

Gave one each to two sons as Xmas presents same time. Both have jumped cars without problems. For that use they are brilliant. But I have never had to use mine on my boat - except it makes a great work light.

Last winter we tried to start the club launch with my pack in freezing temps. It cranked the motor 1/2 doz times for 5, maybe 10 seconds seconds and then was out of capacity - so not nearly as robust as a good lead acid battery. But the guys had already killed a grp 27 flooded battery before I offered up my pack - so that motor was just not going to go. They got it to go days later after fuel system work.

I think my Beta would have easily started in the same circumstances but I'm not going to run down my bank in cold weather just to test, nor disconnect my bank and test (with the pack) with no lead acid buffer for the alternator and possibly damage other devices or the alternator itself. I don't think the lithium pack acts as a capacitive buffer for the alternator in the same way.

I'd say if you have a hard starting motor, then perhaps a lithium pack might not be adequate backup, but I'd be wanting to remedy the starting problem. I prefer the added (doubled) working capacity of using both of my group 27 AGMs as one house bank. So I just keep the Perko switch on A+B and check the lithium pack from time to time. If I were crossing oceans I'd reconsider, but I would not be doing that in a CD27 either.

[Tom Keevil]

We carry one on board. Have never had to use it, and it seems to hold its charge a long time. The idea that you’ve never made a mistake or had a problem with your batteries, so you don’t need a backup is not a good approach in my opinion. We have never had a problem ourselves, but we have used our battery to jump start friends who also had never had a problem in 30 years of cruising. On that occasion we were in central British Columbia up a fjord with no VHF or cell reception. If they had been alone, they would have been in trouble. That’s when we bought our backup starter system. We try to have a backup plan for most problems we can imagine, and from time to time we have to use them.

[wikakaru]

Back in the day--way before you could buy lithium ion battery packs like these, and way before you could get cheap high-output solar panels--we used to keep a really long pair of jumper cables on board that could reach from the battery bank down below over to another boat's battery bank. They were huge and it was a hassle to store them, but we felt it was important enough an issue to carry them around. The modern lithium jump boxes are a much better alternative for most situations (the aforementioned case of a really hard-to-start or malfunctioning engine on a boat with a dead battery being the main exception). They are a fairly inexpensive piece of emergency gear. If you have the money in your boat budget, it's a nice versatile piece of insurance, but not a necessity if your boat budget dollars need to be spent elsewhere.

Smooth sailing,

Jim