VERY useful tool for jumpstarting engine

[Rohan]

Just passing this along as a tip.

This type of item is becoming popular, a portable battery that includes jumper cables because when it is at least 3/4 charged, it is supposed to be strong enough to jumpstart a car or truck engine. The instructions don't say anything about boat engines, but since my Yanmar 29 hp 3YM30 diesel engine is much smaller than many of the engines this thing is supposed to handle, I figured it should work.

It sat around unused for awhile, because I didn't want to purposely run my battery down far enough to test it out. However, last week, one of my battery banks failed, and was down to 11 volts, which is considered a dead battery. I couldn't start the engine. So it gave me a chance to try this out, and it worked like a charm!!

The connection was a little finicky and you have to watch your boat's voltmeter to see when it jumps up a bit and then the connection is solid. But once you got it, you are good.

This is the type I bought for about $80. But I'm not product hawking here. This is just the one I tried, but there are a lot of other similar batteries on the market now that do the same thing. If you search online they are sold everywhere.


Highly recommended. Now I have peace of mind that if both my battery banks fail for some reason, I have a backup to restart the engine. It's also useful for recharging other things, and has a built in flashlight. And takes up very little space.

[Lake-Effect]

Thanks for the report. I have seen those, but haven't heard much about them. What kind of battery do they use, and how do you keep it topped up?

A neighbour bought one and tried to use it to jumpstart a dead car, but it didn't work for him... but maybe he didn't fully charge it beforehand.

[Rohan]

Originally Posted by Lake-Effect

Thanks for the report. I have seen those, but haven't heard much about them. What kind of battery do they use, and how do you keep it topped up?

It's lithium-ion like a cell phone battery. You can charge it by plugging it into anything. I keep it topped off by plugging it in one of my 120v outlets while on
shore power so it's ready to go when I am sailing. And you have to trickle charge it some way, it does lose a lot of charge after three weeks or so.

A neighbour bought one and tried to use it to jumpstart a dead car, but it didn't work for him... but maybe he didn't fully charge it beforehand.

That's possible. It also depends on what type he was using, what was the car battery status, and how cold it was outside. The model I have jumps at 400 Amps which might not be not enough to start a boat motor all by itself if your battery is literally completely dead at zero volts. There are some versions that are as high as 800 Amps and that would probably be enough for that job.

[GreenWave]

A wise gentleman once told me (assuming you have more than one battery bank), that traditional jumper cables may be all you need to start a dead engine battery. For example: I have a house bank, two thruster batts, and a separate genset starter batt. I start my main engine off of the house, but the potential problem is the genset as it only charges itself when the generator is running. So I have had to jump start that before.

[rslifkin]

Originally Posted by GreenWave

A wise gentleman once told me (assuming you have more than one battery bank), that traditional jumper cables may be all you need to start a dead engine battery. For example: I have a house bank, two thruster batts, and a separate genset starter batt. I start my main engine off of the house, but the potential problem is the genset as it only charges itself when the generator is running. So I have had to jump start that before.

Agreed. I've got 2 engine start banks (either engine or the generator can be selected to either start bank with a switch) plus a house bank that could be connected with jumper cables. If I can't get an engine started with all of that, chances are something has gone wrong to the point that a jump pack won't save me (especially considering my engines need power to stay running).

[Simi 60]

VSR is surely a better device.
And cheaper.

The 12v / 24v 120A Cyrix CT battery combiner from Victron Energy is a feature-packed intelligent split charge solution for charging your leisure battery from your alternator and ensuring you never accidentally flatten your starter battery. More commonly known as a voltage sensitive (or sensing) split charge relay, this unit will automatically connect your starter and leisure batteries when a charging voltage is sensed and will automatically disconnect them when it senses the voltage drop away when the engine is turned off. This isolates the batteries when they are not charging so your starter battery cannot be drained by your domestic circuits.

This relay features voltage trending software to overcome short-term fluctuations in voltage levels and prevent unwanted disconnection (e.g. when first connected to a leisure battery with very low charge and/or of a very high capacity, the resultant voltage drop across the starter battery can be significant and can trigger a false disconnect in some other voltage sensing relays - sometimes referred to as 'chatter' as the relay quickly opens and closes repeatedly).

Another useful function is the emergency start assist. If the starter battery has become flattened and you wish to use the leisure battery to start the vehicle, you can manually close the relay using a momentary switch wired to terminal 85 (relay remains closed for 30 seconds).

https://www.12voltplanet.co.uk/victr...224v-120a.html

[Cheechako]

I have one. Researched it, got the one with good reviews. at about $90. Bought it for the boat. I've used it a few times for cars etc. Trouble is, it wont start a car or a boat unless you charge it quite often. So just leaving it in the trunk, or lazarrette etc ain't gonna help.
I never have figured out if it was just defective from the start or typical. So I just leave it plugged in in the garage in case I need it at home, it charges whenever the garage light is on.

[gonesail]

I had one of those jump starters once. never used it but carried it in my truck. once while moving the boat I found the batteries too low to start the yanmar 3GM. thought I would have to wait hours so they could charge with the shore power. then I remembered the jump starter .. 5 minutes later I was on my way

[zengirl]

$70 bucks on amazon

[Lancerbye]

I have had one of these for about 3 years now. Have never used it to start my own engines but have passed it over to several stranded people with low or dead batteries. Their small diesel engines started right up. I have used it mainly as a 12 volt source to test things like pumps, fans and electronic gear. I even use it as a power supply to a small ATV winch which I use to go up and down the mast.

[bcboomer]

I had one and used it once. It worked but there was a part on the cable that melted and started to drip burning plastic. Pretty exciting at the time.

[Gary Matthesen]

I got one a few years back, cant recall how many amps, but bigger is better. I tried it without the boat batteries on a 21 HP Universal Diesel. While it could crank the motor, it was not aggressive enough to start it. Bottom line, as an assist to low batteries your good.

[jim King]

I picked up a very similar power pack at Costco about four years ago. It is small and light weight so I kept it aboard while cruising. I only needed it once when my boat batteries had gone too low to start the engine. Worked like a charm. One time was more than worth the cost of the power pack.
Jim

[SV Bacchus]

Originally Posted by bcboomer

I had one and used it once. It worked but there was a part on the cable that melted and started to drip burning plastic. Pretty exciting at the time.

WOW, I can imagine it would be quite exciting! Did you chunk it (trash) or put on larger cables?

[Tom_F]

I have one of these https://tinyurl.com/y9wdaauo and love it. I got mine on sale at my local auto parts store for, I think, US$79. We had a bad engine battery and some charging issues (not a good combination) and used this to start our engine on several occasions. If the battery is very flat, you may have to turn the charger on and let it charge the battery for a few minutes before it will start. The battery pack retains a charge for quite some time.

Just one caution - this manufacturer makes several models. This one says it will start a diesel engine up to 3 litres, but some smaller ones say they are for small gas engines only.