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Do You Carry A "Jump Start" Battery?

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Jun 3, 2004
418
Island Packet Island Packet 29 West River, MD
Just curious if anyone carries a jump start battery and if so how much power does it produce? I have a Yanmar 3GMF and an isolated starting battery. When I motor I place the battery switch in the "ALL" position. I admit that every once in a while I forget to switch it to the house side when the engine is off. It's never caused a problem but I decided it would be a good investment to get one of those jump start batteries just in case I really draw down both the starter and house batteries. I read my engine manual and it stated the engine needed 75 amps to turn over. So I bought a 300 amp battery jump starter. It's the type that has a small air compressor included. I decided to test it out but it wasn't powerful enough to start the Yanmar. I disconnected the cables from the on board starter battery and connected them to the jump starter. When I turned the ignition key it just wasn't nearly enough power to turn the engine over. I released two of the compression levers to see if that would help but still it wasn't enough.

Maybe I read the engine manual incorrectly and it requires a more powerful battery. I'm looking for some advice. I already have Boat US unlimited and my insurance policy will also pay up to $500 but I'd prefer a quicker remedy in the event I encounter this problem.

Thanks,
Joe Mullee
 

NYSail

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Jan 6, 2006
2,317
Beneteau 423 Mt. Sinai, NY
I have one that I carry..... Never had to use it but one never knows.

Did you power everything off when you attempted the jump? What about a direct jump to the starter?
 
Sep 25, 2008
5,515
Alden 50 Sarasota, Florida
You don't really have an "isolated" start battery but rather a separated start battery common on many boats having an A/B switch. As an alternative, you have the option of actually isolating the engine battery completely from the house bank but with a switch to allow cross-over only if the need arises. This obviously presumes you have a charger capable of managing two banks or an ACR relay or eco-charger, either of which is easier and probably cheaper than one of those emergency batteries which, by the way, also require recharging maintenance often forgotten until the need arises.
I suggest this only to provide a different perspective and opinions obviously vary as to which system is better.
 

Johnb

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Jan 22, 2008
1,130
Hunter 37-cutter Richmond CA
I suggest that multiple batteries, properly installed, maintained and managed should be the first goal, after which the likliehood of ever needing an emergency starting battery would be about zip.

Everyone should know the trick of deploying the decompression lever to get the engine spinning. I have started engines tha would not even turn over otherwise.
 

BarryL

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May 21, 2004
746
C&C 110 Mt. Sinai, NY
Hello,

I have a West Marine unit. No compressor but it does have an LED light. Anyway it does have enough power to start the Universal Diesel M25.

Were you sure you have good connection between the jump pack and the starter? A small battery should be able to turn over a small diesel engine.

Barry
 

LloydB

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Jan 15, 2006
406
Macgregor 22 Silverton
In a word yes, for a variety of reasons. Now because of your experience I intend to reassess my plan.
 
May 28, 2009
764
Hunter 376 Pensacola, FL
I would think your jump starter should do the job if you use it as a "booster" to assist a depleted starting battery. Even if your starting battery has been deeply discharged, you should still be able to get some amps out of it to help the jump starter turn over the engine. If you want to try to start the engine using only the jump starter (i.e. starting battery completely removed from the circuit), well, I'll be surprised if you ever get that to work using one of those consumer grade lunchbox types. I think you'd need to have short, direct runs of large diameter battery cables with bright shiny connectors on them to pull enough amperage to roll the engine.
 
Jan 20, 2009
15
Endeavour 32 Fredericton, NB
Jump Starter? Yes

Here's what you need:
http://www.amazon.com/Clore-Automotive-JNC660-12-Volt-Starter/dp/B000JFJLP6/ref=sr_1_1?ie=UTF8&qid=1332874401&sr=8-1

It cost $126 with free shipping when I got it. It starts my 3.4 litre diesel Land Cruiser in the winter so there is certainly no problem with my boat's little diesel. Its a professional tool designed for used car lots and auto auctions. There's an internal automatic charger - just plug it in, no wall wart. There's a cig lighter connection and double-ended male/male cig lighter wire. Charge through your cig lighter while under way. I've also used the cig lighter connection to drive a 400 watt inverter that will power my 4.5 inch 120 volt angle grinder - better than stringing extension cords for small jobs. Big gauge cables, volt gauge so you know its charge status. The specs say that the internal battery has a capacity of 45 amp/hours - good enough for some real work. Mine came with a coupon for a new internal battery for when it needs to be replaced - unlike most units like this that you toss when the battery starts to die.

Doesn't have a light, air compressor, radio, invertor. It just does one job and does it well. I feel good enough about this unit that I use it as bank 2. My two 6 volt golf cart batteries are bank 1. One big bank means more useable power and no switch issues. We are always on bank 1 except when we leave the boat and turn the switch to off.

Paul in New Brunswick
 
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gpdno

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May 16, 2011
144
Watkins 27 Venice
Yup. I have one for the boat (Yanmar 2GM ) and one for the car. Bought them both a Lowe's for about $60 a piece. Haven't used the one on the boat but I've used the one for the car.
 
Aug 2, 2009
418
Catalina 28MKII Muskegon
I can't see the point of carrying a portable jumpstart system, provided one has their batteries configured sensibly.

On my 31 footer, I have two golf cart batteries wired for 12 volts that I use for everything. They're hooked to a battery monitor so I know their state of charge.

My backup starter battery is a 12v group 24, that's strictly for emergencies.
 
Apr 29, 2011
137
Finnsailer 38 Massachusetts
I used to carry a big jump start battery around until I reconfigured my boat's electrical system to always start from a dedicated starting battery, and to always draw house loads from the much bigger dedicated house bank. All charging sources go direct to the house bank and some charging is then diverted to the starter battery via a Trik L Start. This has worked perfectly for me. The start battery does nothing but start the engine. I replace it every five years or so whether it needs it or not--they are just cheapish car-type batteries and not worth milking every possible year out of them. Trade it in and get a new one every five years and you always know you have a good battery for starting.
 
Nov 6, 2006
8,508
Hunter 34 Mandeville Louisiana
I carry one of the "600" ampre ones.. I have used it connected directly to the starter just to make sure it would work. It does. I was having the typical starter trouble and fixed that with cleaned connections.. so the jump battery was not necessary, but I carry it anyway.
 
Mar 28, 2007
637
Oday 23 Anna Maria Isl.
also, if you had a dead battery and were able to sail the boat, I am pretty sure you could "bump start" the engine, in gear, by opening the compression levers and slowly closing them as the engine started to spin.
 

CarlN

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Jan 4, 2009
420
Ketch 55 Bristol, RI
Even though I have a dedicated start battery, I carry a spare Optima Red Top battery that I bought at Costco for $110. I can't imagine ever needing it but "can't imagine" events happen on boats - at least to me. Optima's hold their charge very well if not connected, so I just charge it once a year for a full night. It's five years old and I expect 10 years+ since it is never discharged. Cheap insurance.

Carl

PS - So far I have twice taken the optima in the dinghy over to other boats with battery problems.
 
Jan 22, 2008
597
Oday 35 and Mariner 2+2 Alexandria, VA
I carry a home depot purchased jump kit. Never needed it for my boat, but I have lent it out several times to powerboaters whose batteries were toasted after a day of music etc. I also have used it twice to jump start someones car in the marina lot after we went sailing and they decided to test their cars' deep cycle capacities by leaving headlights on all day. So all in all, I guess I would never leave home without it, even if I never need it for myself.
 
Jul 28, 2010
914
Boston Whaler Montauk New Orleans
I've used mine 3 times in the last 6 years. Once on my Whaler; once on my car; and once when another boater had a dead battery. As for using it to help someone else, it's a lot easier than using jumper cables on the water. Just hand it over to the other guy, and when he's done, he just hands it back.
 
Feb 6, 1998
11,096
Canadian Sailcraft 36T Casco Bay, ME
I have a Yanmar 3GMF and an isolated starting battery. When I motor I place the battery switch in the "ALL" position. I admit that every once in a while I forget to switch it to the house side when the engine is off. It's never caused a problem but I decided it would be a good investment to get one of those jump start batteries just in case I really draw down both the starter and house batteries. I read my engine manual and it stated the engine needed 75 amps to turn over.
The manual suggests a 12V battery of 70Ah as a minimum (the manual I have says 75Ah minimum). This is NOT amps or cranking amps it is an "amp hour" rating and there's a big difference.

What Yanmar is saying is that a battery with a 70Ah rating should be sufficient enough to start the 3GM. A 70Ah battery battery will have about 600+/- cranking amps......

This is what a 2QM hits the batteries with....

Also keep in mind when "jumping" to not be connected to the larger house bank, either directly, or via the 1/2/BOTH in BOTH. The big bank will suck any life in these small starter packs and leave little to nothing to start the motor with. Once you connect it your "jump pack" is trying to both charge the large bank and start the motor.. It is far to small to do both... Connect it to the smallest battery on your boat for jumping....

That said, with a well designed system there should never be a need for one of these devices...
 
Sep 20, 2006
2,674
Hunter 33 Georgian Bay, Ontario, Canada
Why have a back-up system for your back-up system.. Do you really need that redundancy?

I have 2 house batteries which I use all the time, for starting ( 29hp 3YM30) and all electrical needs. I have a 3rd "start" battery on an echo charger, which keeps it fully charged, but is never in use. I've used it a few times when I ran down the house bank to start up the engine.
 
Feb 26, 2004
20,849
Catalina 34 224 Maple Bay, BC, Canada
I had this discussion many, many times. I agree with Scott and others. The ONLY valid answer I once got was that the owner of the jump start took it off his boat all the time to use for his car! A more stable basic electrical system will get you all that without lugging it around and remembering to have to charge it.
 
Apr 8, 2010
1,224
Ericson Yachts Olson 34 Portland OR
Why have a back-up system for your back-up system.. Do you really need that redundancy?

I have 2 house batteries which I use all the time, for starting ( 29hp 3YM30) and all electrical needs. I have a 3rd "start" battery on an echo charger, which keeps it fully charged, but is never in use. I've used it a few times when I ran down the house bank to start up the engine.
"Plus One"
Purdy well sums it up. We have a house bank consisting of two GC batteries and use it for all loads including starting. We have a separate "emergency/starting" battery for backup. As noted, this separate bank should not be combined with a flat house bank if that house bank is too low to start the diesel.

Further, our three cylinder diesel uses very little total starting power, expressed in amp hours (minutes!) to start our engine, even when cold using the glow plugs.
As an example of the reserve capacity in our house bank alone, we can and have anchored out two full days and nights, fridge running all the time, and still started the engine easily.

Loren
 
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