Emergency Battery Packs

[Traveler 45C]

Do you guys keep aboard one of those emergency battery packs that you can use to jump the battery, that’s also a compressor, an inverter, weather radio, flashlight, etc.?

Which do ya’ use?

[Boatsb]

They are great for the car. I tried one on the genny once and no joy. It does not have the power to start a real motor.

gas engines maybe but other than that I have a flashlight, Air pump and Radio aboard

[Genesis]

Most of those will start a generator but not a prayer in hell they'll start a diesel main. Don't even try it. An 8kw genny, however, it should start. I've jumped an 8kw generator off a PWC battery (which is basically what is in those); it will work.

If your systems are more-or-less working you only need ONE engine to start to (eventually) get your batteries charged up enough to start the rest, so this is indeed useful.

[REBrueckner]

You can make a rough judgement from the power characteristics of the power pacs compared with your engine or genny start batteries...CCA or amp hours,etc.....likely a typical pack is maybe 10% or 15% (just a guess) of a pair of marine main eng start batts and so would be essentially useless on main engine diesels...puny.....

Much better to keep a bank of existing batteries as spare via light use and or isolation...and carry a pair of jumper cables if you don't have appropriate switching if needed.

When anchoring I used to run all on board appliances from a mix of starboard and house banks and kept my port bank as idle backup....it was used only to occasionally start my diesel generator.....and had battery cables as well as switching available. And if all that failed I had a portable gas genny ready to go in the cockpit. Never worried a moment even in remote islands of Maine and Nova Scotia; never even came close to a power problem.

[Traveler 45C]

Even with all proper precautions and good operating practices in place you just never know when a comedy of failures can take place and leave you stuck.

I keep a spare battery charger on board and I figure it’ll be a good idea to have one of these emergency battery packs on board too.

I’ve seen ‘em coupled with compressors and inverters; might be useful to have.

Just wondering if any of you guys had a recommendation for one.