External Jump Starter

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tmh
Posts: 21
Joined: Thu Jul 16, 2015 11:44 am

External Jump Starter

Post by tmh » Thu Nov 14, 2019 1:53 pm

I am considering adding a dedicated start battery, but do not have it now.
I the meantime I was thinking about getting an external Jump Starter.
I currently have the two 4D AGM batteries that are now 4 years old and not holding a charge well, so I will replace these soon.
I have seen some external Jump Start batteries for less than $200. A lead-acid one from West Marine [big and heavy] and a lithium-ion one from defender [small and light weight]
Any advice pro or con would be appreciated.

Mike
C350 #227
IRISH AYES
Mike
Irish Ayes
#227

wolfe10
Posts: 383
Joined: Mon Dec 11, 2006 2:58 pm
Location: League City, Texas

Re: External Jump Starter

Post by wolfe10 » Thu Nov 14, 2019 2:38 pm

Mike,

Another option is to install another smaller (like group 31) AGM just forward of the current battery location as a backup-- under the aft end of the port settee.

How "seamless" your installation and wiring is up to you. Pretty easy to use a simple marine ON-OFF switch to connect it (positive )to the other batteries or directly to the main battery switch. ON for charging it and using it as an emergency start. OFF for when engine not running/shore power not connected so it doesn't discharge with the other batteries. OR, even simpler, jumper cables you can connect to it.
Brett Wolfe
C350 #180
"Vindaloo"
League City, TX

cuthbert
Posts: 30
Joined: Fri Apr 27, 2012 1:20 pm

Re: External Jump Starter

Post by cuthbert » Thu Nov 14, 2019 9:37 pm

I followed the path of many 350 owners and went with a type 51 car start battery (700CCA or so easily starts the engine) on the 2nd switch position and then a group of 4 6V golf cart batteries (Costco have date of manufacture on their batteries and great prices) on the first switch position. By going this route all 5 batteries fit in the existing space and you don't lose any storage space, but you will need to make some stout and short connecting cables to put 2 x two 6V in series and connect the two 12V batties this forms into one bank.

All mine are flooded lead acid batteries but both golf cart and type 51 are available in AGM.

I typically never use the start battery its there just in case of a failure of the main bank.

tmh
Posts: 21
Joined: Thu Jul 16, 2015 11:44 am

Re: External Jump Starter

Post by tmh » Sat Nov 16, 2019 2:11 pm

Brett and Mr. Cuthbert [sorry could not find a first name]
Thank you all so much for your prompt and expert suggestions.
As I am "electrically challenged", I will share this detailed information with my mechanic [who is also a sailor] and get started.
Thanks again for sharing your ideas and experience.

Mike
Mike
Irish Ayes
#227

KenKrawford
Posts: 439
Joined: Wed Nov 02, 2005 8:54 pm
Location: Atlanta, GA

Re: External Jump Starter

Post by KenKrawford » Sun Nov 17, 2019 7:38 am

Mike, there was an interesting discussion on the C34 message board about jump start batteries. Especially check out the comment from Mainsail. He's a pretty respected authority on boat repair.
Ken Krawford
Message Board Moderator
C350 # 351
Lake Lanier, GA

tmh
Posts: 21
Joined: Thu Jul 16, 2015 11:44 am

Re: External Jump Starter

Post by tmh » Sun Nov 17, 2019 6:29 pm

Thanks Ken, I will do that!
Mike
Mike
Irish Ayes
#227

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