old and new batteries connection

[Guan]

Please kindly express opinions re connecting old and new batteries.
my electrician connected one new c31 AGM to the 'apparently still good' ten years old 4D for house. Probably he couldn't remove and replace that heavy brute in the confine space.
I read that it'll damage the new battery.
Any suggestions?

 

[Maine Sail]

my electrician connected one new c31 AGM to the 'apparently still good' ten years old 4D for house.


Any suggestions?

Find a new "electrician"...

 

[Don S/V ILLusion]

There is no such thing as a “still good” 10 year old battery

 

[DougM]

A 10 year old battery tied to the new AGM is a perfect way to kill the new one. Bite the bullet and scrap the old.

 

[Justin_NSA]

Disconnect the old one until you can remove it

 

[Stu Jackson]

And when you do, do not replace it with another 4D. Not only are they beasts to move, but they are not true deep cycle batteries.

Also do some research on whether or not AGMs are the proper candidate for your use.

AGM Batteries - Making The Choice (from Maine Sail)

AGM Batteries - Making The Choice

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
Darn AGM Batteries

Additional Observations on the Limits of AGMs Electrical Systems 101

Good luck.

 

[Guan]

l am in complete agreement with everyone. only two exceptions.
1.boat electrician are impossible to find here and now. one even charge $300 an hr.
2. disconnect the old 4D leaving those leads. can I just take up the red and black separately and it's ok?

 

[Guan]

tape up separately?

 

[Stu Jackson]

tape up separately?

Yes.

Then get a boat electrical book and start studying. None of us was born an electrician, we all learned. Somehow...

 

[Don S/V ILLusion]

l am in complete agreement with everyone. only two exceptions.
1.boat electrician are impossible to find here and now. one even charge $300 an hr.
2. disconnect the old 4D leaving those leads. can I just take up the red and black separately and it's ok?

Remove the un-used cables until needed for two reasons:
The potential for a short no amount of tape can eliminate, and
Good time to clean the contacts.
Also, I infer from the comment that there are two cables going to the old battery (red and black). If so, it isn’t wired correctly in a manner to equally carry the load on both parallel batteries.

 

[Guan]

tks all again. most helpful and almost most timely too. very good helpful group.

 

[Guan]

thanks to all. most help and timely

 

[Hello Below]

boat electrician are impossible to find here and now

@Ralph Johnstone may chime in here but if you are in the Vancouver, BC area you will not find a better marine electrician than Jeff Cote, Pacific Yacht Systems.
Pacific Yacht Systems

 

[Guan]

agree but long bookings!

 

[Guan]

And when you do, do not replace it with another 4D. Not only are they beasts to move, but they are not true deep cycle batteries.

Also do some research on whether or not AGMs are the proper candidate for your use.

AGM Batteries - Making The Choice (from Maine Sail)

AGM Batteries - Making The Choice

AGM Battery Issues and the Blue Seas Dual Circuit Switch (from Maine Sail) "DARN AGM Batteries"
Darn AGM Batteries

Additional Observations on the Limits of AGMs Electrical Systems 101

Good luck.

tks for the info will reassess AGM... but no more 4D for sure. Still trying to get paid muscles to remove that one.