Replacement House Batteries

[skunther]

I currently have two Deka GC25 (relatively new) batteries and need to replace two aged 8AGC2 batteries.
My question is if I should get identical GC25 batteries to replace the old 8AGC2 ones, or if the GC15 from Lowes (or any other available battery) is an acceptable alternate to pair with the GC25 ones. There are also Duracell SLIGC125 batteries available for nearby pickup - I understand Deka made Duracell (or vice versa?).
The GC25 have been a little harder to find.
I'm new to managing electronics systems and am ignorant to the nuances.

 

[dlochner]

I currently have two Deka GC25 (relatively new) batteries and need to replace two aged 8AGC2 batteries.
My question is if I should get identical GC25 batteries to replace the old 8AGC2 ones, or if the GC15 from Lowes (or any other available battery) is an acceptable alternate to pair with the GC25 ones. There are also Duracell SLIGC125 batteries available nearby pickup - I understand Deka made Duracell (or vice versa?).
The GC25 have been a little harder to find.
I'm new to managing electronics systems and am ignorant to the nuances.

If you are putting all of the batteries in the same bank, they should be as close as possible to the same age and kind. There is more flexibility if they are in 2 banks, in your case 2 banks of 2 6v GC batteries. Deka has several flavors with different capacities. You check their website.

Dekka is made by East Penn Manufacturing. In addition to their own brands they put other companies' label on East Penn Batteries. At one time Duracel had their batteries made by East Penn, I'm not sure if they still do. NAPA batteries are made by East Penn as are some (all) of West Marine Batteries. However, you will pay healthy premium for buying from West Marine.

In the PWN, Dyno Battery has a good reputation.

East Penn Manufacturing – The world's largest single site, family-owned lead-acid battery manufacturer

East Penn Manufacturing is a private company and the world’s largest single-site, lead-acid battery facility. Serving the transportation, motive power, reserve power, and wire and cable markets.

www.eastpennmanufacturing.com

Dyno Battery - Premium Quality Battery Manufacturing - Made in the USA

www.dynobattery.com

 

[skunther]

Thanks for that @dlochner.

I see that the local NAPA store has in stock the East Penn GC15 (https://www.napaonline.com/en/p/NBP8144), which is 230Ah instead of the GC25 higher 235Ah. I'm not sure if that's significant enough to warrant finding a 235Ah alternate. They don't seem as convenient to top off as the GC25 are either. Other than that, are they acceptable to combine with the GC25 bank?

No one local seems to carry the GC25.

The price is good, but I'll hold off to get the right ones if necessary.

 

[dlochner]

These are going into the same bank?

I'm walking at the edge of my understanding of batteries. My best guess is that nothing bad will happen. It may have some modest adverse affect on the longevity, but it shouldn't fry anything important. Since they are from the same manufacturer and are very close in size all will probably be ok. But I'm not a battery expert.

Where you get into real trouble is mixing batteries with different charging profiles, like AGMs with FLA or with very different ages in the batteries.

 

[skunther]

Great, much thanks.

Yes, both into the same house bank. They are split into 2 separate cockpit lockers, one starboard and one port. The batteries in each set of 2 are connected in "series". I do not know how the two sepatare sets are connected (I assume parallel).

 

[skunther]

I just spoke with East Penn directly, and they said the Duracell SLIGC125 is the Deka 25 with a different label. I'll go pick those up today.

When installing them, I assume I'm just to turn off the AC charger, after which I can simply disconnect the terminals and reconnect the cables to the new batteries, correct?

 

[dlochner]

I just spoke with East Penn directly, and they said the Duracell SLIGC125 is the Deka 25 with a different label. I'll go pick those up today.

When installing them, I assume I'm just to turn off the AC charger, after which I can simply disconnect the terminals and reconnect the cables to the new batteries, correct?

That's pretty much how I do it.

 

[Davidasailor26]

All I’d add is that it’s best practice to disconnect the ground wire first, and reconnect it last. If your wrench touches something grounded it’ll be much less exciting that way.

Also, if replacing batteries of different sizes, if you do the bigger battery first you might think “oh, handy, this wrench isn’t long enough to span the terminals, glad I don’t need to worry about that.” But then you might be surprised to find that the same wrench is, in fact, long enough to span the terminals on a smaller battery. (Yes, I’ve got the t-shirt for that one.)

 

[dlochner]

All I’d add is that it’s best practice to disconnect the ground wire first, and reconnect it last. If your wrench touches something grounded it’ll be much less exciting that way.

Also, if replacing batteries of different sizes, if you do the bigger battery first you might think “oh, handy, this wrench isn’t long enough to span the terminals, glad I don’t need to worry about that.” But then you might be surprised to find that the same wrench is, in fact, long enough to span the terminals on a smaller battery. (Yes, I’ve got the t-shirt for that one.)

No wrenches. Use a ratchet and socket with an extension.

Save the fireworks for Independence Day.