12v vs 6v in 2nd bank

[woodysca]

I need to replace the batteries in the 2nd bank on my Catalina 34. As purchased used, it came with four 6v batteries wired in series/parallel. What are the pros/cons of replacing as is, or switching to four 12v batteries wired in parallel?

TIA,
Woody
San Diego

[atmartin]

Well it depends on the quality of the batteries used. Sounds like these four 6v batteries are your house bank. Are they Trojan T-105s or similar? Golf cart batteries are well-suited to house bank, deep cycle use.

I would keep the same battery type unless you'd like to switch from wet-cells to some kind of newer gel, agm or whatever. Otherwise you're going to need to make up new battery cables and maybe rearrange your battery trays to fit some kind of 12v.

[john61ct]

Nothing beats 6V GCs for value.

So many 12V are fraudulently labeled.

If you want to go 12V, post the specific mfg & model for feedback

[Peregrine1983]

+1 for keeping the 6v's if they are golf car batts for the house bank. I have been very happy with mine.

Sams's club has them cheap if you have one out there. If you're not a member they have a guest membership pass that you can use for a day. That's what I did.

https://www.samsclub.com/sams/golf-c...ies/3990117.cp

[john61ct]

Also at Batteries+, make sure to get FLA not sealed!

Actually made by East Penn (Deka) great mfg.

But Trojan T-105s are better, RE variant even more so.

[desertsailor]

I have an RV, an interim vehicle until I find my dream boat, and this is a hot topic on RV forums as well. Personally, I have two 12 volt batteries wired in parallel, and they have provided ample power for my needs. However, the general gist of discussions I've read is that using 6 volt deep cycle batteries, i.e. golf cart batteries, will provide a stronger battery with longer life for the same amount of money spent on comparable 12 volt batteries.

[john61ct]

Often **much** longer life, and for less money.

[GordMay]

Greetings and welcome aboard the CF, Woody.

[Bleemus]

What is the "RE variant" mentioned?

[wolfesmy]

6v any day. More amp hrs/$ and longer life.
Have both of my big boats house banks fitted for 6V. 12V for starter only.
Never run out of power yet.
Though as with any bank don't let them get below 50% as that shortens life.

[woodysca]

A BIG thank you to all who responded !
I'll research 6v golf cart batteries to see if I can find a size similar to what is there
(Trojan 125)

regards,
Woody

[EmeraldCoastSailor]

I have had good luck with Interstate 6v GC batts. And they give good service should there be a problem.

[john61ct]

Interstate does not make any batteries, they are a marketing/distribution brand, also supply Costco. I believe all their FLA are made by Johnson Controls. Not saying "bad", but the Duracell/Deka are more robust and last longer, better value for money. Then Trojans, a step up but a bit pricier.

You can keep going up the ladder, to Rolls / Surrette at the top.

With the top-notch vendors like that, they can be trusted to properly differentiate their "true deep cycle" from "dual purpose" starters, even in 12V models.

But they are more expensive, a huge step up in quality from what most people are willing to pay for.

So, it's not that 6V (or 2V, or 3, 4) is inherently better than 12V, it's just that at the bottom of the market, within consumer and automotive retail channels, the vendors all lie, and only the 6V FLA golf car batts are actually designed for deep cycling.

[john61ct]

Originally Posted by Bleemus

What is the "RE variant" mentioned?

Stands for Renewable Energy.

Google T-105-RE or shop around from local Trojan dealers and you'll see, usually quite a bit pricier than the regular version.

[TheThunderbird]

Trojan 125 PLUS are my choice. They use T2 technology (carbon?)

in europe, most use 12V. I had to fight a bit Before finding 6V deep cycle.

Cranking 6 batteries into the same basket, other than 3, comes at a cost... (thinner plates, more. Foamy compound, lighter mass)