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6 Volt conversion in F38 or F36?

PostPosted: Fri Sep 18, 2015 6:39 pm
by Ereiss
I will need to purchase a new house bank. Mine is limping in for the season. At would seam that going with 6 volt batteries would give a major boost in amp/hours. Has anyone done this in an F36/38? Wondering how well it fits under the nav station and if there were any other issues that need to be considered.

Just thinking.

Ed

Re: 6 Volt conversion in F38 or F36?

PostPosted: Fri Sep 18, 2015 9:18 pm
by rafontaine1
Ed
I installed 4 six volt golf cart batteries under the galley sink. Under the nav station where batteries use to be I installed inverter/charger and other electronics. Engine battery is Groip 30 installed in sail locker behind engine compartment. I can provide pictures and if you are in the Portsmouth RI area I can give you a full detailed description of installation. Coming to Newport Show this weekend. Contact me and stop by at East Passage Yachting Center in Portsmouth. Not your typical F36 installation.
Rich Fontaine
F36, Liberte
Portsmouth RI

Re: 6 Volt conversion in F38 or F36?

PostPosted: Sat Sep 19, 2015 8:19 am
by PH39
For a given battery chemistry type what do you think going 6V vs 12V would give you beyond more flexibility in having smaller sized building blocks for your battery bank and more wiring complexity/failure points?

Lifeline AGMs
12V 4DL = 2,520VA @ 1,560c" & 124lb for $667
12v 31XT = 1,500VAH @ 807c" & 74lb
12v 31T = 1,260VAH @ 807c" & 64lb for $377
6V 4CT = 1,320VAH @ 720c" & 66lb for $377

So for the same AGM chemistry by the same quality manufacturer that 6V 4CT ~ 12V 31T ~ 50% 12V 4DL... TANSTAAFL. Though note that 1 4DL is cheaper than 2 of the other 2 sizes. If one went w/that single 4DL it would be the cheapest simplest solution, or one could go w/2 x 31XT for the greatest power density. The 12V 31T and 6V 4CT are roughly equivalent. What am I missing?

FYI, I replaced my last pair of 4DLs after 11.5y (albeit w/a quality charger), Lifeline rocks.

Re: 6 Volt conversion in F38 or F36?

PostPosted: Sat Sep 19, 2015 1:18 pm
by bbarnewolt
Ed,
I'm in the same boat, having 4 group 31 AGMs under the nav station that are on their last legs. There is a lot of room in that spot, so I can't imagine a problem with space. I am considering the new Firefly batteries, but haven't yet pulled the trigger. I am thinking that the next round will be lithium, but for me it is still early.
http://fireflyenergy.com

Briein

Re: 6 Volt conversion in F38 or F36?

PostPosted: Sat Sep 19, 2015 11:45 pm
by Ereiss
PH39

It looked to me that two 6v batteries gave much more amp hours than one 12. From MaineSail's site the cross section of the batteries show much great lead density in a 6 vs a 12.

I could very well be wrong, I'm only a civil engineer which means I just know which way sh$t flows.

Help make me smarter.

Thanks

Re: 6 Volt conversion in F38 or F36?

PostPosted: Sat Sep 19, 2015 11:54 pm
by Ereiss
Practical Sailor recently wrote about the Firefly. Sounds promising.

http://www.practical-sailor.com/blog/Ca ... 694-1.html

Re: 6 Volt conversion in F38 or F36?

PostPosted: Sun Sep 20, 2015 10:44 am
by PH39
Lifeline AGMs
12V 4DL = 2,520VA @ 1,560c" & 124lb for $667
12v 31XT = 1,500VAH @ 807c" & 74lb
12v 31T = 1,260VAH @ 807c" & 64lb for $377
6V 4CT = 1,320VAH @ 720c" & 66lb for $377
Firefly
12V G31 = 1,200VAH @ 840c" @ 72lb for $425 (?)

While Firefly tech may be promising, not so much energy density.

IMO, one has to also consider availability, retail distribution, and everything on a boat over a 10y capex timeframe (minimum). So for example, Balmar, Garhauer, Lifeline, Maxwell, Mermaid, Optima, Rarita, Rule, Standard, Statpower/Xantrex, Vacuflush, Yanmar... have all proven to be solid choices for me. OTOH, Apollo, Barient, Glacier Bay, Raymarine, SW Windpower... have been more of a mixed bag.

At the EOD, if comparing like w/like tech. then the #s alone should make for a simpler decision. In the case of Firefly, while an incremental improvement, one must also consider current and prospective track records as well as commitment to the pleasure marine market.

Re: 6 Volt conversion in F38 or F36?

PostPosted: Sun Sep 20, 2015 11:59 am
by cberdie
I've found the biggest contributor to good battery life is matching all the batteries. Take a voltmeter to the store with you and make sure that all the batteries are the same voltage and same manufacture date. I've been using Sam's Club trolling motor batteries with very good luck. The problem is when on shorepower with the heater and hot water heater on, some how the plug gets disconnected and the invertor drains your battery down before you notice it. Present batteries are five years old and in fine shape, (I've never had to add water), total cost was under $250 for four batteries. More expensive batteries may be better, but, for the money I'll keep with the cheap ones as long as they are all the same.
Carl Berdie
F40 Running Free

Re: 6 Volt conversion in F38 or F36?

PostPosted: Mon Aug 08, 2016 11:00 am
by MaloPoMalo
I installed four 6volt Sonnenshein gel batteries under the nav station, and constructed an engine battery box in lazarette attached to the wood wall between the refrigeration compressor and the ice box ... to the port of the trash can. I upgraded my batteries to gels circa 1990 and have only had to buy one replacement set in all these years.