two different batteries

[anaisdog]

i have, in my 1986 c34, two different batteries - a deka 24m7 and a deka 24n6.  knowing that nothing is normal, on our boats, is this normal, to have two different sizes of batteries?  is there a manufacturer to stay away from?  i see no reason not to get deka again but i don't know any better either.  thanks

becki kain

[KWKloeber]

24n6, or 24M6?

kk

[anaisdog]

as far as i could read, in the dark, 24m7 and a deka 24n6 but it could have been m6.  i know the other was was 24m7.  what are they?

[anaisdog]

how do you tell how they are rigged?

[KWKloeber]

as far as i could read, in the dark, 24m7 and a deka 24n6 but it could have been m6.  i know the other was was 24m7.  what are they?

they're both East Penn/Deka Marine batteries - group 24.  Did you have a specific question about them?  If yo google the part number you can see the specs on each.

k

[anaisdog]

is there any reason to have two different batteries or are they really the same?  this is all new to me, as you know.

[anaisdog]

and do you recommend deka or does it really matter?

[KWKloeber]

is there any reason to have two different batteries or are they really the same?  this is all new to me, as you know.

It all depends on how you use the boat, time on a hook, etc. -- your power budget, alternator (and regulator) output, and  how often (and how) they're recharged. The answer depends on doing an accurate power budget and comparing that to your charging profile.  Basically the "worst case" difference between use and charging has to be made up by the battery capacity (the house battery.)

Imagine the difference in energy used by a sailor who simply motors off the dock for 2 minutes, races one night / 3 hours a week during daylight (no nav light load), returns, and never uses the fridge -- versus one who sails 8 hours (away from shore power) on weekends, on a hook weekends, and is in on shore power all other times.  What size batter(ies) you need depends on your amp-hour needs - or whether all you need is starting power.

You basically have two starting batteries now.

kk

[anaisdog]

i only do day sails and the fridge is only on with shore power, of course.

[anaisdog]

thanks about the type of batteries

[KWKloeber]

thanks about the type of batteries

spec sheet
http://www.eastpennmanufacturing.com/wp-content/uploads/Marine-Master-Spec-Sheet-0194.pdf

kk

[anaisdog]

thanks.  i must have misread the N part.

[KWKloeber]

thanks.  i must have misread the N part.

So the best way to decide on battery capacity needs, I'd have someone help you come up with an accurate estimate of power usage for a worst case, and look at switching to LEDs and increasing efficiency wherever possible.  Then balance that against your charging profile and make up the needs for a house battery on those two.   

Or just guess and go with the largest, cheapest that will fit, which is what many (most?) do.  Or maybe you need only starting batteries like you have now.  Without going into the data showing charge/discharge cycles-battery life -- Understand that, no matter how much false advertising by battery mfgrs, there's really no true 12v deep cycle battery made -- unless you go to to a 6v deep cycle type battery.

Deka is a middle of the road, made by East Penn along with other store branded batteries.  Probably no better or worse than the average. Many fail prematurely, but so do others.

Look at US Battery if you want a top of the line.  And of course there's Trojan.

Also, "naturally?" - many run their fridge off a battery bank.  It just has to be sized for it, and whether you have a holding plate evaporator.

k

[Jeff Kaplan]

when I first got #219 years ago, I had to replace the batteries and I went with 2 group 27's.  This year I upgraded to 2 group 31's, truck batteries.  Started like a champ all summer.  There is room for these and my suggestion is to move up to this size.  I too am a day sailor, boat out on a mooring.  Unfortunately boat coming out this weekend, season is over.

[anaisdog]

thanks.  i really didn't understand the group part.  i will call deka. thanks