Visit our Popular Forums

suiramor · 10-12-2019, 12:07

What factors should I consider when looking for new house batteries for my Benetau 46 (I currently have 2x NG-4D, 9 yrs old! - I think 500AH)? At this time I am mainly doing coastal sailing, day trips, sometimes on anchor but usually on marina power in cooler (Pacific NW) climes.

**Adelie** · 10-12-2019, 12:46

Budget
Charging sources
Tolerance for simpler vs more complex systems.

sailorboy1 · 10-12-2019, 13:59

You don’t seem to know lot about your current batteries, but got 9 years out of them. That’s like less $100/yr. just get the same ones.

Bill O · 10-12-2019, 14:08

I believe the NG-4D is only 160 Ah each so you have ~ 320 Ah. If that's working for you, I'd agree w/sailorboy to stick with that amount.

Bill O.

john61ct · 10-12-2019, 14:49

Can you do flooded, or do you need sealed?

suiramor · 10-12-2019, 15:22

The current ones are flooded. What would be the reason to change to sealed?

boom23 · 10-12-2019, 15:50

Quote:

Originally Posted by suiramor

The current ones are flooded. What would be the reason to change to sealed?

I just helped to replace 4 house batteries on a Beneteau 49 with flooded deep cycle. Unless you go to AGM or GEL, sealed Lead Acid batteries are usually dual purpose Starting/Deep Cycle. The battery guy said it is best to use single purpose batteries.

If you decide on AGM or GEL, you need to change the charging parameters on your charger and Alternator.

john61ct · 10-12-2019, 16:42

Quote:

Originally Posted by boom23

I just helped to replace 4 house batteries on a Beneteau 49 with flooded deep cycle. Unless you go to AGM or GEL, sealed Lead Acid batteries are usually dual purpose Starting/Deep Cycle. The battery guy said it is best to use single purpose batteries.

There are only a few makers of quality AGM or GEL batteries that are well suited to deep cycling.

Some of them make dual-use lines that are indeed excellent, even in 12V format.

Mass market stuff available from automotive or big box channels is indeed 99.99% crap, only good for starting.

But FLA batteries from quality makers are in general much better value, as in per Ah per year.

And some are nearly as cheap as what you'd buy from Costco or Walmart.

**roverhi** · 10-12-2019, 20:31

Golf cart batteries are designed for the abuse of deep cycling and last if you keep the fluid level up. More importantly To me they are relatively light so even my 75 year old body can schlep them around.

OneHullPaul · 10-12-2019, 20:43

Firefly batteries will give you 70% usable Amp hours, AGM 50%, Regular lead acid 30% and sulfuric acid in your bilge eating your keel bolts.

From 80-100% batteries cannot be bulk charged so isn't usable in the same way. Lead acid shouldn't be drawn down below50% AGM 30% and 10% for firefly.

Hope that helps some. Bluefly are the priciest but will probably last you a lifetime with the number of charging cycles of them.

Good luck. Just don't let the smoke out and the job will be easy.

john61ct · 10-12-2019, 21:08

Quote:

Originally Posted by suiramor

The current ones are flooded. What would be the reason to change to sealed?

Only go to sealed if **you** have a compelling reason to do so.

Check your maximum physical dimensions against these possibilities:

The best battery value by far is Duracell (actually Deka/East Penn) FLA deep cycle golf cart batteries, 2x6V, around $200 per 200+AH @12V pair from BatteriesPlus or Sam's Club. Deka labeled same batts also sold at Lowes.

Other quality makers include Rolls/Surette, Trojan, U.S. Battery, Crown and Superior.

Your total Ah capacity can be around what you already have, or likely a bit lower would be fine too.

EmeraldCoastSailor · 11-12-2019, 08:58

I'd repeat what you have or go the golf cart approach. I am quite happy with my conversion to 6v GC batts 5 years ago. The benefits IMHO are cost per AH, lightweight, easy availability, and durability/usability.

roland stockham · 11-12-2019, 09:07

Agree, on the principal that you don't need to fix what aint broke, replace with the same. If you feel the need to increase capacity go with 2 6v batteries. The bigger the battery the longer they last (I mean battery here not battery bank). Don' go for sealed unless you have a good reason, they are way more expensive and need more careful charging.