BoatBanter.com - View Single Post - Batteries - what's best and cheapest for long term cruising these days

Salomon Fringe

On Wednesday 18 June 2008 02:25, wrote:

On Jun 17, 3:07*pm, Salomon Fringe wrote:
I wish I could answer the cycling question better.

Yes I wish there were battery monitors that would integrate the number of
kWh taken from the battery over its lifespan, and do something smart with
every low and high % charge so people could finally really check and
compare performance.

My tactic is to get
a charger of some sort on the batteries when the voltage starts
dropping below ~11.9v when hit with a load. That load is typically ~8
amps when the fridge and freezer compressors pop on.
....

Does your battery monitor show % discharge of your bank? If so that might be
better than relying on voltage that changes depending on load.

As for loads, well, I think my boat is pretty systems heavy but we
stop short of the washer/dryer and microwave. We do have two
computers a 12v refrigerator and a 12v freezer each w/their own
compressor, an electric auto-pilot, SSB, VHF, RADAR, GPSs, 1500 watt
inverter, instruments, a diesel heater (seldom used), an electric
windlass and lights (and probably some other stuff I'm forgetting).
....
What does your1500w inverter power? I suppose the inverter will be the
heaviest load at possibly 120A @12v.

Your set-up is in a whole other league, though. I'm kind of in awe.
I can see with a bank that size that cost must be a much more serious
factor. How do you like 24 volts?

-- Tom.

Cost is always a factor, but as I said, I have never met anybody that had
his AGM (or gel) batteries outlive even their semi-traction batteries and I
didn't feel brave enough to try to be the first to prove it with my new
main bank...
WRT 24v - I have never used 12v so I can't compare. I can see things getting
cheaper and easier to install when halving all currents. Especially when
you have some distance to go.
Apart from all navigation equipment and some pumps everything here is just
running at 230v through the inverters. So outside the wheelhouse and the
engine room I actually don't see much 24v.