GBM wrote:
"Jeff" wrote in message
...
Finally I got an EchoCharge for about $100
....

So perhaps this would work in my case? If my house bank gets up to 13v
before this kicks in, and starting battery is at 12v or less, hopefully with
my small alternator, voltage does not drop below 13v causing cycling?


The actual use for starting is about 60 amps times a few seconds, so
the starting battery is never discharged more than a few percent
(unless its been off a charger for a few weeks or more). While is may
use a significant portion of the alternator output for a few minutes,
it will quickly settle into a trickle charge mode.

... if you want thoughtful advice on this you'll have to
tell us want you plan to power with this!


Presently, the boat (32 foot sail) would be used for short cruises - maybe
up to a week long. It will have new refrigeration that will draw 4 amps when
running and hopefully no more than 40AH per day. Other loads are lights,
radios, instruments, Autohelm (seldom used), windlass (not presently
connected). I expect I will have to run engine for a couple of hours per day
or get back to shore power.

Our previous boat was similar to yours (2 6v batteries) and we had an
older Danfoss system. The load was about 50-65 AH per day, which took
about 1.5 hours to recharge. Even though we had a high output
alternator, the smaller bank limited the charge rate. The cheapest
thing we could have done, though not always the easiest thing on a
small boat, would be to add more battery storage. If you have a good
place to stash 2 more 6v bats, you could double capacity for under
$200. This would mean you could go 2-3 days without running the
engine, greatly increasing the chance you recharge in the normal
course of using the boat.

This is a frustrating issue, because the urge is to find a "proper"
solution, but that costs money. I would love to find a "half decent"
alternator/regulator that was under $500, or an amp-hour meter for
$50. The only thing that seems cheap are the batteries!



I would like to get one too. I could probably sell the idea to the
"management" as a safety item for home power back up next time we have an
ice-storm or other unforeseen power outage. On the boat, our engine does
not have a heat exchanger, and I have considered this as a way of producing
hot water - Run the generator for a while - charge the batteries and heat
the hot water. A bit of an expensive solution, but a nice-to-have!

For this I do have a solution: the black bag. My old boat even had a
propane hot water heater, but we preferred the black bag, especially
for summer vacations. This was even a way to conserve water and get
exercise, since I would row into the town dock to fill up one or two
black bags.