On Wed, 25 Jul 2007 11:04:43 -0500, "KLC Lewis"
wrote:


"Pete C" wrote in message
roups.com...
On Jul 25, 2:37 pm, "KLC Lewis" wrote:
"Pete C" wrote in message

Pete, do you propose using a hydrometer everytime you want to know your
state of charge? This could be a couple of times each day, or more.

Hi,

For those who know a bit about electrics and can use a hydrometer I
would propose:

Do an energy budget/audit.

Size the battery bank for 40% DoD (depth of discharge) on a normal
days/period of use

Use the hydro to verify the above a few times as well as check the
batts are getting fully charged.

Use the hydro to check a few times that an exceptional days/period of
demand doesn't draw the batts below 80% DoD

Comments???

cheers,
Pete.




My own energy needs are quite modest. Nav instruments, VHF, stereo, running
and anchor lights, computer (laptop), the occasional cabin light for short
periods (converting to led units). No refer, no power windlass. Of course, I
do need to be able to start-up the iron genny from time to time.

My battery bank is 4 new-this-seasonTrojan T-105's and a 40 amp smart
charger for dockside use. 2 US32 solar panels rated at 64 watts. Voltmeter
always reads "top of the green" at 13 volts after dockside charging, bottom
middle of the green after sailing for a day and anchoring out overnight with
the anchor light lit. Engine starts right up like it has a fully-charged
battery when weighing anchor in the morning. But translating this to "how
much power do I have left?" leaves me paranoid.

And you have 450AH available ;-) I have customers who live on their
boat with less than that!
Paranoid is a bit OTT but aware is sensible.

--
Richard

Nb "Pound Eater" Parkend G+S
"Governments are like Nappies, they should be changed often."
(For the same reason)