Electrical Information

Discussion about my Power Needs (November 2004)

The original battery that I ordered with my boat was a 75 amp hour gel cell battery. I have upgraded to two 92 amp hour AGM batteries (the $155 8A27 from www.BatteryStuff.com).
Each battery weighs 69 pounds and is 12.65" long, 6.75" wide and 9.88" tall.
I have wired the batteries in parallel to give me a total of 184 amp hours.
As I understand it you are not supposed to use more 50% of your batteries rated power which for my new batteries would be 92 amp hours.
The solar panels will add some charge back. For a sunny day I expect about 1 amp from the 11watt panel and maybe 4 amps from the 22watt panel (if I set it up) but I don't count on anything from the solar panels.

Battery state by voltage
It is best to not let the battery discharge to below 11.9 volts (see Deep Cycle Battery FAQ).
Voltages are for batteries that have been at rest for 3 hours or more. For longest life, batteries should stay in the green zone.
Occasional dips into the yellow are not harmful, but continual discharges to those levels will shorten battery life considerably.
It is important to realize that voltage measurements are only approximate. For gel cells, subtract .2 volts.

Morningstar SunSaver-6 Users Manual Charge Regulator to keep solar panel from frying the battery.
For Gel batteries, the jumber should be installed.
From the manufacturer: For the AGM battery "you will need to use the Flooded battery setting by removing the metal jumper. This will provide a 14.4V charging setpoint, which should satisfy the Bulk charging requirements specified for your AGM batteries."
So I have removed the jumper.

Here is my 11watt Unisol solar panel. It does a great job of keeping the battery topped off.
Rated power: 10.3 Watts, Battery Voltage: 12 Volts, Typical Amp Hours/Day: 4, Bypass Diode Included: Yes, Length: 21.03", Width: 16.7", Weight: 2 lbs.
In full sun, I believe that I measured the output to be around .5 amps

SE-1500 Solar Panel for Large Boats & RVs, 1.5A, 7.5Ah, 22.5 Watts, 39.4" x 13.8" x 1.2"
In spring of 2009, I purchased a supplemental solar panel to use here at home and on longer sailing trips where I will set it up when it looks like I am depleting the batteries faster than expected.
It came with a nice assortment of wires and gizzmos connecting in a variety of combinations.
I plan to install a 12volt receptable that will lead to the solar inputs of the charge controller.

I replaced the 3 amp Battery Pal charger with a 12 amp charger that explicitly stated that it supported multiple battery types. It is now set for AGM (not high performance).

VoltMinder
The little 12 volt reader that I had just wasn't working right. I got this instead and so far seems to be working like a champ. It is connected to the "Load" on the Sun Saver charge regulator.

From West Marine catalog.