Batteries

[grady]

I know there is a lot of battery conversation right now but I still beleive in Optima batteries. I have two blue top D31M's. I had a solar panel issue last year and it wiped out my house battery that was purchased in 2012. Optima replaced it for free. Just checked the engine battery that was purchased in 2012 and it tested at 85% capacity. Plenty for the backup battery. Batteries were always charged with a Battery Minder temp compensated charger. Now they are charged with a Battery Minder temp compensated solar charger. Swapping to a 60w panel to keep up.

Here is a pic of the mount I bonded down in the bow of the boat.

[Russ]

Where in the bow and how do you run cables? (photos?)

Seems logical to keep weight up there. Our boat needs weight up there.

[yukonbob]

I know there is a lot of battery conversation right now but I still beleive in Optima batteries. I have two blue top D31M's. I had a solar panel issue last year and it wiped out my house battery that was purchased in 2012. Optima replaced it for free. Just checked the engine battery that was purchased in 2012 and it tested at 85% capacity. Plenty for the backup battery. Batteries were always charged with a Battery Minder temp compensated charger. Now they are charged with a Battery Minder temp compensated solar charger. Swapping to a 60w panel to keep up.

Here is a pic of the mount I bonded down in the bow of the boat.

I'll second that. 2011 and sat all winter (inside no charger) tested them when they went in and no problems Make sure you get the blue top deep cycle as they make one deep cycle and one starter, both blue tops the starter has a darker base. Look for the light grey just like in Grady's pic.

[grady]

Where in the bow and how do you run cables? (photos?)

Seems logical to keep weight up there. Our boat needs weight up there.

Mine is an S model but I do have a 9.9 four stroke Yamaha. Not the best engine for weight and racing but a good engine for crusing. All the cables are run on the right side of the boat and the positive wires where they are not visible/accessable they are covered in a anti chaffe sleve. The engine uses parallel number 6 wire and the boat uses single number 6 wire. I will be reinstalling the batteries tomorrow and will try to get some pictures.

[grady]

[grady]

[RobertB]

Batteries in the bow: what is your voltage drop with the longer wiring?

[Russ]

Batteries in the bow: what is your voltage drop with the longer wiring?

Looks like heavy gauge wire he's using. There will be a drop, but my guess is not enough to keep from starting the outboard. What else do we have on our boats that needs a lot of juice? All my lamps are LEDs. My fridge has a heavy wire going to it. That's about it.

I like the batteries up there. I just replaced one of mine and it's a b*tch to get it out of that spot under the steps.

[grady]

Have not check with a meter but if you use a voltage drop calculator 6awg, 12.5v, 26feet, 15 amp, =.3v drop. Not enought to worry about. The most voltage critical componet I have is probably the stero. GPS, AP, LED's, Wind indicator will run at 9V. The engine is ran on a seperate circut of paralell #6awg wires.

[dlandersson]

Should not be much. My batteries are just aft of the bow (under the forward table seat - and any loss is hardly noticeable.

Have not check with a meter but if you use a voltage drop calculator 6awg, 12.5v, 26feet, 15 amp, =.3v drop. Not enought to worry about. The most voltage critical componet I have is probably the stero. GPS, AP, LED's, Wind indicator will run at 9V. The engine is ran on a seperate circut of paralell #6awg wires.

[RobertB]

I have worked real hard to minimize voltage drop primarily due to the battery protection circuit on my Dometic cooler/refrigerator. Before I did, the unit would start cycling on and right back off - drove me nuts at night. Also, due to reading the current article in Practical Sailor discussing battery sulfation, it is very important to minimize wiring losses in order for the intelligent chargers to maintain the battery properly.
BTW, the calculations for sizing wire to voltage drop deal with total wire run - the cumulative length of the positive and negative leads. So, a battery 26 feet away is a 52 foot wire length. http://assets.bluesea.com/files/resourc ... hartlg.jpg 6 AWG is good for 10-15 amps (as described the last message) - my system is sized to draw much more than this with the cooler, stereo, pumps, and instruments (LED lighting is negligible). I use 6 AWG to charge the batteries for a distance of 6-10 feet between the charger and the batteries.
One last point, wire should be sized for the total distance between source and terminal circuit. So, lets take the batteries in the bow, the fuse panel in the stock location over the galley, and lets say a GPS in the pedestal; the actual run to consider is 24 feet x 2 from the battery to the stern, 12 x 2 from the stern to the fuse panel, 18 x 2 from the fuse panel to the top of the pedestal. Total run in the instrument circuit is 108 feet (but low current so not a worst case issue). Or take my worst case: 24 x 2 from the battery to the stern, 12 x 2 stern to fuse panel, 12 x 2 fuse to stern, and 18 x 2 stern to cooler: 132 feet for a high draw voltage sensitive appliance. I would need 2 or 4 AWG for the entire circuit - but this is not possible considering a fuse panel cannot accommodate much over 12 AWG.

[dlandersson]

So, you're suggesting I may have overdone it when I got (stole it really) that wire from the power company line outside my house?

One last point, wire should be sized for the total distance between source and terminal circuit.

[grady]

So, you're suggesting I may have overdone it when I got (stole it really) that wire from the power company line outside my house?

One last point, wire should be sized for the total distance between source and terminal circuit.

No you are supose to sell that wire and buy the wire you need and a couple of 40's

[bobbob]

So if I wanted to relocate my batteries to the bow, and I am running nothing of consequence inside (ie. the main consideration is power to start the motor, and likewise the ability for the motor to charge the batteries properly), what gauge should I be using?

[RobertB]

So, if you never intend to operate accessories that have an electric motor, electronics that are sensitive to voltage levels, to operate a battery charger, and are OK with undercharging your batteries and reducing their life, then it really does not matter what wire gauge you use. My motor to battery cables at the stock location are a very heavy gauge wire - way heavier than 6 AWG. I cannot tell you what gauge to use, this needs to be calculated for your setup - current and planned.
Consider the stock wiring:
Very heavy gauge motor to battery to minimize losses - this is a high current circuit.
Fairly light gauge to the fuse panel since this is intended for lights only - low current total draw.
Very light gauge to lights since these draw very little current and are not particularly sensitive to low voltage (but low voltage does make them dimmer).

If you want to add anything, I recommend you first heavy up the circuit between your batteries and the fuse panel (or add another panel as I originally did). Then consider losses for every part of the run from the battery to the terminal device.
Check out my wiring project.http://www.macgregorsailors.com/forum/v ... er#p290913
I retained the heavy gauge wiring between the motor and battery. I used heavy gauge wire to the breaker panels (4 to 8 AWG) and minimized this run by locating the panels so they were much closer to the batteries. I steped down in wire size the closer I got to the terminal device by judging the expected current on each wire. Only LED light circuits use 14 AWG wire.

When considering a wiring project, consider that the wire is a major part of the cost.