*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
Random Quote: Civilization Stops at the shore line
I am doing some electronic upgrades and need to know what Battery arangement would be the best: I run a single engine 225 Merc (60amp alt.)
Here is what I will be running off the battery-batteries when I am done.
1.Furuno 1733c 4kw Navnet -Chartplotter ((Can be powered by 12v-24v))
2.Furuno 1650df (Chartplotter backup) Primary use will be sonar
3.Simrad AP12h Auto pilot
4.Icom 502a VHF (primary radio)
5.Standard Horizon VHF (backup)
6. lights Flood & Navigation lights
7. Merc 225 Motor cranking
8. Flowscan 7000
9. Lenco Troll/Tabs
Tabs are on 12 volt.
trolling motors are on 24 volt.
What I have now is one house battery Group 27 and two group 27's for the trolling motors which are seldom used. The house/cranking battery is the only battery that gets charged by the motor.The other two are charged by battery charger at the house along with Batt.1.There is a guest battery switch on board But only the house battery (Batt.1)is conected to it. (switch is bat.1,both,Bat.2,off)
Options?
1. Connect everything to one battery?
2. Connect everything but the 1733c to one battery and power the 1733c with the 24v battery setup for the trolling motors which I very seldom use? How long would they last not being charged by the Merc?
3. Scrap the 24v system for the trolling motors. Take one of the two 27group batteries wire it to the battery switch as battery 2 . And wire it to the other battery so it could be used as a backup to battery 1.Use battery 1 for everything & Batt. 2 as a backup
4 Battery isolator for two batteries I know nothing about?
I would scrub the 24V system and have 2 12V batteries. I would use an isolator so you can charge both batteries at the same time. Battery 1 could used to start your engine and battery 2 for all your electronics. This will also give you redundancy in case one fails.
I'm going through the same issues with my battery setup.
Having to buy a battery at 24 hour walmart to save a trip forced the issue with me.
I have an on/off switch on each battery plus a 1/both/2/off selector that goes to the engine.
The on/off switches on each battery let you turn a battery off and isolate it if it starts drawing or gets too low.
With the 1/both/2 switch you can still supply power to your whole system.
I'm using 1 battery for starting and all boat accessories (lights, washdown.....)and backup electronics.
Battery 2 is for electronics.
There is an isolator that allows both batteries to charge when the motor is running.
I have 2 bilge pumps, 1 connected to each battery before the on/off switch.
I have my VHF connected to the battery selector switch. (Waterproof Hand Held is my backup)
In the past we had an electrical emergency and when we switched the battery switch to off, VHF, GPS and everything went out.
Ron
there are at least a dozen ways to do it, but i'd opt for max simplicity rather than max bells and whistles. and you did mention you don't use trll'n'tabs very much.
btw, what kind of boat ya got?
get yourself 4 AGM batteries, biggest that will fit (grp 27s or 31s). they do starting and deep cycle very well, and discharge very slowly when sitting in driveway. and some short jumper cables, and 12 gauge wire attached to alligator clips.
put two batteries in series for 24v trll'n-tabs. other two are off the battery switch, for starting and house. run all electronics off the battery switch for start/hosue (make the furuno 12v).
use battery #1 on odd days, #2 on even days. if you ever have two weak batteries, you can put on "both/all" for 15-20 minutes to recharge (but only for 15-20 minutes!!!! for "both/all").
just use jumper cables to attach trlling batteries to start/hosue if, by some chance, BOTH start/house batteries are dead. the alligator clips are for emergencies when you might need to attach VHF and electronics directly to a battery.
Thanks for all the input so far!! It has been a great help. What about the isolator? Exactly how do they work? Does a isolator determine which battery needs to be charged? If So it must automaticly switch to the battery needed to be charged when the voltage drops to a certain point? Any draw back to the Isolator? Thanks Mark
Isloators are devices that let batteries charge from the alternator (or another battery).
They are basically diodes that will let current run from the alternator to the batteries, but not from battery to battery.
They will also help protect the battery from discharging if there is a failure (short) in the alternator.
The "diode" only lets charging current flow in one direction.
Let me start by saying,I am not just saying this becuase I have one for sale.
I would look into a battery combiner to help solve your problems. A combiner connects all your batteries together and lets you charge all of them from one or two engines. The combiner seeks out the weakest battery and sends the most charge to it. It also isolates the batteries from one another and when the engines are not running it isolates the starting battery to protect it. They also eliminate the need for the 1/2/both switches. The one I have for sale is the Batt max Voltseeker II/ 3 battery 110amp model you can find details about it here www.wellsmarinetech.com look under the Batt Max Voltseeker II link.
I have room for four batteries but I would think that 3 group 27"s are enough for a single motor to handle. Just exploring options with what I have but not opposed to either the combiner or isolator.
Right now all three batteries are in the same compartment and easy to access.I would Have to put one up in the V-berth if I added one more. Mark
This is how I had the batteries wired on my Trophy 1802:
I will also be wiring the batteries on the 2005 Trophy 2052 the same way with one exception and that is the use of a combiner instead of an isolator. An isolator is a diode which only allows current to flow in one direction. Hence the batteries can not feed back to each other thereby the weaker battery draining down the stronger battery. Both batteries will charge equally but there will be a voltage drop of approximately 5% - 10% accross the isolator. A combiner combines the batteries for charging when the voltage reaches 13.5 +/- or more and separates them when you are starting or not running the motor (absence of a charging condition). There is no loss of voltage accross a combiner.
The setup above uses one 1-all-2-off switch and an on/off switch. All house load is on battery number 2. You can parallel two of your batteries as battery number 2 thereby doubling the current capability while remaining at 12v. The 1-all-2-off switch stays on position 1 making battery number one the start/run battery and battery number two the house battery (as long as the on/off switch is in the on position). I did this to make it idiot proof for myself in that I don't have to remember to change the switch positions in order to keep both batteries fully charged. In an emergency you can start from either battery or both just by changing the settings on the 1-all-2-off switch. If battery two were to fail (blow up, crack, etc) you can put the 1-all-2-off switch on "all" and turn the on/off switch "off" to run the house load. If battery number one were to fail you can place the 1-all-2-off switch in the "2" position to start and run the motor. If, God forbid, there were an electrical fire you can turn the on/off switch to "off" to kill the house load and still start and run the motor off of battery one. As you can see the different combinations of the swtches above can give many desired affects.
I have to tell you, I think that system can be greatly simplified to add to its ruggidness and do away with the expense of a couple of its parts while giving you greater dependability. Here's how:
Throw away that Isolator, you don't need one, and connect the line now going from the "Regulator" to the Common lug on the battery switch. Connect the "House Load" to this terminal too. Next throw away the "Power Terminal" (what was it in there for?) and the separate "On/Off" switch in Battery 2's line and just connect the positive terminal from it directly to input lug 2 on the 1-2-Both Battery switch. That's all you need. Then you simply run the battery switch in position 1 or position 2 but never in the both positon. Alternate which position, 1 or 2, you use from one boat use to another. You always have one fully charged battery in reserve in a very uncomplicated system. If both of the batterys are low they can be combined to get the engine started. Throw an on-board battery charger into the mix so you know that you start each day with both batterys at 100% and you will be in fine shape.
I have to tell you, I think that system can be greatly simplified to add to its ruggidness and do away with the expense of a couple of its parts while giving you greater dependability. Here's how:
Throw away that Isolator, you don't need one, and connect the line now going from the "Regulator" to the Common lug on the battery switch. Connect the "House Load" to this terminal too. Next throw away the "Power Terminal" (what was it in there for?) and the separate "On/Off" switch in Battery 2's line and just connect the positive terminal from it directly to input lug 2 on the 1-2-Both Battery switch. That's all you need. Then you simply run the battery switch in position 1 or position 2 but never in the both positon. Alternate which position, 1 or 2, you use from one boat use to another. You always have one fully charged battery in reserve in a very uncomplicated system. If both of the batterys are low they can be combined to get the engine started. Throw an on-board battery charger into the mix so you know that you start each day with both batterys at 100% and you will be in fine shape.
Thom
Ummmmm...that is the original setup which is exactly what I didn't want. lol Your way, you have to remember to move the switch from 1 to 2 and back and forth and back and forth to charge both batteries. Remember, when I'm out on the ocean I won't have my shore charger there. Second, your house load draws down whichever battery the switch is set to and you have an uncharged battery as back up. Third you can't isolate the load...that is...say you have an electrical short on your main feed or wires melt together. You have to pull the fuse or trip the breaker. Then you have to pull the 1-all-2-off switch out and remove the feed to the house load or cut it just outside the switch. Only then can you just start/run the motor. If I'm out 10 miles I know I don't want to do that....I'll just turn off the feed to the house load thank you very much. Each battery has it's purpose and is totally isolated from the other unless an emergency comes up and each will charge without me having to do anything. I'm trying to idiot proof it from this idiot.
By the way...the power post is feeding a second house fuse box which I installed in addition to the original fuse box. It made things easier for me since I didn't have to stack wires on the post on the on/off switch and I had additional terminals around the post to make attachments. Yes, it's not needed since you can make those connections at the posts on the switch(es). But, I don't like wires stacked on my batteries nor on switch posts. It's cleaner, easier to trace and easier to do repairs.
Birdman...very nice setup. It's like mine but for two motors. That's exactly how I would do it with dual motors.
I decided to run one cranking battery, and wire the other two group 27's in parallel for the house battery. The two group 27's ought to give me plenty of power for my needs. There will also be a combiner installed. As far as the troll-tabs I will work out a solution for them this winter. Mark
I'm going to upgrade my batt system next year. Grp 27 for starting and 2 golf batts for the house. Add a chargepack (which everyone should carry for the boat and tow truck ) and you got your bases covered.
Actually I'm going to redo most of wiring next year. Anybody know a good/cheap source for marine grade wiring and crimps?
Battery setup help???? 
