24 volts

[sabbett4]

when two batteries are converted into a 24-volt system, can you still use them for things that require only 12 volts.<br />Thanks

 

[vipzach]

Re: 24 volts

yes you can, you just use the pos. and neg. from one of the batteries for the 12v connections.

 

[sabbett4]

Re: 24 volts

Thanks

 

[sabbett4]

Re: 24 volts

I've now been told this isn't possible with an on-board battery charger. My situation: I've got an on-board battery charger hooked to all three of my batteries...is the 24-volt system still possible with this using only my three batteries?...I can't imagine having a fourth battery. If this isn't feasible, any suggestions on best way to go.

 

[byacey]

Re: 24 volts

How are you getting 24 volts using three batteries, or is one of them dedicated for a starter on an outboard? Is your charger a dual output 12 and 24v outputs at the same time? If you are going to tap off 12V from the two batteries in series that make up the 24 volt supply, take the negative for the 12V from the battery that has the negative post connected to ground, and the positive for the 12v taken it from the jumper that is connected between the + terminal of the first battery and the negative of the second battery. This ensures that whatever load you connect will have the negative at the same ground potential as the rest of the boat. If you use the other battery you could have a potential fire if the negative side of the load came in contact with the metal hull of your boat (assuming a metal hull.)

 

[sabbett4]

Re: 24 volts

I was hoping to use the three batteries and not buy a fourth. I have my starter battery which I use for starting the motor and main electrics for the boat--lights, bilge, etc. I have the two other batteries that I use for fish finders, anchor, trolling motor, etc. Between the three batteries, I have an on-board charger hooked up to them. As far as the 24-volt system, I haven't done anything yet. What I want to do is to convert my two batteries that I use for the fish finders, trolling motor, etc. into the 24-volt system and still use the batteries for my fish finders and anchor using 12 volts. In addition to doing this, I still want to use my on-board charger for all three batteries. Is this possible?<br />Thanks

 

[Silvertip]

Re: 24 volts

Yes - you can do what you want to do. There are a couple of BUTs however. First, your on-board charger MUST be 12/24V capable. Just because you have a bunch of 12V outputs doesn't mean you can can charge two batteries simultaneously. The reason is that some of the older chargers have a common ground meaning that all three ground wires are common with each other. On a 24V system you will have the positive lead of one set of leads on one battery and the negative lead of the second pair at the same point in the circuit (this happens at the jumper between the two batteries). On common ground chargers you will get sparks. If thats what you have, you cannot charge two series wired batteries simultaneously. You would have to separate them when charging, and disconnect on lead when running which is a real pain unless you add switch that will perform that function. If you indeed have a charger with isolated (meaning electrically separate) grounds, then you can connect one set of outputs to each battery and things will work fine. I'll warn you one more time, just because the charger has separate ground leads for each bank doesn't mean the grounds are isolated. As for your electronics, YES you can connect 12V electronics to EITHER of the two batteries wired in series. It is best however to wire them to the battery whose NEGATIVE post is the NEGATIVE side of the trolling motor circuit.