dumb battery question

I am having a little trouble running some added electronics and have replaced both batteries but still get a little trouble pushing some energy hungry devices. I noticed that the previous owner has 10 gauge main wire coming from the batteries to the main bus bar at the dash. Instead of replacing this huge mess of wires can I just add good quality marine grade 8 gauge positive and negative leads from the batteries to the main bus bars at the dash location while leaving the original wires there?
Any help is appreciated.

Re: dumb battery question

It depends on what the problem is. By running 8 awg, you will have more amperage available at the bus bar. If there are other problems with your "huge mess" it would make no difference how much amperage is available.

Re: dumb battery question

You could do that but it may not solve your problem. You'd have to really be pulling power off the battery to max out 10 gauge wire.
How much draw do you need? What is happening specifically?

Re: dumb battery question

Poor crimps, corroded connections, or loose connections are more likely to be a cause for voltage drop than 10 gauge wire being too small. I have to agree that unless you are powering a very high current consuming audio system, 10 gauge wire is probably not the issue.

Re: dumb battery question

I am going to be using a raymarine bottom machine and a Garmin chartplotter w a secondary transducer (1kw) xm sat., regular radio w 4 speakers, and autopilot. I think it may be the corroded 10 gauge wires but the supply lines are the only thing that look bad so what if I just add this 8 gauge in addition to what is there? I think it will solve it because then I willl have the connection needed and probably more than enough to draw on. I just hope I am not messing something up by added more supply lines w/o taking the old off.

Re: dumb battery question

Welcome to the board .
You can add the 8 gauge wire but before you do I would measure the voltage at your buss bar with.
a meter and see if you have a voltage drop.

Also it you just add the 8 gauge to the 12 volt buss bar with the proper fuse then you also need to make sure the ground buss also has at least a 8 gauge wire and a 10 gauge wire.
Every amp that goes to the 12 volt buss bar also returns to the battery ground. If the you have a 8 gauge and a 10 gauge going to the 12 volt buss and only a 10 gage on the ground bus you could cause the ground wire to over heat and cause a fire.

Personally I would not have 2 12 volt lines going to the same buss.

It would be much better to have one 12 Volt wire of the proper size going to the positive buss and a next size larger wire going to the ground buss. The 12 volt line needs to have the proper size fuse or circuit breaker as close to the battery as possible.
Then each device wired to the bus should have the right size wire and fuse for it. The fuses are to protect your devices and prevent electrical fires.

If your voltage is low on the 12 volt buss then a better idea would be to install a second buss box with fuses for your high current devices.
Never forget that the ground buss has to be as big or bigger than the 12 volt side or you create a fire hazard.

Re: dumb battery question

Why is it you have no problem "adding" a second line but you seem hesitant to check/repair/remove the existing line. A bad connection will remain a bad connection and will continue to create heat at the point of the poor connection.
None of the items you will be running (combined) draw anywhere near the capacity of the 10 gauge feed.