Another battery issue

[ppkaprince98]

I just installed a new stereo with an amp. I have my positive cable to the amp attached to one of the batteries and the ground cable grounded in the cabin at the panel. When i change the battery selector switch to 1 or 2 the amp powers off. It will only work when the battery switch is on both, why is that?

 

[ardeprint]

I'll take a stab and assume your ground is running off a house (bat) circuit. If your audio system's amp is being powered from a (+) positive lead on a bat which is not a house bat, you have broken the circuit. When you run both bats your are joining bats therefore you have a + and - circuit.

Your radio must be running off the same battery for ground and positive. By you grounding at the cabin panel you are grounding with your house battery. As a result, your positive lead MUST be hooked up to the house battery.

 

[ppkaprince98]

I'll take a stab and assume your ground is running off a house (bat) circuit. If your audio system's amp is being powered from a (+) positive lead on a bat which is not a house bat, you have broken the circuit. When you run both bats your are joining bats therefore you have a + and - circuit.

Your radio must be running off the same battery for ground and positive. By you grounding at the cabin panel you are grounding with your house battery. As a result, your positive lead MUST be hooked up to the house battery.

Ahhhhh I did not know that. And I think you are correct now that I think about it. So really all I have to do to test this theory is to switch the positive cable from the amp to the other battery. Correct?

 

[ardeprint]

Ahhhhh I did not know that. And I think you are correct now that I think about it. So really all I have to do to test this theory is to switch the positive cable from the amp to the other battery. Correct?

Yes... It sounds like that might be your problem. Good luck!

 

[Westie]

Sorry bad advice above. The grounds of both of your batteries SHOULD be connected to the same point or connected directly together. If they are not get them set up properly right away.

Your problem can be a few things. One the battery you are connecting to is bad. Two the positive connection to that battery is bad, when did you last clean and check the connection. Or three the connection to the negative of that battery is bad, again check and clean your connections.
Easiest way to figure out what is wrong is get out the voltmeter.

 

[ardeprint]

Westie I respectfully disagree. Your statement regarding the ground is correct, but if you turn off the battery running the amp at the switch you break the circuit. If you want the amp to work regardless of the battery switch you have to do what I suggested. Yes, the negative is linked, but the positive is not, unless you turn the switch to "Both" bats.

I could be wrong, but I am pretty sure I got this right.

 

[electricaldoctor]

"The grounds of both of your batteries SHOULD be connected to the same point or connected directly together." Start here my friend.

 

[chandalen]

Just for the record... everything should be grounded ALWAYS. If not you have a potential electrical HAZARD. The battery switch interrupts the POS terminal NOT the neg terminal. Just like the ignition switch is a POS connection (as the engine is already grounded). The fact that the radio does not work when you connected the POS directly to the battery is actually a dangerous symptom. It means your radio is NOT properly grounded. In theory... connecting a multimeter to the engine block you should have continuity (a short) between every ground on your boat. The only exception would be a second engine IF its isolated, and has its own battery.

Dual batteries should have a common ground wire connecting both NEG terminals, the POS would be separate and goto the battery selector. You should also only have fuses on a POS line, not a NEG one. (as most devices are grounded in multiple places a fused ground is moot)

I would reverse and ground the amp to the battery, and possibly attach the POS to the battery selector, then it will be on only when the batteries are on. Else.. dont forget to turn the amp off.

 

[Westie]

In theory... connecting a multimeter to the engine block you should have continuity (a short) between every ground on your boat. The only exception would be a second engine IF its isolated, and has its own battery.

Chandalen : totally right on your post.

Not sure it would be worth the trouble to even try to isolate a second engine. Everything it the wiring harness would have to be isolated, all the gauges for it would have to be on the second ground. Everything mechanically would also have to be isolated, just not practical and no reason at all that you would want to isolate it.
Best and easiest thing to do is make sure ALL your grounds are connected together, then you don't have to worry about which battery you are powering things from.

 

[ardeprint]

Did you fix it?

Did you check your ground connections?

 

[ppkaprince98]

Westie I respectfully disagree. Your statement regarding the ground is correct, but if you turn off the battery running the amp at the switch you break the circuit. If you want the amp to work regardless of the battery switch you have to do what I suggested. Yes, the negative is linked, but the positive is not, unless you turn the switch to "Both" bats.

I could be wrong, but I am pretty sure I got this right.

I agree with this.

"The grounds of both of your batteries SHOULD be connected to the same point or connected directly together." Start here my friend.

They are connected together and then grounded to a buss that is grounded to the engine.

Just for the record... everything should be grounded ALWAYS. If not you have a potential electrical HAZARD. The battery switch interrupts the POS terminal NOT the neg terminal. Just like the ignition switch is a POS connection (as the engine is already grounded). The fact that the radio does not work when you connected the POS directly to the battery is actually a dangerous symptom. It means your radio is NOT properly grounded. In theory... connecting a multimeter to the engine block you should have continuity (a short) between every ground on your boat. The only exception would be a second engine IF its isolated, and has its own battery.

Dual batteries should have a common ground wire connecting both NEG terminals, the POS would be separate and goto the battery selector. You should also only have fuses on a POS line, not a NEG one. (as most devices are grounded in multiple places a fused ground is moot)

I would reverse and ground the amp to the battery, and possibly attach the POS to the battery selector, then it will be on only when the batteries are on. Else.. dont forget to turn the amp off.

My issue was with the POS cable not the NEG. My grounds are all grounded and good.

Did you fix it?

Did you check your ground connections?

Yes, I did fix it. Your first comment to me was correct. I had the POS cable from my amp attached to the starting battery. Once I switched it over to my deep cycle battery and circuit was then correct and the battery switch when turned to #1 or both runs the amp/stereo. When tured to #2 or off its dead. Prior to me making this change, the amp/stereo had power at all battery switch locations (#1, #2 and both).

 

[ardeprint]

I'm glad it worked out! Enjoy the tunes.