12 Volt power panel

[NCBrew]

All of the breaker posts read 7.4 volts and not 12 V

 

[NCBrew]

Like my stereo is slow coming on out works after a slight delay

 

[Davidasailor26]

At 7.4 volts a lot of things wouldn’t work at all, and some things might be overstressed from the low voltage.

What points are you measuring the voltage between? There could a voltage drop either on the positive side or the ground side. Is anything turned on when you test the voltage?

 

[Don S/V ILLusion]

All of the breaker posts read 7.4 volts and not 12 V

More info…. What have you found when checking voltages at different points in the supply side? Have you checked connections?

 

[dlochner]

There are a limited number of reasons why the voltage is so low.

1. The battery is weak to begin with and on its last legs.
2. There are bad connections along the way.
3. There is a very large load on the system and anything else that is turned on drops the voltage even more.
4. Undersized wiring causing voltage drop.
5. All of the above or a combination of the above .

My vote is for #5. (Edited choice from 4 to 5).

Inspect all connections to make certain they are tight and not corroded.

Start with the battery. What is the voltage with no loads on it? Start turning things on and measure the voltage at the battery. Write it down.

If you haven't solved the puzzle by then, bring the data back to us.

 

[Ralph Johnstone]

There are bad connections along the way.

My vote is for #2. Nobody could undersize any of the wiring that much.

The bad connection is ahead the breaker posts. Start at the incoming wire to your main DC breaker and note where you first see at battery voltage above the 12V+ range.

Can you vary the 7.4V at the breaker posts by adding load or removing load ?

 

[dlochner]

There are a limited number of reasons why the voltage is so low.

1. The battery is weak to begin with and on its last legs.
2. There are bad connections along the way.
3. There is a very large load on the system and anything else that is turned on drops the voltage even more.
4. Undersized wiring causing voltage drop.
5. All of the above or a combination of the above .

My vote is for #5. (Edited choice from 4 to 5).

Inspect all connections to make certain they are tight and not corroded.

Start with the battery. What is the voltage with no loads on it? Start turning things on and measure the voltage at the battery. Write it down.

If you haven't solved the puzzle by then, bring the data back to us.

My choice was changed to #5. Originally it was #4 and then I added a new #4 which made my choice, all of the above, #5.

Thank you @Ralph Johnstone for drawing my attention to my error.