Voltage Issues

[curtisray 0]

2004 Avalanche C4 with 350 Mag Merc

I am having issues with voltage. I'll start with what I'm running.

2 Jabsco Reversible Pumps (only use while engine is running)

2 Stock aerator pumps for center tank.

2 Amps - Kicker 300watt RMS for tower speakers & MB Quart for in boats and 8" sub.

2 Batteries with Blue Seas Add-a-Battery system (has switch w/On, Off, Both & isolator charging relay)

Stock Alternator (at least I think it's stock, not sure what amps)

 

This is the problem I'm having.

Without ballast full I have no issues with voltage. But when all ballast is full (2,300lbs) and on plane, voltage begins to drop to around 10 volts and low voltage alarm beeps every few seconds. Nothing stops working. Perfect Pass stays on, stereo stays on, and all dash stays on. But voltage gauge reads 10 volts and the alarm keep beeping. When off plane, voltage returns to normal 12-13 volts.

 

I plan to replace the power hungry reversible pumps with Tsunami pumps for speed and less power consumption.

I did not have this problem until I upgraded the rear ballast from twin 450lb sacs to 800lb sacs.

I'm wondering if the voltage regulator is malfunctioning under load or if I just need an onshore charging system?

[duramat 462]

On a side note: I'd take your pumps to your battery direct and not use the power distribution block underneath the helm. I think too many are overloading it not knowing. I had issues when I had my johnsons wired to it. (Alarms)

[Bigcatpt 408]

It doesn't make much sense to me for their to be a voltage drop going from resting at idle in the water and then going on plane. As you go up on plane you ramp up your RPM's which is spinning your alternator more and creating more voltage. Voltage should increase as you increase throttle.

 

Have you isolated all the variables? Pumps off, stereo off, perfect pass off....and it still does it?

 

Sounds like you have a short to me. But I am not an electrician.

[RhuntIII 555]

This is a hard one for sure. I had issues with my alternator a few years back and it was the electrical terminations. I'm not sure which wire it was but I'm assuming it was a positive and #10 awg in size. What I found was a burned up terminal and wire at the alternator. I was having alarms going off at various speeds until everything just quit, batteries were dead. Check your electrical terminations at the Alternator. Good luck.

[Wylie_Tunes 146]

 

 

Without ballast full I have no issues with voltage. But when all ballast is full (2,300lbs) and on plane, voltage begins to drop to around 10 volts and low voltage alarm beeps every few seconds.

If the ballast is already filled and pumps are off, the power hungry reversible pumps are not the issue.

 

Here is what I would like to know. At the ballast full speed that you are weeing the voltage drop, record the RPM. Next, dump the ballast and return the boat speed to that same recorded RPM and now watch the volt gauge. Ballast weight or load has zero effect on the alternator's output, but RPM does.

 

You need to make sure the alternator is working as it should and that both batteries are in good shape and fully charged. A bad or undercharged battery will put a heavy load on the alternator.

 

A Tsunami T1200 will draw a 3rd less current then a typical impeller pump, but your flow rate at the sac, will not be that much more. I would not suggest this change. Rather, I would question where you are drawing the B+ and B- for those pump switches?

 

 

 

When off plane, voltage returns to normal 12-13 volts

Sounds like a slipping belt

[curtisray 0]

Thanks for all of the replies. Sorry I haven't responded sooner.

 

Bigcatpt, I think I have isolated everything. I've tried turning off everything while I'm getting low voltage and nothing seems to help. I agree that higher RPMs should result is better voltage. This is why I'm confused. Only happens when ballast is full. Without ballast I have no issues. Also, usually with low voltage things stop working (stereo, perfect pass, etc) but everything just keeps working fine all day long. Just have this annoying alarm going off all day.

 

Wylie, I have not checked the RPM that you suggested. I'll do that when I'm on the water next time. I'm thinking that since I don't have a on shore charger that maybe the batteries being low are overworking the alternator. You mentioned the belt slipping. Have you heard of ballast weight causing the belt to slip? I ask because without ballast I have no issues.

[RhuntIII 555]

I have herd of a loose connection and when listed it makes the connection worse. I've also herd of one bad battery killing the entire system by over working the alternator and battery. Wylie has brought an excellent testing procedure. Check all terminations, battery cells, belt and alternator. What size batteries do you have? On shore charging is a excellent add on.