This is a question right up Bill's alley.

My company work truck (2007 Chevy 1500) will cause my 700W inverter to go into a high voltage shutdown (HVSD) sometimes because the electrical system will go above 15VDC.

My previous truck (2000 Chevy 1500) never had an issue that I noticed.

One difference is the inverter, as the newer one has a LED bar graph to show the DC voltage and the older one did not.

Today as I was driving home from work, the inverter stayed in HVSD the entire time (30 minutes). It was cold today (20-25 F), and I am sure the battery was fighting the cold temps, but that seems like a long time to be pushing 15VDC.

This has occurred at other times, but I only notice it when I need the inverter power.

In your opinion, is this just they way the vehicles are made now? I will try to connect my meter in the morning to see what I can document.

Tom

Tom:

There is a Fluke Tech Note that states a fully charged battery in a running vehicle should read no higher than 15.3V but I also have read that to be 14.5V max. That's at normal operating temperature. At lower temperature, it'll be higher but I've never read how much higher.

After the truck is driven for a while, check the volltage while it's still running. See how much over 15V it is or not.

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Bill

That's what I thought also.

The colder temp made me wonder....normally, the voltage is not that high. By watching the bar graph under "normal" conditions, it will change often.

I guess sitting over the weekend since Friday, with the colder temps, lowered the voltage in the battery and the charging system "sensed" the lower potential. Therefore, it increased the system output to equalize the difference.

That makes perfect sense to me.

My drive to work (as mentioned) is around 30 minutes. Other than the commute, I did very little driving today. It just seems it would have fully charged by then, but it did not get below 15VDC on the inverter LED bar graph.

Again, I will try to get some measurements tomorrow (if I remember).

I connected the 289 to a 12V inverter power cable which was plugged into the accessory port. As expected, everything behaved as you would think. The voltage peaked around 14.8V, but quickly came down to what you would consider normal.

I don't really see this as a problem, but it really stinks when you need your inverter!!

Tom:

Try to measure it with your inverter ON. I don't know much about inverters but is it a large one? Is this battery smaller than the one in the other truck? Just guessing!

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Bill

Bill,

I forgot to mention that the inverter was ON this morning. The voltage bar graph did match the 289 reading. This method of measurement was easier as the connections on the inverter are against the floor.

It is a large inverter with direct power feeds from the battery. Everything else should be similar to the other truck.

I think this truck has the "snowplow" package, which most likely means the charging system has a higher capacity altenator.

Just a thought....

Tom:

Why don't you use the 289's recording feature to monitor the voltage to see if you get a HVSD and a peak on the 289 at the same time?

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Bill

I did record, but I am not "thrilled" with the Fluke View Forms....yet. It is going to take some time to get comfortable with it.

I have only had the 289 a few weeks, so I am still learning. I did manage to get the graph off the form. This is from this morning.....

Tom

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Tom:

Looks like you have a good minute over 14.5V whichs seems a bit long for the regulator to allow.

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Bill

I gotta ask, are you sure its not the ac side its shutting down on?