I have a "phantom" drainer and need to track him down - Page 2

**daveb** · 11-27-2015, 09:52 PM

That would be similar to the SMB master DC disconnect switch. I opted out of that. I also figure that due to RIVA requirements that the CO detector is wired hard to the battery system but I never have looked to verify. The inverter in my case has a auto transfer switch...it see's shore power and reacts. But off shore power my inverter still activates when turned on. So if I leave the inverter on it will pull power to operate even if it supplies no power to anything. My issue is similar to yours when camping... I power it up to use AC power to run something and if I forget to turn it off it drains my house system.

boywonder · 11-28-2015, 08:35 AM

How many watts is your inverter? 7 amps idle current sounds about right for a larger inverter....7A x 12V=84 watts......84W/1500W=5.6%....about 94% efficient for a 1500W inverter.

pfacdb · 11-28-2015, 09:22 AM

BW, check this out. Somebody with a Roadtrek has had way too much time on their hands. On the pull down for vehicle, choose 2009 190. I have 2011 190 but it is the same. Everything else is off but inverter switch is left on. As you can see, you get 7 amps at outlet.

By the way, it's a small tripp-lite inverter at 750W.

Here's the link: http://www.metrotrekkers.org/utility/electrical.htm

pfacdb · 11-28-2015, 09:32 AM

Hey, thanks again for the help and interesting conversation. Awhile back when I was in heavy electronics learning phase--BASIC--I asked in this forum for some help in practical testing of things that could go wrong with the van's electronics. This recent real problem gave me a good real world learning experience, and the comments and links really helped.

I am now happily retired and enjoy photography. If anyone that came by here is interested, here's a blog that I have with a recent trip to San Raphael swell. This first one has bit of text-about 5 min or so--and it's a little introspective, so if that's not your cup of tea, just enjoy the photos.

Here's the link.

http://exploringwithmerlin.com

Scalf77 · 11-29-2015, 10:57 AM

Quote:

Originally Posted by pfacdb

BW, check this out. Somebody with a Roadtrek has had way too much time on their hands. On the pull down for vehicle, choose 2009 190. I have 2011 190 but it is the same. Everything else is off but inverter switch is left on. As you can see, you get 7 amps at outlet.

By the way, it's a small tripp-lite inverter at 750W.

Here's the link: http://www.metrotrekkers.org/utility/electrical.htm

While this is a very nice link, you are confusing the what it is trying to tell you. With the inverter on you have 7 amps available at your AC outlets, if plugged in you have 15 Amps. While all that is true, with out anything plugged into the outlet or outlets you would not be drawing any actual current out of the inverter.

But, you still identified correctly the problem as the inverter being on, the power being used would be considered the no load current or idle current. That is the price you pay in power for the idle conversion. This value would be part of the efficiency curve but should be listed separately in the specifications Many inverters will minimize the effect of this by have a search mode. turning fully on only after seeing a minimum load (adjustable).

Efficiency would be the conversion of power, this is sometimes identified as peak efficiency. In reality it is a curve based on the amount of power being converted, heat, etc plus adding in idle current. Large inverters generally have a very low efficiency while powering smaller loads even though their listed peak efficiency maybe the same.

probably took this further then it needed to go, but some may be interested.
Nice website
-greg

Viva · 11-29-2015, 11:57 AM

Quote:

Originally Posted by Scalf77

probably took this further then it needed to go, but some may be interested.

-greg

Greg,

Just wanted to say thanks for the post just above. Since my "strategy" is just to live a 99% 12-volt life*, I haven't ever had a "real" inverter. I knew some of the things you posted, but not the good-to-know details that you added. Who knows, maybe I'll want one someday and now I know some things to look for. Thanks!

Viva

*For the remaining 1% I just use a small inverter that plugs into a cigarette outlet which I dig out every few weeks or so to charge things like drill batteries that simply have to have 110.

boywonder · 11-29-2015, 12:02 PM

Quote:

Originally Posted by Scalf77

probably took this further then it needed to go, but some may be interested.

-greg

Nice Explanation Greg!

For the OP....use your multimeter to determine the 12VDC idle current of your inverter (use the 10 amp range on the meter!).....Those amps get pulled directly from your house batteries....If you know the Amp-hour rating of your batteries divide the battery amp hours by the inverter DC current draw....that will give you the time in hours that the batteries will be drained with the inverter idling.

When doing this measurement, be certain that there are no AC loads on the inverter...if there are the DC current may well exceed 10 amps resulting in a popped fuse in your meter...

pfacdb · 11-29-2015, 01:07 PM

Boywonder: So from what Greg wrote, I understand that the 7amps was only the current "available" if a device was plugged in. I do understand now how to check the amount of "parasitic" drain on battery by loosening the negative terminal and doing in line amp test at 10a with multimeter.

Beginner here: How exactly does one test amp draw for the inverter? Sorry, but mean the very most basic instructions.

Much appreciated.

dana

**daveb** · 11-29-2015, 01:48 PM

Many folks have built in power monitors. They serve different uses including what is being pulled off the house batteries. They monitor voltage, current draw and also act as a battery fuel gauge. I have a Xantrex link-10 (no longer made) that shows me what items pull. For instance my Prosine 2.0 2000 watt inverter pulls about 3 amps sitting idle. My portable fantastic fan on high also pulls about 3 amps. When I saw that a 12v fluorescent light fixture pulled between 2-4 amps I quickly replaced them with LED's. I was also surprised to see those little plug-in inverters weren't as efficient as I thought they would be. Gauges like these are well worth having IMO.

BTW you can use a digital multi meter set to amps to see what the inverter pulls at idle just like you did to check for a drain...just have to make sure all you're reading is the inverter and not something being used off the battery or inverter. If you can't turn off some items, measure the amp draw with the inverter off then turn it on and note the difference.

boywonder · 11-29-2015, 02:55 PM

Quote:

Originally Posted by pfacdb

Boywonder: So from what Greg wrote, I understand that the 7amps was only the current "available" if a device was plugged in. I do understand now how to check the amount of "parasitic" drain on battery by loosening the negative terminal and doing in line amp test at 10a with multimeter.

Beginner here: How exactly does one test amp draw for the inverter? Sorry, but mean the very most basic instructions.

Much appreciated.

dana

Set the meter to 10 amp mode

Put the meter inline (break the circuit, insert the meter, it'll be a large cable) going to the inverter 12V+. Measure amps with inverter on and off.