PAoutdoorsman
South Central PA
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I was getting tired of my battery draining down when not using the camper for a week or two so I started doing some testing, but I'm not 100% certain what the results mean.
I topped the battery with a smart charger. It is a single 12v deep cycle. I place my multi-meter between the positive lead and + battery terminal. I had the multimeter set to 200MA since my 10A fuse is blown.
With everything I knew of turned off the meter read -1
Pulled fuses 1 by 1 and when I pulled the fridge fuse the meter dropped to -008.3. After reading the manual I found the climate control switch hidden and realized it was on. Turned it off and re-installed the fridge fuse and the amp draw stayed at -008.3.
Pulled all remaining 15A fuses and draw stayed at -008.3.
Pulled the 30A fuse that says Converter + and the amp draw went to 0.
Re-installed the Converter + fuse and the CO2 sensor fuse and my draw went to -078.
I think my biggest problem was the climate control switch, but I'm curious how I could calculate the drain on the battery if I leave the converter and CO2 sensor fuse installed. Will I still have a low battery in a couple weeks?
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YC 1
Yuba City Calif.
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Joined: 01/11/2005
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I think your biggest problem is the use of the meter.
If I understand you correctly you stated your 10 amp fuse is blown in the meter ? I can understand why with the way you are describing the use of the meter.
You cannot put an ammeter across a load. You will blow the internal protection fuse.
The lower scales may be protected by their design.
Here is how you should be using the meter when trying to measure amps. Visualize two garden hoses connected to a sprinkler. You would like to measure how much flow/current is running through the hoses. To make that measurement you need to seperate the hoses and place a meter inline with the hose so water flows through it in series.
To use the meter as a voltmeter and not an amp meter you need to do exactly as you describe and measure across the terminals.
Another way to use the ammeter is to simply remove the fuse from the circuit you would like to measure and use the meter to replace the fuse by placing your probes into the fuse socket.
That ten amp fuse in the meter is to protect the meter from over current which can damage or destroy it. Sometimes finding a replacement fuse is difficult but Radio Shack may have the right physical size one.
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TXiceman
(Near) Houston,TX
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Joined: 11/17/2000
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Simple solution is to install a manual battery disconnect switch and just shut down all of the parasitic loads.
Ken
KE5DFR
Vintage 1979 Silver Streak Supreme Rocket toted by a 2002 F350, crewcab dually, 7.3L,4.10 axle,SCMT. Travel with two miniature Schnauzers and one African Gray parrot. Practicing for retirement!
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Bubby's RV
CA
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Joined: 07/22/2003
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I'm going to assume the battery is about 100 Amp-hours (AH) at the 20-hr rate. 078 milliamps times 24 hours is 1.9 AH per day, call it 2 AH/day. With this low a discharge rate, the battery acts like a larger battery, thanks to a guy named Peukert. Let's assume that it acts like a 200 AH battery. Given those two pieces of information, you would expect the battery to fully discharge in 100 days. Well, batteries will self-discharge all on their own at a rate that would probably shorten that to 50 days.
That's why some people install a battery disconnect switch.
John, Winnebago Minnie 24V
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PAoutdoorsman
South Central PA
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YC 1 wrote:I think your biggest problem is the use of the meter.
If I understand you correctly you stated your 10 amp fuse is blown in the meter ? I can understand why with the way you are describing the use of the meter.
You cannot put an ammeter across a load. You will blow the internal protection fuse.
The lower scales may be protected by their design.
Here is how you should be using the meter when trying to measure amps. Visualize two garden hoses connected to a sprinkler. You would like to measure how much flow/current is running through the hoses. To make that measurement you need to seperate the hoses and place a meter inline with the hose so water flows through it in series.
To use the meter as a voltmeter and not an amp meter you need to do exactly as you describe and measure across the terminals.
Another way to use the ammeter is to simply remove the fuse from the circuit you would like to measure and use the meter to replace the fuse by placing your probes into the fuse socket.
That ten amp fuse in the meter is to protect the meter from over current which can damage or destroy it. Sometimes finding a replacement fuse is difficult but Radio Shack may have the right physical size one.
YC 1, yes the 10 amp fuse in the meter is blown from a previous flub when I attempted to measure more than I should have.
I'm trying to understand you sprinkler explanation but I might be too dense. I think I did have my meter in-line as you are suggesting. I took the positive battery cable off, then clipped one side of the meter to the positve battery terminal, and clipped the other side of the meter to the battery cable I just removed from the positive terminal - effectively placing it inline and running all current accross it. Did I do this right?
I never thought of just testing accross the fuse socket. That would have saved some time going back and forth from the battery to the electric panel a dozen times!
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PAoutdoorsman
South Central PA
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TXiceman wrote:Simple solution is to install a manual battery disconnect switch and just shut down all of the parasitic loads.
Ken
I did buy a battery disconnect switch but when I started considering how I would mount it on my TT a-frame, I didn't like any of the options I came up with so I thought I would take a chance and try to get smarter than it before putting in another point of failure.
As a side note... would there be any drawback for this disconnect to be mounted in the TT at the electrical panel where the negative battery lead connects?
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PAoutdoorsman
South Central PA
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Bubby's RV wrote:I'm going to assume the battery is about 100 Amp-hours (AH) at the 20-hr rate. 078 milliamps times 24 hours is 1.9 AH per day, call it 2 AH/day. With this low a discharge rate, the battery acts like a larger battery, thanks to a guy named Peukert. Let's assume that it acts like a 200 AH battery. Given those two pieces of information, you would expect the battery to fully discharge in 100 days. Well, batteries will self-discharge all on their own at a rate that would probably shorten that to 50 days.
That's why some people install a battery disconnect switch.
Thanks for that explanation Bubby! Perfect. Now I guess I need to find out just what quality of battery I have.
If I could get anywhere close to 50 days, I wouldn't even be messing around with this.
I'll try to get a 10A fuse for my multimeter and see what the real draw was with the Dometic fridge 'Climate Control' switch turned on. I assume the -1 on the meter meant that it was more than 200MA? But if that was the case I guess my .2A fuse would have blown? Sorry, I only understand electrical current enough to be dangerous!
Thanks for any help you guys can provide!
* This post was
edited 08/19/08 09:25pm by PAoutdoorsman *
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YC 1
Yuba City Calif.
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Joined: 01/11/2005
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PAoutdoorsman wrote:YC 1 wrote:I think your biggest problem is the use of the meter.
If I understand you correctly you stated your 10 amp fuse is blown in the meter ? I can understand why with the way you are describing the use of the meter.
You cannot put an ammeter across a load. You will blow the internal protection fuse.
The lower scales may be protected by their design.
Here is how you should be using the meter when trying to measure amps. Visualize two garden hoses connected to a sprinkler. You would like to measure how much flow/current is running through the hoses. To make that measurement you need to seperate the hoses and place a meter inline with the hose so water flows through it in series.
To use the meter as a voltmeter and not an amp meter you need to do exactly as you describe and measure across the terminals.
Another way to use the ammeter is to simply remove the fuse from the circuit you would like to measure and use the meter to replace the fuse by placing your probes into the fuse socket.
That ten amp fuse in the meter is to protect the meter from over current which can damage or destroy it. Sometimes finding a replacement fuse is difficult but Radio Shack may have the right physical size one.
YC 1, yes the 10 amp fuse in the meter is blown from a previous flub when I attempted to measure more than I should have.
I'm trying to understand you sprinkler explanation but I might be too dense. I think I did have my meter in-line as you are suggesting. I took the positive battery cable off, then clipped one side of the meter to the positve battery terminal, and clipped the other side of the meter to the battery cable I just removed from the positive terminal - effectively placing it inline and running all current accross it. Did I do this right?
I never thought of just testing accross the fuse socket. That would have saved some time going back and forth from the battery to the electric panel a dozen times!
Yep, you have it. Sorry my splaining wasnt't clearer. By disconnecting the two hoses that feed the sprinkler/ (the sprinkler is the load/ligght etc), you would place the meter with one lead to one hose and one lead to the other hose thus placing the meter in series with the load. Just as you have done by removing the battery leads.
Now after re-reading your post for the third of fourth time it is obvious your were working correctly and found the big culprit draw. Others have offered calculations and I will go find some fresh meds now.
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Bubby's RV
CA
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Joined: 07/22/2003
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PAoutdoorsman wrote: .... I assume the -1 on the meter meant that it was more than 200MA? ...
Yep, that's what mine does.
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Golden_HVAC
Fulltime, CA, USA
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Joined: 08/19/2003
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Hi,
The "Climate Control Switch" on the refrigerator is a really difficult to find switch, I did not find mine until I owned the RV for about 5 years. It causes some heaters to run around the freezer door gasket, so that the gasket will not freeze to the door. Usually you do not need that heater on. If it is really humid, then running it while in a full hookup site will prevent any condensation on the refrigerator door.
For goodness sakes, replace that 10 amp fuse. Radio Shack has them and can install it for you in the store, so you will know how, and that you have the correct fuse. Buy a spare fuse.
I have a e-meter built into my RV, and I can monitor the amperage used by anything in the RV. The E-Meter also keeps track of the amp hours taken out of thebattery bank, then monitors the amp hours going back in, so you have a total amount of power removed from the battery bank at all times. Now that Xanterax owns the company, they call it the Link 10 for one battery bank or Link 20 for two battery banks.
I find that my RV uses about 0.7 amps all the time, and when the refrigerator cycles on it goes up to 1.2 amps per hour. So I figure my 120 watt solar panel will make up the 35 amp hours used daily by the RV propane and carbon monoxide detectors, and the other panels supply the power to watch TV, run the lights, ect.
Fred.
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