Vampires and multimeters

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   I am on a quest to track down the cause of my batteries draining quicker than expected. I am trying to be methodical about it and one step I often see suggested is to pull each fuse and test the circuit with a multimeter. Everything is OFF and aside from the expected .008 (multimeter set to 10A) draw from the LP/Gas detector I was surprised to find the TV antenna circuit @ 0.11 and maybe less surprised by the radio @ 0.08. BTW, both of these were labeled unintelligibly, so I tracked them down myself and verified that they are the only thing (that I can find) on that circuit.
My first question is, is that so small that I shouldn't worry about it. Is there a way to disable those two things that I RARELY use? If I just pull the fuse then the little red light next to the circuit stays on which seems like a draw, too.

My second question is, not being familiar with a multimeter, is 0.10A at the 10A setting one amp or one tenth of an amp or one one hundredth of an amp?

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GLBCamper Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 30 Jun 2015 Location: Oregon Online Status: Offline Posts: 274	Topic: Vampires and multimeters Posted: 07 Aug 2017 at 12:29pm
	I am on a quest to track down the cause of my batteries draining quicker than expected. I am trying to be methodical about it and one step I often see suggested is to pull each fuse and test the circuit with a multimeter. Everything is OFF and aside from the expected .008 (multimeter set to 10A) draw from the LP/Gas detector I was surprised to find the TV antenna circuit @ 0.11 and maybe less surprised by the radio @ 0.08. BTW, both of these were labeled unintelligibly, so I tracked them down myself and verified that they are the only thing (that I can find) on that circuit. My first question is, is that so small that I shouldn't worry about it. Is there a way to disable those two things that I RARELY use? If I just pull the fuse then the little red light next to the circuit stays on which seems like a draw, too. My second question is, not being familiar with a multimeter, is 0.10A at the 10A setting one amp or one tenth of an amp or one one hundredth of an amp?
	Old: 2014 177 HRE 2015 Tacoma V6 4x4 Double Cab New: 2016 EVO ATS 200rd 2016 F150 4x4 Sport

spydie Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 25 Jul 2017 Location: New Mexico Online Status: Offline Posts: 159	Posted: 07 Aug 2017 at 12:33pm
	Makes no difference what you have the multimeter set at, 0.10A is always 1/10, or 10/100ths of an amp. I think there is always going to be some draw on your battery unless you disconnect the battery. Our cars also have phantom draws continuously as there are things running in the background all the time.
	2018 R-pod 176 2017 RAM 1500 5.7L Hemi

GlueGuy Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 May 2017 Location: N. California Online Status: Offline Posts: 2653	Posted: 07 Aug 2017 at 4:13pm
	+1 to what spydie said. To add a teeny bit more information, .1 amp at 12 volts is 1.2 watts. That is pretty low, and I don't know how much it would be worth to eliminate it.
	bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

pgoelz Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 22 Jul 2016 Online Status: Offline Posts: 70	Posted: 08 Aug 2017 at 7:26am
	Even small continuous current drains can add up. Add all of your steady state drains together... that is the amp hours you will be consuming continuously. So lets say you have a total of 0.15A continuous drain. That is 0.15 X 24 = 3.6AH per day. If you have a 50AH battery, just that drain alone will drain it to 50% in just under a week. Not much of an issue if you have solar power, but if you are running off battery without means of recharging that is 3.6AH (or 25AH per week) that you could have been using for something else. On my Rpod, the antenna amp has a similar drain to yours but it is switchable. We have solar power so I have not looked too closely at the steady state parasitic drains..... I would assume they come from the gas detector, the fridge electronics, the radio and the water pump light (if left switched on). One thing that is CRUCIAL since you cannot easily eliminate all parasitic drains is to MAKE SURE you have means of disconnecting the battery when in storage. We bought our Rpod used and the battery was partially damaged because it was never disconnected. The steady state drains ran it down to zero and it was left there for extended periods. That is VERY bad for a lead acid battery. Ours should have been about 50AH capacity but it measured about 32AH in a measured discharge test after a couple equalizing charges. Frankly I was surprised it was that good. I have since replaced that battery with a pair of 50AH deep cycle batteries and have added a simple disconnect so I can shut things down when the trailer is not in use. While we're talking batteries..... if you have a battery box with a vented top cover, make sure the battery box is not full of water. I bought two battery boxes for those two batteries and they had shielded vents in the top cover. Unfortunately, any standing water on the top surface of the cover can easily run through the vent holes and into the box.... which does not have a drain hole. To make matters worse, the battery boxes sit directly under the drip line off the front of the trailer. I plugged the vents and drilled a small drain hole in the bottom of each box. I would have preferred to leave the vents open since hydrogen can potentially accumulate in the upper part of the lid in very still air but I figured the lid is still fairly well ventilated and that was the lesser of two evils. Paul

GLBCamper Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 30 Jun 2015 Location: Oregon Online Status: Offline Posts: 274	Posted: 08 Aug 2017 at 10:04am
	Thanks for the replies. The antenna is drawing 0.11 with the switch OFF. Still it sounds like all of my parasitic loads that I've found so far are not my issue because I can go from a 12.6 to 12.0 in less then 24 hours while boondocking. I have two 6v batteries in series AND a 100w Renogy solar suitcase that is often in direct sunlight for 6-8 hours.The batteries are only a year old and were recently tested by a reputable service center in great condition. I have a battery bypass and they will hold a 12.8+ charge for weeks when bypassed, so they're good. It's something in the trailer and it's frustrating because it's turned into an expensive tent since I don't dare even turn on an LED light while boondocking, which is 90% of my camping.
	Old: 2014 177 HRE 2015 Tacoma V6 4x4 Double Cab New: 2016 EVO ATS 200rd 2016 F150 4x4 Sport

spydie Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 25 Jul 2017 Location: New Mexico Online Status: Offline Posts: 159	Posted: 08 Aug 2017 at 10:12am
	Consider using two 12v batteries in parallel which doubles your camping time. Doubles your amp hours. Two six volt batteries in series only doubles your voltage. No gain in amp hours. As an alternative you are going to have track down the culprit draw
	2018 R-pod 176 2017 RAM 1500 5.7L Hemi

GlueGuy Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 15 May 2017 Location: N. California Online Status: Offline Posts: 2653	Posted: 08 Aug 2017 at 10:16am
	A one or two watt parasitic load will not drain your battery in 24 hours. If you're using the 225 AH batteries that others are using, you have approximately 2,700 watt-hours of capacity. It would take quite a while if you're draining at 24 watts per day (or even 50 watts per day). So you have something that is pulling around 20, 40, or 80 watts (at least a few amps, not a few tenths of an amp). I suspect that your brakes are engaged or something like that.
	bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost

spydie Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 25 Jul 2017 Location: New Mexico Online Status: Offline Posts: 159	Posted: 08 Aug 2017 at 10:20am
	That heavy draw would show up in his tests. I know the batteries have been checked by someone you trust. But all indications point to bad batteries
	2018 R-pod 176 2017 RAM 1500 5.7L Hemi

Keith-N-Dar Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 03 Apr 2011 Location: Mayville, WI Online Status: Offline Posts: 1447	Posted: 08 Aug 2017 at 10:46am
	Please don't take tjis as an insult. I don't know how much you know about measuring current draw. If using a conventional meter you must have the measuring device (meter or appropriate shunt)in series with the load. IOW you need to open the line to the load and insert the meter to get a reading. Clamp on ammeters are different, you put the jaws around the feed wire.
	Keith-N-Dar Boris & Betty (Boston Terriers) 2011 R-Pod 177 2010 Ford F-150

pgoelz Members Profile Send Private Message Find Members Posts Add to Buddy List Groupie Joined: 22 Jul 2016 Online Status: Offline Posts: 70	Posted: 08 Aug 2017 at 10:56am
	Unless you have an intermittent heavy draw that you have not yet observed, it HAS to be the batteries. It is either or. Is the refer on battery power and you don't know it? Is the water pump activating periodically due to a leak somewhere? Are the brakes on? I had not actually thought of that one, but if the breakaway pin got pulled.... Are you absolutely POSITIVE you are measuring the total battery current? Try installing a 12V wattmeter as a temporary monitoring device and see if the total discharge power makes sense. See this (sorry, can't get the danged embedded link function to work on this site so here's the full link): https://www.amazon.com/Power-Analyzer-JZCreater-Backlight-Precision/dp/B01LVTST80/ref=sr_1_1?ie=UTF8&qid=1502207485&sr=8-1&keywords=dc+watt+meter Put it directly inline with the battery. Either you ARE drawing a lot more current than you think, the batteries are bad or they are not at the state of charge you think they are. And I just realized that you are (I think) measuring the current across each fuse position when the fuse is pulled? That may miss things like parasitic currents in the converter if it has an issue. Or any other potential loads that are not fused (like a defective solar controller). And don't get confused about the state of charge on your batteries. Measure with a voltmeter on the batteries when the solar system is NOT charging. The Renogy controller that I have displays state of charge but is only accurate while charging (it is the way it is calibrated). The battery meter in the camper is only accurate when the battery is NOT being charged. You may not be as charged as you think you are. Paul