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Old 01-13-2018, 05:25 AM   #1
jeffba
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Current draw value when battery disconnect switch is off

Hi I have a 2018 HV 379RD. as you know there are things that are still connected to the battery with the switch off. Unfortunately ours is in storage most of the time. I have 2 options I am looking at. Separate battery disconnect switch or small solar panel to supply just enough to supply power to the devices still running and to keep battery fully charged.

I can buy a clamp on amp probe and measure, but before I do that, has anyone measured the current draw already?

Has anyone already done this?

Thanks
 
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Old 01-13-2018, 05:41 AM   #2
Phil P
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Originally Posted by jeffba View Post
Hi I have a 2018 HV 379RD. as you know there are things that are still connected to the battery with the switch off. Unfortunately ours is in storage most of the time. I have 2 options I am looking at. Separate battery disconnect switch or small solar panel to supply just enough to supply power to the devices still running and to keep battery fully charged.

I can buy a clamp on amp probe and measure, but before I do that, has anyone measured the current draw already?

Has anyone already done this?

Thanks

Hi

The standard Amprob clamp on test unit doesn’t measure DC amps.

I will see if I can find the make and model of my DC test unit.

Phil P
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Old 01-13-2018, 07:02 AM   #3
1retired06
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I took the easy solution, mounted a blade cutoff switch directly on the negative post. If power is available, a trickle charger with auto shutoff is another option. Use one on our boat. Good question on the draw, would be good to know.
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Old 01-13-2018, 09:16 AM   #4
CaptnJohn
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I added a real cutoff switch. When stored for the summer batteries hold swell. Never lower than 12.9 over 2 1/2 months.
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Old 01-13-2018, 10:03 AM   #5
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For only once or twice per year, just lift a battery cable. Or install a cutoff switch that mounts directly on the battery.

You can buy AC/DC amp clamps at Home Depot, Lowes, or similar. Cost a little more than an AC only clamp, but not prohibitively so.
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Old 01-13-2018, 01:11 PM   #6
deerrahn
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Battery

Why not just unhook the battery if the unit is going to be in storage for 2-4 weeks. Simple, easy and no worry about a short circuit or something shorting out. Be Safe
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Old 01-13-2018, 01:53 PM   #7
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Why not just unhook the battery if the unit is going to be in storage for 2-4 weeks. Simple, easy and no worry about a short circuit or something shorting out. Be Safe
X2 This is the way to go no Question!!
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Old 01-13-2018, 02:33 PM   #8
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Just a FYI on checking AMP Draw. Disconnect Positive Terminal from Battery Set an ordinary VOM Meter to DC Amp normally 10 AMP setting connect one probe to Battery the other too the Pos. Cable this will give you your AMP Draw. If you what to know what is drawing the load start one at a time pulling DC fuses this will Isolate what is drawing the load. No need for A clamp on Meter unless you what to check High AMP Draw like Slides level system ETC
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Old 01-14-2018, 04:01 AM   #9
Phil P
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The previous recommendation are valid but if you are going to do more than a onetime check or go solar this unit is very useful.

Phil P
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Old 01-16-2018, 10:11 AM   #10
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Okay disconnecting the battery will be a pain. It goes in and out of storage somewhat often. Though some time it could be 6 months. I went with a disconnect switch for now. Took out my old multimeter to measure the current by opening the switch and putting across the switch. It draws no current!! Well it does, only my old multimeter is dead. Guess it is something clear duct tape cannot fix. my new DVM does not go up in current enough to try it.
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Old 01-16-2018, 10:56 AM   #11
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After reading your last post above, I'll just cut to the chase. Boatloads of us use some fashion of a battery disconnect switch or just remove a lead to the battery as it only takes less than a minute. As you have found ... the OEM disconnect does not disconnect everything. Why fret over your amp draw when you cured the issue ... you installed a disconnect switch?
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Old 01-17-2018, 03:52 AM   #12
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Hi

I have been meaning to do the draw test on ours to see if a 100W solar panel would support the unit if needed.

We think we have the stick house and associated airport sold so Montana may sit unattended and unplugged from power for the first time.

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Old 01-20-2018, 07:37 PM   #13
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Simple as mention above. Install a good quality disconnect switch on the negative line to the frame. A disconnected/fully charged battery will stay charged for quite some time if there is no draw on it.

However, if I was storing my unit off site at a storage lot somewhere over the winter, I would remove the batteries any take them to my house were they could be kept a trickle charger.

I would leave them in the camper in the summer in between trips with the battery disconnect on the negative line switched off.
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Old 01-22-2018, 11:54 AM   #14
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So the question posed was Has anyone measured the current draw when the convenience center battery disconnect is disconnected and what is it. Since the discussion has morphed into why installing a battery disconnect is the way to go, and no one has answered my question, I can draw the conclusion that no one has measured it.

I think I will spark a spirited discussion on GPSs by asking for directions somewhere.
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Old 01-22-2018, 02:56 PM   #15
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Quote:
Originally Posted by jeffba View Post
So the question posed was Has anyone measured the current draw when the convenience center battery disconnect is disconnected and what is it. Since the discussion has morphed into why installing a battery disconnect is the way to go, and no one has answered my question, I can draw the conclusion that no one has measured it.

I think I will spark a spirited discussion on GPSs by asking for directions somewhere.
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Old 01-22-2018, 06:51 PM   #16
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I understand that you want to know the draw (I do not know what it is). What I don't get is why it matters. There is enough of a draw to kill the batteries in no time. So why not prevent it from happening and be done with it.
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Old 01-23-2018, 04:12 AM   #17
Phil P
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Hi

In my case I want to determine what sizes solar panel I need to support the battery during storage.

It looks like we have the airport sold and this unit will go in storage while we are out in Kansas getting ready to accept our new unit.

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Old 01-23-2018, 08:29 AM   #18
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I think someone mentioned that the batteries went dead in 2 to 3 weeks. You can kind of figure it out by dividing your battery AH rating by (24x2) - hours to go dead. So a mid-range(?) battery has 100 AH. 100/48 is 2 amps. If they last 3 weeks it is 1 1/3 amps. People, correct me if I am way off here.
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Old 01-23-2018, 04:42 PM   #19
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That's close enough for the government. LOL
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Old 02-21-2018, 02:33 PM   #20
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Tom you were way off. But right on for government work.
Open circuit battery voltage 12.7 volts
Current draw with inverter and "key" switch off, 0.25 Amps
Key off, inverter turned on for refrigerator 9.5 amps (doors were open so lights inside refrigerator were on)
Key on, inverter on, 13.5 amps
Measured with Clamp on meter

So I am thinking a 10 watt solar panel would be what is needed to just maintain the battery and keep what Montana thinks needs to be left on with battery disconnect switch off.
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