12V DC Monitoring

[mesteve]

Does anyone have any recommendations for a 'stand-alone' 12V monitoring panel? I say standalone because at this point I am not looking for anything integrated into solar charger controller of fancy converter setup. Basically something to monitor system voltage, amps in and out, and anything else you may advise keeping an eye on.

Thanks.

 

[JohnDar]

Would something like this work?

http://www.altestore.com/store/Mete...rs/Digital-Amp-Meter-100A-12V24V48V-DC/p2333/

 

[Duramax1]

http://www.xantrex.com/power-products/power-accessories/linklite-battery-monitor.aspx

I had one of these in my previouse RV. It will provide you with all the information you will ever require

 

[cookie]

Well because it is important to have a surge protector of some sort maybe something like THIS would do the trick. This comes in 30 or 50 amp depending on what your Sundance has. It monitors what you are looking for and protects you.

Peace
Dave

 

[JohnDar]

Well because it is important to have a surge protector of some sort maybe something like THIS would do the trick. This comes in 30 or 50 amp depending on what your Sundance has. It monitors what you are looking for and protects you.

Peace
Dave

I have the 50A version of that unit. Unfortunately, it does not measure the current draw on the 12V system, which is what the OP was looking for. It does give continuous voltage and amp readings on both 120V lines, though. And retains error codes, should a problem occur.

 

[watchthebox]

To do what you're asking, you need a battery monitor that includes a shunt, which is a device that is wired in-line on the negative cable near the battery. The LinkLITE unit that Duramax posted is a good suggestion. Another good one, that is a little less expensive, is the Victron BMV-600S: http://www.victronenergy.com/battery-monitors/bmv-600s%20and%20bmv-602s/. A lot of people use the Trimetic too: http://www.bogartengineering.com/.

If you want to keep accurate track of the state of charge of your battery, one of these is the way to go.

 

[mesteve]

Thanks for all the input. I was snooping around ebay and ran across these...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170603446906&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180485043027&ssPageName=STRK:MEWAX:IT

It will take 2, but the price is right...

 

[porthole]

Thanks for all the input. I was snooping around ebay and ran across these...

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170603446906&ssPageName=STRK:MEWAX:IT
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180485043027&ssPageName=STRK:MEWAX:IT

It will take 2, but the price is right...

I've always wondered why digital and LCD 12 V monitors where so expensive. These certainly are cheap enough. I might get a pair of the meters, one for each trailer see how good they are. Although I would not trust an $8 meter an shunt for my trailer. And that shunt is only rated for 50 amps, add a fudge factor of 20% and you might be lucky to have it work up to 40 amps.

 

[mesteve]

I guess I didn't think about it but its a good point. The AC Service for the trailer is only 30A AC, but I suppose it would be real easy to excede that on the DC side. Without calculating for power losses or additional stored power, you're looking at 300A DC off that same service.

What are the real world amp draws people are seeing on the DC side?

 

[branson4020]

10-15A is typical for me. Maybe 25A when furnace is running. Of course there are brief periods of higher draw, like when I'm moving the slides or the landing gear.

 

[watchthebox]

The AC Service for the trailer is only 30A AC, but I suppose it would be real easy to excede that on the DC side. Without calculating for power losses or additional stored power, you're looking at 300A DC off that same service.

What are the real world amp draws people are seeing on the DC side?

I don't have an exact number for you with regards to amps drawn by DC loads, but it's not going to be anywhere near 300A (assuming you don't have an inverter). Most of the big draws in my stock Cyclone, at least, are AC (not DC), like the air conditioner, microwave, etc. You might get away with that monitor/shunt combo you listed. Certainly a low price. Often, though, you get what you pay for. I would recommend the Victron BMV-600S that I listed if you're looking for a bargain but want a quality setup. It can be had for $158, which includes all you need to install it (http://www.jamestowndistributors.co...43&familyName=Victron+BMV+600+Battery+Monitor).

 

[mesteve]

OK, so I decided to see what kind of draws I am really seeing in my trailer so I got out the DMM and went to town. I was not able to measure the larger draws like slides and landing gear as I only had a meter rated to 10A DC. Here is what I found...

Standing Draw on system - .15A, propane leak detector, et al
1 Bulb Incandecent Fixture - 1.3A
2 Bulb Incandecent Fixture - 2.52A
All Lights on Kitchen Switch - 9.35A
Cheapy Bath Fan - 1.1A
Couch Lights (recessed style x2) - 1.67A
Dinette Light - 2.51A (essentially a 2 bulb incandecent fixture)
Fridge - On, Not Firing - .32A
Fridge - Firing - .37A
Furnace Fan - 7.75A
Radio - .33A
Range Hood Fan - .75A
Range Hood Light - .66A
Water Heater - On, not firing - .17A
Water Heater - Firing - .77
Water Pump - 5.85A

Test ran of single 12V house battery measuring 12.65V before and after tests. So in theory and not taking Peukert Effect into account, I could run the furnace alone for jsut over 28 hours before being down to 50% charge with my 2 220AH batteries.

 

[brianharrison]

Thanks mesteve for the info - good to know.

Take care,
Brian