Please Help Me wire my Battery Monitor

[stevek]

This is the schematic that came with my gauge.
Where do I wire the "load" wires to? Thanks
Any recommendations on wire size?
Installation instructions were not very good.

[Mike Jean Bandfield]

Steve, the 'load' is everything your battery powers except the PZEM-51. So, the shunt should be wired in series with the negative cable near the battery. The wire size is dependent on load and length. Assuming you are simply installing an ammeter and not adding batteries or additional load - connect the shunt with the same size wire the factory used (i.e., ~#2awg). The wires to the meter (shown as light grey) can be small; #18-20 awg. -Mike

PS. The diagram indicates the device is rated at 100A. If you have a 2000W inverter running your microwave then you'll need to rethink the wiring. If your inverter is the typical 1000W or less it can be safely included in the 'load'.

[stevek]

Thanks Mike. I am really a novice at all this. Not good on electrical stuff.
I was hoping to use this when I boondock.
Not just for my 300 watt inverter which I seldom use.
I was hoping 100 amps would be enough?
So I guess maybe wire in to my PD Power Converter? That would be my "load", shown in schematic.

Like I said.... only would use this when boon docking, so maybe even an on/off switch?
Since I am limited to 100 amps.

I pretty much have everything I use in my BF on plug in 12VDC. TV, Computer, reading light, radio,etc.
I would use propane heater, plus frig. Plus I have some solar.
Never have really any need to use my 300 pure sign watt inverter.

Or.... I am all wet? Thanks..

Pic of what I have...

[Mike Jean Bandfield]

I think your 300W inverter is most sensible! Anything more is overkill and antithetical to the spirit of boondocking * And the 100A capacity is ample for your needs.

If the meter has an automatic shut-off that completely shuts off power after a short viewing period then I would be tempted to put it in the circuit where it would include everything including the battery cut-off switch, solar panels, solar controller, converter/PD panel and inverter. That means the shunt would likely be in the battery compartment or very nearby. (OBTW, with minor wiring changes you could put it in-line with either the positive or negative battery lead. Choose the one that would make for the easiest installation.) This gives you the ability to monitor the battery anytime by simply pushing the button. Even in storage you'll be absolutely certain there is no drain. By turning things on/off 1 at a time you'll know exactly what they use and you'll be able to find any parasitic drains more easily. Also, if they weren't included with the device, putting inline fuses on the small wires to the meter makes sense so that you don't have unprotected 12vdc wires running through the coach.

Mike

* Some people gotta have their microwave popcorn at midnight or nuke their 5AM donut when running a generator makes campground enemies. I prefer popcorn done the old fashioned way.

[oliverpsmile]

I would install the shunt, as mention above, in the battery compartment. Then, you can monitor both the discharge and the charging of the batteries (the values should be shown with (-) negative value, provided that the monitor is capable of doing it. Otherwise you can reverse the measuring wires with a toggle switch and get reading for DC charge or discharge.

Have fun

PS. One time, by chance I met a lady living full time in BF using very sophisticated battery monitoring system with solar panels. I was amazed to see AH consumed, AH remaining, AH charged. Not me - if I do not disturb anybody and my batteries do not deliver, I let the generator doing its job.

[tomzleapin]

I disconnected the negative battery cable from the frame and bolted one end of my shunt to the frame and the battery cable to other end of the shunt. My meter will read both charge and discharge. It appears that Steve's meter will only display charge current. Usually an isolated power source is required to do both.

[stevek]

Thanks everybody.
But sorry... still confused.
How do I wire and where... "DC Load" shown in below picture, to monitor all of my 12vdc usage.
Only when I am boon docking.
Is it possible?

All the other wiring I understand. Thanks..

[Mike Jean Bandfield]

Steve, We don't know what your current configuration is. Not all BFs are wired the same and people add devices by tapping directly to batteries (i.e., Solar panels, controllers, inverters et. al.) And, cut-off switches and 6v or 12 v batteries change the physical location of wires. It would be easy to mislead you if we were unaware of 'loads' that were added in unconventional ways. -Mike.

PS. See my PM

[tomzleapin]

Your coach is the load. Get rid of the resistor pictured above. Put the shunt somewhere between the negative battery terminal and the coach frame. The easiest for me was to disconnect the negative cable from the frame, bolt one end of the shunt to the frame and the end of the negative cable to the other end of the shunt. Run wires from the shunt (the red ones in your photo) to the meter inside your coach. Connect the blue wire to a +12 volt source inside your coach and the black wire to ground.

[stevek]

Thanks Tom and Mike and everyone for help.
Sorry, I am not very smart when it comes to electrical stuff.
And the old saying picture is worth a thousand of words...
I am also an Escapees Member, so posted topic their.
An Escapees Member replied...should be easy for me to follow and wire up and try out.
But still on the road/ away from home... probably will wait until spring.
What I purchased is a real CheapO from China, so might buy something more $$.
Lou/ Escapees member made me the following schematic..
And, I thank Him..

[tomzleapin]

A recent post on RV.net mentioned a similar meter that would measure both positive and negative current.

Here are links to couple versions on eBay:

http://www.ebay.com/itm/180957167386

http://www.ebay.com/itm/DC-120V-250A-Vo ... 27d37f6c46

[bigdipper]

Steve,
I didn't read all this, but I added knife switch in meter circuit to keep the meter from possibly having a small battery drain when in storage. There are obviously some smart electricians here and I would try to find somebody as smart to do the install. Beyond whatever vagaries may exist between coaches, if you have solar, there is still another system for which you want to know what is going on. Between the solar, the converter, and the engine generator, amps come to the batteries from all directions. Sorry if all this is redundant.
JMO,
Ralph

[stevek]

Thanks Tom and Ralph.
Good idea on the knive blade switch.
Tom...can you give link for the discussion at the Good Sam Forum.

I still have not installed mine yet. Too many projects. HA ha.

[tomzleapin]

Here's a link to the post:

http://www.rv.net/forum/index.cfm/fusea ... 797618.cfm