Rear Power Socket Panel Voltmeter

[Oztourer]

Does anyone out there have a panel mounted voltmeter/ammeter connected to their rear power socket? If so what brands/model work well? I run a Traxide DBS and think it might be handy to have a voltage display available to let me know how the system is sailing. I have a digital multimeter but call me lazy :D!

[p38arover]

I put one on my P38A.

https://www.aulro.com/afvb/images/imported/2016/01/403.jpg

[Oztourer]

I put one on my P38A.


Thanks Ron. Exactly the sort of thing I was thinking of. Where did you get it from?

[p38arover]

I bought it off evilbay, it looks to be the same as this one: http://www.ebay.com.au/itm/LCD-Volt-Panel-Meter-Voltage-BLUE-Voltmeter-Display-Solar-Battery-12V-DC-Car-Van-/131447261936?hash=item1e9ade0af0:g:jRkAAOSwPhdU-PRT

However, I got mine from China for a lot less. Ahh, see here: http://www.ebay.com.au/itm/Blue-LCD-Digital-Voltmeter-Battery-Monitor-Panel-Meter-/170868792819?hash=item27c892ddf3:g:NLYAAOSwZd1VZrz 9

For the L322, I might look at something like this: http://www.ebay.com.au/itm/DC-20A-100V-LCD-Digital-Volt-Voltage-Watt-Current-Power-Meter-Ammeter-Voltmeter-/281766296611?hash=item419a947c23:g:2iEAAOSw9N1VwjN 7

[C00P]

Ron,
The specs on that last one appear to show it has the ability to measure the amount of energy that has gone through the gauge since the last reset. Is that how you read it?
If so, could this be used to measure battery discharge, replacing other meters that do the same thing but cost around the $100 mark?
The only limit I see is the 20 Amp max power. Maybe this could be overcome using a parallel shunt and multiplying the meter reading to get the actual energy used?
Cheers

Coop

[p38arover]

That's the way I read it C00P.

As you say, the 20A limit is, umm, limiting. :angel: A shunt could possibly be fitted but one would have to open it up to see where the add it.

I haven't looked to see if there are any higher rated units on eBay.

EDIT: See http://www.ebay.com.au/itm/DC-90V-20A-Digital-Amp-Volt-Combo-Meter-Battery-Capacity-Power-State-of-Charge-/161600917482?hash=item25a02a4fea:g:9zgAAOSwdpxUWiw 3 There are links to 30A, 100A, 150A, etc., units

[Oztourer]

I wonder if you can buy ones using Hall effect current transducer rather than a shunt. Better accuracy and no voltage drop. Still, for $28 I'm going to give it a try.

[Fluids]

To the OP question ... I installed one of these ...

https://www.baintech.com.au/component/mijoshop/product/1383-baintech-universal-panel-ciga-merit-merit?Itemid=370

No point in an ammeter at the rear for my setup as there's loads that would come off before it hits the meter (other + feeds from the battery system to elsewhere).

Works well. I sandwiched it between the LH side of the drawers carcass and the trim just inside the back door (D2)

... but I didn't pay $195 for it! ;)

[bee utey]

double post

[bee utey]

If I were to mount a volt/amp meter in the rear of the vehicle I would run it with a dedicated 5 wire cable from the engine bay (lightweight cable would do), with a current shunt mounted at the source. Example:

Dual LED Digital Voltmeter Ammeter AMP Volt Meter Current Shunt DC 100V 100A | eBay (http://www.ebay.com.au/itm/Dual-LED-Digital-Voltmeter-Ammeter-Amp-Volt-Meter-Current-Shunt-DC-100V-100A-/141388204851?hash=item20eb64cb33:g:spoAAOSwGvhT~EA E)

Or something cleverer:

DC Programmable Controller Meter 0 90V 250A Voltage AMP Power AH Auto Shunt Down | eBay (http://www.ebay.com.au/itm/DC-Programmable-Controller-Meter-0-90V-250A-Voltage-AMP-Power-AH-Auto-Shunt-Down-/161474181843?hash=item25989c7ad3:g:wvwAAOSwrx5UWjj A)

[p38arover]

The meter in the P38A monitors the second battery which is mounted in the spare wheel well directly below the meter.

[C00P]

These are the devices I had in mind for accurate battery state measurement:
Balmar Smartgauge Battery Monitor (http://shop.pkys.com/Balmar-SmartGauge-Battery-Monitor_p_2776.html)
Expensive at $295.

However, this website also has a comparison of Amp-hour counters with this type of battery state meter, and dismisses Amp-hour counters as being of no use to monitor battery state. Points out that they have their uses, but that monitoring battery state isn't one of them. See here:
SmartGauge Electronics - SmartGauge compared to Amp Hours Counters (http://www.smartgauge.co.uk/sgvahrs.html)

So, the question is: Does $295 make sense when I want to monitor a bank consisting of two 120Ah batteries costing about $300 each.If the monitor helps me to extend the life of the batteries by a year or two, then it would be worthwhile, and I only have to buy it once.
Cheers

Coop

[Oztourer]

So, the question is: Does $295 make sense when I want to monitor a bank consisting of two 120Ah batteries costing about $300 each.If the monitor helps me to extend the life of the batteries by a year or two, then it would be worthwhile, and I only have to buy it once.
Cheers

Coop

I think that battery longevity is maximised by proper charging. A good quality charger would be more beneficial than an expensive monitor which is the route I opted for. I was just interested to know the state of discharge of my aux batt from time to time as I'm running a 12v fridge for the first time in anger and don't want my beers to get warm :D:D.

[DiscoMick]

Really can't see why you would spend $295 on a battery monitor when you can buy them for $30 or so.

Sent from my GT-P5210 using AULRO mobile app

[Toxic_Avenger]

I've got my eyes on some state of charge monitor. Good units are not cheap, but then again, you always get what you pay for when you buy measurement instruments (Learnt that the hard way when I bought some plastic vernier calipers from super cheap :o )

One one extreme there is the simple volt meter, be it the multimeter in the tool box, or something more permanent as was pictured below.
Then there is the hall effect and shunt jobs which measure instantaneous draw and some units can even use information you enter regarding your battery bank to determine remaining Amp Hour rating, or a 'time to empty' value.
Some might argue that measuring what's left is pointless, but then again, having a vehicle that is flat on all batteries, and unable to be restarted to re-charge said batteries is also pointless.

I've used blue sea systems stuff extensively in my build, and it's good quality gear, and has a wide range of products to suit.
They have a new for 2016 product which is a small cigarette socket voltmeter which is pretty trick. Would be an easy install into any off-the-shelf socket panel you can get...

https://www.aulro.com/afvb/images/imported/2016/01/363.jpg

[C00P]

[QUOTE=DiscoMick;2480104]Really can't see why you would spend $295 on a battery monitor when you can buy them for $30 or so.

Because the ones you can buy for $30 or so provide approximate measurements that can readily become more erroneous and can apparently be out by as much as 30% (or more). So instead of discharging your battery pack to (say) 70% you could drop it to about 50% and thereby shorten it's life.
But I agree, if you are only considering a single auxilliary battery in your 4WD then the expensive unit would be overkill, and not be cost-effective. In my case I am looking at a battery bank in a large caravan where the cost of replacing the batteries is quite high, and the more expensive unit might be worth it. But I'm still researching as these are pretty new devices which apparently only came onto the market in 2014.
Cheers

Coop

[Eevo]

If you can afford $300 on a battery monitor.... You might as well just buy another battery...

[Toxic_Avenger]

That's one way to look at it eevo, but on the other hand, the high end stuff is not commonplace on a 2-battery system, but more likely to be on a bank of batteries containing 8 or 10, where the cost of replacement is high. Large motor homes, big boats etc. Cheap insurance in those instances.

[justinc]

Untitled Document (http://www.12voltworld.com.au/)

They have a few options aswell however website is undergoing work so can't see the product pic.

There is also stuff like this;

POWER PANEL SOCKET SUITS NISSAN GU PATROL ENGEL WAECO MERIT HELLA CIGA OUTLET - Baintech (http://www.autobox.com.au/nissan-gu-patrol-power-panel-socket-suit-engel-wae)


Also;

http://www.batteriesdirect.com.au/shop/search/720/baintech-power-products.html'search=baintech&gclid=CNuQh-TdscoCFQsjvQodJcwH7g

Also I think Tim at Traxide was working on something similar a while back? Tim?

JC

[LRD414]

This is what I have done in the D4, some of which would be applicable to other models.

A simple voltmeter with a switch to allow selection between cranking battery or aux battery or turned off.

https://www.aulro.com/afvb/images/imported/2016/12/783.jpg

Here's a wiring schematic. I spliced into the aux battery feed "upstream" of the ABG-25.
This will allow me to read the aux battery voltage even when it is lower than 11.6V and the ABG-25 has activated (cut-out).
And also to monitor as voltage comes back up because the ABG-25 cuts back in at 12.5V
https://www.aulro.com/afvb/images/imported/2016/11/614.jpg

One major consideration was being able to read the voltage without waking up all the vehicle systems, which happens on door opening.
This location was simple to wire and install but is also easy to read from the outside.
The little push-out trim panel seemed an obvious location when I had these things in mind.
https://www.aulro.com/afvb/images/imported/2016/12/785.jpg

I got into the habit of checking voltage first thing every morning before opening car on our recent long trip but around the city I just leave it off.

I know voltage alone is not SoC but it's a good guide for a lightly loaded battery using Tim's chart:
https://www.aulro.com/afvb/images/imported/2016/08/826.jpg

Cheers,
Scott

[drivesafe]

Hi folks, make sure that if you fit one of these types of meters, that they are either an LCD type with a MANUALLY selected BACKLIGHT, or if you use an LED type that it turns off when the motor is not running and/or has a push button control.

These devices can chew quite a bit of power if they are lite up with the motor off.

[LRD414]

These devices can chew quite a bit of power if they are lite up with the motor off.
Tried to test the voltmeter's current draw with an ampclamp but couldn't get consistent results.
Seemed to still have current flow even with voltmeter switch off and the reading was really variable?
Wired up like this:
https://www.aulro.com/afvb/images/imported/2016/11/614.jpg

Ampclamp seems to work just fine.
Checked the battery negative and one of the fuses:

https://www.aulro.com/afvb/images/imported/2016/11/615.jpg

https://www.aulro.com/afvb/images/imported/2016/11/596.jpg

What am I missing with this circuit?

Regards,
Scott