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Battery Voltage display

Posted: 19 Nov 2015, 13:50
by organicmatter
Have searched before and found stuff on here about adding a voltage display for the battery but can't seem to find it now I need it.

Any tips?

Have a petrol so battery under seat.

Re: Battery Voltage display

Posted: 19 Nov 2015, 13:55
by syncroandy
There's nothing really T3-specific about measuring battery voltage. This might be a good starting point for you:

https://en.wikipedia.org/wiki/Voltmeter

The simplest approach would be to acquire a cheap LCD panel meter and wire it across your battery, mounting it on the outside of the battery box so you can easily see it.

Re: Battery Voltage display

Posted: 19 Nov 2015, 14:33
by organicmatter
I remember seeing a post where someone had wired one with a switch to check between the leisure and vehicle battery, had a few photos etc but cant seem to find it.

will get something like this then http://www.ebay.co.uk/itm/Waterproof-3- ... 1e831f6726" onclick="window.open(this.href);return false; and maybe add a switch

Re: Battery Voltage display

Posted: 19 Nov 2015, 14:58
by scoobert
That'll do it. On-off-on switch if you'll be checking two batteries. Or two LCD panels... I've got a panel and switch in the heater duct panel in front of the gear lever. Think there are vids on YouBoob.

Re: Battery Voltage display

Posted: 19 Nov 2015, 16:08
by syncroandy
For two batteries you could use a single-pole double-throw (3 pin) toggle or slider switch . The middle pin would go to the meter, the other two would each to a battery positive terminal.

Re: Battery Voltage display

Posted: 19 Nov 2015, 16:17
by Jeff J
I have one of these, can use it in the cab for main battery or in the rear for leisure battery http://www.ebay.co.uk/itm/DIGITAL-LED-1 ... XQdohREU7A" onclick="window.open(this.href);return false;

Re: Battery Voltage display

Posted: 19 Nov 2015, 17:02
by organicmatter
Jeff J wrote:I have one of these, can use it in the cab for main battery or in the rear for leisure battery http://www.ebay.co.uk/itm/DIGITAL-LED-1 ... XQdohREU7A" onclick="window.open(this.href);return false;

looks good but on my set up would only monitor Vehicle battery, I take it it also means loosing the 12 volt socket?

Re: Battery Voltage display

Posted: 19 Nov 2015, 18:58
by CovKid
Put the meter anywhere you like. It can monitor either with a three pole switch. The video was mine from a while back - think I added it to WIKI:

https://www.youtube.com/watch?v=JVkR4EG2nO8" onclick="window.open(this.href);return false;

Re: Battery Voltage display

Posted: 19 Nov 2015, 19:15
by Jim San
I think its a good idea to put a switch in, hadn't thought of that. Mine is in the dash, they glow pretty bright.

Re: Battery Voltage display

Posted: 20 Nov 2015, 07:45
by 300CE
Was thinking of getting one of these by drilling a small hole into the battery cover:

http://www.ebay.co.uk/ulk/itm/200634417104" onclick="window.open(this.href);return false;

Re: Battery Voltage display

Posted: 20 Nov 2015, 09:47
by ghost123uk
I just today posted the following on another thread. I reckon it's quite an issue if determining lowest safe voltage or maximum charging voltage, where in both cases 1/2 a Volt can make a big difference.

ghost123uk wrote:However, if you do get one, check it's readout against a known good multimeter. I have three of them (not all in the van :roll: ). Two of them are up to .5 a Volt out, which is quite a lot if you consider your regulator might be outputting 14.2 Volts, your new meter might show that as 14.7 :shock: (or the opposite way round).

Re: Battery Voltage display

Posted: 20 Nov 2015, 10:57
by CovKid
Yep, they do need calibration.

Re: Battery Voltage display

Posted: 20 Nov 2015, 11:36
by ghost123uk
Aye, but not always that simple. One of the ones I bought (cheap Chinese carp off Ebay) varies a lot with temperature, a common issue with poorly designed measuring circuits. I can adjust it, internally, to be correct according to my (decent) multimeter, then test it again on another day and it has drifted off again :evil:

I don't actually have one in the van any more. I now have a simple 4 way fag lighter adapter that also features 5 LEDs to indicate battery condition, from a red for "low" through yellow, to a green for "normal" (measured as ~13 Volts) and another red for "high" (comes on at ~14.2 Volts). Easy to fit, easy to read, oh and useful for when I need to charge / power stuff up from more than one fag lighter socket of course ;) (plus it has a USB socket too :) )

Like this one =

Image

Re: Battery Voltage display

Posted: 23 Nov 2015, 23:42
by nesty
I've done it. I bought 2 off ebay
I have 2 LCD displays in the dashboard. One does the starter battery and one does the leisure battery circuit.
ok they might not be spot on but they are near damm enough.
From them I can spot any charging issues and can tell exactly when the split relay charger flicks over!

Re: Battery Voltage display

Posted: 24 Nov 2015, 09:28
by CovKid
As long as you can calibrate them so they match what the multimeter reads, it'll be close enough. The only downside is you can end up being a paranoid meter watcher - get out of that habit. :D