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post #1 of 10 (permalink) Old 02-01-2014, 16:54 Thread Starter
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Wiring Watt Meter

Wiring Watt Meter

I have a 130w solar panel connected to Schaudt LR1218 Solar Controller which is then connected to a Schaudt EBL99. The vans control panel LT410 only shows LED's with battery levels.
I would like to see a digital display of how many amps the solar panel is producing and also a digital display of the leisure battery charge.
I have bought one of these Digital Watt Meter
but do not know where to connect the wires.
Can anyone help me please?
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post #2 of 10 (permalink) Old 02-01-2014, 17:07
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Looks like it needs to be connected "in line" with the leisure batteries.

I assume you want to see current into the batteries on charge and out of them on discharge and also monitor the terminal voltage?

To do this you need to identify the leads going from your control circuits or on board charger (or solar panel) to the leisure batteries and insert the "Watt Meter"

You may need to experiment to find which leads (Source or Load) are connected to the battery (Probably Source) and which to the Hab wiring.

Red to positive, black to negative

There will be lots of experts along shortly to advise on in line fuses etc but really, if you're not sure how to hook it up I would suggest you get an auto electrician to advise and maybe do it for you.

Cheers

Dave
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post #3 of 10 (permalink) Old 02-01-2014, 20:11
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Taking the simplistic approach of assuming that the meter should be wired with the "source" wires direct to the battery terminals and the load direct to the other end, I would be very concerned about the diameter of the conductors. If (as claimed) the unit is capable of handling a continuous 50amps or more, I'd expect the conductors to be 5mm or more in diameter. It's difficult to tell on the photo but those conductors look more like 2mm to me. If so, you'd need to use a shunt resistor to carry the current or the whole thing would be likely to start a fire. Can you confirm the conductor diameters?

EDIT:
Apologies if I've misunderstood your question, after re-reading it seems you anly want to monitor solar charge, not full load leisure battery current. As you would then be talking more of 10 amps maximum the conductor diameter may be sufficient. You would also need to connect the solar output to "source" and the battery to "load". I would still worry about a device that claims to handle 50a+ with that size of conductor though.

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post #4 of 10 (permalink) Old 04-01-2014, 14:42 Thread Starter
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Thanks for your replies. Yes the main thing I want it to do is monitor the solar charge. I'm just not sure do I wire it between the solar regulator & the electroblok or before the solar regulator? I assume the first option.
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post #5 of 10 (permalink) Old 14-12-2014, 10:23
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Hi Mark,

I'm after some advice. I also have a Globecar Roadscout R and have just bought a Schaudt LR1218 solar regulator to connect to the EBL 99.

Can you tell me where your LR 1218 is positioned? The installation instructions say a max of 30cm from the front plate of the EBL which in my case is under the passenger seat.

With thanks
Simon
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post #6 of 10 (permalink) Old 14-12-2014, 11:21
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It will need a current shunt, and you connect the wires across the shunt.

Have a look on ebay dc amp meter and some come with the shunt others do not.

Andy

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post #7 of 10 (permalink) Old 14-12-2014, 12:46 Thread Starter
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Hi Simon, Bonglewagon
Mine is also under the passenger seat and the LR1218 is just on it's side, not fixed to anything but the wiring holds it in place. It's just behind the side panel of the passenger seat on the passenger side door.
Mark
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post #8 of 10 (permalink) Old 14-12-2014, 17:43
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Thanks Mark,

I'll have a look and see how it fits.

My plan is to get a portable solar panel and connect it up when the van is parked up at home or when on site with no hook-up.

Bosch (on Amazon) seem to do some good ones but l reckon l will have to remove their inbuilt solar regulator.

Cheers

Simon
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post #9 of 10 (permalink) Old 07-01-2015, 15:21
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Schaudt LT320

Hi Mark,

For your information Schaudt do an LT320 that connects to the Schaudt LR1218 solar regulator and displays the current (amps) being generated by the solar panels.

Regards
Simon
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post #10 of 10 (permalink) Old 05-02-2015, 22:19
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A word of warning.

I bought a couple of those voltage/current meters in the OP.

I have now investigated them - by taking the covers off and having a look at the cctry.

Basic theory of current measurement (back to good old Herr Ohm and his excellent and simple Laws) is that one measures the voltage generated across a resistor of known value in series with the load.

From V=IR one gets I=V/R.

One knows the value of R, one measures the V and thus the I (current) is easily calculated.

Now, customarily, the resistor would be in the +ve lead and the -ve passes straight through.

HOWEVER - on these devices the measurement series resistor is in the -ve lead and the +ve passes straight through.

Why does that matter to us?

Because in a lot of cases the +ve is wired (as in a piece of wire) direct to the particular device whilst the -ve is very often either a common wire shared with other devices or goes via the chassis metalwork.

If that is the case then the sensing resistor in the -ve lead will be shorted out or shared with other devices.

ANY READINGS WILL THUS BE TOTALLY INCORRECT!

If the connected load is totally isolated from any other negative (or chassis) then all will be fine.

If not then be aware!

Also, I doubt whether I would be happy to use it at the rated continuous duty of 50A - the wiring and soldering does not look up to handling that sort of current, let alone intermittent 100A.

Apart from all the above - not a bad product and at a very good price.
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