12 volt shunt

[BernieQ2]

Hay folks I need enlightenment on shunts.
I will be putting one in the bus just need to know what amp shunt should I use. I will use a analog display I'm not interested in what's happened over several days just what's happening when I look at it.
I intend to have two buzz bars one for the power side the other negative mainly to keep the top of battery clean of wires.
We have 190 lt 12volt fridge TV gas stove gas hot water and eventually diesel heater.
We are not big users of electricity.
Thanks.
Bernie.

[Craig]

Hi Bernie,
have you considered using one of the Enerdrive EBM's?

http://pages.ebay.com/link/?nav=item.vi ... 73&alt=web 

I fitted one like this from this guy. Val is a motorhomer and will set you straight. I like the kit as it includes everything you need to install.

[BernieQ2]

Hi Craig, yep I know Mr Val personally but as I said why pay 300 od $$$ for all I want is a basic shunt.
Under $10 on ebay. I just need to know how many amps that's all.
Thanks.
Bernie.

[jon_d]

Bernie,

What current do you want to measure?

minimum and maximum.

jd

[BernieQ2]

Hi Jon, just the amps being used when I turn any of my appliances on.
Bernie.

[BruceS]

Back many years ago an Ampere gauge had the zero in the middle with a range either side of negative (minus?) or positive (plus?).
Of course these were analogue gauges. (mechanical needle movement)
What will happen to most similar gauges I've seen that have zero on the far left & only a positive range when there is no charging and some discharging current?
Will it bend the needle (sic?), record zero, burst into flames or just make the MH go faster?

I should make this a poll?

[Cuppa]

Hi Jon, just the amps being used when I turn any of my appliances on.
Bernie.

Hi Bernie,
What you need depends the current draw of your appliances/lights. The monitor/shunt needs to have sufficient capacity to handle all the appliances you might possibly switched on at the same time. Each appliance should have it’s current draw on it’s label. However if you don’t know & are unable to find out this info then it will do no harm to go for a larger capacity shunt than you are likely to need. If you check out this ebay seller you can see that they sell monitors/shunts up to 500amps with the variation in costs between the different sizes being only a few dollars. You won’t need a 500amp model but it would do the job for you. Likely that a 100 amp model would suffice, but without knowing the combined current draw of your appliances it is not possible to say.

http://stores.ebay.com.au/Elite-element ... 7675.l2563

The shunt will go between the negative buss bar & the neg battery terminal, & will have small wires coming off it to the monitor.

Cuppa

ps. This is for the 200A one
http://www.ebay.com.au/itm/DC-120V-200A ... 27d29cb83f

[BernieQ2]

Thanks Cuppa, but they all seem to be digital and I only want analogue.
With every thing in the bus running at the same time I don't think I would get to 20 amps. We are not big power users.
So I'm thinking along the lines of only needing a 50 amp shunt and gauge, possible 100amp to cover all bases.
Thanks.
Bernie.

[BruceS]

Good topic!!
I read some info and amongst it I found a few suggestions that I thought might be helpful to someone.
If you're installing a shunt (& gauge) on the engine battery you need to NOT include the wire/current that goes to the starter motor. Most vehicles the red pos wire goes to the solenoid on the starter motor & THEN there is another live (red) wire from there to power the rest of the vehicle.
Contradicting Cuppa (sorry) but the shunt could go in either neg or pos.
It seems like most shunts & gauges that are used through shunts are either 50Mv or 75Mv. Both shunt & gauge MUST be the same 'reduction ratio'.
Some people think a 'shunt' is something else!!
David (Super Sparky) does too........ (He's a steam train buff!!)

[Newcastle George]

I thought it was when some idiot of a driver ran into the rear of your car.

George