Suitable mulitimeters

[Painless]

Whilst visiting Home Depot / Lowes etc for other bits and pieces, I've also been looking around for a multimeter that I can use to reliably monitor the DC current amps etc on my unit, once it is built and in the testing phase, however, the best ones I can find only seem to go to a maximum current of 10 amps DC. I'm hoping to find a multimeter that will measure up to 30 odd amps, but won't break the bank.

Can any of the electronics guru's recommend a source?

[dennis13030]

Hi,

My name is Dennis and I am an electronics engineer. The low cost and high current way to go is this;

1. Buy a cheap digital multimeter(the max current rating is NOT important). Believe me on this.
2. Buy a current sensing resistor. See this link. It is a 0.005 Ohm, 7 Watt resistor and it's real cheap($4.16).
http://www.mouser.com/Search/Product...KYZDPMxg%3d%3d
3. Put this resistor inline with the +12V against the electrolyzer.
4. Use the voltmeter to read the voltage across the sense resistor. Whatever value is displayed, multiple it by 200 for the true current value. This calculation is due to the resistor being 0.005 Ohms.

This gets your cheap DMM an effective maximum current measurement of about 37 Amps.

[Painless]

Cool! That's an interesting idea.

I've been thinking about it and I will be wanting to install some kind of amp gauge in the inside the vehicle, once the installation is complete, so I might just go ahead and buy a suitable in-vehicle gauge and use that whilst testing instead. Would save money in the long run.

[Omega]

Wow dennis, you are one smart cookie!!

[BAD MEDICINE]

Id say my biggest weakness in this venture is understanding/measuring the data. Makes me wish I would have made more of an effort to learn it in school.

[Painless]

I just ordered an automotive amp gauge online from SunPro, it runs +/- 60 amps max which should be ideal. I know that the maxigen systems are pulling well over 40 amps on their setup on a ram just like mine (even same year), so I'm considering working up to that kind of production.

[computerclinic]

Dennis, is there a gauge that I can connect to my laptop to see more than 1 reading and track the voltage, wattage and amperage? I t would be cool to plot the time, temp, and electric stats on a chart so as to get the best results with the cells...

[fly]

Hi,

My name is Dennis and I am an electronics engineer. The low cost and high current way to go is this;

1. Buy a cheap digital multimeter(the max current rating is NOT important). Believe me on this.
2. Buy a current sensing resistor. See this link. It is a 0.005 Ohm, 7 Watt resistor and it's real cheap($4.16).
http://www.mouser.com/Search/Product...KYZDPMxg%3d%3d
3. Put this resistor inline with the +12V against the electrolyzer.
4. Use the voltmeter to read the voltage across the sense resistor. Whatever value is displayed, multiple it by 200 for the true current value. This calculation is due to the resistor being 0.005 Ohms.

This gets your cheap DMM an effective maximum current measurement of about 37 Amps.

Whoa, I was looking for exactly that... Didn't think of that at all although it makes perfect mathematical sense.
Thanks Dennis, I will definitely try it out... Need to measure current WAY stronger than 10 amps which is the max my amp meter is rated for (although it displays up to 19.9 amps).

Thanks! should have thought of it, but hey, I'm no electronician, just a hobbist!

[c02cutter]

If you plan on doing any testing at all, and plan on using it in the furture, buy a fluke!

[BoyntonStu]

If you plan on doing any testing at all, and plan on using it in the furture, buy a fluke!

Not unless you are willing to accept "fluke" readings with a non-Fluke meter.

BoyntonStu