Any decent alternatives to the Victory battery monitors?

For the curious (i was), here's the manual for that DCM120100C monitor.
https://www.hisse-et-oh.com/system/...inal/ELITE_-_Amp-Volt-Ah_metre.pdf?1411106362

Oh, heck ... it's only 107 kbytes... here it is as an attachment: View attachment DCM120100C_-_Amp-Volt-Ah_metre.pdf

Since the one meter seems to be able to handle a bunch of shunt sizes, its calibration method seems quite complicated...

Based upon the manual, SeattleNewbie appears to have it wired correctly.
(but i'll go back and review his drawing)

**WHOOPS** found something ... gimme a minute...

You've got it wired as their "two wire Discharge" drawing (fig 1).
I'll bet a cookie that for bi-directional measurement ("Charging") your meter requires a *separate external* power supply (as their other two diagrams indicate).

Try hooking some other power source (two 9v batteries?) to their Vext pins and see if it starts noticing the Solar input. Completely separate their Vext(-) from your system. (and Vext(+), too).

Acceptable would be a 120vac to 12vdc wall-wart power supply (Goodwill has many) ... plug it into your inverter and then connect it's 12v output to the Vext pins. The inverter should provide adequate isolation.

Since you indicate **No** connection to the Sprinter's frame or battery/alternator, simply a 12v cigar plug into one of the Sprinter's 12v sockets would work perfectly. Under the driver's seat is the EK1 terminal strip with a fused "Battery +" available for "hard wiring".

--dick (one of the reasons why i chose a magnetic sensor instead of a shunt)

Thanks Dick, I think I did miss that external power supply detail. Thanks for pointing it out.

I might have also misjudged this little guy.

The reason I assumed that it was not seeing/counting the income amps is that there's a 2.5-3 amp discrepancy between what the solar controller claims it is outputting and what the shunt sees. When I tested yesterday afternoon the solar controller was putting out ~2 amps (evening sun + float charging stage) and so the meter showed 0 amps... Thus misleading me.

Today (another beautiful cloudy Seattle summer day) the controller is putting out about 5 amps and the meter sees about 2.5 amps (and the "charging" LED is ON)

I'll continue monitoring for a while, try plugging into the Sprinter's battery for external power supply, and get a clamp ammeter to diagnose further.

SeattleNewbie said:

Thanks Dick, I think I did miss that external power supply detail. Thanks for pointing it out.

I might have also misjudged this little guy.

The reason I assumed that it was not seeing/counting the income amps is that there's a 2.5-3 amp discrepancy between what the solar controller claims it is outputting and what the shunt sees. When I tested yesterday afternoon the solar controller was putting out ~2 amps (evening sun + float charging stage) and so the meter showed 0 amps... Thus misleading me.

Today (another beautiful cloudy Seattle summer day) the controller is putting out about 5 amps and the meter sees about 2.5 amps (and the "charging" LED is ON)

I'll continue monitoring for a while, try plugging into the Sprinter's battery for external power supply, and get a clamp ammeter to diagnose further.

Click to expand...

Yes, well you have the wrong panel type for overcast weather. Solarland polys work much better under those conditions.

Exactly, that’s why I wanted him to reverse the shunt leads. When reversed, meter should read charge current.

autostaretx said:

**WHOOPS** found something ... gimme a minute...

You've got it wired as their "two wire Discharge" drawing (fig 1).

Click to expand...

marklg said:

If you are cheap like me, this clamp meter for $36 is working for me:

https://www.amazon.com/gp/product/B0721MKXBC

Regards,

Mark

Click to expand...

The challenge I had was that sometimes I need to measure fairly large DC currents and sometimes fairly small currents. I didn't enjoy doing it, but ended up with two different clamp meters - one for each range.

In some ways, shunts have the same challenge. To measure 200 - 300 amps takes a shunt rated for 500 amps, but that makes measuring 2 - 10 amps coming from solar on the low end of measurement resolution.

Perhaps I am overly conservative, but I consider measurements taken in the lower and upper 10% of an instrument to be "indicators", not really accurate data that you can use for precision use. 5 amps on a 500 amp scale is less ~1% of range, so is it really 3 vs 5? No idea.

There are much more knowledgeable people on the forum with a ton of experience measuring small currents and the intricacies of what is required. It isn't always so easy.

HarryN said:

Yes, well you have the wrong panel type for overcast weather. Solarland polys work much better under those conditions.

Click to expand...

Harry, if I had a dollar every time you've told me that I've bought the wrong components.

Guess what, the Renogy stuff is working fine so far. The batteries are always charged. The 2000 watt inverter powers my 15 Amp table saw just fine. And I am building this van to travel, not to stay in Seattle forever.

My thinking is this: You do the research that you can and commit to some components and get on with your life... Otherwise I'd forever be in analysis paralysis and searching for the perfect solar panels.

Thanks Dick, I think I did miss that external power supply detail. Thanks for pointing it out.

Click to expand...

I connected the external power supply to the meter and the amp reading is still the same (i.e. about 2.5 amps lower than the solar controller claims)

So I think you are probably correct about the error in measuring small currents with this 500 Amp shunt. I should probably leave this alone and get back to plumbing

calbiker said:

Exactly, that’s why I wanted him to reverse the shunt leads. When reversed, meter should read charge current.

Click to expand...

That was a good hunch/suggestion, thanks. I tried it, but that wasn't the source of my error. The discrepancy between amps reported by the solar controller and amps read by the meter is why I initially thought that charge current wasn't read at all.

So, given the "reading ambiguity", is it actually working?
Can you cram a significant (i.e. visible) charge current into the batteries?

--dick

autostaretx said:

So, given the "reading ambiguity", is it actually working?
Can you cram a significant (i.e. visible) charge current into the batteries?

--dick

Click to expand...

Well the ambiguity is consistent. For example, the charge controller says that it is inputting 5 amps and the meter shows 2.5 amps. Later the controller says 8 amps, and the meter shows 5.5 amps.

But yes, I will plug the inverter/charger into AC power when I can to see how it behaves.

Just trying to be helpful.

400 watts of panels making about (8 amps) x (12 volts) = ~ 100 watts from 400 watts of panels.

Good luck with your project - hope it works out for you.