Alternator monitor

[ndutton]

A recommendation from forum member Joe for his Hall effect digital ammeter inspired me to install one dedicated to alternator output. Do I need it? No. Will it change anything I'm doing to charge batteries? No. Is it interesting to monitor? Oh yeah.

I found it on ebay for a reasonable price, had a trophy shop engrave a mounting plate and installed it below my electrical distribution panel. The only time it functions is when a battery is connected to the engine via battery switch. The display scrolls continuously between output voltage and amperage. Particularly satisfying is seeing the output amps drop as the battery SOC rises.

Mildly interesting and unrelated to the monitor itself is I've exchanged several emails with the local West Marine store manager as a result of an online survey regarding the four #4 flat washers used to mount the plate.

[lat 64]

Hi Neil.

Im cooking up ideas for a new panel myself.

Can you disclose the type of meter you bought?
Or, was it just one only on e-bay?


Russ

[ndutton]

I'm cooking up ideas for a new panel myself. Can you disclose the type of meter you bought? Or, was it just one only on e-bay?

Here it is:

http://www.ebay.com/itm/291902818500?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

includes a 15' patch cable from Gauss coil to display.

[Administrator]

He's Baaaaaack!

Welcome back, Russ!

We missed you. Now if we can just figure out where Mo went....

Bill

[joe_db]

Wow - very nice
Mine is just hanging around, I haven't got a mount plate yet

These are on Amazon too: https://www.amazon.com/dp/B01DDQM6Z4...+effect+sensor

[romantic comedy]

I have a 100 amp ammeter dedicated to alternator output also.

[lat 64]

I think Mo is digging out from a snowdrift somewhere.

Thanks Neil.

Happy new year all,

Russ

[JDK]

now thats exactly what i need to monitor alternator charging of my battery bank.......does it use a current shunt like my inverter current monitor does ??

[JDK]

i like those hall effect sensor ones.......i need one of those mounted on the cable to my battery bank thus monitoring alternator charge current.....

[ndutton]

.......does it use a current shunt like my inverter current monitor does ??

No, it uses a Gauss field coil. The coil measures the electromagnetic field around the wire as current flows. Joe correctly uses the term Hall Effect, both refer to the same magnetic principles.

[joe_db]

FYI - I have found the meter a fantastic buy at $16 or so, but it does drift around a bit. I have seen it read 0.2-0.4 amps when no current is flowing. This is a total non-factor for alternator output, 47 amps or 47.2 amps is not going to make a difference.
For monitoring current in and out of the battery - this might make a difference. For one example, trying to keep loads less than the solar panel output, +0.5 amps is charging and -0.5 amps is not.
YMMV

[Bratina]

Since Amazon so helpfully gives suggestions for more things to buy, would this be beneficial?

https://www.amazon.com/bayite-6-5-100V-Display-Multimeter-Voltmeter/dp/B013PKYILS/ref=pd_sim_469_2?_encoding=UTF8&pd_rd_i=B013PKYILS&pd_rd_r=02WMJ7621P1K5M4N2SK9&pd_rd_w=Q53Up&pd_rd_wg=UbH6p&psc=1&refRID=02WMJ7621P1K5M4N2SK9

[ndutton]

Nice instrument. What would you do with the power and energy information?

[romantic comedy]

Seeing that meter at amazon having power and energy figures makes me wonder about the expansive battery monitors. I dont know what they are called, but they measure "amps out" and "amps in" as a way to know energy use and needs.

Would this meter tell the same thing?

[ndutton]

My unsolicited opinion of those fancy battery monitors is they're designed to separate you from your money. Remember, all we're trying to do is charge a simple battery. This can get out of hand quickly and often does.

edit:
I'll take this opportunity to remind everyone to beware of advice from internet experts. The caution is not limited to technical accuracy but practicality too. If someone is advocating several hundreds or thousands of dollars in a charging system when a simple battery switch will do the same at the extreme opposite (K.I.S.S.) end of the spectrum, you should scrutinize the advice. Most of us end up somewhere between the two extremes. Make it your decision, not theirs.

Example:
One well known internet expert refers to the original 1-2-Both battery switch installation as a Builder's Blunder. Really? Five decades of successful installations industry-wide without warranty issues galore and it's a blunder? Sounds a little hyperbolic and brings the advice that follows into question if you ask me.