Inexpensive tool for monitoring current into or out of batteries

[SternWake]

While I have a battery monitor with a large 500 amp shunt that counts all amps into and out of my batteries, it does not do just one item, unless I were to disconnect or power down every other item I did not want to as well.

I bought the following product so I can monitor accurately the amount of current any particular DC device draws over a period of time.

There are limitations, as this device counts current in only one direction, and only 65 amp hours worth.

If one were to wire this device in line with the house battery fuse panel, one could get a fairly accurate reading of how much they are taking from a battery, and make better decisions as to when to recharge or when to stop depleting the battery completely, or just assuage their curiosity as to how much any particular device draws.

I put anderson powerpole connectors on the meter and can flip it around to measure what my charger returns into my batteries, or backover and see how much a particular device draws.

Right now i am measuring how much Amp hours are needed to take 2 Li-ion 18650 batteries from 3.7v to 4.2V

The meter displays:
battery voltage
Minimum battery voltage
Amps
Maximum amps drawn( start up surge)
Watts
maximum watts drawn (start up surge)
Amp hours to 0.001 a/H
Watt hours to 0.001 wH

All these numbers start when the meter is first hooked to a power source, and are lost when disconnected.

This particular meter does not say how long it has been connected

http://www.amazon.com/High-Precision-Power-Meter-Analyzer/dp/B00C596UIA/ref=cm_cr_pr_product_top

The Turnigy version of this meter does tell you how long it has been connected.

http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=10080

The Watts up version of this meter is about twice the price but according to this guy is the most accurate:



As far as the Anderson powerpole connectors, they are pretty good and versatile. I put some inline on a Ciggy plug receptacle, and on my battery charger, and I can pretty much measure just about anything.

I used the 30 amp powerpoles. they come in all different sizes and amperages, and require some crimping skills and tools to use.

http://www.amazon.com/Anderson-Powe...=8-1-fkmr0&keywords=anderson+powerpole+75+amp

12 awg wire barely fits inside these connectors, so i am limiting myself to 30 amp currents with this meter.


While it says it can handle 130 amps, I would not trust it for this much current. The manual says anything over 65 amps should be limited duration to prevent heating.

This meter might be able to count alternator amps back into the house battery, but Starter current should not be passed through it. There are a bunch of limiting factors on the operation of this device, so just beware of trying to run too much current through it.

But for smaller currents that will not exceed 65 amp hours in the allotted timespan, it is a great tool.

It measures spot on with my voltmeters and is fairly close to my DC clamp on Ammeter and similar as well to my shunted meter.

Okay I gave up measuring the 18650 batteries as my laptop battery was down to 10%.

Right now after being hooked for about 10 minutes it is drawing:
5-6 amps bouncing back and forth.
The max inrush current it has pulled is 7.42 amps/89.1 watts.
My battery is around 12.0 volts at the time of this test(18 a/H FROM FULL UNDER A 10 AMP TOTAL LOAD, ACCORDING TO MY LARGE BATTERY MONITOR) and the lowest during this test is 11.96. caps not intentional^^
The laptop has already consumed 1.237 A/h/16.2 watt hours from the battery.

Pretty neat product if you are interested in this stuff.

okay I got to use up the rest of my anderson Connectors as i am phasing out all the SAE 12v connectors which have proven to be disappointing in terms of mife and voltage drop and resistance heating.

Feel free to ask me questions about this product or implementation and I will do my best to answer them.

 

[SternWake]

Here is my new toy inline measuring and counting current consumption on 12v Vitrifrigo compressor fridge:

This is my winter orientation, so that the air forced through the condenser is pushed into the next compartment, instead of outside the louvered window conversion van vent. I have a foam panel which fits tightly, where the meter is residing in this photo, to force hot air out the vent in the summertime.

That screw actuator is from the conversion van tri fold bed so I can open and close the window behind the fridge, electrically

The display is not always easiest to read, and the numbers jump around a lot. Being able to turn off the backlight would be nice.

Interesting seeing the voltage drop on the circuit( voltage at battery terminals was 13.2), as well as the current taper from a surge of 3.99 amps on start up surge, then drop from 3.0 to 2.2 at the end of a 5 minute long compressor cycle.

Last night I hooked it to my mattress heating pad. 7 hours later it revealed I used 14 amp hours, on a fairly low setting

I put some Anderson connectors inline on a ciggy plug extension cord with 18 awg leads. Kind of wish I has some spare 12 awg to minimize voltage drop, but the drop across the spring loaded connections likely accounts for most of it.

NOw I can hook my new toy inline with pretty much any electrical device I currently own. I'm also going to run some more Anderson connectors elsewhere as a power source. I already put some on my laptop car adapter, as the ciggy plugs like to overheat when the spring tension fades and they are passing 70 to 90 watts.

 

[wagoneer]

I have some anderson connectors The Vanner 600 inverter uses this and I learned about them good idea to use them where ever possible thanks. learn just one thing a day. I am pretty much a dummy when it comes to that invisible stuff that passes through copper wire.

 

[Donedirtcheap]

Thanks. Good links. I have a plain jane digital meter but have wanted to go with something that does more. These Andersons are very handy too. 50 amp 120 amp and up

http://www.powerwerx.com/anderson-powerpoles/housings-contacts/sb50-loose-piece-colored-housing.html

 

[SternWake]

Ok, While My local temperatures are about as cold as they ever get in my location, I am a little surprised at what my new electrical toy is saying my Fridge consumed in the last 25 hours. I am having a hard time believing the numbers. The amp draw when the fridge compressor is running are spot on with 2 other meters. The new toy counts the current over time, and I am a little suspicious as to the accuracy.

It is saying that since 25 hours ago, it has consumed 8.426 amp hours/107.1 watt hours of battery, which is a little more than half of what I expected in such ambient temperatures. I was guessing 14 amp hours last night for a 24 hour period..

It is also saying the max amp start up surge measured was 4.2 amps/51.1 watts
The minimum voltage recorded, 11.87 volts.


The interior fridge temp is 35.5 f. That is the maximum I can find pointing my IR thermometer in the usual warmer spots within. The low temp inside my van came down to 53f last night as I was plugged in and running a 200 watt heater with roof vent closed. It got up to 59 degrees F ambient today. Right now it is 47f inside as I am not plugged in and have not been inside all night to help keep the temps from dropping. The ground temperature outside my van is 34.5F. A fence board six feet above the ground is reading 41.5F The fridge interior is reading also reading 34.5f every where on a setting of 1.75 of 7. I did put a half gallon on 55 degree vegetable juice inside the fridge this morning, which I expected to add considerably to the overall fridge consumption.

I have some 75 amp Andersons ordered. 4 pair. Kind of wish I Ordered only 75 amp versions to begin with, but the 10 pair for 10 bucks deal for the 30 amp versions, was a sell. I also got another 10 ordered.

Well, my mattress heating pad is been at half of max for a few hours now, and I have added my engine battery(AGM) into the load loop tonight to give it some exercise. I know it can still crank my engine easily if I were to remove 75% of its capacity, so no real worries. I know I will not approach that level of battery consumption tonight, unless I were to decide to power my 200 watt heater by the inverter. That would take only a few hours to do and take both batteries far too low, and certainly not be worth their beating.

My Ir thermometer says it is 97F under my covers, In I go.

 

[Donedirtcheap]

11.87 isn't good. What was your voltage this morning? I realize that was probably the reading at compressor kick on as the night went on but what did it read this morning?

 

[SternWake]

I'm not stressed over the 11.87. There is nearly .3 volts drop over the 14 awg lines. 10.5v is when the fridge will decide to stop drawing down the battery. The new toy Says the minimum voltage recorded overnight at the fridge was 11.47, and nearly 36 hours after I hooked the meter inline with the fridge, it has used 11.45 amp hours, well under what I expected, but such low ambient temps have a lot to say about that.

I took my house bank to about 40% last night as I fell asleep with the mattress heating pad cranked at 3/4. And woke up truly overheated a few hours later and it took far too long to cool back down.

I plan on cycling this 130 amp hour battery nearly 50% nightly and recharging to to 95% + daily. I use to have 230 amp hours and found I never used more than 75 of them unless I was deliberately trying to do so.

All that extra capacity was just part of the warm and fuzzies for the What if's which never occurred...... and my solar could not meet the minimum recommended charge rates for that much capacity. I am not a believer in the low and slow mentality as far as battery recharging goes. I think there are a bunch of old wives tales concerning how best to recharge a battery, and I am now trying to meet the manufacturer recommendations, rather than what grandpa told somebody 30 years ago.

If I get more than a year out of this single group 31, I'll come out ahead on the return on investment, at least compared to my last two sets of 27's in parallel.

As I said I am not afraid to cycle my AGM engine battery either. I know more or less how much I take from it. That's my amp hour buffer now.