measuring amps

[Mike Gibson]

I am a bit :confused: do you measure amps on the panel, ginny side of the batt. controler or on the 12v side?

[Joe Blake]

As long as you're actually in the circuit, and your polarity is correct, I'm not sure it really makes much difference.

However, you might find this link pretty useful.

http://www.rpc.com.au/products/meters/meters_faq.html

Regards,

Joe

[Rob Beckers]

Hi Mike,

What's your setup? Is this controller in-line with the genny, or a diversion controller that's hooked up parallel to the battery? What controller are you using? This matters because of the wave-form it produces, meaning that it may require a real RMS meter to accurately measure current. Please give us a bit more info so the answer can be more meaningful.

-Rob-

[Mike Gibson]

The controller is parallel with the panels and batt. The controller is made by Specialty concepts, Inc (automatic sequencing charger) ASC-12/8-A What i am trying to figure out if you measure on the panel side with 20V x 4A = 80W but on the batt. side it would be 12V x 4A = 48W. I mean that is the way i see it. My figures may be wrong. I am hoping that it is meaured on the panel side.

[Mark Parsons]

Hi Mike,

Ahhhhh. The notorious lost solar panel wattage syndrome. I have the same problem with my Xantrex C-40 PWM controller.:(

The answer to capture all the watts your solar array is producing is to use a MPPT (Maximum Power Point Tracking) charge controller.

A good description of this feature can be found at http://www.solar-electric.com/charge_controls/mppt.htm

I have been considering purchase of an Outback MX-60 MPPT charge controller http://www.outbackpower.com/MX60.htm to replace the Xantrex C-40 and relegate the C-40 to diversion load duty. I'm not sure yet how the MX-60 will handle the diversion operation of the C-40 happening simultaneously. If any followers of this thread can shed light for me on this configuration, it would be appreciated.

Regards,
Mark

[Rob Beckers]

Don't know the Specialty Concepts charge controller, but Mark seems to indicate it's a PWM type controller. Those are a primitive form of buck controller. If that's the case, the input and output wattage should be about the same, ie. you're not losing 30-some Watt. How can this be? It's all in the phase relation between voltage and current. What PWM controllers do is very rapidly switch the panel output through to the batteries, then open the switch, switch through again, open, etc. The ratio between close and open+close time of the switch determines what percentage of the panel output goes through to the batteries. The (electronic) switch is opened/closed thousands of times every second.

When the switch is open the voltage on the panel side will be the panel's Voc (unloaded voltage), current at that time is zero. So power is zero during that time. When the switch is closed the voltage on the panel side is just about the battery voltage, and the current is whatever the panels can supply. So, when you measure voltage on the panel side, even with an expensive RMS meter, you'll get some value between battery and open panel voltage. The more the close time of the switch, the more the voltage will be the battery voltage. A good part of the time there's no current flowing despite the high voltage you measure, so you can't use this voltage to calculate Watts. The current you'll measure on the panel side will be either the average of the charge current, or its RMS value, depending on your meter (it's a square wave, cheap meters assume it's a sine wave and will thus give the wrong value).

On the battery side you'll always measure battery voltage, and the current will be the same as the one measured on the panel side. To get Watts you'll need to know the RMS value of the current, and multiply that with the battery voltage.

By the way, the fact that you're measuring a voltage that's different from the battery voltage on the panel side means the charge controller is indeed regulating the charge current. In other words, the batteries are (almost) full, and the panels would otherwise overcharge the batteries. So, you're not 'losing' anything, at that time you're just generating potentially more power than you can put to use.

Mark, combining an MX60 and C-40 shouldn't be a problem. It's just a matter of setting the diversion voltage of the C-40 such that it won't kick in until the batteries are full. Setpoints on the MX60 and C-40 are all fully adjustable, so you can set this any way you want (or rather, the way your batteries will live the longest). If you want to only charge from panels then you won't need the C-40, the MX60 would take care of controlling the battery charge. If you want to charge from additional sources (wind/hydro) then the C-40 would be needed.

-Rob-

[Mark Parsons]

The Specialty Concepts ASC series data sheet
http://www.specialtyconcepts.com/SPECIALTY_CONCEPTS_PDF_FILES/ASC_SPEC_SHEET.pdf

It is a PWM shunt regulator. Shorts out the solar array when battery is full.

Mike, Due to the physics of solar cells, they create a maximum amperage proportional to surface area in full sun conditions. This maximum current is independent of terminal voltage. The cells are arranged in an array to produce a maximum voltage that exceeds a full battery charge (14.5V for a 12V system at 77F) and to have room to spare for cold battery ambient conditions (up to 15.5V cold full and 17V cold equalizing). Hence the common 19-20VDC open circuit voltage for solar panels. As we know, power = watts = amps * volts. Maximum power is thus derived by using this higher available terminal voltage since the amps are fixed. Requires a DC-DC converter to capture this. MPPT was born.

Rob, My Hydro and Wind devices will be directly connected to the batteries. The C40 will divert excess energy upon reaching float voltage setting to a water heating dump load. The MX60 will provide the solar MPPT charging. You are indicating that setting the MX60 to a lower full charge voltage than the C40 would be preferable. To harvest all the excess solar energy, wouldn't I want the C40 kicking in at a voltage under where the MX60 starts into float? I am concerned about these 2 devices oscillating or cross talking since both are trying to bring the batteries to full charge through absorption and float stages.

Thanks.
Mark

[Ralph Day]

Hi Mark

I wouldn't be without my MX60 (unless someone dropped a new Midnite unit in my yard). So much to play with you wouldn't believe it!

In diversion mode you can divert while you're absorbing as well as floating. During absorb, as the amps to the batteries decrease there is excess power to utilize. I'm not sure how the hot water elements would use what's available. Are they "on" full power or will they use whatever is sent their way? In my case, the aux function on the mx will energize a relay for a household outlet (heavy duty 12volt from Carquest). Ther'es an oil-filled convection heater plugged in the outlet (or de-humidifier in summer) which uses the excess power (more than enough hot water thanks). Problem arises when the heater wants 400 watts and there's only 50 extra available. To avoid this, i sometimes put the heater on a timer, or just leave the switch off until i check and see if it can be supported.

By changing the aux option to Vent Fan, and fixing the setpoint, you can use the mx to effectively control/divert excess wind power in the night. My H80 wind controller is slow at diverting to it's heat dump, the voltage spikes high before it diverts. this would be a problem with gel or AGM batteries, not so much with flooded lead acid but...I like control. With the vent fan option the heater will turn on immediately when the voltage reaches the setpoint and shut off when it drops approx 1.5-2 volts dc. It's much easier to change settings and setpoints on the MX than on the Southwest windpower wind controller (I never do anymore).

As the power increases during the day i use higher settings on the heater, or add another. The de-humidifier can't run until June (basement temp too low, it ices up) and it needs the timer to prevent rapid on-off cycling of the compressor.

To find out just what the MX can do, go to the Outback site and download the MX60 manual. It makes good reading and will definitely sell you.

ralph

[Mark Parsons]

Thanks Ralph for the wise advice. It is also good to get an opinion from a product user. I know Ric Murphy is also quite happy with his MX60.

I have now downloaded the MX-60 manual. Next, some light reading...:rolleyes:

The C-40 uses PWM for diversion mode so will feed the load resistance with only what is surplus. That way I can have a 24V, 600 Watt water heater element getting only the surplus energy. If the MX60 can do all this, then no worries about cross-talk. I'll find another use for the C-40 (hunt camp).

Regards,
Mark

[Rob Beckers]

My PWM regulator story was about series mode controllers. Since the Specialty Concepts controller is shunt mode (Thanks Mark!) it does not apply. Forget what I said. The thing that bothers me though is that one would expect the measured voltage on the panel side to be between 0 and battery voltage (plus the diode drop), instead Mike reported measuring more than battery voltage (20V)... :confused:

For power into the batteries you'd still need the RMS value of the current on the battery side, times battery voltage. That doesn't change.

Mark, while talking to Xantrex about using their charge controller as a diversion controller for the Scirocco wind turbine (you may remember I was looking for a charge controller for it) their tech support didn't see any problem using it together with other charge controllers, including an MX60. I can see that multiple controllers will at times conflict (one will be trying to bulk/absorb charge while the other is in float mode). As long as they all coincide in bulk charging regularly the batteries should get a full charge. Set points would depend on what the diversion load is going to do for you; If this is a fail-safe to prevent overcharging, while you don't really do anything useful with the energy, then a higher set point would make sense. If you want to switch on a useful load when possible then a set point equal to that of the MX60 would make sense IMO (for both bulk/absorb and float). I think you'd have to observe battery voltage for a bit, and take all other loads you have on them into account. The objective would be to set things such that the batteries get fully charged regularly, so they live a long life.

I like Ralph's idea of using the MX60's Aux output to do diversion control. I have an MX60 sitting next to me, in a state of disassembly :eek: because I reverse engineered the electronics a few weeks ago to see how it gets the job done. From the manual it would seem that the MX60 can switch on a diversion load for you in all of its charging modes. What I can't tell from the manual is if it can do this while still charging from panels (so the Aux output is just switched based on voltage and charge mode), of if using it this way disables solar charging. I'd guess it can do both, you wouldn't even need the C-40 in that case (I can ask Outback for you, these days I have a good tech contact there).

Interesting stuff!

-Rob-

[Paul Bailey]

Your inverter (most higher end units), most makes and models can possibly switch on AUX loads based on battery voltage as well.! As Ralph stated the Mx is a dream.. they have sold 20,000 0f them already.Datalogging is good. Adjustability features in all areas of control is second to none.These guys have done some serious, forward, out the box thinking to get this to market.That other manufacturers just don't get it.. Outback also has a forum such questions as yours. Paul:)

[Mark Parsons]

Good point Paul about using the Outback forum for specific questions. I will investigate.

Well... A good read on the MX60 user's manual. A very flexible machine. I'm looking forward to purchase and integration, although I need some more PV to bring the MX60 into reasonable efficiency range. With only 165Watts of PV the MX60 is in the low 90's (still better than my curent non-MPPT connect config).

Excerpts from the manual concerning aux output set to diversion mode:
Diversion
Used when a wind or hydro generator is connected directly to the batteries and excess power needs to be
diverted away when the battery is full. The AUX output terminals will become active when the battery voltage
reaches the ABSORB or FLOAT voltage relative to a user adjustable value. The value is adjustable in tenths of
a volt from -5.0 volts to 5.0 volts relative to the ABSORB or FLOAT set point (temperature compensated
Absorb or Float voltage set point if the OutBack BTS is installed). A Hysteresis (HYST) adjustment controls
when the Aux output will go inactive again, after the battery voltage falls below the relative voltage minus the
HYST voltage value. The HOLD time determines the minimum time the output stays active after the battery
voltage falls below the hysteresis voltage.
Diversion using hydro or wind power:
When the wind or hydro generator is connected to the battery terminals as an external DC source, keep the MX60s
diversion voltage slightly above the MX60s Absorb and Float voltages so the MX60 can do it’s job, but the wind
and/or hydro DC sources stay slightly out of the way voltage wise.

My head has been around the rule of using a dump load that exceeds maximum Wind and Hydro capacity by a factor of 2 to always ensure a diversion load is present and prevent runaway conditions. Using a PWM diversion controller keeps the batteries topped up and only the extra energy is diverted to the load. The keeps the wind and hydro devices 'seeing' a pretty constant load. Using the MX60 aux output in diversion mode would mean that it could cycle the load relay pretty heavily in high wind and water conditions. It appears that the aux output is solid state, so I guess I could apply it to switch a solid state relay and use AC power for the diversion load. Certainly opens up more options for water heating elements. Is there any fear of excess battery cycling or shock loading concerns on wind and hydro machines when aux cycles a large load at 100%?

Thanks.
Mark

[Ralph Day]

Hello again Mark

Your reading of the MX manual is accurate. My aux setup is as you described it, the mx drives a heavy duty 12v relay and yes, in high/gusty winds, or when the batteries are full and wind is gusty it cycles the relay a lot. Yesterday for example. I got to thinking that i didn't have a replacement relay from Carquest in the house...something for the shopping list.

If you're around and watching things you can avoid the constant rapid cycling by putting your diversion load (heater, dehumidifier) on a regular house circuit. as long as you don't forget about it and drain batteries smack smack smack!

How adjustable is your PWM controller for setpoints? Dip switches, adjustable pots, factory settings only?

Ralph

[Mark Parsons]

Hi Ralph,

Thanks for confirming my suspicions. How long have you been using the Carquest heavy duty relay? Most industrial relays have design life expectancies of around 1 million operations under rated load. I'm not sure about automotive devices.

Excerpts from my Xantrex C-40 Manual:
Diversion Controller
The C-Series controller can operate as a Diversion Controller,
also called a shunt regulator, to manage battery charging from
alternative energy sources such as PV, wind or hydroelectric
generators. A diversion controller monitors battery voltage
and, when the voltage exceeds the settings for your charge
stage (whether bulk or float), the power is diverted from the
source (solar, wind, or hydro generator) to a “dump” load
which will dissipate the excess power into heat.
When used for this purpose, the C-Series controller varies an
amount of battery voltage to a “dump load” in order to
redirect the excess power generated from over-charging the
batteries. This allows the charging source to remain under
constant load to prevent an over-speed condition which could
occur if the charging source is suddenly disconnected from
the battery–as series regulators do.

Adjusting the C-Series Voltage Settings
The charging voltage setpoints and voltage reconnect/
disconnect setting of the controller are adjustable using two
rotary potentiometer controls. The knobs are removable to
reduce the likelihood of accidental mis-adjustment if
bumped.
Calibrated scales, shown as scale marks, are provided to
allow setting of the control without requiring the use of a
digital voltmeter.
For more information regarding bulk and float charging
voltages, see “Three-Stage Battery Charging” on page 4.
Setting Voltage Parameters for Charge Control Mode
To set the controller to a specific voltage, point the setting
indicator at the scale mark representing the desired voltage.
The potentiometer scale for BULK charge voltage is
calibrated as follows:
• 12-volt system: 13.0 to 15.0 volts
in increments of 0.2 volts,
• 24-volt system: 26.0 to 30.0 volts
in increments of 0.4 volts,
• 48-volt system: 52.0 to 60.0 volts
in increments of 0.8 volts.
Figure 2-9 Bulk and Float Charge Potentiometers (pots)

Full manual with imbedded images can be downloaded at:
http://www.xantrex.com/web/id/72/p/1/pt/25/product.asp

In your case of on or off dehumdifier via inverter means a variable PWM diversion isn't possible. Resistance water heating with the DC makes the most sense for PWM diversion.

I guess I'm still thinking the cleanest answer is getting a MX60 for MPPT solar charge control and using the Xantrex C40 for diversion load control and setting the bulk voltage for the two instruments pretty close. I would hope they also track closely with battery temperature sensors. My battery compartment is in the unheated garage.

Regards,
Mark

[Ric Murphy]

Hey Mark,
If you want we can experiment with my MX60. I've been wanting to try it anyway to try and utilize the excess solar I occasionally have (more so now in the summer).
Ric

[Mark Parsons]

Hi Ric,

What are you thinking of using the excess power for - water heating, water pumping, air circulating, other?

I would definitely be interested to know how much cycling the diversion relay does. I assume your logging software would pick this event up?

Thanks,
Mark

[Ric Murphy]

Mark,
Long term plan (meaning not this week!!!) would be to add a sub panel in the house and run an underground line back from the power house to it. The sub panel would contain some critical house loads. The sub panel would be switched back and forth with a transfer switch controlled by the Aux output of the MX60. The objective would be twofold:
a) utilize excess energy to offset current household grid consumption.
b) back up for critical house loads during power outages
Not sure about the mechanics of the switching hardware. The MX60 aux output is 12vdc. The house sub panel would be no more than 40aac. Would I need a relay and a tranfer switch or does someone make a single unit that would accomplish the same thing? Keep in mind the MX60 is about 125' from the sub panel location. I can pick up the req'd items to perform some testing before I get the panel and line installed. I think the repeated cycling of the relay can be minimized by finding an appropriate delay time. In my case I'm thinking of using the float mode as the trigger. So the sun shines bright, the battery is fully charged, the MX60 goes into float mode and the Aux out activates. Shortly after the load is added the MX60 goes out of float mode and the aux out would deactivate. But since the sun is out it's safe to assume we will have continued power available so could use lets say a 1 hr delay before the aux deactivates. Thats just one option but I admit I haven't spent a lot of time looking at the different ways the MX60 could accomplish the task. Thoughts????
Ric

[Ric Murphy]

Sorry Mark I forgot to respond to your last question. Yes I believe Wattplot will record events associated with the MX60 aux output. So anything we might wire up to test would be recorded over time.
Ric

[Mark Parsons]

Hi Ric,

In your case it is pretty simple. Use a 12VDC coil definite purpose contactor in your power shed wired to your MS60 Aux. Switch your Power Shed Inverter 120VAC output through this contactor to the underground house line and new pony panel.
http://relays.tycoelectronics.com/datasheets/P3141_DS.pdf

If you had a couple of intermittent loads (like hot water element) you could just leave them connected to the new pony panel. They would go live and dead with the Aux signal.

If you wanted loads to automatically switch between grid and Aux then a transfer switch or device is needed. Pre-configured automatic transfer switches are relatively pricey.
http://www.asco.com/Products/ATS/series300l/300lcat.html

If this feature is required, I would likely just use another pair of interlocked contactors in the house, coil power is 120VAC on these. One is powered by the Aux supply, the other by the grid. The Aux contactor normally closed contact interrupts the coil power to the grid feed contactor and thus supplies your load with Aux power when present. This would keep the load constantly supplied but with very brief interruptions during switching. I can supply a schematic and parts costing, if you wish.
http://www.ab.com/en/epub/catalogs/12768/229240/229254/229461/229481/

In the event of a power failure, program the MS60 Aux for a lower diversion voltage setpoint and power your essential loads from the pony panel.

Of course, you could just select Grid Tie with your Outback Inverter and back feed your house main power panel. Is it UL1741?

Regards,
Mark

[Ralph Day]

And in the event of power failure, one of the aux settings is Manual...on/off. Handy, no setpoints to juggle.

Ralph

[Andrew Welch]

Yes I believe Wattplot will record events associated with the MX60 aux output. So anything we might wire up to test would be recorded over time.

Actually, Ric, I'm not sure that the Mate supplies this information to the serial port, so WattPlot would not be able to record MX Aux port changes. The Mate does tell WattPlot (every second!) what the MX Aux port mode is. So every second, you know what the port has been setup for (Disabled, Diversion, Remote, Manual, Vent Fan, or PV Trigger). However there is no indication that this value changes when the MX Aux port is turned on or off. :confused: A very poor choice of data notification, in my opinion. (Please let me know if the value does change on your system and it is just the documentation that is misleading.)

What is really odd about this is that the Mate does not say what mode the FX Aux port has been configured for, but it does say when the FX Aux port is ON or OFF.:confused: (What the hell was OutBack thinking...?!?)

Perhaps an alternate way to solve your problem is to upgrade to WattPlot PRO. That software has the capability of reacting to any number of system mode or voltage changes, logging them and/or sending emails as the occur. It still would not know directly if the MX switched the MX Aux port on or off, but it might be able to detect the same trigger that the MX uses.

Andrew Welch
Developer, WattPlot(tm) (http://WattPlot.com)

[Ric Murphy]

Hi Andrew,
Thanks for the info. Will let you know what we find after some experimentation with the Aux ports.
Ric

[Mark Parsons]

Hi Ric,

Just wondering about your timing. I figure most of your crops should be in the ground by now. When were you thinking of experimenting with your MX60 aux for excess power?

My schedule is loose for the next couple of weeks if you want to get together and design a test scenario.

Regards,
Mark

[Ric Murphy]

Hey Mark,
Tuesdays and Thursdays are bad for me the next 2 weeks but any other weekday is ok. You pick the day and let me know. Also if you could bring anything we might need (switches, relays, etc) I can compensate you when you get here. I think just something simple to test the aux activation is all we need.
Later,
Ric

[Mark Parsons]

Hi Ric,

I found a 12VDC relay in our inventory. The coil terminals will wire to the MX60 AUX output. The relay contacts are rated for up to 240VAC 10A. I assume you have a 120VAC cube heater or something we can use for a dump load. Should be under 1,000W. What I don't know is what you have to pull power from your inverter. I assume a local duplex receptacle? If so, I will scrounge up a plug, cord and socket and wire through the relay contacts.

Give me a call.

Mark

[Ric Murphy]

Hey Mark,
Yes I have a heater in the power house we can use. It has 3 levels, 2 are under 1000w. Also have 2 - 110v receptacles....each on separate breakers. Even though Andrew says the Mate will not send a signal to Wattplot regarding aux status in the MX60 we should still be able to see when the dump load kicked in on the inverter penplots. Each day I'll just look at the previous days data and make note of the activity. Have to admit I haven't had much time to spend on this project lately so thanks for the prompting. Pretty bad when I have 300w of additional solar panels sitting in the shop and can't even find time to hook them up!!!! Also in regards to the MX60 there's been quite a few fan failures reported on the Outback forum. I've noticed this week that mine is starting to make noises so I expect it will need replacement soon. Hope Outback has found a more robust unit for current/future product. Most users have reported they are failing even under moderate usage. A lot of guys are pulling off the front cover and using stand alone fans (some AC, some DC). Also heard there's been some good software improvements recently. Likely should get the upgrades myself as mine is now a couple of years old.
Talk to you soon,
Ric

[Mark Parsons]

Hi Ric,

Thank you for your hospitality yesterday. The slightly rotted barley juice certainly hit the refreshment button...:D

I look forward to seeing some data on the MX60 AUX usage. Once you have some data, if you could leave a post with AUX configuration (left as FLOAT mode) and maybe a Wattplot graph and/or spreadsheet data with cycling based on load and RE capture for all those interested to analyze.

The one main observation was the very tiny wire terminals the MX60 has for the AUX connections. I'm not sure that the wires we finally placed are clamped securely. Outback could have done a better job in this area.

Thanks again.

Mark

[Ric Murphy]

Hey Mark,
Sorry I haven't had a chance until now to report back on the MX60 Aux function. It was a week or so after we installed the relay that I actually seen the aux activated. I quickly found a problem with using the "float" mode as the trigger though. The way my system parameters are setup I'm usually connected to the grid while the MX60 recharges the battery and eventually goes into float mode. Just ended up buying electricity to run the load connected to the relay. I haven't taken the time to try using any of the other triggers available but the Aux output appears to work fine.

I finally got the next 2 solar panels mounted and wired last week. Sure glad I got to that project on a warm day!!! The one picture below is of the panels (now 8x150w). The other is a screen shot of Wattplot around noon of the first sunny day. I was on track to hit a new high that day until the clouds came out after lunch. Still hit 6kwh though. I would expect to see as high as 8kwh on a perfect day.

I've also just discovered a new problem (I guess I've known about it but didn't realize the extent). I had a few days last week with zero AC usage as logged by Wattplot. I have the computer running 24/7 and one blower in the greenhouse. I should see a minimum of 1.5 kwh/day with just those 2 items. The following is from the Wattplot website:

WattPlot is reporting unexpected zero values and/or my summary wattages seem low or inconsistent.
The accuracy of WattPlot's data is limited by the poor resolution of data reported to it by the OutBack equipment through the Mate. The worst example of this is in Amps values, which are truncated by the FX to an integer value for 120V systems. This means that a current of 0.9 Amps will be reported as ZERO!

The other impact is that the effect on output wattages is worse because the voltages are higher. In other words, an actual 9.9 Amps at 24 VDC coming into the batteries truncates to 9 x 24, which calculates to 216 Watts IN (instead of 237.6 W). However the corresponding inverter current of 1.9 Amps at 125 VAC is truncated to 1 x 125, resulting in a calculated wattage of 125 Watts OUT (instead of 237.5 W)!

Another example of the effect of this truncation behaviour is 'remarkable' MX efficiency. Since PV panel voltages coming in to the MX are often greater than the battery bank voltage, their truncation has a greater effect on PV wattage-IN values than on the MX charger wattage-OUT values. As a result, it can often look like the MX puts more wattage on to the batteries than was produced by your panels!

The good news is that OutBack has announced the new FLEXnet DC monitor that will report currents with much greater accuracy. Read about WattPlot and the FLEXnet DC.

So this means all the data I've collected so far this year is less than accurate to say the least. However these conditions likely explain my "perceived" system inefficiences!!! Nice to know it's not as bad as I had thought. So I'm looking into the the new Flexnet DC monitor. The beauty of this is that it can monitor up to 3 shunts. I should finally be able to see the turbine and solar outputs individually. It's just too bad it's going to cost another $600.00 (approx) and won't make me any additional electricity. Oh well....it's only money!!!

The only other new thing out here is I also finished my super insulated vegetable storage room. I can't believe how well the spray foam works. The inside temperature barley changes no matter what the outside temp is. I swear I can heat it with a light bulb and cool it with an ice cube!!! Back in the summer when I transferred everything into the new room and was running the AC 24/7, my daily usage just for the AC was less than half of what it was and the new room is nearly 50% larger. If I get out of the vegetable business it'll make a great recording studio!!!!
Later,
Ric
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[Mark Parsons]

Hi Ric,

Thank you very much for the update and great photos!

The low resolution of amperage indication seems a common theme among charge controllers. My Xantrex C40 only displays to the nearest amp as well. Why is this? Anyone with a reasonable answer to this lack of measuring (or displaying) resolution? Certainly amperage meters for almost a couple of centuries have been able to measure to milliamps. Today's instrumentation is capable of resolving picoamps. Why intentionally degrade the readings?

I would be interested to learn of other charge controller product options that measure and display actual values to the accuracy limit of the instrumentation technology used. Guessing games with power generation and product efficiency would be eliminated. Maybe this is the problem? Would allow the user to quickly test the veracity of the specifications of the RE products implemented? Are manufacturer's afraid their products won't meet their specs?

Best regards,
Mark