Connect Enphase M215 to 24 volt battery + 240 vac?
Ever noticed all those little blinking blue lights all over your house after the sun goes down? They are on the microwave, electric stove, network routers, mini-split, indoor-outdoor weather station, washing machine, and
If I include the power draw of the ceiling fan in the bedroom, these little "vampire drains" add up to almost 400 watts every hour, although it does depend on what speed the ceiling fan is set on.
So, the purpose of this blog is to collect everything I can find concerning whether or not an Enphase M215 Micro-inverter can be connected to a large 24 volt battery, and the 240 VAC grid so it would feed several hundred watts into my household grid all night long.
From the data sheet the input voltage range can be from 16 to 48V, but the MPPT voltage range (voltage range that the switching supply will convert the solar panel voltage to a signal that can be useable for the AC output voltage stage) is limited from 27V to 39V. So if you want to use this with 12V type solar panels, you should be fine. Typically they are around 19.5V open circuit, so that would leave you quite a bit of voltage range when they are loaded by the MPPT to still drive this device properly. Double check the open circuit voltage of your specific 12V solar panels that they do not exceed 24 volts each, but there is probably no danger of over-voltaging the input, and if there is any issue it would be just that the MPPT would drop out sooner than if a MPPT designed for 12V solar panels was to be used. No danger of a problem, just total solar power might be compromised in a shaded or sun down condition. Of course you need to run the solar panels in series here., but as the sunlight drops and the series voltage drops, the MPPT will drop out and you will no longer get any AC power out of the inverter. Running them in parallel won't work. As for the other issue of power, the product is rated at 215 watts continuous AC output, so 200W of solar panel would not be an issue. Keep in mind the solar panel output power is maximum and usually one would not see that much power out of the solar panel except in absolute maximum sunlight. Also the efficiency of the AC conversion on the data sheet is stated at 96.5% and the efficiency of the MPPT is stated at 99.4% so if we multiply the input power by the rated inefficiencies, the most the 200W of solar panel power could cause in the AC output is around 192 watts in the afternoon in Arizona in the summertime. So summarizing, you won't be able to harvest as much solar energy out of your 12V solar panels if you use this inverter as opposed to one which is made to work with 12V solar panels, but you will still get a reasonable amount and it won't damage anything. But note this is a 240V product.
August 18, 2019 I found an interesting Master's Thesis from 2011 regarding connecting a wind generator to the grid using an Enphase M190 and some super capacitors, as well as quite a bit of other circuitry. https://krex.k-state.edu/dspace/bitstream/handle/2097/8754/ChristopherEldridge2011.pdf?sequence=1&isAllowed=y
August 19, 2019 Willie just sent a link where a Tesla Powerwall2 owner was trying to inject some power into his system using the car's 12 volt battery to power a 24 volt grid tied inverter via a 12v to 24 volt converter. This discussion then turned to using the Enphase M215 to do this. https://teslamotorsclub.com/tmc/threads/powerwall-2-0-backup-runtime-extender.126358/
August 29 After reading a 300 page lab report by a student at Cal Poly who was attempting to connect an exercise machine to an M215 through various DC-DC Converters, I searched my YouTube history to re-watch an Enphase M250 actually working with a Midnight Solar Classic charge controller/wind generator/super-capacitors. https://youtu.be/wvnSh4iX110
If I include the power draw of the ceiling fan in the bedroom, these little "vampire drains" add up to almost 400 watts every hour, although it does depend on what speed the ceiling fan is set on.
So, the purpose of this blog is to collect everything I can find concerning whether or not an Enphase M215 Micro-inverter can be connected to a large 24 volt battery, and the 240 VAC grid so it would feed several hundred watts into my household grid all night long.
From the data sheet the input voltage range can be from 16 to 48V, but the MPPT voltage range (voltage range that the switching supply will convert the solar panel voltage to a signal that can be useable for the AC output voltage stage) is limited from 27V to 39V. So if you want to use this with 12V type solar panels, you should be fine. Typically they are around 19.5V open circuit, so that would leave you quite a bit of voltage range when they are loaded by the MPPT to still drive this device properly. Double check the open circuit voltage of your specific 12V solar panels that they do not exceed 24 volts each, but there is probably no danger of over-voltaging the input, and if there is any issue it would be just that the MPPT would drop out sooner than if a MPPT designed for 12V solar panels was to be used. No danger of a problem, just total solar power might be compromised in a shaded or sun down condition. Of course you need to run the solar panels in series here., but as the sunlight drops and the series voltage drops, the MPPT will drop out and you will no longer get any AC power out of the inverter. Running them in parallel won't work. As for the other issue of power, the product is rated at 215 watts continuous AC output, so 200W of solar panel would not be an issue. Keep in mind the solar panel output power is maximum and usually one would not see that much power out of the solar panel except in absolute maximum sunlight. Also the efficiency of the AC conversion on the data sheet is stated at 96.5% and the efficiency of the MPPT is stated at 99.4% so if we multiply the input power by the rated inefficiencies, the most the 200W of solar panel power could cause in the AC output is around 192 watts in the afternoon in Arizona in the summertime. So summarizing, you won't be able to harvest as much solar energy out of your 12V solar panels if you use this inverter as opposed to one which is made to work with 12V solar panels, but you will still get a reasonable amount and it won't damage anything. But note this is a 240V product.
August 18, 2019 I found an interesting Master's Thesis from 2011 regarding connecting a wind generator to the grid using an Enphase M190 and some super capacitors, as well as quite a bit of other circuitry. https://krex.k-state.edu/dspace/bitstream/handle/2097/8754/ChristopherEldridge2011.pdf?sequence=1&isAllowed=y
August 19, 2019 Willie just sent a link where a Tesla Powerwall2 owner was trying to inject some power into his system using the car's 12 volt battery to power a 24 volt grid tied inverter via a 12v to 24 volt converter. This discussion then turned to using the Enphase M215 to do this. https://teslamotorsclub.com/tmc/threads/powerwall-2-0-backup-runtime-extender.126358/
August 29 After reading a 300 page lab report by a student at Cal Poly who was attempting to connect an exercise machine to an M215 through various DC-DC Converters, I searched my YouTube history to re-watch an Enphase M250 actually working with a Midnight Solar Classic charge controller/wind generator/super-capacitors. https://youtu.be/wvnSh4iX110
Popped right up on my ThunderBird RSS feed!
ReplyDeleteMight you be williing to adjust text and/or background to give better contrast?
As you compose, you can highlight URLs, then hit the "link" icon above the compose screen. That should turn your text into a clickable link. To use the above links, I have to copy and paste.
"If I include the power draw of the ceiling fan in the bedroom, these little "vampire drains" add up to almost 400 watts every hour, although it does depend on what speed the ceiling fan is set on."
ReplyDeleteTime is not relevant to power. Suggest: "If I include the power draw of the ceiling fan in the bedroom, these little "vampire drains" add up to almost 400 watts" or ".4kwh/hour".
"Pendatic" is the word you're looking for. :-)
As I recall, you had a bunch of specs on 60 cell, 245w panels. I found that a useful reference. Did you remove it? Having such specs on the M215 posted would also be useful.
ReplyDelete