Brucey
Solar Wizard
Unfortunately the smaller multipluses less than 2000VA aren't available in 120V for US. However with a lot of PC equipment being 240V capable maybe that's not such a big limitation for a ups function.
UPS alternatives?
- Thread starter archjeb
- Start date
The MPP 3048LV-MK (3KW 48V) claims double conversion. "True double conversion AC-DC-AC / zero transfer time for sensitive load"
For the price ($465), it's tempting to try for a UPS.
maximumsolar.online
For the price ($465), it's tempting to try for a UPS.
3048LV-MK (3KW 48V) – Maximum Solar Online
maximumsolar.online
JMACK61
New Member
Victron is the way to go. Just getting my feet wet 5 years ago A discarded APC UPS was the way to go. It has a clean sine wave and fast switchover from utility to inverter and back. But man they are so inefficient converting the DC to AC. When I win the lottery I’m getting Victron.
Just curious, how are you managing the Multiplus during a long outage?
My current old /crappy UPS, I have a raspberry pi attached that executes a bunch of shutdown scripts on the servers to gracefully shut things down. I'd like to do something similar, but not familiar with what you can do with the Multiplus and the VE.Direct interface preferably with some Python modules.
The big or the small one?
On the big one I only have necessary loads and we usually never have outages longer than 3 hours, with PV input it can hold up for that time. The small one is just the ups for my rack, when I see that its a longer outage I shut everything besides router and wifi off so that it can last 5 to 6 hours too
Ya, the small one.
My issue is...some times, I'm not around and want everything to gracefully shutdown; which is why I have the Raspberry pi with my existing APC/Cyberpower setup, which after a couple minutes of no power, it will log in and gracefully shutdown a bunch of VMs running on a couple of ESXi hosts.
The scripts also slack message me about the status along the way. And then using the NUT driver interface...will shut the UPS down and power back up when utility power returns. I want to do something similar but with longer runtime and something that is easier to maintain. These dinky little 9Ah Lead Acid batteries and little dinky UPS are just not able to handle much of a runtime.
I just need a simple API (heck even a simple RS232 interface is fine) to interact with the UPS/Inverter. If I have to screen scrap via a serial connection, I can use pexpect if I have to.
fmeili1
Solar Enthusiast
In this Tasmota issue #8433 are some possible options linked how to communicate with Victron components. It may be helpful to implement something DIY, ESP8266/ESP32 or RaspberryPi based, to implement graceful shutdown features. In case of a RaspberryPi you may execute some ssh command to remote shutdown your systems if the SOC drops below a specific value... just an idea (I don't own large Victron inverters).
I was thinking of doing something similar. Having a schematic would help isolate what to clip (this is assuming there is no dip switch or anything to actually disable it).
Here is a pic of the control/inverter board on one of the Cyberpower UPSs.
Would love to know if someone has already figured out how to disable charging
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Actually I figured it out.
I'm getting 27VDC output from Schottky Rectifier Diode (circled) SS26. By severing the cathode side (pointed towards the battery connection); you cut off the pseudo charge circuit.
This also means that the control board fully relies on the battery for power (the display, etc). As long as there is at least 24vdc on the battery terminals; it should continue to function just fine. On AC power, there is a relay that provides pass through.
The bad thing is...I took this out of the junk pile and found there is something already broken on the inverter circuit...so I'll have to find another one and test/confirm this modification.
I'm getting 27VDC output from Schottky Rectifier Diode (circled) SS26. By severing the cathode side (pointed towards the battery connection); you cut off the pseudo charge circuit.
This also means that the control board fully relies on the battery for power (the display, etc). As long as there is at least 24vdc on the battery terminals; it should continue to function just fine. On AC power, there is a relay that provides pass through.
The bad thing is...I took this out of the junk pile and found there is something already broken on the inverter circuit...so I'll have to find another one and test/confirm this modification.
I think I found something that might work. I'll give them a call in the morning and see if I can chat with them a little more. It looks like it has an RS232 interface that I might be able to write an interface to.
I don't know why its so hard to find a 24v lower wattage inverter/charger for 120VAC output. It would seem like the demand would be high for these in vans, boats, etc in the US. I'm surprised the Victron Multiplus's are not available in 120VAC for the lower wattage units.
Cotek SC1200-124 1200W, 24V Pure Sine Inverter/Charger | DonRowe.com
The Cotek SC1200-124, 1200 Watt, 24 Volt Pure Sine Wave Inverter/Charger is a compact inverter/charger designed for mobile and off-grid applications
www.donrowe.com
I don't know why its so hard to find a 24v lower wattage inverter/charger for 120VAC output. It would seem like the demand would be high for these in vans, boats, etc in the US. I'm surprised the Victron Multiplus's are not available in 120VAC for the lower wattage units.
Tried that with an Eaton ECO 1200, Toasted it.
Edit:
Btw, If anyone (from germany) needs 2 Eaton Eco ups boards, one 800VA one 1200VA, cant remember which one exactly I toasted and which one worked but I gave up, contact me
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The small Multiplus has a VE.Bus port, but you usually need an expensive adapter to connect it to usb and even then I can't say what you can read out or do with the interface.
Would be simpler to put an ESP in to measure battery voltage and maybe a DC current sensor or shunt to calculate remaining time
I'm going to give the Cotek inverter/charger a shot. Just got off the phone with them. Looks like it will work just fine. the RJ12 has RS232 pins and I can easily write an interface with pexpect to do what I need to do. Via the same interface I can configure the charge profile/voltage and it has a configuration for the charge current. Switch over time is spec'd at 10ms so that should work.
Auto Neutral/ground bonding when on battery...floating neutral in bypass mode...looks like it hits all the marks.
The local distributor is just 20min away that handles the warranty - so pretty much local distribution.
I'm still shocked that there are not more 24v inverter/chargers in this power output for the US market.
Auto Neutral/ground bonding when on battery...floating neutral in bypass mode...looks like it hits all the marks.
The local distributor is just 20min away that handles the warranty - so pretty much local distribution.
I'm still shocked that there are not more 24v inverter/chargers in this power output for the US market.
Honestly, without having the board in front of me I couldn't tell you much. The most simple way to do it is to add a diode to the charging circuit. Power can come back to the system, but not go into the battery. However, that only works on some UPS's, others will read the battery at 0 volts and not function.I was thinking of doing something similar. Having a schematic would help isolate what to clip (this is assuming there is no dip switch or anything to actually disable it).
Here is a pic of the control/inverter board on one of the Cyberpower UPSs.
Would love to know if someone has already figured out how to disable charging
View attachment 190981
I was able to poke around with a multimeter and find to charging circuit, and then cut a few leads. But that's all model specific.
I think it's also worth noting that I have added external fans to every one of my UPS's. The transformers in those things get ridiculously hot, and I'm surprised the manufacturer doesn't have a fan in them. The transformer temps were approaching 150° f, I added the fan, and now it hovers around 90°f. It's pretty simple to solder up a 12 volt fan with a switch and cut a small hole in the side of the unit near the transformer as an air inlet. This seems to make my UPS's last much longer.
In post #30, I was actually able to get it on the bench and figure it out. I decided to go down the Inverter/Charger path. Its on order. Will report how it goes after I get it on the bench and test it.
JMACK61
New Member
I used two APC SU2200 UPS’s as is with my 16s50p, 26650 DIY powerwall. The chargers are not strong enough to do any damage to a 48 volt 150 Ah battery. Most the charging comes from my solar panels. Rarely is the UPS on Utility power put I have an external relay on the UPS power cord to take me to Utility power should I get too low on battery power. This keeps power to the house and charge the battery a little bit because that charger would take several days to charge a 150 Ah battery. Took 24 hours to charge the dinky 9Ah sealed leads that it comes with.
Alright, I've got the inverter/charger and 100Ah 24v LiFePo4 pack sitting in the rack. Its been running for a couple weeks now and its working great!
Ended up using the following battery:
Of course did a full battery capacity test beforehand - it was a little over 101Ah.
I still need to finish building a shroud/cover with some HDPE that I have on hand. And also need to get the Serial interface connected to the Raspberry PI for management. But I've ran it with a constant load for 1 hour at 1200W on battery without any issues - and still capacity left. My target is 1 hour which is significantly better than the 10min I was getting from a Cyberpower UPS. So its working as advertised and covers my needs to get enough run time to gracefully shut down the equipment or to get the generator running. Over an hour of runtime is more than adequate.
The Cotek SC1200-124 1200W - from Don Rowe.com is what I ended up with. It was one of the very few 24V inverter/chargers available in the wattage/size.
Thanks folks for the feedback and the discuss. I'm happy with what I ended up with.
Ended up using the following battery:
Of course did a full battery capacity test beforehand - it was a little over 101Ah.
I still need to finish building a shroud/cover with some HDPE that I have on hand. And also need to get the Serial interface connected to the Raspberry PI for management. But I've ran it with a constant load for 1 hour at 1200W on battery without any issues - and still capacity left. My target is 1 hour which is significantly better than the 10min I was getting from a Cyberpower UPS. So its working as advertised and covers my needs to get enough run time to gracefully shut down the equipment or to get the generator running. Over an hour of runtime is more than adequate.
The Cotek SC1200-124 1200W - from Don Rowe.com is what I ended up with. It was one of the very few 24V inverter/chargers available in the wattage/size.
Thanks folks for the feedback and the discuss. I'm happy with what I ended up with.
