Solar Panel, Inverter and Large UPS's - Offgrid system help pls

Howdy fastfwd and welcome to Solar Panel Talk. Dont want to rain on your parade but the reason they got rid of the batteries is that they are very likely getting towards the end of their life, not to worry you might still get some good use out of them, I would suggest you start with reading the off-grid stickies, you need a charge controller, that inverter will be next to useless ( iam guessing) you are going about things backwards, in designing an off grid system you must star with the load, you are basically just going to get whatever the system you have will produce, any way a good learning experience for you, good luck with it, keep reading, cheers

Thanks a bunch mate, <--- fyi im aussie also if you haven't guess already so we are talking 240v's

as i said in the previous post i only replaced these UPS's for the business as they are a government organisation that needs all equipment such as this to remain in warranty. These were just out of warranty but the last time they were plugged in they were fully functional. I would almost go as far as saying they had 85-90% of their battery life from new in them. They were great units.

So to start off i wasnt looking at running to much. My server rack under my staircase is a maximum of 100watts which consists of a NAS, small custom server, switch, router, modem and wifi through a power injector. I have calculated this wattage through a power monitor so its always under 100watts. I have a fridge that is on the adjacent wall to where my server rack is under my staircase (storage room). So i was also thinking off adding the fridge onto this system also. I havent monitored the power usage on the fridge but from the manufactures website it says 680kw/h usage per year. If my calculations are correct 680kw/h per year = 1.8kw per day. my Server rack calculation is 2.4kw per day so add them both up thats 4.2kWh per day total (4.2kWh/day).


All these items are the only items in my house that run 24/7 which is why i wish to put them on the solar system.

so i know my Draw roughly and im pretty sure the setup i have in equipment above is more than enough for the task, i just need to know what to do to get this running.

Also from what you have said that i need a charge controller (CC). Does that mean i will be removing all the battery's from my UPS's and connecting them to a Charge controller? then running back through the UPS after the charge controller to convert DC to AC?

I think i might need someone to draw me a crude diagram...

There is no way a 40A UPS can run a whole building AND a server rack. Though server racks (and servers) come in many different capacities. I had some very dense server racks full of blades, each fed by dual 60A 3phase, that could best most home electric furnace systems.

The batteries in the UPS are not meant for continual cycling and the UPS is not meant for continual use. You likely could use one of the better ones to keep up some circuits in your home completely independently from a solar system.
I think that inverter is grid tie so no direct connection to batteries. Keep the two system separate.

Congratulations. You now are the proud owner of a new Boat Anchor. Only problem is they are extremely poisonous to aquatic wildlife. As such are pretty much useless.

The building it powered was not as large as your thinking. It was basically the size of a small 1 Bedroom Apartment and it most defiantly did keep it running for power outage purposes (6 hours was the provisioned amount). Other than the Server Rack rack there was an Aircon system, 4 PC's, 2 TV's and some other small appliances here and there. The server rack only had 1 server 2 switches and a DVR so its not a fully stacked 42RU server rack. Plus if you look at the pictures you would see the the 2 x MX4000 UPS with 3 x XB Battery modules attached to each UPS. So Two of the MX4000's with 3 XB battery modules on each have a run time of 240 minutes new at 100% load. These UPS's would sit together at around 40% utilization. The run time on the UPS's would say 5.5-6.5 hours depending on the load at the time. It was never fully utilized to the 6 hours provisioned, max it ever got to was 4 hours outage as main power never went out long enough to test it.

The batterys in these were replaced toward the end of the 3rd year of its warranty life so they are still fairly new as far as UPS batterys go.

I figured these UPS batterys might not be good for cycling that rapidly but I have seen some youtube video's of people recycling UPS battery's and adding them to cheap solar power storage solutions.

I got all of this for free so i can basically chuck it out at any time i just figured it would be a cool project to play with.

Can you please explain what you mean by keeping the two separate?

The goal was to only power a few appliances in my home, not my complete home. 4.2kWh/day to be exact, which other calculations I've been doing would be a 15% utilization of the 2 x MX4000 UPS's with their battery packs. This should hold power through a winter night where i live (12 hours). I mean this is all theoretical i have no idea what it would be like when properly tested.

If you believe these UPS's are worthless for my design, what can i use out of my items to build a small off grid system? and what would i need to acquire to complete it otherwise?

Technically all items are still in storage at my client and can be picked up or chucked out at any time so no skin off my back.

But some information as to why they are useless would serve me much better than a detailed description on how these could be used as a boat anchor.

Howdy Mate, UPS batteries arnt meant to by cycled and they are charged by AC (mains powered) CC (charge controler/battery charger) so what you are talking about doing is running your 4 250watt grid tie panels ( 1kW system) and the inverter it came with and incorporate the battereis to make a stand alone PV system. Trouble is what you got dont really work together, BUT you could get something working if you got a hybrid type inverter. Do you know what the stats are on those batteries are? How many kWh are they rated to at what depth of discharge. It might be helpful for you to read up in the offgrid section. I feel your main prob will be not enough solar panels to charge the batteries and you will be forced to charge them via mains power which kinda defeats the purpose, keep reading

Thanks for the info Pete, very helpful.

I have 6 panels so its 1500WATT. You may be correct the UPS's are 3600WATT max per UPS totaling 7200WATT if you add them up but that is usage on stored power not actual power needed to charge them.

I agree its probably going to be useless as UPS's batteries are made to hold charge and not cycle daily. What i could do is pull one of the batteries out as they are easily accessible. The last time i checked they were Phillips or Panasonic made. I will check the actual details on the batteries themselves. If they are suitable i might be able to pull all the batteries out and daisy change them to a charge controller or something.

Really just trying to use what i can for free for the time being. These UPS's themselves were 30-40k AUD each including battery banks and there's 4 of them and plus the solar stuff there's over 150k worth of equipment as new value. I have seen some people online do some stuff like this i just need some direction where to start.

It would be interesting to get the proper specs for the batteries, we have several resident battery experts who might chime in. Sounds like you should be able to do something with them, I am no techy so I wont be much good to you with this project. It could be that those batteries are still worth a bit of $$

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These are the batteries. There is 2 banks of 15 in each EXB which makes 30 batteries per EXB and i believe the UPS models have 20. So at a minimum there's 110 of these batteries per UPS stack...if i run the two UPS stacks with the connector to both UPS's there is a minimum of 220 of these batteries for the 2 x MX4000 series UPS's.

The battery says 12V, 22WPC/15min./1.30VPC/25C

Website for the battery - http://www.bb-battery.com/productpages/HR/HR5.5-12.pdf

here are some more images of me pulling apart the UPS.



Here is the pictures/details on the solar panels and the Inverter:




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Before i find out if these batteries would be fine for cycling daily. Just doing some research on draw requirements and what these UPS's will hold.

So the 175watts of power draw to hold up my fridge, small switch rack and server at home which i have calculated with my power monitor for 12 hours.

http://powerquality.eaton.com/UPS/se.../byLoad_01.asp - using this online eaton calculator i put in 175 watts and maximum time allowed and it recommended the MX2200 series with 3 x EXB battery modules which is what i have already. Its the smaller of the 2 sets of UPS's i have. This says it will keep alive 175 watts of draw for 12.5 hours. These UPS's have a max draw of 1900 Watts and my Solar panels have a max of 1500 Watts. I cant find information on this but from memory they take 3-6 hours to charge once they have depleted. I think 1500Watt of solar charge through a 12 hour day should be enough to charge them.

now just to find out if someone can take a look at these batteries to see if i can cycle them daily.

NO, those AGM batteries are NOT meant for daily cycling. Notice the "HR" designation. That's the "high-rate" discharge version, even worse than the general purpose models for cycling.

Essentially, these are the wrong batteries, similar to an SLI, or automotive starter battery, which is the wrong type to use with a solar setup.

But could you? Yes, or course - but you'll only get about 300 cycles, if you are lucky, from them for daily cycling to 50% DOD, and that is if they are indeed in nearly perfect shape.

Adding to that, is the problem that nobody recommends a large bank made up of small cells in a large series/parallel arrangement for capacity. At least not here. Back in the 90's, maybe the EV guys would have to do this (and they did so primarily with Genesis 18ah agm's). YOURS are even smaller at only 5.5ah capacity each.

The biggest problem is that you will learn basically nothing from this setup if you are interested in solar, aside from doing a one-off benchtop hack for an inappropriate UPS bank.

Still, they are free, so if you want to fool around, then pick only TWO of the best ones at most to parallel for a 12v system. That would be about an 11ah rating. Recycle the rest.

Now, with two of them in parallel, use no more than a 60W panel and a small pwm charge controller. These batteries are rated at a current no larger then .3C, so 11ah * .3 = 3.3A. A 60 watt panel (60w / 18v = 3.3a) is a perfect fit.

What to do with it now? Attach a mobile 5v USB adapter and charge tablets and cellphones. Or a small 12v dc/ac inverter, and run an LED (40w equivalent that actually pulls about .7W) bulb in a nearby tablelamp. Since only half the battery's power is usable for any sort of cycle life, that means you'd be able to run that LED bulb for about 7.5 hours before needing to recharge. And don't expect more than a year's life out of these faux-starter batteries.

So, there is some stuff you can goof on, but most of it is trash for our purposes. If you must press on, grab a Tecmate-Optimate 3, or model 6 charger to cull the best from the pack.

Great information thankyou,

lets say i ditch the idea of using my UPS's as battery banks as it does seem a little difficult for what i will get out of it. Going forward with my 6 x 255watt panels(1500watt total) providing they work (having them tested today). What would i need for an offgrid system to be equal to the amount of power my solar setup will generate? Example: batteries, charge controller etc. Looking to run a minimum of 4.2kWh/day to a maximum of how much the 1500watt solar panels and battery bank can take.

I'm happy to spend a bit of money providing its going to save equal to the same ammount or more over a few years. Here in Aus the price of power is ludicris at roughly 26c per unit.