MJLorton Solar Power and Electronic Measurement Equipment Forum
Product Reviews => Product Reviews => Topic started by: kibi on November 11, 2012, 12:47:41 PM
-
Over the past few years I have been searching for a good quality inverter as part of my quest to eventually go off grid, which, I might add, is a very long road.
I have about 480Ah worth of batteries which I found in a dumpster several years ago. They were out of a large APC UPS. I last gave them a maintenance charge about 2 years ago and today they measure 12.5v at the terminals, so I reckon they are in good nick.
There are loads of pure sinewave inverters about on the net, but most of them are high frequency ones sold under dubious brand names. I was after a good quality low frequency (50Hz) pure sinewave inverter.
So finally, this Victron showed up on ebay the other day for an extremely reasonable price. I used to work with Victron UPS's back in Africa many years ago, so I am familiar with the brand and the quality. This particular inverter came out of an old ambulance.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2219.JPG)
This particular model is a 12V, 2KVA inverter with a 80A battery charger. The charger is a bonus because this means I can actually have a system that runs on batteries during the daytime and charges at night when the electricity is much cheaper. I cannot afford solar panels just yet, but this inverter is just one of the pieces of the puzzle. 2KVA is not massive, but it's more than ample for my current needs. A maximum of six of these inverters can be tied together in parallel, split phase, or three phase as and when needs arise.
Another bonus with this buy is that the welding cables were included in the sale along with a staunch 350A Anderson / Forklift connector, this saves a bucketload of money. The cables are 2/0AWG (about 65mm˛ in english) which is good for about 250A IRC. This inverter is a baby so it only needs about 160A at full chat.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2220.JPG)
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2221.JPG)
Right then, let's get the lid off.
This the bottom compartment where all the cables enter and the 230V in and out terminals are located. The battery and UTP cables proceed into the main compartment.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2222.JPG)
Here you can see the termination of the battery cables inside the main compartment.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2236.JPG)
Over current protection on the DC side is provided buy a 250A not-so-little Littelfuse MEGA :)
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2223.JPG)
The current then goes through a busbar with a crude HF filter on it and then on to the MOSFETs.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2241.JPG)
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2225.JPG)
There are twelve Fairchild FDP8896 MOSFET's (six on the top heatsink and six below) driving each half wave into the transformer.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2226.JPG)
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2228.JPG)
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2237.JPG)
Here are the leads for the primary windings (in inverter mode) for the transformer.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2227.JPG)
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2228.JPG)
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2229.JPG)
The secondary of the transformer then feeds into a nice filter arrangement.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2230.JPG)
and a pair of CT's
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2231.JPG)
and a front panel circuit breaker.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2239.JPG)
The control PCB,
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2224.JPG)
with terminals for battery temperature sensing, remote alarm contacts and remote switching contacts for a generator etc. The RJ45 connector on the left is the RS-485 port for configuring the parameters of the inverter.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2240.JPG)
There is an impressive suite parameters that can be configured on this inverter. This model is aimed at the marine market, so things like maximum shore power can be configured. Should the inverter supply the excess power or not if appliances exceed the maximum shore power.
You can set the threshold of the power saving feature of which you have two choices, modified sinewave or hunt mode. Hunt mode puts out pure sinewave for a few seconds at a time and measures the load. If the load is above your pre-determined threshold, the inverter switches on.
There are many more parameters available for configuration.
That's all I have for now. I'll do a separate thread detailing the commissioning of this unit.
-
Nice inverter there. Should warm up the shed nicely as well, very important now the cold weather is coming, and the batteries do not like cold.
Have you checked water level in those batteries recently? This should be good to charge them up to stir the electrolyte around.
-
This was my thinking too. If the inverter is running the heating at any point, then it would be 100% efficient. The rest of the time any excess heat would not go to waste, bonus.
The batteries I have are SLA's. There are 96 of them and they are 5Ah each.
There are 12 battery cases with 8 batteries in each case. Unfortunately, they are wired is series for 96V, so some re-configuration is required.
The original 7.5KVA APC that they came out of liked each battery case in a series / parallel configuration for a fruity 192V DC, yummy.
I also have a few car batteries lying around which are in reasonable condition, but I am not so sure about mixing different battery types on the same charger. Besides, car batteries don't like being discharged at all, so probably best to leave them out of this equation.
-
Enjoy the trimming and joining. So they are internally a basic 12V alarm style battery. Well, if you put enough in parallel the current per battery will be quite low. just make all the jumper wires the same length for current sharing.
-
Ja, the current for each individual battery will normally be a couple of hundred milliamps with an absolute maximum of about 1.6A
Sure, the jumpers need to all be the same length, I'll have to make up a little jig I think. Also the power must be taken off at opposite ends of each string of batteries and each string fused.
-
Good luck getting it all back into the battery box then......... Hope you have gone looking on fleaBay for an automatic crimping machine that will handle the 1/4 spade connectors.
-
If it all goes to plan, it'll all fit in. I think I'll have to make a tool to crimp the big connectors.
-
I just solder them. Place wire end in, crimp lightly with any method you like ( pliers, hammer and punch) and then use a torch and thick solder along with some liquid flux to get it going. Slide a piece of heatshrink over before and shrink it on when it has cooled some.
-
OK cool. I like your thinking.
I was going to make busbars to connect the packs together, but I might use short welding cables if it works out cheaper.
-
New toys arrived today.
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_0147.JPG)
-
Bought from Martin's Amazon store? Going to do a video of it being installed.
-
I did not get them from Martin's store, unfortunately, I could not see these on there.
-
Donate a few Zimdollars then to him.......... Or a few pictures of the Queen. Sure he will appreciate it.
-
(http://www.kirbyw.pwp.blueyonder.co.uk/Images/VEMultiplus/IMG_2244.JPG)
-
You would still need 5kg of these to buy a loaf of bread...............
-
Classic! great to see the insides and I'm sure you will enjoy the functionality of the BMV.
I'm sure the US dept crisis could be resolved with a few of those bank notes!
I see from the battery connecting terminals in your unit (as well as mine) that the negative pole nut is soldered to the PCB and the positive is not. I found that the positive bolt became loose when I changed the cable on it. I thus resorted to tightening and soldering that nut too.
I was not sure if it had been missed in manufacture or left that way for a particular reason.....
-
Hey
I wonder if some of the inverter/chargers of Victron Energy are bidirectional? i mean, if there's some spare power from the solar array, can i use a grid-tied inverter of another branch to feed energy back to the grid through the MultiPlus??
Thanks a lot
-
The Multiplus and Quattro inverters are bi-directional so they can feed back to the grid. Another brand of grid-tie inverter "can" be used...but you need to check with Victron. I know some brands are changing their firmware so that they can communicate with Victron.
Exsolar (www.exsolar.co.za) have been doing work in this regard so you might want to communicate with them.