Product Information > Product Support
Power Jack LF 5000W Inverter Board Swap
dochubert:
Maybe a dump load or two set to kick in just before things equalize? Keep it off balance
I hope you keep us up on your progress. I hope to try the gti/pj setup when I get to my off grid location and am very interested in how yours works out. I've got a xantrex gt3.0 gti I plan to use for that. It has large transformers and has been working as a normal gti for me for more than ten years now, so have high hopes for it paired to my pj.
Btw, how is your solution for raising the ac output voltage holding up? (something else I'm very interested in) Any chance that mod is contributing to the other problem? Just a thought ( and hope its not)
cheers
lighthunter:
Hi again :) I will keep you up on progress, its awesome there are others who like this kinda stuff. My wife is the artist type and really has that blank look whenever anything with numbers or electricity is mentioned but she is an awesome painter..does that 5 min painting stuff with aerosol cans like on u tube. Anyway, the pairing of a grid tie with another inverter is way more fun than a single inv and battery charge control, its almost like an engine, has some fun challenges too!
Good idea on the dump load to offbalance.
I ditched my first pj voltage mod and put things back to original. What im using now seems to be flawless. A pic will follow post to help describe it. My voltage needs were to match a gti of 240/120 60hz with the 6000lf single phase 112vac. The gti monitors phase to neutral on each side as well as the phase to phase. Those parameters were vph130 vpl107 vh266 vl177 it also watches for rate of voltage change.
I removed cover from pj and removed toroid, then removed bat leads from 2 of the bat terminals and connected those two (now unused) terminals to where the toroid primary used to connect. The PJ box is empty except for the boards and fans. Some time ago i had snagged a powertronix 3kw medical toroid with ratings... sec 37v pri 235v @12.5A. So after carefully checking phase relationships with a meter (light bulb works too) i paralleled the high current windings together onto the pj hbridge terminals now on the end of the inverter. The secondaries were then wired in series. One of the secondary leads were also connected back into the pj box through another canibalized terminal in front. (the white plastic terminals) keeping all original xfmr phase relationships, connect the one lead back to maintx (the one that didnt have current sensor). The other lead gets bolted together and heatshrinked with all of its original wires but not to the boardl anymore. This way the board can still monitor current but not voltage. Then I found an efficient 20lb transformer with many secondaries and a240v primary, plugged it into grid mains 240v and probed and seriesed secondaries till i got 112v. This procedure will verify your output regulation voltage before you even hook it up :) next (observing phase relationship) tie this 240v primary to the 240v output of the two toroids, then bring the 112v leads back to the pj cntrl board on maintx L and maintx N.
Turn on and test, if all is correct, connect the grid tie to the 240v output of series toroids and connect any 120v loads to the original outlet plugs. ( i used 112v because thats what my pj regulated at originally. Before making the modification, its helpful to measure the toroid primary while idling. Mine was 17vAC (use Trms meter). After the modification the primaries(now two) measured 18vac. This is caused by the control board having to run the primary harder to get the 112v back that it needs to be in balance, the significance of this is now your batteries have one less volt of headroom for voltage sag. There are 3 ways to correct this, stay away from heavy loads, add a few turns to the secondaries of each transformer, or order LiFePo4 batteries. I have been avoiding long term heavy loads and recently ordered lithium iron bats, i havent received them yet.
This PJ is now very solid 117/239 VAC split phase under 2kw load, the two toroids are almost identical primary and secondary voltages open circuit. That wouldnt be necessary but it makes things simpler. one nice thing about this circuit is that when the GTI is pushing high power into the secondaries, at 240 and you have loads connected to the 117v (only one of the toroids) the other unloaded toroid passes its magnetic current to its primary looping to the loaded toroid primary without having to go through the pj fets.
I hope this isnt too hard to follow, feel free to ask for clarification.
Lighthunter
lighthunter:
That pic is horrible, oh well its good simulator software but i cant edit with text. So the two xfmrs in a pair are the two 3kw toroids in series sec parallel primary. The v source on the left is a gti inverter with a series resistor mostly to force the auto trace routing to make a square corner. The xfmr on the far left is the voltage mod xfmr that samples the full 240 and feeds back 112 to the PJ control board represented by the ctr ic. The h-bridge is representative of the pj main board or fet board.
Hope everyone is having fun,
Lighthunter
dochubert:
All I can say is Wow! Very impressive! I'm a bit slow, but I've read your description 3 times (so far) and am starting to get a glimmering. I'll keep at it until that lightbulb over my head blinks on. I actually have quite a few years of electrical and electronics experience, but you and the other guys on this site make me feel like 12 years old with my first multimeter looking for things to measure. I'm hoping to ride some coattails here long enough to learn enough not to blow myself or my house up building my power system.
Got a good chuckle reading about your wife's blank look. Could have sworn you were describing my wife. She has that same look when I get excited and start telling her about my latest project.
I'm looking forward to your next update. It may be too soon to ask but wondering how you control the system when your batteries are full.
ClockmanFrance:
"Be interesting to know if anyone else has that problem with a single gti/pj pair. Come to think of it, is anyone else besides Oztules pairing a pj with grid tie? I think he uses more than one gti so that problem may not exist."
Hi Lighthunter,
Yes, I am running GTI's with PV with my 6kW OzInverter, with the 15kW PJ Boards.
I have 5 SMA SB's, not all installed yet, the low frequency types that are heavy, some are used some our new but old stock. They are cheap as chips as they are small, ie below or at 3kW.
What I have found is as Oz has said, the GTI back feeds to the batteries with out any problems. I also have 5kw of PV DC direct charging through Midnite Classic and Tristar controllers. If the batteries are full the DC controllers back the PV off, but then the AC output voltage of the OzInverter starts to climb, I can shut down the GTI's and their PV if no loads are on, by adjusting the GTI shut down voltage.
The GTI….. Most come ready set up with the appropriate Country code settings, now with the United Kingdom this code is G83/1.1 this means that the GTI normally at 230vac 50HZ and will only work within a set AC Grid range of 207vac to 262vac however the SMA Sunny boys are normally set to automatically disconnect at about 247vac. So in general your GTI will shut down anyway if the mini grid it is connected too rises to 250vac. However, the process of the GTI re-starting itself may take several minutes.
Oz reckons that the GTI's can backfeed through the OZInverter at about 8kW, but heck that's a lot of raw power going into the batteries, so hence me using small GTI installations so I can adjust each for different voltage shut downs.
In essence I can now balance the loads being used against the GTI's output with out thrashing the 1300ah C10 48v batteries, and allow the 5kW of DC coupled Controllers to fine tune the batts.
However, if you are using standard torroids then there may be other limiting factors at play. With the OzInverter we wind the toroid to achieve the best and robust functions.
I trust this helps.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version