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Re: Powerstar W7 Inverter modification

PostPosted: Sat Oct 19, 2013 11:11 am
by davidg
Do you have access to a regular non inverter generator try one of them. The way inverter generators work often defeats the El-cheapo battery type inverters or "Home UPS" as they often have printed on them.

ShaneG wrote:Powerstar W7, PS2024E 3000W 24VDC.

ShaneG wrote:The unit is miss reading the input voltage coming from the generator

Is it or they true RMS meters?

ShaneG wrote:Honda generator is outputting a constant 230VAC (Checked with 2 meters) - PS W7 detects this as 286 VAC and therefore out of range.

Did you try placing a load on the generator (say flood light of 250 to 500watts) and then connect the inverter.

ShaneG wrote:My question is this, is there ant way to adjust or trim the input voltage reading that the W7 is sensing.

No they don't offer any details on them for a reason. I have two of them here I tested to destruction and had replaced under warranty a few times until the warranty ran out. I think the supplier was breathing sigh of relief when it did. They do not comply with Australian Standards, treat them with a great deal of respect.

ShaneG wrote:If you guys can't help me then it's an anchor!

Terrible energy hogs, wasteful of energy at least 20% of all power produced from batteries is thrown away in heat.

Re: Powerstar W7 Inverter modification

PostPosted: Mon Oct 21, 2013 7:14 am
by brucedownunder
[quote="brucedownunder"]Thanks for the temp. advice.

Do any of you know if I can place this transformer in an adjacent steel container,only a half mtr or so away ,with ,say,very heavy battery cable for the fly-leads ?? just a thought.. and a fan , temp sensor ,etc.?


Because of it's "now" physical size, the above question could be helpfull. I could manage to have it as close to ,say, 300mm from the connections ,within the original enclosure.

(work has stopped for 3 weeks on everything around here, I'm recovering from a heart op,(Pacemaker) ,,I've been warned not to do anything in my workshop. )


Re: Powerstar W7 Inverter modification

PostPosted: Mon Oct 21, 2013 12:25 pm
by Tracker
Physically , how big is that torroid..

Could it not mount on the base, with a cutout either side of the cover.. Some "Suitable foam tape would seal the openings so that the cooling fan still works..

Re: Powerstar W7 Inverter modification

PostPosted: Mon Oct 21, 2013 2:35 pm
by brucedownunder
Thanks for coming back ,Tracker.

It's around 225mm X 80 mm high when finished . So,it's better if I can mont it in a "biscuit-Tin" and run the necessary leads out to the original connections . I would be able to mount a computer fan and temp sensor in the lid of the tin and drill lots of small holes in the base.

What do you think...?


Re: Powerstar W7 Inverter modification

PostPosted: Thu Nov 07, 2013 12:12 pm
by astro_optics
How about the idea of raising the case cover, making it higher with some "panel" spacers" and vertically mounting the Thoroid. As in the attached pic...

Re: Powerstar W7 Inverter modification

PostPosted: Thu Nov 07, 2013 7:18 pm
by brucedownunder
Thanks Astro ,,

I'm still out of action ,under strict doctors orders to not use my left arm for another week. He is worried I'll dislodge my pacemaker leads to my heart..

So, I've got a nice steel container that is about the same size of the finished Toriodal and the 'e" size choke.

I've been in touch with the member that did this particular type of conversion . I'll go for this method ,rather than panel beat the original cover ..And space where I've got the inverter is fairly tight,anyhow.

I would suggest that anyone doing this mod use a very,very multicore cable .Welding cable with silicon inner insulation seems to be the go -remove the outer plastic sheathing carefully and you have a minimun sized dia cable to work with.


Re: Powerstar W7 Inverter modification

PostPosted: Mon Nov 11, 2013 6:37 am
by DonSuth
what size filter capacitors did you use on your make shift charger :D

Re: Powerstar W7 Inverter modification

PostPosted: Tue Nov 12, 2013 5:46 am
by brucedownunder
Hi Don .

I'm a bit confused ,re you're wording "Make shift Charger" ??

What do you mean ,,this mod is not a charger, it's an inverter powered by 48volts dc nom.

The capacitors ,? nothing will be changed ,,just the re-winding of the new Toridial, an "E" size choke and thats it ..

Read Oztules mod , it tells all.


Re: Powerstar W7 Inverter modification

PostPosted: Tue Nov 12, 2013 6:27 am
by DonSuth
sorry Bruce the link connect me to you its looks like Andrew is the one the question should have been addressed to

Re: Powerstar W7 Inverter modification

PostPosted: Mon Dec 09, 2013 6:54 am
by oztules
Bruce, didn't see this until now.....
I would put the transformer back where the old ones were.... simple.

The inverter has some miles under it's belt now.
Driving it with a grid tie inverter/s has run over 4.5kw back into the batteries in tests, but more usually around 50-60 amps.
Using the grid ties this way keeps the temps down for some reason.

It will happily drive short term loads of over 5kw, and continuous of 3kw or more without the transformer getting over 75c.

Running overnight, the house uses only 4kwh/13hr night runs, but it is driving a 60" telly all the time as well as 700ltr freezer and twin door ice making fridge.... thats where most of the power is going.

Idle current is insignificant and adds way less than .25kwh per night to the losses.
I have gotten it down to less than 40ma idle current in testing, but the waveform suffers slightly.

I have tried to kill it by overloads, putting the output into the 240v input, and everywhere and everything in between... don't seem to be able to kill it so far.

The internal inverter charger is pretty inefficient, and the transformer gets up to 75c at only 50-55 amps.... seems to run cooler on the grid tie reverse charging system

For those interested, this unit can run backwards with synchronous switching so that putting a grid tie on the output will see the grid tie drive the house loads AND charge the batteries at the same time if solar permits, and the inverter picks up the slack when cloudy... handy when the hot water or oven is used in the daytime, and loads may exceed 5kw or more. The grid ties can drive this, while the inverter just provides the timing for the grid ties. ( I have up to 6kw of grid tie I can connect up to it).

The down side, is there is no control of the charge currents in this configuration, unless you have a dump load arrangement on the batteries like the windmills would use, or a simple comparator cutting off the grid ties one at a time etc.... will soon be developing a high power mppt controller for the panels not grid tied to it

The earth wire was a test that has not been replaced, as it seems to work fine... and I'm lazy. Interestingly, the 240v winding gets hotter than the 48v winding at high power.

I expect it will easily run and survive at over 100c ( boiling water temp), but have not ever seen it over 75c ( rear fan running as well ). I would have no problem driving it at 100c or a bit more even, but it is hard to get that sort of a load for extended periods, and still feel good about the batteries..... yes it will do over 16kw for short bursts... but gee when I see over 150 amps on the gauge, I feel for the batteries if I try that for an extended time.... rare to drive loads of more than 2kw for any extended period.... mostly it runs at <500w, but for the hot water heater and oven... then still only a few kw.... and the grid ties cop most or all of that in the day time.