Starting a new thread to discuss technical and administrative issues related to a Facebook group of the same name, created in late 2025 with the purpose of collaborating as a group to build Wiseguy inverters for DIY solar applications, mainly  supported by IFLA (Industrial Flooded Lead Acid) batteries - also in association with a related Facebook group.

We were inspired by the Ozinverter and have decided to follow the WiseGuy build, being an updated and improved version of the same.

We have several members committed to a build and have already held several online meetings, one in the presence of Wiseguy himself. My toroid is finished, and we're ready to push the button on PCB ordering.

Updates and associated posts to follow.

It's so pleasing to hear that the Wiseguy design has been taken up by others.

You obviously realise just how robust and technically superior it is in almost every way, when compared to what had come before this Inverter design.

From a servicing perspective, his design is also brilliant, especially if the build layout is thought thought and designed accordingly.

   

KeepIS, thanks for the positive reply. We've been trying to get in touch with you. Would you be open to joining one of our conference calls in the next few weeks? your input would be invaluable.

Please bear in mind that this is a beginner level DIY project for most of us and we are piecing things together from multiple sources, the technical content of which we often struggle with. However, we're having a go because a completed and functioning project will be a game changer for our systems.

A couple of starting questions:

1. Does the Wiseguy inverter accommodate backcharging of a battery from an AC source, as per the AC coupling arrangement suggested in the Ozinverter book?

2. What size and design (toroids, cable type and size, number of windings) would be recommended for my toroid? Images of which are attached below through various stages of building. This has been constructed as per the Ozinverter design to draw 6kW continuously and I'm the first cab off the rank with regards to transformer construction.

I gleaned that Wiseguy suggests 37 uH with lower values giving higher idle current and higher values giving better efficiency under load. I need guidance for the design and/or calculations.

No.1: OD 181 mm, ID 89 mm, width 170 mm, mass 24.6 kg.
No. 2: OD 188 mm, ID 91 mm, width 160 mm, mass 25.1 kg.
(one for myself and one for a friend)

That could be possible, however I'm not on social media and not running windows, so it depends on your conference setup.

You can always PM me and I can give you contact details if you wish.

Mike.

As far as Toroid design, it will be the same as the Ozinverter design for a given expected operating, lowest input voltage, for your selected battery type.

Those look fine as starting point, primary side (inverter powerboard and choke input) is easy to adjust when testing starts.

Those chokes are not going to fly.

You want 4AWG around 21mm2 for for the chokes, this gives a little more protection for the FETS, and is easier to wind through the cores.

What is the Choke core material? should be a number on them somewhere. If we know what the cores are, we could suggest the correct number of turns for the required inductance.

EDIT: For your initial choke testing, you should just grab some 2 Gauge flex copper cable.

I used this for a long time on the chokes in testing without any problems, way less costly for testing and extra safety, depending on the cores, we aim for you around 17uH to 21uH with 4 to 6 turns of 2AWG, you would use two chokes for each inverter.

Mike.
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Edited 2026-03-23 11:50 by KeepIS

Thanks Mike,

We're buying our chokes new & will order ones made of Sendust, apart from that it's an open book. From another thread you had two types of Choke ring: a black one and blue one, and there were some specs on one of the threads. What do you suggest? I understand they're not expensive and if we have a spec we could start ordering and get a few extra.

We have firm quotes for PCBs and are ready to order.

Do you have access to Zoom? if so, I'll make an appointment with the group & get back to you by PM, we have had 3 to 5 attendees so far and 5 pm AEST on Saturdays works for most. Otherwise, if you're happy for us to post queries here.

Michael

Those cores are getting hard to find and were expensive last time I looked, the blue units are fine. No access to Zoom at the moment, fine to ask any questions here, other on here will be happy to chime in and help if they can, good bunch here.

I'll send you a PM with some contact info if needed.

Notice: I posted a bit more in the previous post.

Thanks, in that case I'll have another look through my scrapped inverter components for toroids. I have the chokes from an Aerosharp but they're not suitable, from what I gather. The other builders may have to wear the costs, as they are planning to buy everything new, including primary toroid cores.

We'll hold on a conference call for now, but there may be some technical queries that would justify a voice contact and I'll get back to you if and when they arise.

So, the choke install isn't just 'plug and play', there is some pre commissioning testing required for each toroid? And if so, what equipment are we looking at?

Hi GleamBright I got my choke senddust toroids on Ali

I used 6 of them on each choke and 25qm wire for 4 turns thru.

Volume: 57.1x26.4x15.2mm

AU$31.19 for three.

Last selection box.

Allow 6 for each choke, 4 sets of 3 needed.

Model:MS226060-2
Outer diameter:57.1 mm
Inner diameter:26.4 mm
Height:15.2 mm
Magnetic conductivity:60μ
Inductance coefficient:138 nH/N2
Material:85% iron +6% aluminum+9% silicon

FYI, despite what they say, they are slow to ship and tracking sucks.

But my last lot from them at least arrived.

I can answer q1:- mine accepts backfeed from a gti (or 2) just fine.