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Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14
Posted: 04:46am 12 Mar 2025
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By way of introduction...
Hiya folks,
Electronics, you would think is a hard science but I see it as where physics and art meet. Deploy good designs principles then lots of fudging until it works good enough.
Simple systems are robust and increasing complexity increases opportunities for failure.
That's a sweeping statement but there is a tension in both directions. Trying to keep the design simple and solving problems with the lightest touch is where my head is at.
My journey started the same as many others, a desire for an alternative to the grid after a large storm took out the power for 2 weeks. You can't look at the world in the same way after that.
Who knows what the future may hold but from this vantage point things look not-so hot-so.
Why not build some resiliency and learn something?
A fairly typical story arc...
Started with 18650 li-ion and a HF inverter, then Ni-Cd and PowerJack, then a huge leap forward to LIFEPO4 and a Chinese EGS002. This was light years ahead of the PJ and the HF. More modest improvements were made with EGS002 mods, the Aerosharp toroid and sendust choke. This seems like most of the low hanging fruit, however the learning and system changes continue.
I've been enrolled in thebackshed university for some years now, haven't graduated and probably won't ever but I have learned and grown in confidence enough to overcome my huge lack of theory, knowledge and practical experience. I really am riding on the shoulders of giants.
Next stop, modularising with 100 x 100 pcbs then I'll dive into charge controllers.
Off grid since 2018 and I've been surprised how painless it's been.
Specs: PV 8.5kW CC 4 x 60A LIFEPO4 16s, 1200Ah, ~76kWh (I no longer take notice of rainy days). Ni-Cd 35s, 390Ah, ~16kWh Inverter 2 x 4kW EGS002 (2 circuits), 1 x 5kW HF (backup)
Random pictures:
Quick and dirty in home indication of battery condition.
Original battery LIFEPO4 with Headway 10Ah cells 32p 16s
2nd battery LIFEPO4 with CALB 100Ah cells 3p 16s
3rd battery LIFEPO4 with EVE 280Ah cells 1p 16s 4th battery LIFEPO4 with EVE 300Ah cells 2p 16s
5th battery Ni-Cd with Saft 195Ah cells 2p 35s
Failed basket weaving however this one works great!
A visual indication when pre-charging the inverter's capacitors. No breaker splat!
LIFEPO4 battery overflow - dump system.
When the main LIFEPO4 battery is at maximum voltage then this system dumps the excess energy.
The top module switches on HWS elements (I'm learning oled implementation. I will redo this with the oled screen mounted directly on the board. This is showing 4 hot water elements are on. Signal is sent via RF).
The bottom module switches on the dump to the Ni-Cd battery and when that is full it dumps to heat bars.
Choke saturation tester. No longer flying blind :)
Cheers
da
FET cemetery Regular Member Joined: 17/04/2024 Location: AustraliaPosts: 45
Posted: 07:37am 12 Mar 2025
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Right there with you on the quick and dirty in home battery condition indicator, and the incandescent globe as a visual indicator of capacitor charging! Edited 2025-03-12 17:44 by FET cemeteryNo stone unturned, no FET unburned.
Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14
Posted: 08:19am 12 Mar 2025
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Cheers FET cemetery,
That name is gold btw ✔✔
Yeah, I love old panel equipment, anything steam punk-esq is the bomb...
Somewhat related, but check this out!... extremely cool imho.
This installation was put together on a prominent farm house near me in 1927.
Housed in a sandstock brick barn.
This sowed the seed back 40 years ago when I first saw it.
These off grid cats have been around for a while ;)
da
FET cemetery Regular Member Joined: 17/04/2024 Location: AustraliaPosts: 45
Posted: 08:54am 12 Mar 2025
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There's nothing quite like a Bakelite ammeter to improve the look of a project...
Is that a 32V DC setup with Edison batteries? I once saw an ancient working 240V DC generator at a clearing sale. Terrifying, but I guess safety standards were a bit different back then.No stone unturned, no FET unburned.
Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1114
Posted: 09:09am 12 Mar 2025
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Love the old engine genset 1926 Lister XO, perhaps Cheers Aaron Off The Grid
CaptainBoing Guru Joined: 07/09/2016 Location: United KingdomPosts: 2137
Posted: 09:46am 12 Mar 2025
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Sweet setup Dougie. I am jealous, I would love to go off grid but i just don't have the space. Top tip - get rid of those pig-tail antennas and go for a full wave using a bit of single core telephone jumper wire for ***DRAMATIC*** improvement in range/quality of the link
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1431
Posted: 10:00am 12 Mar 2025
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good to see you!wronger than a phone book full of wrong phone numbers
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 882
Posted: 11:22am 12 Mar 2025
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Welcome and great to see how others have tackled the off-grid journey.
I quite like analogue meters too, in fact I have some identical to the ones Fet cemetery showed, along with some matching ammeters. If I ever get to build covers for my gear I will mount some in as well.
The genset you showed is very similar to what I remember as a kid having on the farm. If the lights started to go dim while we were having tea, one of us would have to go down to the engine room and start up the generator. We were only little at the time ... maybe only 5 or 6 ... and I vaguely recall the generator was used as a motor to start up the engine. There was a big knife switch involved somewhere too. Haha.Cheers, Roger
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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