Hello world

[argongon]

The one thing I will say with tig is if you don’t use it you lose it

Thanks for the warning. Last week I found I couldn't remember which way up to draw an electrolytic capacitor = nasty surprise.

What thickness and main materials are you looking to weld?

In Al & SS, probably only thin to 2mm.
In mild, maybe up to 5mm but no reason to go thicker - it's not like I have the tools to lift that kind of metal anyway.

 

[argongon]

I'm now losing my welding focus but this topic does keep coming back...

You can use grid-tie inverters if you use the right ones which are made for grid/off-grid. As made by SMA, Victron.

One of those is what I see in the magazines, and they're clearly for people who just want to buy the thing and have it "just work" without needing to understand what's going on. And they're prepared to pay dearly for that.

I would rather have something that's within my capabilities & budget, and can be tinkered with... but I will be careful to avoid paying the ultimate price such as can be had with careless designs.

But you don't need AC Grid Tie I suspect - just a regular intelligent Iinverter-Charger.

Yes. I just suspect that with the market for grid tied being much larger or at least promising to grow rapidly, they may become cheaper. Not because they're simpler or intrinsically need less testing for safety (the opposite) but because that cost is spread more.
(I haven't looked so it's just a guess)

On a boat any Solar or Turbine you added are so close to the battery store that they can be DC output via Charge Controller directly into the battery store.

Yes, that's my second step. Physical mounting for the solar is the first step.

Your clever inverter then just needs to be set with the size & voltage of the Battery Store, your charge level parameters, Absorption Duration etc. to suit. (You can get 48v nominal Inverters btw to reduce DC current and DC cable diameters).

Yes they're clever, but entirely proprietary. What if I don't want all those features, or need some different ones?What if I want to tweak the firmware?

Earlier on I preferred the 48v idea, but now I would rather stick within SELV and the DC range of cheap discrete components... the only downside is thicker copper to run the short distance to the inverter and/or heavy charger.

(How can one call it Safe when it will cheerfully supply 200A, or more until the fuse go pop? )

The right inverter will [...] synch with the AC supply, ramp any onboard load to AC seamlessly,

That's a neat trick which I wouldn't try to reproduce - it sounds pretty close to a grid-tie capability unless full isolation of inverted/grid is maintained?

I'm afraid I don't have any clue about the LifePo Lithium batteries.... apart from their eye-watering price. [...]

They are pricey, but they should last at least a decade and when compared to the higher capacity Li-ion types are apparently less eager to become indoor fireworks.

( [...] the tech now sold as innovative & new on Hybrid cars and so on, is decades-old in truth - just refined and drastically over-complicated & over-populated with electronics like everything else )

My theory: some relevant patents have expired.
i.e. previously the folks who invented that stuff insisted on being payed for it, and industry ignored them. No there is no need to pay the royalties.

For comparison, look at what happened with mechanisms for controlling steam engines back in the day.

 

[GRW]

Yes, the inverters we used don't full-time parallel or export to Mains Grid. The "AC Grid-Tie" bit refers to your on-site Network (e.g. your main inverter is the Master, and then Solar/Wind Producers run thru Inverters, and then synch with the Master, so all power producers feed onto the same cable distribution at their location.
Dead handy if say your house and primary genset and inverter are several hundred metres from a Wind Turbine or Solar Array & outbuildings - you need only run (relatively) small 230vac cable to link the house & outbuildings and not very heavy expensive DC cables back to the house to the battery store.

However - given the short cable runs on a boat, I think you'd save money and have a much less complicated system by just using the Solar as a Supplementary battery charger into your battery store.

BTW... we have had quite a few users get over 10-years from their Lead-Acid Traction Battery packs. Like anything, good base charge/discharge setup and maintenance is the key to efficiency and longevity