Wrong damn angle ...

I got in touch with Kuranda in Whaley Bridge.

Got Brett. Engaged. But message - no way. He said you'd need a battery about the size of what's used in a milk-float

He said lead-acid only works because maybe couple of seconds of cranking an engine, max. Chortling about starting diesels on a frosty morning by getting the LPG-fueled forklift to tow you and you drop the clutch and crank the engine that way until it fires. Had a laugh, but as i said, he says no way will idea work of couple of car batteries...

Had a laugh, but as i said, he says no way will idea work of couple of car batteries...

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I didn't want to tell you that, instead I hinted at it and looked for relatively simple and inexpensive ways to get around the issues, like a 400A alternator and adjustable voltage regulator. Even with it the vehicle batteries won't stabilize and filter the voltage at 26V because their internal impedance is too high when nearly fully charged. They might absorb

A good welder might be able to repair a 400A alternator with a cracked mount, well enough to run from a riding mower engine. I expect your time is more valuable welding than tinkering, but a smaller version is on my list to consider if I stumble onto the parts. Two days before you posted it I had stopped at a heavy construction equipment electrical shop that might have had a used alternator and ideas on adapting it, not that a used part in the USA does you any good. He's provided me other things to modify or solve problems, like fixing my truck's starter with a $20 brush assembly instead of replacing it, and the carbons to make new Variac brushes.

In Army electrical school I heard a story about someone in Vietnam improvising a stabilized high current power supply from a Jeep alternator and a string of NiCads, which give 1.2V step resolution. In hot, steamy New Guinea my father's Ordnance company improvised a beer cooler using part of a Jeep engine for the compressor. A native made drinking glasses from beer bottles by heating a ring of the glass in the center hole of a hot wheel hub, then quenching the bottles to crack them along the hot line. Another fire melted and smoothed the break. Their General Kenney was an inventor himself and encouraged innovation.

I got work by showing I could solve problems, not by laughing at them, unless the inventor was too disconnected from reality. Even then I helped with an E-Cat (cold fusion) until I could lead him to convince himself it was a scam.

I know you can buy special purpose data loggers, I designed and built a custom one myself, with adequate government funding. The projects I built with proper new components and to industrial standards tended to cost upwards of $50,000. My home versions cost maybe 1% of that, for example I paid $22 used for a 1 Ohm 1KW variable resistor that is $1500 new, and $20 for an instrument that was originally $4000. It can measure the resistance of 1 inch of welding cable.

I got in touch with Kuranda in Whaley Bridge.

Got Brett. Engaged. But message - no way. He said you'd need a battery about the size of what's used in a milk-float

He knew his welding. Feel of authenticity about his judgment. He said Amp-hours look to only about 25% of rated for lead-acid. He said Lithium you could look to 100% of rated.

{{{ But Li lacks the high current capacity. Marine dual-purpose lead-acid batteries are a possible compromise. }}}

Costs - he said getting to around GBP10000 (not far off US$).

{{{ The inverter welder I looked at as comparable cost $9,000+. }}}

When he realised I know the power in kW and the like, he ran with the detail and said even for doing test welds which would be typically less than a foot long, cost and size --- well it would defeat the point (cheap and small).

He said lead-acid only works because maybe couple of seconds of cranking an engine, max.

{{{ When I was doing automotive electrical engineering I heard 30 seconds. Kettering's breakthrough was to make a 5HP electric motor much too small and light to run continuously without overheating. Starters depend on thermal mass and low duty cycle and don't even have cooling fans. }}}

Chortling about starting diesels on a frosty morning by getting the LPG-fueled forklift to tow you and you drop the clutch and crank the engine that way until it fires.

{{{ I've started a VW with a dead battery by putting it in 4th, jacking up a rear wheel and turning it by hand, then diving in to knock it out of gear as it lugged at very low speed. I'd tried to coast-start it but reached the bottom of the slope. }}}

Had a laugh, but as i said, he says no way will idea work of couple of car batteries...

{{{ The idea wasn't dumb, it works for less demanding welding conditions. Some things don't scale up well, see how long it took to match Brunel's Great Eastern. }}}

Thanks for being indulgent. I simply have no idea of this.

I was lead astray because someone quoted as if fact that welders can use a couple of car batteries to weld with gasless FCAW. That cannot be? I was "taken in" by that.

Anyway, all is learning.

It's real... but maybe not for how you intended to use it. A few comments in this video worth reading too. See:

READY WELDER: a long-term review by Chris DesertDog

Anyway, all is learning.

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It is, and innovation is exploring unknown territory. I call backing out of dead ends the "Re" inherent to Research. If we took "Impossible" too seriously we wouldn't have space flight, and maybe metal tools.