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 1 
 on: Today at 03:54:41 PM 
Started by Warble - Last post by Warble
What is the round trip efficiency for lithium?

 2 
 on: Today at 03:27:58 PM 
Started by Warble - Last post by pdf27
That's one of the worst articles it's been my misfortune to read in some time. Reading the US Army article that it comes from, what is actually going on is that the US Army have found a particular nanostructure of aluminium which when mixed with water produces aluminium oxide and hydrogen gas in a few minutes rather than a few days. That's helpful if you want to store a lot of hydrogen in a very dense and lightweight form (e.g. for military applications), but for civil applications it's the round-trip efficiency which counts and that's what matters here.

The article says that 1kg of aluminium will produce hydrogen equivalent to 220kW for 3 minutes (11 kWh/kg). Average worldwide energy consumption to make aluminium is about 15 kWh/kg, and hydrogen fuel cells run at about 80% efficiency - so the round trip efficiency of the suggested system is only about 60%. It has some advantages - notably ease of transporting the fuel - but it looks like the sort of thing you'd use for vehicle APU use or possibly as an alternative to radio batteries if you can get it small enough rather than to power a hydrogen economy.

 3 
 on: Today at 03:16:48 PM 
Started by biff - Last post by Scruff
22.5Watt losses across the shunt per shunt at full load Steve.  police
{Edit}; You only need one shunt though, just wire all the sense connections from the same terminal pair.

Bog standard to be honest.  tomatosplat
No offence I use them for non-essential systems.

' course the wife would probably waste more power without it. Tongue

I'm more of a 50mV 500A fancier myself with nominal design load ~65A: 3W parasitic instead.

 4 
 on: Today at 03:14:18 PM 
Started by Warble - Last post by dan_b
Naah.

 5 
 on: Today at 03:09:22 PM 
Started by Warble - Last post by Warble
Hydrogen generators may replace lithium batteries in future if these aluminium alloy/water generators work out:-

https://futurism.com/hydrogen-fuel-could-become-a-viable-energy-alternative-thanks-to-this-aluminum-alloy/

 6 
 on: Today at 03:05:28 PM 
Started by stannn - Last post by stannn
https://cleantechnica.com/2017/08/21/solarstratos-first-solar-powered-plane-journey-space/

 7 
 on: Today at 02:41:10 PM 
Started by biff - Last post by eabadger
re wireless, no idea, sorry, but if you cut the lead and extend then yes, as instructions state it is rs422/485.
it may work wireless, the thing can use the tested voltage or external lower supply, i will try and post copy of instructions that came with it.
you can set the relay to trigger at a certain low or high voltage or when current high or low, so versatile.
you can see current and power going in or out and set capacity of battery bank to get an idea of what you have used, the wife useful bit.

steve

 8 
 on: Today at 02:00:28 PM 
Started by biff - Last post by biff
 Yup I understand now,
                     Would the wireless remote control cover 75 yards,? If it were 12v, I could power it of the charger,s 12v starting battery. Just using it to power the solenoid back and forth.
                              Biff

 9 
 on: Today at 01:47:16 PM 
Started by JohnS - Last post by JohnS
Per the Financial Times there was no problem with power companies coping with the eclipse.

https://www.ft.com/content/d5119962-868f-11e7-8bb1-5ba57d47eff7

 10 
 on: Today at 01:40:44 PM 
Started by biff - Last post by eabadger
i would have thought at 1500 it would not eat tyres?
you tried big dc contactors or solenoids?
i wasnt suggesting runing the high dc through the ebay thing, just use that to switch somthing bigger.

too blooming hot here today, was mending the 4x4 brakes and have given up for a cold drink and sit down.

steve

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