Regarding your comment about the South Pole Stations. I was supposed to Winter-over at Amundsen-Scott, aka South Pole Station back in 1996 after I separated from the Air Force. The NSF/OPP needed a Meteorologist, slash Computer (IT), slash Electronics Engineer person. I happen to be working with a company called Barton ATC at the time, which was awarded some Weather contracts down there that needed to be filled. Sadly, I had to decline the position at the last minute due to a sudden illness in the family. I'm still kicking myself for not going anyways. It would have been an amazing experience.
Rob - I too think that working in Antarctica would be an amazing experience! Author "brr" in their writing comes pretty close to the amazement I would feel at the ingenuity, adaptation, and just good engineering (and no small amount of logistics) that keeps people alive there, especially in the "winter" period when they're physically isolated. I'm an avid fan of the brr.fyi blog and read every post as soon as I see then in my RSS feed.
If it weren't for health complications, I'd jump at another chance to go there, Summer or Winter. McMurdo, Amundsen-Scott, or Palmer, any would do. Mostly to see native polar bears and the Aurora Borealis. =)
Upon reading your article, I promptly subscribed to the Brr.fyi blog. Very good reading.
My emergency solar power supply uses 12 V because of my ham radio equipment. LiFePO4 batteries provide a voltage that can be used directly by most transceivers. But the limits of this technology are clear: If you have to cope with more than about 1 kW, you need extremely short, extremely thick cables. My the biggest problems arouse between the solar charge controller and the battery: For the charge controller to work correctly, you should limit the voltage drop to the battery to less than 150 mV. Try to do that for 50A or even more! You should even have a fuse in this circuit...
Alexander - I agree that Amateur Radio gear will continue for the immediate future to use 12 volts. Fortunately there are ample DC-DC converters available so that power systems can be 48V, but 12V is also available for use by the radio equipment. I've read that Tesla recognized from its beginnings that using existing electronics and techniques, conversion losses were too high. Thus Tesla developed very efficient, and perhaps unique DC-DC, AC-DC, and DC-AC conversion electronics. Eventually that high efficiency will trickle down to more mundane applications like our shacks.
I replaced my old Goal Zero powerbank with a Ecoflow Delta Max unit with updated solar panels and their generator. The goal is to have a 100% electric campsite and use the generator for critical loads backup at home, and field day operations/extended camping. The battery bank is a 48VDC system, as are the expansion connectors. The 1500W generator can connect to the Delta's 48 V bus and can suply a fast charging current so that it will quickly recharge the battery once it reaches a programmed low charge level, then shut off when recharged. The generator is isolated from the load and only runs if/when the battery bank calls for it. It also allows higher voltage solar input, up to 100V, so series wiring with smaller gauge cables is possible too. If we get a spring this year I might actually get to test it out!
One thing that's a change from most battery traditional setups is that the +12 VDC output isn't going to be enough to run a high power radio. For that I use the inverter and a 12 VDC power supply. Not as efficient for sure, and potential for inverter noise. I use some of the large filters from Palomar Engineers on the AC lines and that seems to do a pretty good job of supressing the RFI. But having the flexible inputs is a good tradeoff.
ReadyKilowatt - I've seen a few of the higher energy integrated battery systems are already using 48 volts, so I was already following the 48 volt trend. If I understand your usage, it's 48V DC battery > 120V AC inverter > 120V AC to 12V DC power supply > Amateur Radio equipment? In theory, it would seem more efficient to do 48V DC to 12V DC conversion, but in the real world, the extra conversion step (and more reasonable expense) is tolerable.
The 48 VDC ports have some charging logic so they only output if the system is producing power that can charge the external battery. There's some communications lines integrated into the interconnect cable too. Probably could be hacked, but for now having the AC stage is probably fine. Besides I can run camp stuff off 120 AC like an induction cooker, electric blanket and small heater, so the addition of a 12 V PSU for the radios isn't that big of a deal.
Simple DC-DC converters can have quite astonishing efficiency, especially if they use FETs instead of diodes. But especially for emergency equipment an important guideline is: What is not there, cannot be broken. Add the basic problem we started at: Switching supplies might produce noise. The greatest problem I have with 12 V is battery charging at the solar charge controller. Especially in a relatively wet climate as here in central Europe you tend to over-dimension the solar panels so you get enough energy within a few sunny hours.
Regarding your comment about the South Pole Stations. I was supposed to Winter-over at Amundsen-Scott, aka South Pole Station back in 1996 after I separated from the Air Force. The NSF/OPP needed a Meteorologist, slash Computer (IT), slash Electronics Engineer person. I happen to be working with a company called Barton ATC at the time, which was awarded some Weather contracts down there that needed to be filled. Sadly, I had to decline the position at the last minute due to a sudden illness in the family. I'm still kicking myself for not going anyways. It would have been an amazing experience.
Rob - I too think that working in Antarctica would be an amazing experience! Author "brr" in their writing comes pretty close to the amazement I would feel at the ingenuity, adaptation, and just good engineering (and no small amount of logistics) that keeps people alive there, especially in the "winter" period when they're physically isolated. I'm an avid fan of the brr.fyi blog and read every post as soon as I see then in my RSS feed.
If it weren't for health complications, I'd jump at another chance to go there, Summer or Winter. McMurdo, Amundsen-Scott, or Palmer, any would do. Mostly to see native polar bears and the Aurora Borealis. =)
Upon reading your article, I promptly subscribed to the Brr.fyi blog. Very good reading.
Thanks Steve & 73.
My emergency solar power supply uses 12 V because of my ham radio equipment. LiFePO4 batteries provide a voltage that can be used directly by most transceivers. But the limits of this technology are clear: If you have to cope with more than about 1 kW, you need extremely short, extremely thick cables. My the biggest problems arouse between the solar charge controller and the battery: For the charge controller to work correctly, you should limit the voltage drop to the battery to less than 150 mV. Try to do that for 50A or even more! You should even have a fuse in this circuit...
Alexander - I agree that Amateur Radio gear will continue for the immediate future to use 12 volts. Fortunately there are ample DC-DC converters available so that power systems can be 48V, but 12V is also available for use by the radio equipment. I've read that Tesla recognized from its beginnings that using existing electronics and techniques, conversion losses were too high. Thus Tesla developed very efficient, and perhaps unique DC-DC, AC-DC, and DC-AC conversion electronics. Eventually that high efficiency will trickle down to more mundane applications like our shacks.
I replaced my old Goal Zero powerbank with a Ecoflow Delta Max unit with updated solar panels and their generator. The goal is to have a 100% electric campsite and use the generator for critical loads backup at home, and field day operations/extended camping. The battery bank is a 48VDC system, as are the expansion connectors. The 1500W generator can connect to the Delta's 48 V bus and can suply a fast charging current so that it will quickly recharge the battery once it reaches a programmed low charge level, then shut off when recharged. The generator is isolated from the load and only runs if/when the battery bank calls for it. It also allows higher voltage solar input, up to 100V, so series wiring with smaller gauge cables is possible too. If we get a spring this year I might actually get to test it out!
One thing that's a change from most battery traditional setups is that the +12 VDC output isn't going to be enough to run a high power radio. For that I use the inverter and a 12 VDC power supply. Not as efficient for sure, and potential for inverter noise. I use some of the large filters from Palomar Engineers on the AC lines and that seems to do a pretty good job of supressing the RFI. But having the flexible inputs is a good tradeoff.
ReadyKilowatt - I've seen a few of the higher energy integrated battery systems are already using 48 volts, so I was already following the 48 volt trend. If I understand your usage, it's 48V DC battery > 120V AC inverter > 120V AC to 12V DC power supply > Amateur Radio equipment? In theory, it would seem more efficient to do 48V DC to 12V DC conversion, but in the real world, the extra conversion step (and more reasonable expense) is tolerable.
The 48 VDC ports have some charging logic so they only output if the system is producing power that can charge the external battery. There's some communications lines integrated into the interconnect cable too. Probably could be hacked, but for now having the AC stage is probably fine. Besides I can run camp stuff off 120 AC like an induction cooker, electric blanket and small heater, so the addition of a 12 V PSU for the radios isn't that big of a deal.
Simple DC-DC converters can have quite astonishing efficiency, especially if they use FETs instead of diodes. But especially for emergency equipment an important guideline is: What is not there, cannot be broken. Add the basic problem we started at: Switching supplies might produce noise. The greatest problem I have with 12 V is battery charging at the solar charge controller. Especially in a relatively wet climate as here in central Europe you tend to over-dimension the solar panels so you get enough energy within a few sunny hours.