Endless Sphere

I have a black and decker 12v drill, and I wanted to use it’s charger for a custom 12v battery pack I built. I measured the voltage with my multimeter, and it shows and output of 24v (same as is labeled on the charger). Why is this? Is there some way this is safe for my battery? What chemistry is y...

sendler2112 wrote: ↑

Jan 17 2019 5:37pm

And electrified heavy rail replacing diesel rail, cross country trucking and air freight.

Or electrified trucking using catenaries. That allows the US to continue their love affair with road-based transport and solves the last-mile problem at the same time.

I don't think this will be an issue as we can make endless amounts of stationary energy that can be transferred through the grid to manufacture on a global scale Given the problems countries have with blackouts, high power prices and grid stability - I don't think that's true. And much of it depend...

The day is still young, they can declare bankruptcy again. As a dozen solar companies have. That doesn't mean that the technology behind solar-PV is a failure - just that people made bad business decisions. As for Chinese... those guys operate under completely different parameters, I wouldn't try t...

So, for both types, units connected serially, need to be actively, explicitly balanced, whether done manually or automated. Not really. For serial connections of lead acid you just have to charge them. You can equalize charge if you want, but usually that's not needed due to the self-balancing aspe...

Even if now **larger** Voltage / SoC differences exist between the 2V cells, (as above, no charge source), no current will flow when paralleled? When cells are paralleled, current will flow until the voltages in each cell are identical. This will do a good job of balancing paralleled LiFePO4 batter...

Two sets of battery cells #1. 6x lead cells vs #2. 4x LFP cells within each set, each cell resting at slightly different voltages / SoC, small enough any "self balancing flow" current rate issues are minor. Two separate intra-pack wiring configurations: A. the set connected in series, both sets at ...

cricketo wrote: ↑

Jan 16 2019 2:15pm

We might be settling on Mars before that stuff happens

We are settling Mars within 3 years? Why was I not told?

Work on that is already ongoing.

Agreed. Vogtle 3 will be open by 2021, Vogtle 4 will be open a year after that. The Chinese AP1000's are already up and running.

If the emissions laws were more reasonable the clean deisel would be cheaper and I could get something like the deisel Mazda 6 wagon which seems to be available everywhere else but "coming soon" for about 6 years here. What is unreasonable about them? I'll go ahead and repeat that the current laws ...

cricketo wrote: ↑

Jan 16 2019 1:17pm

Sure, but reactors aren't happening for non-technical reasons. I guess that's another major difference.

Well, except they are happening, just slowly. We should start working on things that are possible today and see where it gets us.

So I assume you mean a series'd unit, say 6V, rather than separate 2V cells like Rolls Surrette, which could be put in parallel before serial. Yes, a large string in series, not parallel. Are you saying that works differently for lead than it does for LFP? Yes. LFP don't need to be fully charged to...

How about we stop fantasizing, and start working on things that are possible today and see where it gets us first ? Exactly, that's been my argument. In engineering we have to experiment and try out things, push the boundaries. There have been people like you in the past, who had well-supported pos...

I agree. Cars kill more people in US than guns. We're trying to ban guns, not cars though :) Well, I'd say we're trying to regulate both. Cars have seen more success with regulation than guns. We are more likely to accept elevated risks when it is truly the only choice and/or a great necessity. I t...

You can certainly make a reactor to any level of safety. No, you can't. Of course you can. You can design a reactor to any level of safety you like - if you are willing to pay for it. MSR's dump their entire core into a big concrete pit if temperatures exceed safe levels, for example - with no inpu...

but going past three **strings** in parallel can lead to balancing issues. I believe that is true, even with a proper balanced wiring scheme using buss bars in place, as per "Method 3" here: You're applying lead acid rules to LiFePO4 here. Since LiFePO4 does not have an inherent balancing mechanism...

I went to KG & early gradeschool Huntington Beach until a couple years before that, and I remember me and my younger brother having (sometimes a lot of) trouble breathing in "sports", and him going to the hospital a few times. After we moved to Phoenix, we only really had problems during the dust s...

What you describe isn't familiarity so much as it is direct control. Putting very complex and dangerous operations in the hands of others certainly is something that should give a person pause IMO. Yet we get in airplanes as passengers all the time. Funny about the sunbathing bit. I was just readin...

Well, a couple of other options would be some clever long-term energy storage or shipping energy from the sunny parts via High Voltage DC transmission lines (very low losses). OK let's run the numbers on the latter. A HV transmission line from Arizona (big generation potential) to New York (big loa...

This gives you easy redundancy. Each half of the bank is still 12V, so if one cell dies, you just split the bank IF you remove that string once the cell dies. But you have to stay on top of it. Letting that string sit at a bizarre VPC while the system is trying to cycle it can be bad news. So in th...

Where did you find the info that superconductors also have great thermal conductivity coefficients? An article in Nature a while back talking about thermal conductivity in ceramic high temperature superconductors. But this is a metallic hydride rather than a ceramic, so that doesn't necessarily app...

I somewhat agree, but I draw a different conclusion. Falling from roofs is not an integral part of photovoltaic operation. It is a kind of industrial accident that is well understood, is specific to certain types of activities (photovoltaic deployment on pitched roofs is one tiny subset - gutter cl...

I brought this up before. There is a group here that doesn't consider inherently dangerous handling of nuclear materials as an integral part of nuclear reactor operation, and then goes to compare nuclear safety with solar installers falling from roofs. Some logical acrobatics, not less. Personally ...

Are you saying that machines never bind up and fail to do what they are supposed to do? Sure, they can. It is merely unlikely. Because most of my paying work comes from machines doing exactly that. And those machines don't have to cope with stuff like superheated water or molten salt. True. But the...

There is superheated pressurized water, so there is the risk of explosion. There is a mechanism to insert the control rods, so there is a mechanism that can fail to insert the control rods. The AP1000, like many reactors, has an active control that keeps the control rods retracted. If the system fa...

That is one weird sentence. First of all, how can any nuclear reactor be "inherently safe?" That seems to imply foolproof, and the reality is that human beans get fooled all the time. Well, nothing (including solar) is foolproof. But reactors have varying degrees of shutdown safety. One is "walk aw...