Follow Slashdot stories on Twitter

 



Forgot your password?
typodupeerror
Get HideMyAss! VPN, PC Mag's Top 10 VPNs of 2016 for 55% off for a Limited Time ×

Comment Re:Stop the paranoia, please (Score 3, Insightful) 127

The difference is that with AC, there is no way to correlate posts and put a person's statement in context. It is impossible to know if this is someone that is always rude, calling people names just because they disagree without any counter-argument - or if this a person who actually adds some thoughtful insight to a topic. There is also no way to know if this is a shill, or if this person has a particular axe to grind. There is also no way to know if someone makes a statement and then follows up with a bunch of others agreeing with their own post.

That said, I do agree with the premise of your question. You don't know who I am. But at least you can look at my other posts and get an idea whether I am trying to make a serious point or just being a jerk or shill.

I am a moderator on a different forum - one that requires full real names. It is amazing how thoughtful and polite people are when they have to personally stand behind the statements they make.

Comment Re:Energy storage is expensive (Score 1) 149

No, 10 cents per *amortized* KWH is correct.

My system has 4 Surrette 6CS-25PS. About 28-30 KWH total storage, stored at 24v.

Those batteries cost about $1100 each, depending where you buy them. 6v, 1158 AH (20 hour rate)

So, without splitting hairs on load rates and voltage, $1100/(6x1.156) = $159/KWH

But when amortized against the rated 3300 cycles to 50%: $159 / 3300 / .5 = $0.096 per KWH to store your energy. Again, I've done a lot of research, and that's the best I could come up with.

Amortized cost is the number you need to look at when pricing a system.

Comment Re:Energy storage is expensive (Score 1) 149

Your cells are the cheaper ones. Rolls specs say 3300 cycles for Series-5000 cells.

"5000 series is no-compromise solution for extended use. Dual container construction, 10 year limited warranty. Rated for 5000 cycles at 20% depth of discharge. 3300 cycles at 50%. Capacities are listed at 100 Hr. rate." http://www.cosolar.com/catalog...

They are designed for a 15 year lifespan. Mine are still nearly good as new after 10 years.

Comment Energy storage is expensive (Score 5, Informative) 149

Sorry, I don't have time this morning to glean exact numbers. But there is a misconception that energy storage is free. I just went through these calculations for my off-grid dream home. (My cabin has been off-grid for 20+ years, so I am intimately familiar with wind+solar+storage.)

In reality, batteries don't last forever. The best of the best Rolls/Surette sealed lead acid batteries are good for 3,300 discharges to 50%. So, when you calculate the cost of those batteries against their total number of KWH that they will EVER store, it works out to approximately 10 cents per KWH. I've looked at every option available, and there are no other options close to flood lead acid storage amortized price.

According to https://en.wikipedia.org/wiki/... the Tesla powerwall has/had projected cycle life of 1000–1500 cycles. On a cost per KWH of new battery, they are about 3x the cost of flooded lead acid. So, for 3x the price, you get about half the energy storage over their lifespan. Again, apologies for not presenting the arithmetic. But the stored energy will cost somewhere between 30-50 cents per KWH. So, it is already not competitive with on-demand generation - even if the cost of generation is zero.

Comment Re:Nice way to try and destroy Apple's image (Score 5, Funny) 255

Basically some hacker found that they could hook a device up the phones innards and just try brute forcing the 4-digit PIN and that if they cut all power to the device on a failed attempt quickly enough that the system wouldn't register the failed attempt and wipe the device.

But that would void the warranty.

Comment Re:Home DC (Score 1) 297

For those of us who run off-grid, those pesky wall warts drive our inverters nuts. When nothing needs energy, the inverter goes into sleep mode. I have mine pulsing the wires every 2 seconds, looking for reason to power up. If it senses 15 watts or more of load, it powers up. Problem is that the wall warts tend to use some energy when they are initially plugged in (probably to charge capacitors). So, the inverter powers up, only to see that there is nothing to do, then it powers down. Repeat every 2 seconds. I ended up having to run a 12v circuit to replace the wall warts.

Comment Re:Ah yes, the meeting of Politics and Science (Score 1) 568

The lesson to be learned is that it works well for the politicians and religious leaders. It also works well for the scientists who support those leaders.

It is only bad for everyone else -- i.e., those don't matter. And very bad for the scientists who don't go along with the status quo.

Comment Re:Because... (Score 1) 132

"...if there's one thing education is about, it's ensuring ideas are never shared with others."

Seems like it. The whole point of education is to learn from what others have already figured out, and move forward from there. But if all ideas are owned and guarded, then there is nothing to learn from.

What will be in the CS textbooks: Algorithms, Data Structures, Numerical Recipes, Networks, Operating Systems, Architecture, ...? They can all be replaced with a list of patent numbers owned by huge corporations and trolls.

Even if you happen to come up with an idea on your own, it still might belong to someone else and be off-limits. So much for progress.

Slashdot Top Deals

Five is a sufficiently close approximation to infinity. -- Robert Firth "One, two, five." -- Monty Python and the Holy Grail

Working...