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Author Topic: Blasphemy..... Solar power.  (Read 75003 times)

glort

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Re: Blasphemy..... Solar power.
« Reply #30 on: May 15, 2016, 03:16:19 AM »
1.4Kwhr of reserve is really only 0.4Kwhr of usable capacity. Deep cycling any battery, lead acid starting batteries in particular will cause rapid failure. 

Yeah, that is the thing.
It would be a trade off between the lower price of battery's with less practical capacity against the higher cost of battery's you cold get a lot more AH out of. That said, if one had a source of low cost or free car batteries, then it still may be worth while. Being the case, if you did have the occasional need to take them down lower than ideal, it still may not matter.

I just bought some Cheap Chinese Solar battery chargers rated at 20A. I have been testing these a couple of weeks not and they seem to do an excellent job.  What I really want them for is to built them into a high power battery charger for my father. His old ones have fallen over and don't have an auto function.  By incorporating these controllers, he will have a low cost, full auto high power unit.
I'm thinking of Buying a high output Transformer and putting 2 of these in a case  with some cheap but also very good digital volt meters so he can run 2 battery's at the same time out of the same unit.

Coupled to a decent solar panel, his charger could be completely automatic. Start charging in the morning when he starts and shut off in the afternoon when he finishes.  :0)

Johndoh

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Re: Blasphemy..... Solar power.
« Reply #31 on: May 16, 2016, 04:30:11 PM »
I been reading about Tesla home battery packs that are 10kw hr, thats a lot of power on standby. Has anyone tried or read a review of them?
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buickanddeere

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Re: Blasphemy..... Solar power.
« Reply #32 on: May 17, 2016, 03:09:56 PM »
I been reading about Tesla home battery packs that are 10kw hr, thats a lot of power on standby. Has anyone tried or read a review of them?

Useful capacity of the 10Kw Tesla pack is about 6MWhr.
What is the cost of your on peak vs off peak power?  What is the loss in efficiency to charge, discharge and invert to AC ? What does the additional grid tie inverter cost.
    If planning on powering your home when the grid is down with your Tesla. Add in the cost of a transfer switch.

glort

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Re: Blasphemy..... Solar power.
« Reply #33 on: May 17, 2016, 11:33:29 PM »
I been reading about Tesla home battery packs that are 10kw hr, thats a lot of power on standby. Has anyone tried or read a review of them?

I have read a number of reviews of the things and they all say the same.
The amount they save you on power bills over their lifetime is only worth about 60% of their purchase cost.  In other words you'd be far better off leaving your money in the bank earning interest for now.

What I also read said that by 2020, if not sooner, the price of the packs and those numerous similar ones from, LG, samsung and others will come down to a viable level. ATM the conventional Battery banks as people here have are by far and away the most economical and the Lipo packs are a neat and stylish extravagance that have no chance of doing what they purport in saving money.
If you could get them falling off the back of a truck. great. If you have to buy them, $15K for a tesla  here, that's more power than what they can save you in their expected lifetime.

quinnbrian

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Re: Blasphemy..... Solar power.
« Reply #34 on: May 18, 2016, 01:21:57 AM »
I been reading about Tesla home battery packs that are 10kw hr, thats a lot of power on standby. Has anyone tried or read a review of them?

There a guy on utube that show you how to build one...for a faction of the cost of buying one. He also goes through...the good and bad of them, and how there made. I'll see if I can find the link.
Here it is:
https://www.youtube.com/watch?v=Bk50IuWXg-c
Hope this helps
Cheers
Brian

LowGear

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Re: Blasphemy..... Solar power.
« Reply #35 on: May 18, 2016, 05:31:10 PM »
I thought Tesla stopped sales of the 10 KWH units.

Of course I covet two of them or maybe four.  I'm pretty sure they're 120 volts out so you need two for 240 volt use. Yes, as the Supreme Commander I shall edict "No 240 appliances aver 3:00 or before 10:00 but the naives don't always obey!  Remember my caveat:  I've been mistaken before.  Now to check out the above link.

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BruceM

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Re: Blasphemy..... Solar power.
« Reply #36 on: May 18, 2016, 06:16:04 PM »
I've read that Tesla's batteries have quite a bit of battery charge balancing circuitry, which this DIY hobbyist is ignoring.  If you just charge large numbers of cells configured in both parallel and series, individual cells will always over or under-perform and problems will result.  Lithium cells are somewhat simpler to charge manage as they just need to be voltage limited, and voltage can be used to determine state of charge.  But still, cell charge management of some sort is needed. Lithium cells will not last long if charged as if they were lead acid cells.

Typically they would have quite a bit of electronics added to monitor cell voltage and regulate charge, to redirect charge current around full cells, to underchaged cells, in order to conserve battery life and keep the cells balanced in charge.

I also don't believe the numbers have changed since I evaluated lithium for my off grid home over a decade ago, and gave them a thumbs down.  They only make sense if weight and energy density are a big issue, or operation at elevated temperatures would make lead acid batteries die very quickly.  Both those issues make lithium a good choice for cars, but a bad one for home power, at present.  If improvements lead to greater cycle life, that could change quickly.  We can only hope that the next big battery breakthrough, promised for the last 70 years plus, will soon actually happen. 




Tom

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Re: Blasphemy..... Solar power.
« Reply #37 on: May 18, 2016, 08:04:54 PM »
Yes I to hope for new and long lived battery tech. The 48kw of industrial batteries in the basement are now 9 years old and starting to show some signs of aging. The were only $8k in '07, don't know what they'll cost now. The prismatic LiFePo high amp hour units do look viable as a replacement to me. There are other factors than KW and cycles. Acceptance and equalization burns a lot of amp hours turning H2O into gas.
Tom
2004 Ashwamegh 6/1 #217 - ST5 just over 3k hours.

glort

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Re: Blasphemy..... Solar power.
« Reply #38 on: May 19, 2016, 04:53:44 AM »

There a guy on utube that show you how to build one...for a faction of the cost of buying one. He also goes through...the good and bad of them, and how there made. I'll see if I can find the link.
Here it is:
https://www.youtube.com/watch?v=Bk50IuWXg-c
Hope this helps
Cheers
Brian

Watched the vid and the first thing that hit me was the price... $3000 for the smaller unit obviously being in the US
I had to check that was accurate and a look on the net seems it was along with the local price I had in my mind..... $15,000!!
I know there is a currency difference and other things that go with it but a 12K difference?  And I bet you yanks complain about 3500!

Dunno what you guys pay for power but the average 2 adult, 2 kid home here is taken to pay between 2500 and 3K a year for power and I'd say that is on the money.  If we could get them for even $4k allowing for dollar difference, they would be a 4 year return at very worst allowing for install etc.

The vid while possibly  practical  ( and most likley not here, can't think where you would get that many old laptop batterys) is also incorrect in that the powerwalls do not use lipos and not 1850's as stated but actually a manganese based battery.
While there is a vid on how to test the used batterys in the pack, i'd have to question the wisdom of using  old batterys in a pack like that. Sure they might test good today but tomorrow or in a weeks time??  As far as I can tell, the cost of New 18650s Would make this a far more serious investment than something most people would be prepared to risk with a cobbled together project.

If one were to use salvaged cells.  Bruces comment becomes significant about the charge regulation and balancing. It's likley a lot of cells would fall over in a fairly short amount of time and just having a fuse to take them out of circuit would diminish the pack quickly when proper regulation may make it last a lot longer.

Maybe I'm taking the vid too seriously. It seemed to be a serious vid but maybe not a well thought out one or it could have been more of an intended "If you wanted to, but probably won't " type production.

I was looking on gumtree this morning and there is a guy selling 4 yo 225 and 250W panels in excellent condition for $50 ea.  The price of generation has come down, The price of storage is still quite high.

broncodriver99

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Re: Blasphemy..... Solar power.
« Reply #39 on: May 19, 2016, 06:39:47 AM »
Watched the vid and the first thing that hit me was the price... $3000 for the smaller unit obviously being in the US
I had to check that was accurate and a look on the net seems it was along with the local price I had in my mind..... $15,000!!
I know there is a currency difference and other things that go with it but a 12K difference?  And I bet you yanks complain about 3500!

Dunno what you guys pay for power but the average 2 adult, 2 kid home here is taken to pay between 2500 and 3K a year for power and I'd say that is on the money.  If we could get them for even $4k allowing for dollar difference, they would be a 4 year return at very worst allowing for install etc.

WOW. That is a heck of a disparity. The currency exchange shouldn't be but about 40%. There may be some import tariffs on your end as the US doesn't do much of anything with export tariffs. Tesla did get a boat load of taxpayer money to aid developing their different technologies so maybe we in the US get to reap the benefit of our investment where the rest of the world may not. That generally isn't the case with our industry but who knows. We generally get hosed for high prices while the same company sells the same product in developing areas for pennies.  ::)

The US averages $0.12 per kilowatt hour for electricity. It is hard to nail down a national average for the standard family household as we have everything from dessert with evaporative cooling to northern areas that have basically 1 month of summer.
« Last Edit: May 19, 2016, 06:43:46 AM by broncodriver99 »

Johndoh

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Re: Blasphemy..... Solar power.
« Reply #40 on: May 19, 2016, 11:10:52 AM »
The video was quite interesting however like others here I'd not be happy using old laptop batteries, the tend to be very old most people just leave the battery in situ and use AC power when the battery dies.

I saw mention of an Indian diesel scooter some time ago, http://motorbikewriter.com/india-unveils-innovative-diesel-scooter/, it seems to be a useful idea but like a battery that's affordable practical and long lasting the scooter never made it to production. An old guy like me would look silly on the scooter anyway! Surely there are better batteries coming down the line?
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LowGear

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Re: Blasphemy..... Solar power.
« Reply #41 on: May 19, 2016, 04:11:05 PM »
All in all I think we all know whimsical hot air when we see it. 

     1)   Compared used crap to brand new warrantied stuff.
     2)   Not including all of the included equipment.
     3)   Not discussing all of the not included equipment.

glort:     Oh my Gosh, I agree with you again and there's almost two weeks left in this month.

broncodriver99:   We have 6 KW of panels and still pay from $250 to $500 a month for electricity.  Yup, in Hawaii we are currently paying 31 cents a KWH.  And guess what?  The utilities commission just cut grid tie program by 50%.  Over generate at noon and get 15 cents a KWH credit and buy back a KWH at midnight for only 31 cents.  So HELCO is making 100% return per day on my investment.  Monopolies are good.  They make life simple.

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broncodriver99

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Re: Blasphemy..... Solar power.
« Reply #42 on: May 19, 2016, 04:30:57 PM »
broncodriver99:   We have 6 KW of panels and still pay from $250 to $500 a month for electricity.  Yup, in Hawaii we are currently paying 31 cents a KWH.  And guess what?  The utilities commission just cut grid tie program by 50%.  Over generate at noon and get 15 cents a KWH credit and buy back a KWH at midnight for only 31 cents.  So HELCO is making 100% return per day on my investment.  Monopolies are good.  They make life simple.

You guys in Hawaii definitely get the short end of the stick on a lot of things. Sounds like the greed is strong with your electric company.

Can't beat the view though, eh?
« Last Edit: May 19, 2016, 04:33:27 PM by broncodriver99 »

BruceM

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Re: Blasphemy..... Solar power.
« Reply #43 on: May 19, 2016, 07:14:32 PM »
Casey, I was just wondering where all that power goes- A/C?  Is the house insulated? How many SF?  Solar hot water?  Electric clothes dryer?



buickanddeere

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Re: Blasphemy..... Solar power.
« Reply #44 on: May 19, 2016, 07:33:05 PM »
broncodriver99:   We have 6 KW of panels and still pay from $250 to $500 a month for electricity.  Yup, in Hawaii we are currently paying 31 cents a KWH.  And guess what?  The utilities commission just cut grid tie program by 50%.  Over generate at noon and get 15 cents a KWH credit and buy back a KWH at midnight for only 31 cents.  So HELCO is making 100% return per day on my investment.  Monopolies are good.  They make life simple.

You guys in Hawaii definitely get the short end of the stick on a lot of things. Sounds like the greed is strong with your electric company.

Can't beat the view though, eh?

Hawaii suffers from do gooders that would make California do gooders jealous. No low cost nuclear , limited coal base load utility grid power generation. Hawaii generation is reciprocating diesel and some heavy oil and gas turbines that burn lighter more $$$ kerosene or #2 diesel. Hydraulic power generation is rather modest being run of river as the bunny huggers and high land prices preclude water storage dams.
   A couple of ship mounted nuclear units that are earthquake proof is the only way to lower Hawaii prices .
    However the other existing investors make $$$ supplying Hawaii would differ in opinion about nuclear.