connecting batteries in parallel or series, myth and theory

danny burstein wrote:


Larger oil patch diesels often have hydraulic starters. Huge electric ones are too hard on the ring gear and assorted fittings. A hydraulic motor can be eased on slowly to full power.
There is a smaller auxiliary engine that first starts up to provide the hydraulic pressure. That engine usually drives the alternator also. In nicer set ups, the coolant for the large engine is also warmed up a bit before start up. They have to, as in cold weather, the lubricating oil is like molasses and 12 or 16 pistons don't like moving in it.
mike
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Larger oil patch diesels often have hydraulic starters. Huge electric ones are too hard on the ring gear and assorted fittings. A hydraulic motor can be eased on slowly to full power.
There is a smaller auxiliary engine that first starts up to provide the hydraulic pressure. That engine usually drives the alternator also. In nicer set ups, the coolant for the large engine is also warmed up a bit before start up. They have to, as in cold weather, the lubricating oil is like molasses and 12 or 16 pistons don't like moving in it.
mike
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Don T wrote:

Someone once said that there's nothing new under the sun. My only experience with a Deere tractor was hand starting a two cylinder gasoline version. You had to open the compression releases by hand, spin the flywheel and when the thing was chuffing, close the valves. It was really brutal on cold mornings.
mike
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wrote:

And many trucks and tractors also use 2 huge 6 volt batteries in SERIES for starting batteries. Then there's the old standard - 24 volt starter and 12 volt lighting and charging with the solenoid series/parallel switch. To start the truck the battery string goes to series for 24 volt starting which only requires roughly half the current - then the system shifts back to shunt for charging - and the batteries share charge and load. (Delco system on GM, White, Kenworth, Mack, and Chevy HD trucks and Waukesha Industrial applications, as well as some Cat equipment)
I think there is more than one reason why that system passed from the scene about 20 or 30 years ago. (reliability of the series/parallel switcher being a large part of it)
Anyone doubting they exist look up Napa SPS844 and SPS845 as well as the SPS866 and SPS867

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That is basically how the diesel aux generator in my nuclear submarine started, compressed air straight into the cylinder. After a 60 day submerged cruise we would place bets on how many tries it would take to get the thing to start. It was seldom pretty.
Vaughn
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wrote:

You mean compressed-air start? During my year of OTR truck driving I saw one ragged-out old yard dog with air start. Sucker fired the thing off right beside my sleeper while I was napping. I almost hit the roof.
Batteries and starters are so good now that starting a big diesel is just like starting a car. Mine has glow plugs but I've never used 'em. The company tractor that I drove didn't have any start-assist. Just turn the key and it cranked. Even in -20 deg weather. It was the big 13 liter, 525 hp Detroit too. Amazing. -- John De Armond See my website for my current email address http://www.neon-john.com http://www.johndearmond.com <-- best little blog on the net! Tellico Plains, Occupied TN Sporadic E is the Earth's aluminum foil beanie for the 'global warming' sheep.
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On Aug 7, 2:43pm, snipped-for-privacy@ipal.net wrote:

http://www.allaboutcircuits.com/vol_1/chpt_11/5.html
I've done a fair amount of work on battery control circuits, which monitor voltage, current and charge state and shut off a bad cell if needed. A safe circuit isn't easy to design and test and an unsafe one is a serious fire/explosion hazard. WW2 submarines connected their batteries in parallel sometimes, with a full-time operator on watch. They kept a log of the specific gravity of each cell, though. I think it's possible but not worth the trouble.
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Here's one of the simpler battery monitoring ICs that you could use to monitor the capacity of a series string of cells. http://focus.ti.com/lit/ds/symlink/bq2013h.pdf
High-performance Lithium packs almost require electronic monitoring. The technology could be useful for a home battery bank of old, questionable lead-acid batteries so you'd know when one should be checked.
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I have been doing it for years with no ill effects, but I recognize that it is not an optimal configuration (currently two sets of two 6-volt batteries, formerly four 12-volt batteries). I protect against possible high circulating currents with fuses.
My batteries are there mostly for an emergency, so they seldom see a high DOD, and that may be why I have no problems.
Vaughn
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On Aug 8, 4:43 am, snipped-for-privacy@ipal.net wrote:

Series parallel batteries.
First, whether you use 2V cells or batteries you end up with "A Battery"
The problem with parallel strings is that they do not all charge or discharge together.
When I was getting my accreditation for solar design and installation we were shown the results of a series parallel bank, if memory serves, of 36 x 2V cells. That is six parallel strings of six cells.
The up shot was that under charge or discharge the strings did not operate as a single battery. i.e. Under charge the strings would charge one at a time.
1 4 3 6 1 5 4 6 5
The same for discharge. There were also very high transient voltages across the array.
No, I no longer have the notes for the course, it was twenty years ago.
Parallel string should be avoided wherever possible.
If parallel strings can't be avoided you should try to use a cell that is large enough to not exceed two parallel strings.
Yes, there are situations that may make parallel strings unavoidable. One of the most common is space restrictions dictate the dimensions of cells to the point where you might be able to fit 12 / 500Ah 2V cells in a given space where you can't fit 6 / 1000Ah 2V cells. Another excuse that is used is that you can buy T105s cheaper than Surrettes.

Yes, A single string of series cell is the ideal. Parallel strings are the second best choice for battery storage systems.

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On Thu, 7 Aug 2008 17:22:44 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

Accreditation? What organization has given you this accreditation? Or is this just something else you've made up? --ron
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S.E.I.A.A.
Solar Energy Industries Association Australia
Now Known as B.C.S.E.
Business Council of Sustainable Energy
AKA - Boring Curmudgeons Spreading Entropy.
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On Thu, 7 Aug 2008 21:25:04 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

Hmmm. Interesting. I note that you are NOT listed on the BCSE Accredited Designers and Installers List at
http://www.bcse.org.au/docs/STA/Installers%20List/AccInstallers%20List%20-%20all%20-%20080807.pdf
Searching for Solar Energy Industries Association Australia leads me to Sustainable Energy Industry Association(Australia) Ltd and the link to that web site redirects from http://www.seia.com.au/ to http://www.insurancecompared.com.au /, and insurance company website! --ron
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If you had asked I could have told you that. No secret there. I haven't been a member for perhaps seven years, maybe eight.

fromhttp://www.seia.com.au/tohttp://www.insurancecompared.com.au /, and insurance company website!
I told you they became BCSE.
What you won't find on their site is the fact that the BCSE is teetering on the brink of revolt from the members. Has been for several years.
The entire industry is dead in the water. Full of cowboys and government spin doctors. Sad really, OZ had the chance to lead the world in solar power use and threw it all away. Now it's all yuppie driven status seeking.
Still, the cowboys keep me working, I haven't advertised for years and I still get phone calls from people who can't get their installer to return phone calls or show up to repair their stuff ups.
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On Fri, 8 Aug 2008 05:45:46 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

There are plenty of non-members on that list.

fromhttp://www.seia.com.au/tohttp://www.insurancecompared.com.au /, and insurance company website!

Yup, that's why I first looked at www.bcse.org.au, the BCSE web site portal. When I didn't find you listed as an accredited designer/installer, I searched elsewhere, but in vain.

Don't you need to be a certified designer/installer in order that your clients might benefit from the government rebates? --ron
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Yep, and a whole world of people who aren't. What a surprise. It is possible to be accredited and not be a member.

fromhttp://www.seia.com.au/tohttp://www.insurancecompared.com.au /, and insurance company website!

Yes, that's the only reason to be accredited. There is no other benefit to having accreditation. But as I no longer install full systems, why should I keep giving them money.
I suppose that it is the same for the US. Which means that you did not design or install your system. But once installed you became an expert. That is a common occurrence. A person moves to a community, has a house built for them, has a PV system designed and installed for them, and all of a sudden they are master builders and PV experts in the eyes of the uninformed.
I have never received a rebate for my system. I built my house and designed and installed my system.
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On Fri, 8 Aug 2008 16:15:00 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

fromhttp://www.seia.com.au/tohttp://www.insurancecompared.com.au /, and insurance company website!

There you go again George. It seems it is not possible to have a civil conversation with you. You quickly start making false assumptions by which you try to put down myself (and others).
I can play that game also. As I've previously written, I did design my own system, after spending a few years educating myself. I relied on both published experts like Gipe and Strong; and conversations with researchers at NREL who devised simulation programs, as well as engineers at Bergey and Surrette to help me understand things, and provide some assurance that my design would accomplish the goals I set.
I don't pretend to be an expert, as you pretend to be.
And dealing with real experts has made it relatively easy for me to recognize the BS artists and con men such as yourself who frequent both the commercial landscape and the Internet world, and whose skills are limited in so many areas.
It doesn't surprise me that you are NOT accredited. Maybe you had a provisional accreditation at one time based on completing the required training (although I seriously doubt that). But clearly you would have failed the BCSE requirements for Full Accreditation, which require that your skills be verified with real case studies. --ron
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fromhttp://www.seia.com.au/tohttp://www.insurancecompared.com.au /, and insurance company website!

Me thinks you have that ass about. I never pretend.

Actually, I am one of the handful of people that has read the BCSE competency standards. Most in the industry don't even know such a document exists, and that includes many of the executives.
This is one of the reasons I no longer have accreditation. The process for re-accreditation is largely dependent on the applicant attending the annual piss up, subscribing to a couple of magazines and installing "ONE" system that may or may not be inspected some time in the next ten years. Oh, and don't forget to hand over the $420 dollars.
Your slur is not unexpected.
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fromhttp://www.seia.com.au/tohttp://www.insurancecompared.com.au /, and insurance company website!

Well then, you should be able to show your energy audit listing all item run, the watts they use and how long they are run as well as the total daily Whs total.
Then the calculations for the system sizing.
The interesting part will be to see if Ron can do this. After all, he claims to have designed his system so it would not br unfair to assume that he knows this information.
But I am sure that he will have several excuses for not doing so.
1) His system design is so advanced that no one here could possibly understand it.
Read as "He can't do it".
2) His system has too many discretionary loads.
Read as "He can't do it".
3) He could but won't.
Read as "He can't do it".
4) George will make his numbers look silly.
Read as "He can't do it".
5) He doesn't have the time.
Read as "He can't do it".
Let's see how long his list will be.
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On Sat, 9 Aug 2008 05:09:12 -0700 (PDT), snipped-for-privacy@gmail.com wrote:

There he goes again. Couldn't leave well enough alone.
The only person that George makes seem silly is George. When he sets up his little "challenges" and claims he knows the response, he is starting to cover up his own ignorance. Another of his ploys is to accuse "others" of lying about numbers. If sufficiently challenged, his insecurities and ignorance will lead him into name-calling which will become progressively obscure as he delves into local and made-up sources for his comments.
George, you seem to have an overwhelming need to denigrate others in order to try to prove something about yourself. This is common in immature and insecure people and even cultures, so I guess that explains this phenomenon.
I wouldn't bother to recreate the data in any detail, because you have demonstrated many times that you are unable to understand real data, or even comprehend the nature, value or trade-offs of sophisticated simulations. You've never posted anything to indicate that you can even perform simple sensitiviy analyses (or even know what they are).
All you can do is plug stuff into a simple spreadsheet, and most of the time you don't even get that correct, without a great deal of prompting (and sometimes not even then).
Your "tool" -- your spreadsheet, doesn't even include the cost of grid extension, propane (or other fossil fuel), cost of grid-supplied electricity, proper computations for battery capacity at different battery loads, and all the other items that are important not only in designing a system, but also in determining whether the system even makes economic sense to install at all. It has zero ability to determine, for example, whether the system is better if it has, for example, more batteries and fewer panels, or vice versa. Or the effect of adding in a wind-turbine. Or the effect of adding in a micro-hydro turbine. Or what the effect of $4/gal propane will be if you are using a propane generator for supplemental battery charging.
My system was designed to supply a certain amount of energy per day -- I don't have the sheets handy, but, as I recall, it was about 16-17kWh/day in the summer, and about 21 kWh/day in the winter. It was also designed to supply the maximum power that the house might draw, with no requirement for a backup generator to do anything other than charge batteries when the renewable resources were insufficient.
Because it was also designed to do that as economically as possible, a system that did not rely 100% on renewable sources was considered.
That involved not only simple-minded stuff like some of the calculations you try to do with your spreadsheet, but also data on costs of wind turbines, PV installations, propane generator, batteries, cost of propane, actual solar resource, actual wind resource, cost of money, inflation rates, capacity of the battery chargers, battery setpoint SOC (to what level should the battery charges take the battery, if the generator had to be used) and numerous other items.
My system performed within 5% of the simulation predictions.
Initially, the simulation demonstrated that I would obtain about 80% of my energy from wind, and 20% from a backup propane generator (used only to charge batteries, not to power any unaccounted-for loads).
It didn't do quite as well, with the split being 75% wind, 25% generator. The reason was easy to see as the wind resource was slightly less than the preceding 10 year average winds for the area (from a local sensor).
But my simulation also gave me a price point on propane where adding solar panels made more economic sense than running the generator. I did that at the appropriate time, and the system is continuing to perform as predicted by the simulation, even to the gallons of propane required to run the generator. And it tells me how much higher the cost of propane would have to go to make it worthwhile to add even more panels.
On the other hand, your confusion, demonstrated by your postings, about power, energy, volts, amps, watts, time and so forth is legendary, and well documented at http://www.citlink.net/~wmbjk/tbfduwisdumb.htm
Your attempt to make false claims is transparent. Why, only in this thread you have posted:

when there is absolutely zero evidence that you ever had any real accreditation from any worthwhile accrediting board. When I asked why you weren't listed, you wrote that, well, you are not accredited now.
In a discussion of energy consumption, you write:

as if this makes a difference in energy use.
In other posts you write about
panels for a 12V nominal system having a 17V output under open circuit conditions, again showcasing your ignorance;
you claim minimum battery requirements for a particular system as being 180Ah at the 100 hr rate when it should have been at the 30 minute rate, and you do this repeatedly even when challenged.
you claim you have better numbers than those published by the mfg in determining battery capacity, so the battery should have 50% more capacity than that determined by the mfg. http://groups.google.com/group/alt.solar.photovoltaic/msg/380c9390d20b7f15
You even claimed that 1.15 hrs was only 0.09 minutes more than 1 hr, demonstrating your limited math skills at: snipped-for-privacy@h17g2000prg.googlegroups.com

GG: Do you really think that .09 of a minute is going to make that much of a difference.
Nick Pine (1999): "Who would hire this PV nitwit" Wayne (2008):     "... a true Renaissance nitwit" --ron
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