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OK, the article is way old, but I just ran across it yesterday. It’s an entertaining, opinionated look at what a PC power supply is, what is should be, and why you should (or shouldn’t) care:

http://www.dansdata.com/top420p4.htm

Thoughts: 1. You are sure the 2S pack is in serial to the 12S pack, and only the whole 12S bundles are in parallel to one another? I know, I know, this is a fairly obvious question, but deserves asking. 2. What’s your total wire length for each pack, and for the parallel/serial connectors per pack (if you’re using something like a Dean’s parallel/serial board or Anderson Power Pole, note that too)? 3. Can you take a picture or two of your setup and post it? Ideally, post one picture of how you are connecting your batteries to the ESC (probably easiest to show without being in the heli), and post another picture of how they are connected when you are charging. 4. What gauge of wire are you using on your 2S and 10S packs? What’s the total length of wire (including both sides, wire under shrink wrap as well as exposed).

My initial reaction is that you may be seeing the result of varying resistance values across the pack wiring (which highlights some of the problems of ganging separate packs versus building a single, uniform pack). Let’s do some math.

Assumption 1: Your batteries are all using 16-gauge wire with a resistance of .00473R per foot. Assumption 2: Your 2S packs have only a total (both + and – sides) of 1 foot of 16-gauge wire before reaching the serial Y-connector, while the 10S pack requires a total of two feet of the same wire. Assumption 3: Your peak draw is a combined total of 100A, or 50A per 12S ganged battery. Assumption 4: We’re operating at around 77F temperature. Assumption 5: Your 16-gauge wire is industry-standard, with a a loss of around 122.3 feet per ohm. Assumption 6: Your batteries are hot off the charger, running 3.6v apiece.

Voltage Drop (V) = Amperage(I) * Resistance(R)

10S battery: V = I * R V = 50 * (.00473 * 2) V= 0.473v drop purely due to line resistance

2S battery: V = I * R V = 50 * (.00473 * 1) V = 0.2365v drop due to line resistance

So a difference of one foot of length of 16-gauge wire is a loss (resistance) of a quarter of a volt. So to see why your 2S battery might be delivering more amps, your 50A draw results in the total voltage across both packs dropping to 2.9 v/cell on average, but the 2S pack will be delivering substantially more amps due to the higher voltage to the Y-connector, thus the actual voltage of the 2S pack will be sagging more… In short, it is delivering substantially more current to the motor than the 10S pack.

You should be able to see this, ideally, with two wattmeters in-line prior to the Y-connector, one per side of the ganged serial battery. You could also do what I do: build two identical shunts, pick up a pair of identical $3 digital multimeters from Harbor Freight, and watch what happens.

I’ve also ignored the electrical loss due to the inter-battery connectors within your 10S pack. There’s a lot of extra metal connecting those batteries, with its own electrical loss. Steel is not a great conductor.

Tips: 1. If you are ganging packs, make sure the wire for all packs are exactly the same length to the Y-Connector, exactly the same gauge, and preferably the same make/manufacturer, purchased around the same time. You might possibly wish to allow a slightly longer connector for the lower-voltage packs due to the intra-pack electrical losses. 2. If possible, use the same-size packs or similar-size packs. For instance, I use four 3S packs as a 6S2P in my trainer setup. This way, your intra-pack electrical losses are similar or identical. A friend gangs 2S and 3S packs using Anderson Power Poles to create whatever voltage he needs. Because there’s just one extra tab on the 3S packs, the intra-pack losses are only very slightly different (30% more). On a 10S pack of A123 cells, you have five times the electrical resistance within the pack than you have on a 2S pack. 3. You could try soldering copper bars on top of the 10S pack steel tabs. This would reduce intra-pack electrical losses, resulting in higher voltage to the Y-connector. 4. Measure the total resistance using a multimeter, from the tip of the end of one pack lead to the tip of the other pack lead. Make sure there is no circuit engaged when testing this, or you will obtain false readings and possibly damage your meter. After measuring the resistance of your 10S pack, re-solder leads to your 2S pack, and then start trimming the wire until you have just as much overall resistance on your 2S pack as your 12S pack.

I don’t like Option #4, since I’m not totally sure about the effect of the internal resistance of the batteries themselves on voltage disparities to the Y-connector, but I think it should work for the goal of delivering identical volts at the Y-connector. I prefer to use similar-size packs (3S and 2S) so that I don’t have to deal with, you know, science and stuff 🙂

In the latest bout of White House douchebaggery, the White House forbids anyone to open an email from the EPA suggesting that greenhouse gases are a pollutant. Yep, disagree with the findings before you even read the report, and forbid anyone to read it because you disagree with it without reading it? Sure, sounds like an open-minded, American approach to me.

John McCain blames the run-up in oil prices on “Reckless Wagering”. Barack Obama is proposing legislation to stop the fuel price rise driven by “a few energy lobbyists and speculators.” The Wall Street Journal has a different theory, though, that defies the dogma of speculation.

I agree with the WSJ.

I have been studying foreign exchange markets for the past few months. In intra-day and inter-day trading, you can see the swings caused by speculation. There are even some longer-term trends fueled by speculation. However, these trends are tiny compared to the money policy embraced by a nation and its central banks. These central banks are the engine driving the price of money around the world; speculators are akin to a handful of horses, tied to the engine, trying to hold it back.

They have some small effect, but the train moves on where it is going, directed by the money-engineers driving it in response to expected conditions ahead.

The historic plunge of the value of the dollar in the past two years has not been fueled by speculation. It has been fueled by an intentional weak-dollar policy on the part of a Federal Reserve trying to blunt the effect of crushing national debt and fight inevitable inflation.

So, too, is the case with oil prices. That weak-dollar strategy turned investors to commodities, adding a few extra horses to try to hold that locomotive back. But, by and large, the prices are rising because demand is overwhelming supply.

Unless some new facts come to light, it certainly appears that we are finally approaching the summit of Peak Oil: global demand is outstripping diminishing easy supply. I caveat “easy” supply, because it seems to be true there is plenty of oil left in the world, but it is much harder to get to than the easy oil-strikes of the past century. And I fully expect that we’ll see quite a few advances in oil extraction in the next ten to twenty years that will help keep pace with peak oil demands, at least for a while.

On the plus side, it appears that higher energy prices have begun to highlight the false economy of moving manufacturing jobs overseas, and high shipping costs are bringing some jobs back to the USA.

Energy costs are expensive enough that I’m seeing the impact in my monthly budget of paying three times as much for gasoline as when I made that budget. I cannot wait for the day that UltraMegaCorp finishes the new data center planned just 8 miles from my house, and I can begin to ride my bike to work on a regular basis. In fact, I think the rise in fuel prices may be a long-term net win for the USA, but the cost to my wallet gives me pause about taking one for the team.

If you have ever been involved in implementing a klunky solution to a difficult problem, you’ll appreciate this story: http://thedailywtf.com/Articles/The-Stalled-Server-Room.aspx

At work, we have an odd tradition: once every few months, we go buy several pounds of bacon, and fry it up at Dave’s house for lunch. Not much point to it, really, but today we had some weird Japanese contest show called the Extreme Championships on the TV. It got funnier the more beers spread around the room, and the bacon smell permeated Dave’s house.

Yep. 7 people, 5 pounds of bacon. Good lunch!

I voted for Bush. Twice. Two times.

First time, it was because honestly, he seemed like the better choice. He did a good job in texas, people liked him, he reached across the aisle, and yeah.. he shared osme of my moral beliefs.

Second time, it was more complicated. I watched Farhenheit 911 the night before.. I was thiiisss close to Kerry.. but the man, dammit.. every time he was asked about his plan, all he could do was say “Bush did…” – his entire campaign was about anti-Bush.. and at least GW was FOR something..

Turns out, GW is the worst president we’ve probably ever had.. whoops..

So.. if Hilary had gotten the democratic nomination.. I might have found myself in the same predicament. McCain, I Like him.. he was, at one time.. really cool.. and I like to think he is pandering to get his base back, but really.. just wants to be that cool guy again. Hilary was over-political, dirty-fighting, cold-n-calculating, accusatory, and unable to engage in any real positive messages except her health care plan (which, admitteldy, I really liked). So I might have found myself torn and going with the GOP (of which I am a registered member) yet again.

But.. nope. I am a Republican, and I am voting for Barack Obama. He is positive, lightning-quick, well spoken, informed, savvy, and able to sit down with those world leaders and be respected. He is new blood, and, if he wins, he may be, finally, the return to presidentiality we have yearned for. Face it.. Johnson was seedy, Nixon was a loser, Ford was a lame duck form moment one, Carter was a wet noodle, Reagan was good but “likeable” and fuzzy, Clinton played the sax and a fat intern and GW went form lovable laughing stock to dangerous man-child with his finger on the f**kin Button..

JFK, Lincoln, FDR, Teddy, Adams, Washington, Jefferson (George AND Weezie) – they all had that Je Ne Sais pas, that ting about them.. and Obama may well have it too.. so.. yeah.. I am Republican, and I am voting for Barack Obama.

A man in New Zealand was excommunicated from the LDS church for indecent acts with one boy under age 12, and several others aged 12 to 16, including an act including a bull mastiff dog. The church excommunicated him without notifying law enforcement…

http://www.stuff.co.nz/4584766a11.html

Does a church have an obligation to report illegal activities disclosed in the confessional? Legally, in many US states, they do not:

http://www.childwelfare.gov/systemwide/laws_policies/statutes/clergymandated.cfm

Ethically, however, should a clergyman be required to report known or suspected child abuse?

Utah is weird.

There, I said it. It’s just a plain weird place to live. I went to a picnic the other day, and the most distinguishing characteristics about it were the utter lack of any minorities, any alcohol, and the undercooked hamburgers busily worked over by a tall white guy named Brian. There were hordes of smiling white faces eating rare burgers with perfect teeth, while fat, pink babies crawled or toddled on the grass.

I grew up near Washington, D.C. Ethnic and habit diversity is something I’m used to. The monoculture of race and habit is unsettling.

Utah is also weird for its unique restriction on the distribution of “hard liquor”. Only three places are allowed to sell hard liquor: state-owned liquor stores that make an enormous profit, “private clubs” that in any other state would be called “bars”, and restaurants which derive more than 50% of their gross profits from the sale of foodstuffs other than alcohol. You aren’t allowed to have an open container of alcohol anywhere in public in Salt Lake City, Park City, and a number of other municipalities.

Like I said, weird.

A “private club” is an odd beast. Basically, to enter any bar in Utah, you have to fill out a lengthy form, show ID, and pay a club membership fee (minimum $5 or more). This makes bar-hopping a very expensive and time-consuming proposition for visitors. There are also specific rules about how many guests a private club member is allowed to bring with her into the bar. The oddest thing is these rules are codified into laws, with like actual jail time attached if you bring 8 friends with you into a private club rather than 7 or fewer.

Anyway, yesterday the Utah State Alcoholic Beverage Control Commission invited the public to comment on the issue. The quotes that sticks out to me, though, came from opponents of allowing “bars” in Utah. Their arguments were:

1. That not requiring name, address, phone number, and emergency contact information at bars would make it more difficult to prove drunk drivers had been drinking because there would be no written record of their entry to a bar,
2. That maintaining a list of every person who drinks at a bar in Utah is required for law-enforcement purposes,
3. That removing the “private club” restriction would send a mixed-message to youth; while we’re spending millions of dollars on the DARE program to convince children not to use alcohol or drugs, we’re also liberalizing our bar laws and thereby promoting the use of a “potentially dangerous controlled substance” (her words),
4. And finally, that we should not send the message that Utah’s moral standard on liquor can be abrogated for money from tourism and business.

My questions are: Do other states have a problem proving the guilt of a drunk driver using a Breathalyzer or traditional drunkenness tests? Are those who go to bars any more likely than the general public to commit a crime where their private-club record will help the case? Doesn’t DARE stand for “Drug Abuse Resistance Education”, and can’t responsible adults imbibe from time to time without it being “abuse”? Does the “moral standard” of those who oppose the private clubs modification really require that they make it as difficult as possible to get a drink in Utah?

I’m with Governor Huntsman on this one: get rid of the ridiculous “private club” requirement to serve liquor in Utah. It is a burden on visitors and those who wish to legally imbibe. It’s an arbitrary distinction that amounts to nothing more than a drinking tax imposed by those who want to bend the rest of the state to the will of the religious majority.

From a post today on another board, I decided to archive my opinion. Like I’ve said before, I learn what I think when I read what I write:

I would guess a bunch of the “abstinence is evil” crowd has an STD and/or has had an abortion. Regardless, we should use them as our model of acceptable behavior. :blink:

Abstinence-ONLY education (Title V) is evil insofar as it leads to an increased rate of sexually-transmitted diseases and unwanted pregnancy among teens. Note I’ve never had an STD or suggested abortion as you impugn. Abstinence is not evil; abstinence-ONLY education in its current form — bribing school districts to abandon comprehensive sex education that brought down the epidemic rates of abortion and STDs of the late twentieth century — is evil.

Title V restricts discussion of or advocacy for any birth-control method other than abstinence. Violation of this restriction by even a single teacher in a district endangers the entire district’s federal funding. Is it the American way to pay schools to silence conscientious teachers who favor comprehensive sex education and don’t echo the party line?

What do you think the people in New York have been taught – abstinence? Hardly.

New York is an urban area, with a birth rate and STD rate among teens consistent with other demographically-similar cities. New York rejected the federal abstinence-only education grant because of the strings attached: federal interference in local education efforts. “Abstinence-ONLY” funds are statistically ineffective at reducing teen birth rates and STD rates, while comprehensive sex education — including abstinence — leads directly to a 60% reduction in teen birth rate, with a modest reduction in STD rates.

New York’s rejection of the Federal purse with strings attached was a smart move if the goal is to reduce teen birth and STD rates. Abstinence-ONLY education is ineffective policy, at best. Since abstinence-ONLY’s introduction in 1996, teen pregnancy has been on the rise. Comprehensive sex education, which was common until the 1996 Title V introduction, showed dramatic results in both STD reduction and teen-pregnancy reduction according to several CDC statistics.

Comprehensive sex education programs introduced in the 1970s and 1980s rebuilt the dam bridged by the rampant promiscuity of an earlier era. Today’s modification into “abstinence-ONLY”, at best, is a finger in the dike attempting to hold back the flow of STDs and unwanted pregnancy, with negligible results.