Voltage Multiplier

Well, I can do this bit:

http://www.linear.com/designtools/software/?gclid=CP_ciPXojL0CFaQfwwoda7oAzg#LTspice

Sounds like you had a very productive day, compared to many other people's. Yes, mine included!

Good Luck, Old Salt

Growing old is unavoidable.

Growing up is optional.

Growing old is better than the alternative!

I agree 100%.

I would rather be old and infinitely curious than young and have all the answers.

I do not want to go back to my youth,once through was enough for me.

I just threw in my previous post to lighten up the conversation a bit.

Always someone who has got it worse than you.

I used to complain that I had no shoes.Then I saw a guy that had no feet.

So I took his shoes.

Reminds me... Don't criticize a man until you have walked a mile in his shoes. Then when he hears about it, you got a good head start and he'll never catch up to you without his shoes.

Having my 'youth' back is not in the cards for any of us, but I wouldn't mind reacquiring the 'back' of my youth.

JCase-

As with developing the circuitry for a voltage multiplier, sometimes some things or sequence of things that shouldn't work or have slim chances of happening in the sequence that they have DO WORK OUT. To me and many others the world, especially the fields encompassed within science and engineering, is too orderly to have been created by mortal persons. Without taking this theory any further, for fear of inciting an out of place argument, I am not going to discuss this any further. If you don't agree respect the rights of others.

As for the alternative, what would you call this: A person has a heart attack, plumbing problem, and while Drs attempt to insert a stent the person's heart stops for 2 minutes. Clinically dead. Also of note an "out of body experience".

Same person years later has another attack, electrical problem. Heart stops for 6 minutes, clinically dead. Heart kick started by "electrical engineered" methods, AED. Statistics state that for each minute that the heart is stopped the chances of recovery go down by 10%. This person had a 40% chance of getting away from the "alternative" and coming back.

To my count that is two (2) times that the person was in the "alternative" to life. His Dr. also agrees.

This is BioMech, BioMed, BioElect, BioChem-Eng, a lot of luck and some faith in many disciplines and other things. I don't know why you "don't believe you've died twice" but it happened. I really don't care. If someone doesn't believe that this sort of thing happens perhaps they should communicate with someone who has experienced it. This must be done with an open mind since the listener has no experience to learn by. Experience is the best teacher and the person who experienced is the best qualified to learn from.

Also, modern medicine is wonderful. What about the child that fell through the ice, was underwater for over 30 minutes, was rescued and is alive today?

In summary, sometimes things happen that we don't think possible. Don't question them, accept them and enjoy the opportunities that they have created. While here make the world a little bit better when you finally leave than it was when you arrived. It also helps to believe that miracles do happen. They happen more often that way.

Good Luck, Old Salt

According to scientists, Baryonic (normal) matter is only around 5% of all the matter in the universe.And what percent of that 5% is a human being?

WE are truly the ghosts in the machine.There is so much more about reality that we do not understand.

I could relate to critics events that have occurred in my life that they would refuse to believe,so I don't waste my time.

Life after death is not an illusion created by an oxygen deprived brain.

If so, all of reality is an illusion,for we do not see total reality as it is.Our 5 senses limit what we can sense.There is so much more.

I have seen the light, and it is hard to turn away,but afterwards, there is no fear of

death anymore,only a sense of urgency to help others as much as

possible,remembering that everyone has an unseen burden to bear.

There will always be nay-sayers,and they have my sympathy and understanding.

I did not know till I had been there and back.

HiTekRedNek-

There are many words of wisdom and reality in your comments. Many people do not believe in some of the things you and I state based on our experiences and deep thoughts, but that is their loss. They will finally believe when they are in similar but different experiences. Different in that the alternative is the only thing possible. Your words of:

I have seen the light, and it is hard to turn away, but afterwards, there is no fear of

death anymore, only a sense of urgency to help others as much as

possible, remembering that everyone has an unseen burden to bear. are extremely true and are exactly my thoughts and mission statement of life.

I knew not to fear when my Grandfather told me not to. He went to the alternative two years before I was born.

Thank you for your excellent words of wisdom and guidance to others.

Good Luck, Old Salt

Sounds something like a Marx generator....

http://en.wikipedia.org/wiki/Marx_generator

Not the same.Here is a link to a schematic of the doubler.I am considering replacing the capacitors with batteries to enable charging in parallel and discharge(Through the load) in series.

http://www.coolcircuit.com/circuit/voltage/

Looks doable to me.

Anyone see a reason why this would not work?

I intend to fuse the circuitry for protection due to the high energy potential of the batteries.

See also Cockcroft-Walton multiplier circuit (similar to the tripler/quadrupler circuits you mentioned).

See also half-wave doubler as used in microwave oven HT supply.

If you look at that circuit, and consider the lower Vin as 0V, you will see that there are two separate charger circuits, each capacitor (battery) being charged on alternate half cycles of Vin (upper). (Some batteries are not happy being charged this way so beware.)

Batteries will then produce +Vin and -Vin, (neglecting square root of 2 multiplier). So batteries are not actually being charged in parallel, so no actual charge balancing will occur.

You can extend to cover more batteries using capacitors and diodes, but the further away from the input, the lower will be charging current due to losses in the diodes.

I don't think you can beat relays to ensure charge balancing. Make sure you use appropriately rated BREAK BEFORE MAKE contacts! Of course, you cannot use the battery whilst it is being charged.

Re: Voltage Multiplier
I considered relays at first,but because of the high current Max needed (400 amps DC),the expense was over budget.I have the diodes in stock from disassembling old equipment.
An I/C is out of the question also because of the high current.
I do not intend to attempt to apply the load while charging.
Do you have any ideas on how to insure a balanced charge on all 6 batteries while
being charged in series, perhaps using Zener diodes to bypass batteries at a certain voltage?
Again, the high current is the tough part to handle.Would probably have to use a large transistor and heat sink on each battery to accomplish this.
I am open for suggestions.
Thanks for the feedback.

The above is the circuit you are talking about for voltage multiplying.

This can quite happily work at low currents and with appropriately sized components, will work at higher currents. I have not done the sums for the capacitors, but even without doing that, I don't think this is feasible for a high current charger. You seem to have a good supply of high current diodes, why not get some transformers with appropriate output voltage , either multi output or multi transformers!

There is of course no "control" of the battery charging.

An alternative is just to use a number of battery chargers, one for each battery.

Best of luck.

I would think the batteries would see AC or at least extreme ripple at the power supply frequency which the batteries would not like at all.

Maybe this would work?

How would you turn 'em off?

OP

"It seems to me, at first glance, that this circuit could be modified to charge a series of batteries in parallel and discharge them in series,as in a golf cart.The charger would need to have an A/C output instead of the typical DC output,and the rectification would be performed by the guiding,blocking diodes."

The SCR's would have to be installed in the charger output upstream of the "guiding, blocking diodes.

When the AC waveform hits "zero" the SCR turns off.

Designing the SCR cutoff point (voltage threshold) would take some thought time and maybe a little experimentation but I am sure it could work.

Given the op amp seeks equilibrum between the inverted and non-inverted input and the Gain of the op amp = Rfb/ Rin, then a properly sized resistor in conjunction with a capacitor or zener diode in series inserted in the op amp feedback circuit could be used to regulate the voltage applied to the SCR gate and thereby control the voltage/current applied to each battery.

The charge time of the capacitor would dictate/control the firing angle of the SCR in reference to time and therefore dictate the voltage/current amplitude of the output.

The DC pulse caused by use of the SCR could be filtered out (smoothed) by installing a properly sized RLC network across the battery (+) & (-) downstream of the blocking diodes.

This is an elaborate solution and I would think that the original circuit posted by the OP would function adequately if the DC pulses were filtered/smoothed using an RLC network at each of the battery terminals.

I am pretty sure that as each battery reaches maximum/full charge the counter emf would prevent overcharging and eventually the entire battery rack would be at equalization unless there is a bad battery in the chain.

Re: Voltage Multiplier
The charging current is no problem, it is the load current through the diodes that can be quite extreme under heavy load.The Drive module controls the current to the motor to around 200 amps,but can be updated to 400 amp high horsepower type with same batteries.I want to have the option to upgrade without changing diodes,so I want to design in a lot of overkill.

A 6volt Lead/acid battery is fully charged at 6.4 volts.What if I put a 6.4 volt zener, of course with current limiting,across each battery(Charging amps only 20 amps). This would bypass the battery when fully charged,and pass the current on to the next battery in series,in effect,acting like a shunt only when fully charged.Gonna be hard to find a zener to handle that current, so what if I use it to trigger a transistor(s) to take the load?The battery charger will regulate the current when a battery is dropped(Bypassed) from the circuit.(And they will be "ignored" when under load) Or perhaps as mentioned elsewhere, an op amp would be better for sensing and triggering a bypass transistor using the rectified voltage and current from the standard charger?The goal is to get an equal and balanced voltage on all batteries.

That way there would be no need to charge in parallel,and all batteries should end up with proper charge.

Thanks to everyone for the help on this brainstorming session.

Only thing good about getting old is it beats the alternative! -- JHF

Sorry, I don't get you.

You charge capacitors with DC, not AC.

You can put a double pole, double throw switch (or relay) between each cell to convert from serial to parallel configuration.

Lots of switches rated at 400 amps DC.Lots of $ I don't have.(6 batteries in series.)

Good idea,though.

Another way is to chop you low voltage DC charging voltage to create square wave AC. Couple it to each battery via capacitors or transformers. Rectify the result and use it to charge each battery. I think this is a lot more complicated than "rewiring" using relays. High current relays called contactors are available and are commonly used in appliances such as washing machines.

May sound excessive, but the only good way to maintain proper charge and maximize battery life is to buy/build a separate charger for each battery. The 120Vac(to ~20Vac) transformer in each charger provides the isolation needed to charge a series string of batteries WITHOUT using heavy duty switches and diodes. Each charger should be the "smart" type which senses and compensates for temperature changes and provides bulk charge, topping charge, and maintenance charge.

IF the application has the space and can carry a few extra pounds, you can install all the chargers and have a single 120Vac connection for charging. Other option is to wire a multi-pin connector with wires going to an external socket. Each battery terminal or junction (between two series batteries) would need 1 pin.