Great Scott!

Posted at 10:14 am on Nov 12th, 2006 by Jakeh

wow, bare bones power supply. That’ll produce quite a current on the DC Side of the charger, I can imagine that it is rather effective (don’t know the requirements for these EV Batteries) but would require constant supervision while in use. Not planning on building one of these, I’ll stick with my 40 dollar 15amp powersupply from rat shack, granted it can’t charge a 152v battery cluster but… I’m not powering anything that intensive!

Posted at 11:21 am on Nov 12th, 2006 by jimmy d

/grimace

Posted at 11:33 am on Nov 12th, 2006 by Evansbee

Gosh! that’s scary!! With all due respect, you don’t know much about how a dimmer work and its limitations. Dimmers are not designed to manage inductive loads, humming badly and producing horrible results, including overheating of it. In addition, the circuit doesn’t even has a protective fuse!!! Buddy, don’t recommend these type of circuits to others and make sure that your house insurance is up to date!!

Posted at 11:50 am on Nov 12th, 2006 by sqnewton

Just make sure you were rubber shoes!! THat is some scary stuff right there.

Posted at 12:02 pm on Nov 12th, 2006 by Ledhed

It’s fine if you want a backup so you won’t be off the road, but use it regularly and it’s easy to kill a $2k pack. Spend your money on a good charger, then buy batteries with what’s left over.

Posted at 12:11 pm on Nov 12th, 2006 by jepel

also doubles as a remedy for stopping that pesky thumping in your chest.

Posted at 12:42 pm on Nov 12th, 2006 by agentofboom

holy crud

Posted at 1:59 pm on Nov 12th, 2006 by nobody_6.1

Holy Zombie Jesus!

That’s not actually DC coming out of the bridge… mind you, it has a DC offset and no reverse current .. but still … put some bulk caps and smooth that sucker out!

I wonder what effect the AC components of the signal has on the batteries…

Posted at 3:12 pm on Nov 12th, 2006 by HungSoLow

Electric razors use only 1 diode for the power supply and to charge batteries. I dont think its harmful to the battery to have the voltage and current go up and down.

Posted at 4:02 pm on Nov 12th, 2006 by android_04

whats the rating on the ‘dimmer switch’, your not going to get more than 600 watts out if its just a home depot run of the mill one,

definatley some ghetto engineering. i approve.

emperordane

Posted at 4:35 pm on Nov 12th, 2006 by Dane Kouttron

RE: pulsing current

Generaly a good idea for nicads, NiMH, and lead-acid. On the first two it blows out “crystals” or something that forms on the plates, shorting the battery out. In lead-acid cells, the pulsing fights sulfation.

In fact there are devices that draw off current from the battery, and then recycle that power into a charging pulse. It still slowly discharges the battery, but it uses some of the juice to fight sulfation buildup, keeping the battery useful.

Posted at 4:54 pm on Nov 12th, 2006 by Standard Mischief

I think you meant to say Mike Chancey (with an e before the y).

His website: http://www.geocities.com/electric_honda

Posted at 5:29 pm on Nov 12th, 2006 by electricmotorcycles.net

I would turn it on (with a 10 foot pole) :)

Posted at 9:57 pm on Nov 12th, 2006 by Alan

Simple bridge rectifier DC circuit.

yea, some pretty bad “DC” commin out the other side

Posted at 10:45 pm on Nov 12th, 2006 by Chupa

Admittedly the circuit is pretty damn scary… But when you consider that they are hooking it up to a battery bank capable of sourcing thousands of amps and >100v that is really scary.

But even more scary is that the person who built it not only got shocked several times (that should not happen regardless of how shaky a circuit is, you should ALWAYS turn it off when you are fiddling with anything with >40v in it) but that he managed to melt a dimmer… Ever heard of a variac, or at least a fuse?

No offense Tom, but serously x_X

In any case, I am impressed by your ingenuity, but I can’t quite figure out why you did not just run the dimmer into a 1:1 isolation transformer with a bridge rectifier on it…

Unless that transformer is like 2:1 or something (thus allowing you to double the max current you can pull for a rated dimmer while compressing your range from 1-160v to 80-160v) I don’t see the point for that incredibly scary circuit…

Posted at 11:25 pm on Nov 12th, 2006 by ...

vell zif uoo look ez little closuer you will see zat zee transformer outpoot is wired in reverze… so zee powver through zee dimmer vill cancel zee powver though zee secondry. no dimming, no powver flow… a little diming of zee primary and a little powver vill flow. iz a little mure complex zan it loogz. no???

Posted at 3:54 am on Nov 13th, 2006 by HeBD

People keep posting “scary”, but they’re not really saying why. This setup is abusive to nearly every component in the circuit.

1) The transformer isn’t fused.
2) Inductive loads will kill a light dimmer.
3) God knows what the load on the transformer secondary is.

But, most importantly:

4) Dumping unregulated current into lead-acid batterys can cause them to emit flamable hydrogen, as a best case, and cause a deadly explosion (of acid and lead!) as a worst case. Nobody should use this ridiculous technique. It’s like plugging high wattage speakers into wall current- yeah, it’ll make a really loud 60 hz tone, but it’s way-stupid.

Posted at 4:16 pm on Nov 15th, 2006 by Scafativ

Bad Design, but a few good ideas

Bad Part – Dimmer – Most dimmers are for resistive loads, not inductive, that’s why he kept blowing them up.

How it works, there is no details on the transformer, but if correctly wired, it will increase the output voltage.

E.G. if input was 120v and output was 40v, wired 1 way you would get 160v (if phases are correct), and the other 80v (if phases are incorrect)

as the battery packs are >120V, you have to step the mains up to be able to charge them.

The supply is unregulated, some batteries prefer this as the stops the build up of problems in the cells

Early car battery chargers were just a sutable transformer and a bridge rectifier, and as long as it was the correct transformer, the output was ok for a car battery, as the battery started to fill, the voltage difference between the charger and battery drop, current drops, and once the Battery is the same voltage as the charger – it stops.

Nice Ideas, but I would exspect a better design for an expensive battery for you electric car.

Posted at 5:35 pm on Nov 21st, 2006 by Wonko The Sane

A better idea for controlling the current; Use a filament transformer, say 120v to.. maybe 12v, as some current, maybe 10A or better, hook a large reostat ( LARGE power adjstable resistor ) across the low voltage side, and use the PRIMARY of the transformer IN SERIES with the load you want to control.
Ovbiously you want to play with values to figure out what the optomium values are for whatever you want to control, OR what you can get out of what you have on hand.

CH

Posted at 2:07 am on Dec 11th, 2006 by ch

sd

Posted at 11:47 am on Sep 14th, 2008 by rondinele