----- Original Message -----
From: "Lee Hart" <
[hidden email]>
To: "Electric Vehicle Discussion List" <
[hidden email]>
Sent: Wednesday, November 04, 2009 3:13 PM
Subject: Re: [EVDL] Fair Radio Charger. Remember them?
> David Chapman wrote:
>> IIRC my FR Charger has a plate and toggle switch on the front to change
>> from 110 to 220 input, you just take the plate off and reverse it which
>> locks the toggle in the other position. Regards, David Chapman.
Hi EVerybody;
My FIRST thought. Flipped the 120/240 volt switch over plugged it into
240; A Horrundous Buzz, circus breaker tripped and it took out one or more
diodes as the breaker trips no matter WHAT, now! I'm guessing, it's shorted
diode? So it's DOA on the garage floor., for now!
Other thoughts as I'm only TRYING to come up with Cheep and dirty way to
feed the 144 volt truk OTHER than my 240 volt "Monster Charge" setup that
LIVES on my bench as it takes 2 guyz to easily move it! Something
breadboarded out Mike can throw in the back of the truk to take home to
charge with for NOW! It's beating heart, Monster Charge, is a Variac that is
12" in dia! A Superior Electric , made in Bristol CT, they are STILL made in
Bristol, CT, but are not exactly Wal *Mart material, one like that costs
THOUSANDS of bux if you go retail! But they are beartifully made, sorta
ooze quality. I called them and asked JUST for the brush that rides on the
coils to give you the var in Variable. As they wern't SURE but they threw
out a price of hundreds of bux! A sorta "Bum's Rush!""We may not be able to
supply this item?" etc? Yeah? Right? for 2 hundred bux, plus they could MAKE
ya one! But Not interested .I'll MAKE my OWN Godamn brush setup! Starter
motors STILL have braided brushes! Goot sourse of a carbon brish, sharpen it
to the angle Superior did!Let's see that's project 3243 or? 4?
Soooo, ANOTHER brain fart here; Howbout hooking a 15 amp variac, a 120
one as I'm fresh OUT of 240 volt jobs, sigh! In series with a 120 volt line
in SERIES? I could "trim" the output voltage, with the variac, as I'm
looking for about 150? volts or so, to put through my little 10-15 amp setup
I had on the Rabbit, before Manzanita Daze, bad boy setup, along with my 60'
foot 'stench cord I use for YEARS charging at the RR yard.It's on a little
heatsink with a little shady pole motor, on a fan. It is compact and runs
cool! All this crap is a make- do, setup, maybe put a timer on it, so it
won't fry the batteries although I think ya would fry the vairac, first? All
this IS temporary, until Mike can sift through the battery charger options.
He likes my Manzanita Micro one which I just plug it in to what's handy; 240
or 120 volts on the AC side. Guyz! You don't KNOW how handy this feature
is!!!AND it regulates automaticly! But Mike has shot his load on EV parts an
stuff for now, so we'll hafta cheap out on a charger FOR NOW!Yeah! Babysitt
it for now, we ALL went through this curve in the EV Story?Of course this
wouldn't be an option with Lithiums? You HAVE to have the RIGHT charing
setup from the get-go!
> Right! However, you also need to replace the plug on the cord with a
> 240vac version.
Not a problem, got lottsa adapters!
> Bob Rice asked:
>>> ISN'T there a way to double the output, but at HALF the
>>> amps? I THINK there is a trick, with making 36 volt chargers 72 volts?
>
> David Roden wrote:
>> This works with a center-tapped (push-pull) transformer and 2-diode
>> setup,
>> as is typical with golf car chargers. You ignore the center tap and put a
>> 4-
>> diode full bridge across the full secondary.
>>
>> However, the Fair Radio chargers are already set up that way - they
>> already
>> use a full bridge.
>
> Right. I have the schematic around here for it. It's basically a
> transformer with twin 120vac primaries, a lot of secondary taps
> (selected two by switches, in 1v and 10v steps), and a full wave bridge
> rectifier built with four separate diodes.
Thank you! THAT'S what I thought, too!
> To get more voltage at lower current, you could rewire it as a voltage
> doubler circuit. This will use two of the existing diodes, plus two very
> large capacitors. Wire it like this:
> _________pack positive
> | |
> _|_ _|_+ big capacitor
> /_\ ___ 1000uF 250vdc
> | |
> wire from voltage_____| |____wire from
> selector switch | | transformer
> | |
> _|_ _|_+ big capacitor
> /_\ ___ 1000uF 250vdc
> | |
> |_____|__pack negative
>
> These capacitors will lead a hard life. The ripple current in them is
> about half your charging current. Use the big pop-can-size ones with
> screw terminals. Don't try this with cheap little electrolytics with
> wire leads (unless you use a bunch of them in parallel).
WHERE do ya get Crapaciters like that?Are they expensive, etc?Checking
my options.
> If you have access to the center tap of your pack, then you can connect
> it to the connection between the two capacitors and wire to the
> transformer. This makes the batteries serve as the capacitor; then they
> they deal with the high ripple current.
That''s a thought as it's a 144 volt truck traction pack. I DO have 2
Quick Charge 72 volters, I guess I could hook them both up?Hmmm?? Could ya
hook them up in SERIES for a 144 volt output without messing up their
minds??Other than being a godamn HEAVY setup as a Quick Charge is bult on a
BIG ass transformer!But I guess I could just hook up each the QC's to 72
volts worth of the pack, I wouldn't hafta split it, electrically?THEY, I
THINK are isolated, unlike that OTHER fearsome crap I'm proposing!
>> You might be able to get away with applying 240v to the 120v input tap on
>> the primary side of the transformer. But be careful that the output
>> voltage
>> doesn't exceed the diodes' PIV voltage rating.
>
> This won't work. The transformer will saturate, draw a horrendous
> current, and trip the input circuit breaker.
>
Oh! You bet! see above! Next best thing to a "Short Circus!"Wimpy diodes,
too!
Seeya
Bob
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