Re: (ET) Lifts and DC-DC Converters

["Clean Power Supply" <cleanpower att net>]

 Daryl and All,
 I have a small quantity (5) of DC-DC converters here with an 18-72VDC 
input and a 13.2VDC output at 5 amps. Not enough for a lift but good 
enough for LEDs, etc. I would sell those for WAY less than $150 if anybody 
is looking for one.  I also have access to some with outputs  of up to 30 
amps. I will have to get pricing on those, though. 
 On running lifts on more than 18 Volts: If Chris Tromley still has the 
tractor he used to have it is a New Idea and that lift motor is totally 
different than those used on the GE versions. I have run the New Idea lift 
motors on 36 volts for years and don't feel it is a problem. I usually run 
the GE lift motors on 24 volts and again, seems to work out fine.
 Sincerely,
 Harold Zimmerman
 Clean Power Supply
 Ephrata PA

On December 22, 2012 at 5:18pm -0500, you wrote:
>I have looked for a 36-volt nominal input to 14.2 volts regulated and
>steady output device for years, which is expected to survive more than
>one use and be in the affordable range (under $150 retail).  Never found
>one.  I figure there are plenty of automotive 12-volt devices I would
>like to run from the whole pack - like winches, lighting, horns, etc.
>
>My son the electronics tech says this is an easy unit to design and
>build.  However, he figures if he goes to the trouble of designing and
>testing one, we should be looking to make a few to justify the effort.
>His question is, what current rating is required(on the output side)?  I
>have struggled with that one.  Price goes up with power handling.  It's
>stepwise based on components, so not quite linear (power/cost).  The
>winch I am using seems to pull about 15 amps.  I would likely rewire my
>original lifts to the 14 volts from the sagging 18 to extend their life.
>  Lighting will likely be a pretty small load (thanks to LEDs).
>
>So, is anybody else interested in a 36 nom to 14.2 regulated volts DC-DC
>converter (fully isolated - 2 leads in, 2 leads out), and if so, what
>current (output) would you consider desirable?  If there is any
>response, I will chat over the information provided with him over the
>holidays and see what we can come up with.  (I already know he'll say we
>don't need any new projects - but my response is that we have been
>talking about this for so long it's an old project <smile>.)
>
>Darryl McMahon
>
>On 22/12/2012 4:15 PM, The CZ Unit wrote:
>> On 12/22/2012 11:30 AM, Chris Tromley wrote:
>>
>>> For the lift, how big a deal is it to just run it on 36V?  If it only
>>> runs for a few seconds at a time and has plenty of cool-off time, why
>>> would it hurt?  If it is a problem, I wonder if you could use a cheapo
>>> off-the-shelf scooter controller?
>>
>> Honestly? I don't know. It probably would be ok, the problem is the lift
>> current breaker would probably fuse instantly if it tried to open due to
>> overload, that would be a problem.
>>
>> Hm. Actually I have a bunch of apart-lift motors, I'll give it an honest
>> shot. The question is how do we current-limit it so the overload can
>> work? Maybe bypass it completely and use a 5 amp circuit breaker instead
>> of a fuse? What would be a good auto-reset 5-10 amp circuit breaker?
>>
>>> How common are 36V-to-12V DC/DC converters that would be suitable for
>>> the lights?  Are there any 48V input models that would still work with 
>>> a
>>> sagging 36V pack?
>>
>> I used to use a Vicor DC-DC that would put out 12 volts for the um
>> E-meter and lights. But one morning I came out and found it had
>> literally blown up, which was odd. Might have been over-voltaged, but it
>> should have been able to handle up to 50 volts input.
>>
>> Where I really need to limit current is on the sweeper. The motor on
>> that is just too darn fast, it beats up the brushes and the grass. Maybe
>> I could get a much smaller pulley or something.
>>
>
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