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Re: (ET) More Power Inverters



Bill Alburty wrote
>I was probably nearly correct about the amps pulled by my furnace blower 
>( I said it was 11). I had estimated 11, allowing for a big surge. So I 
>measured it. The start up surge went to 8.4 on my galvo type meter ( but 
>the actual peak, if displayed on a scope, could be twice that for a very 
>short time). Suppressing that surge may be the key to making an inverter 
>do the job without kicking circuit breakers.  The run current measured 
>only 4.7 amps, indicating that 115  X 4.7  = 540 VA would  handle the 
>running current. 

That's a lot better (nearly 7 hrs off of a 100Ahr pack).  Less due to
efficiency and load issues.  More since the pack is larger and you
presumably won't run the fan 100% of the time.

>A 1kw inverter is therefore probably enough to run a 
>furnace, refrigerator, a TV, and a few lights (for running current 
>only). Would a big capacitor handle that pesky surge?

Capacitors are not the issue.  The inverter's power semiconductors are
going to be the limiting factor in a surge.

>    Whats bothering me now is Russ's getting only 6-9 hours out of the 
>36 volt pack. I was hoping for for much longer.

Call it a lesson in the energy density of a battery.  

You might keep the furnace running for a while but other than that you
would want to rely on time tested methods for making it through a winter
power outage.  Early to bed, leave the refrigerator closed (or use the
great outdoor fridge ), candles, lamps and radio.

Robert


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