KJ4VOV wrote:raptor wrote:KJ4VOV wrote:raptor wrote:Why reinvent the wheel when all that is need is sufficient electricity in the correct voltage and the knowledge to tie into the panel.
Why reinvent the wheel (or rewire the station) when all you need is a hand pump, some hose, the measuring stick for the tank, and a couple of hose clamps? And personally, I don't normally carry my 7kw generator on the BOV...
No but most large vehicles have a 150 amp alternator. 150 amps @ 12volts = 1,800 watts which also happens to be the normal circuit breaker capacity for the 120 volt pump. If you have a 2,000 watt inverter which are cheap and common you can get a single pump operational with just a quick wiring job and a vehicle running at an rpm high enough to produce 150 amps of power. An inverter of this size is only about $130 and is small.
http://www.amazon.com/Whistler-Pro-2000 ... B003R7M6CS
That said even a small 2 to 3 kw unit would be adequate. My comment about a 7 kw unit was to get the station operational with a reserve power supply for other needs, not a bare bones approach. Also if you have gas I promise you, the gas station operator will find someone willing to trade a generator for fuel.
It depends on the vehicle as to how big the alternator is, and the size of the vehicle isn't always indicative of the size of the alternator. For example, my '99 GMC utility truck, complete with full DOT warning lights, came with a 100 amp (stupid choice on the part of GMC and the shop that added the utility body and lights, but it was what it had until I upgraded it). Also, most inverters produce a "modified sine wave" (AKA - square wave) and there are many things that do not run well, or at all, on anything but a true sine wave. And what if you need 220v, as many pump motors do, or three phase? You're SOL trying to get that from an inverter. It's much, much simpler (and no danger of a short from your patched together wiring job causing an arc and blowing you sky high) to use a simple hand pump.
I agree only the more expensive inverters produce 240 or 3 phase. The majority of the retail pumps though are 120 volts and not 3 phase due to the extra cost of wiring. Most pump motors will work on dirty power for a while.
Also the key point is that you do not tap in at the pump. You tap in at the breaker box which is always well away from the pumps. Hence any arcs which if the power is off will not happen will occur well away from the pump.
In addition if a 15 amp circuit breaker is needed that means the circuit will draw less than 15 amps typically less than 10 amps. So you may get a 15 amp surge on start up but the power draw will be less. Thus the inverter will draw the extra power from the battery on short term basis. In the mean time the alternator will supply power. An 85 amp alternator will produce 1,020 watts which is 8.5 amps @ 120 volts. That should be enough to run most pumps. A 100 amp alternator will supply 10 amps @120 volts.
It takes about 750 watts of power to produce 1 horsepower.
This is a link to a typical modern pump's installation manual. Note page 4 shows shows power requirements at either 120 or 240 volts but a total only 660 watts needed. This requires only about 55 amps through the inverter.
http://www.bennettpump.com/uploads/file ... 111102.pdf