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Originally Posted by thingstodo
I agree. I don't know much about fork trucks or their batteries. I heard from the service guy I was talking to that they get traded in when they won't last a shift, or half a shift. He said that there is still some life in them when they are traded in for the core charge.
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Brand New Lead Acid batteries are usually less than about ~40wh/kg ... these older ones they are replacing will most likely be significantly less than that ... but you can test them easily enough when you get them.
Given what you know already about the batteries ... 12V and weighs about ~150 pounds ... that means it is safe to assume when they were new they had something around ~230 Ah... until you test them to better quantify where they stand now it is reasonable to expect them to be somewhere less than ~80% of the original capacity ... which means , until you can quantify differently I would expect these batteries to offer less than ~180 Ah @ 12V ... when discharged at a ~20 hour rate.
The rate is important because of Peukert effects on the amount of usable battery capacity at a given discharge rate.... Depending on the type of Lead Acid it can range from about 1.05 to 1.6 ... The high Amp rate needed for the battery side for this DC-DC step up concept forces a large Peukert hit to the useful battery capacity ... a far larger Peukert hit than one would see from a higher voltage lower current battery system for the same power output ... if we assume a conservative Peukert k value of ~1.2 ... @ ~500 Amps we might expect to see something around ~80Ah usable ... 12*80=960*6= ~5.7kwh expected ... of course you can improve the accuracy of that estimate with some better quantified specs from testing these batteries to get on real numbers and not just estimates.
You should not be at full power 100% of the time ... so if your vehicle can manage about ~4 miles per kwh average vehicle efficiency ... you might expect to see around ~23 miles of range ... +/- YMMV.... if you do 100% DoD ... which is a bad idea for Lead Acid battery service life... and you will also loose additional usable range when the batteries get cold... Maybe somewhere around ~12 Miles per charge would be reasonable to expect in the winter time.
Quote:
Originally Posted by thingstodo
It is a GE industrial motor, 575V, three phase, medium efficiency, rated 1766 rpm at 36.8 amps. Class B insulation (affects maximum temperature), service factor 1.15. Totally enclosed, fan cooled. This thing weighs a lot - maybe 500 lbs? I'm not really worried about this motor overheating. It will take a lot more abuse than I can dish out.
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Extra Large Motor + Extra Large Controller + additional inverters = a lot vehicle space and weight is getting used by non-battery / non-energy storing devices.
But it should be functional ... I still have some doubts about how practical it will be.
Quote:
Originally Posted by thingstodo
The VFD is quite a bit over-sized. It is an Allen Bradley 1336 Plus II (circa 1998) rated at 302A, 150% for 30 seconds.
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Well that has a lot of documentation for it.
Link