Cord Management on Grid-Connected Electric Tractors and Mobile Equipment

[Phil Timmons]

A kilometer of cord is only 6/10 of a mile. Up here in northern Indiana, for example, most fields are divided into 80 acres. They're 1/2 mile long by 1/4 mile wide. So there's 8 - 80 acre fields in a square mile, or 640 acres. You could put 1 tap in the center of the square mile and hit all of the 640 acres with a 1 mile long cable if you went straight to an edge, then 90 degrees in either direction.

You'd only need 1 tap for every 640 acres.

Deere said in that video that the length of the cable is scalable. So it's very doable.

Got that part. One thing we noted was that to get to center of anything, you had to go under an edge, so that generally meant an edge connection point was generally a do-able thing, as well.

What is your take on the mystery of going barn-to-field, or field-to(distant)-field? That is where we were thinking some small-ish battery drive was desirable? or maybe tow the thing? So you did not have cord stretched out between two areas?

 

[MossRoad]

Tow it to wherever you need it if it's farther than a mile from the barn. Average farm size in Indiana is under 300 acres, or less than half a square mile.

Average farm size in the US is under 450 acres.

Anyhow, I'm sure it will fill a niche where long distance roading of a machine isn't necessary. And who knows?

 

[Phil Timmons]

Tow it to wherever you need it if it's farther than a mile from the barn. Average farm size in Indiana is under 300 acres, or less than half a square mile.

Average farm size in the US is under 450 acres.

Anyhow, I'm sure it will fill a niche where long distance roading of a machine isn't necessary. And who knows?

Agree on towing. I am thinking driving it anywhere leaves you picking up the cord?

Any thoughts on the HP size? I had misquoted up above. This is actually doing 100,000 Watt (about 100 HP) for the Traction portion, and 200,000 Watt for the accessories.

I am not seeing applications that large, unless they figured that they had to over-do and then step back down -- about like Tesla, in that regard. We are looking at 100 HP (about 100,000 Watts) on board, max for everything.

 

[herm0016]

100 hp is 74500 watts. by definition. do you really need 25% overhead? electric should be more efficient than that.

 

[Phil Timmons]

100 hp is 74500 watts. by definition. do you really need 25% overhead? electric should be more efficient than that.

Good question. It is olde skool rule-of-thumb math. NEC Code Book has a table with exact numbers.

746 Watts = 1 HP is the non-existent ideal 100% efficiency model.

Real World:
Typical motors have around .9 or 90% efficiency.
Typical induction motors have around .9 power factor. (some conditions are much worse)

Put those together and you have .9 x .9 = .81 or around 80%.

So 746 watts /.8 = 932 Watts.

So if we allow (in practice) 1 HP = 1000 Watts, these are reasonable (and very fast and easy math).

In practice, I will be with all VFDs (Variable Frequency Drives), so that helps things, as well. But I am still wondering what they are doing with that much HP on board? 200 HP for accessories? A 20 foot rototiller? Usually a PTO load on a typical tractor?

 

[MossRoad]

You need to be able to pull stuff (drawbar pull), and you need to be able to power implements (PTO HP).

 

[herm0016]

besides bailing hay and mowing, i'm struggling to think of implements used in a larger operation that are pto driven and not hydraulic/electric/ground driven. for implement drive, like a planter you need maybe 50 or 60 gpm at 2250 to 3k psi ... so like 75 hyd. hp?