Is there a reason for too big of wire?

[evblazer]

Im trying to figure out if there is a reason beside decreasing resistance to use too large of wires?
I have a hustler zeon mower which uses 4 12v Trojan 31 flooded batteries in series for 48 volts. The odd thing to me is it uses 3/0 awg wires between the batteries and to the controllers then much smaller reasonably sized wiring to the motors. I can't understand the reason for the huge wires on the batteries when to make their range target It would have to pull around 50amps which is what i show on the eMeter with the standard blades.
I'm putting in a new pack of leaf cells and wondering if I need to keep such large wiring?

 

[spinningmagnets]

Inductance?

The three motor phase wires can be long and "just adequate". The two wires (red/black) from the battery to the controller should be short and fat.

 

[major]

3/0 cable is overkill in my opinion. However those cables carry current for all 4 motor plus a dc converter. And I didn't see a fuse in the battery circuit. All the motors (AC) run from controllers which each have current limiters. If all motors are maxed out, battery current could go pretty high. Being a consumer product they likely had to test worst case without fire in the battery box. Extra large cables would help and might be needed to survive until battery is drained. Large cables and big lugs pull heat away from the battery terminals which are failure prone. So I'd leave the 3/0 or install battery fuse and smaller gauge cables.

major

 

[evblazer]

I had always thought it was fear of someone's reaction looking over the mower for sale and seeing some tiny wires and thinking it was weak. Thank you it is good to know there are some other reasons. I've been tracking amp usage for a while and the highest ive seen is in the 90s mulching thick tall grass with blades that I got rid of. My normal mowing blades average in the 30s in normal mowing at a decent speed and with a mulch kit on with mulching blades im running in the 50s.

I'm planning to fuse it right after the battery before the shunt I added. I may also be able to cut 3+ feet of wiring because my new packs connections are different. Hustler had this weird loop going under the whole box that holds the batteries and then returns in the.box all the way to the back for the negative side. Maybe it was some other safety thing so it could be cut from the outside or an easy layout to replace/disconnect the batteries safely.

If I need to make a new a new short run 1/0 still has plenty of headroom I think.

 

[dogman dan]

It could be vibrations, and or bending when the battery gets replaced makes strands break on the battery wires at the connector, so the fat up so that when half are severed, it still is plenty. It does sound like darn fat wire.

 

[evblazer]

It is some pretty big welding wire with some huge lugs. I'm planning on reusing as much as I can but it did get fuses to put right up on the battery output.
Here is what the fuses look like not my wire.

 

[SniperGaulois]

lightness, aluminium is more conductive for the same weight of metal, so if you have fat alu wires you will save weight over thing copper ones.

 

[liveforphysics]

Sometimes excessive cross section cabling is used to be a heatsink for the devices terminated onto it.

 

[atarijedi]

They are probably following engineering standards for wire gauge given the amount of current it will be carrying, but based on AC numbers, not DC.