Electric conversion: Project ForkenSwiift

[Silveredwings]

Originally Posted by MetroMPG

I too have read about the hazards of loose connections. You've no doubt also seen the current "lead" story on evconvert.com

Here's a question: can you go too thick with cabling, etc? Is too much of a good thing a bad thing in that regard?

No I hadn't seen the new evconvert article yet (I check it almost daily), thanks for letting me know.

Non-superconducting wires all have some finite amount of resistance and so will cause some amount of voltage drop across them (proportional to current). This loss of wattage amounts to loss as heat. Note that this wattage doesn't need much voltage when the current is high (ex. 1.88V * 400A = 752W or more than 1 hp).

Somewhere there exists well proven recommendations for the guage wire for a given current. As for voltage, thickness of wire is irrelevant, but thickness of insulation is, but you'll not likely exceed the wires' voltage ratings.

There's no electrical reason not to go too thick with your cables, but at some point it adds too much weight and expense (for both cables and connections). Copper is heavy and I don't recommend aluminum wires. Very heavy cables may also be more diffucult to work with.

[JanGeo]

Cables that are a little on the light side will protect you from overloading the batteries by providing you with a little series resistance and heat when things start to go wrong. The input shaft of the tranny is designed to handle the load of the clutch being dumped with a ICE reving so you have the torque load and the inertia load of the flywheel to consider. If you knew the torque output of the electric motor or at least the Torque constant NM/AMP or voltage constant rpm/volt you could get a good idea of the torque output. Chances are that you are NOT going to exceed the tranny limits unless you start pushing 1000+ amps into the motor. Actually if you know the rpm and watts you are pushing into the motor you can figure out the HP and the Torque but then you would be running it and would already know. Only consideration with the coupling is the shifting without the clutch when moving . . . them syncros are going to get a workout!

[Silveredwings]

Originally Posted by JanGeo

Cables that are a little on the light side will protect you from overloading the batteries by providing you with a little series resistance and heat when things start to go wrong.

That's an interesting point. There's also the internal resistance of each battery to add into the loop which also has a current limiting effect.

[MetroMPG]

[quote=JanGeo]The input shaft of the

[MetroMPG]

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[Silveredwings]

Wow, out through the bottom? I haven't seen that since the old beetles.

I once took an engine out using an old swingset and a come-along, another with a chain over some garage rafters with the come-along, and a couple with a shop crane. The most memorable was the MGB engine I took out with another guy by looping a chain across some head bolts and sticking a long log through the chain. We lifted each end of the log up, and hurled the block up and over the radiator support and down into the dirt (I only wanted the the engine for the crankshaft).

[GasSavers_DaX]

Originally Posted by Silveredwings

Wow, out through the bottom? I haven't seen that since the old beetles.

It's how most shops remove engines...for Hondas anyhow.

I became familiar with the "out-from-under" trick with my 914...there is NO way to get it out from the top.

[onegammyleg]

Originally Posted by DaX

It's how most shops remove engines...for Hondas anyhow.

I became familiar with the "out-from-under" trick with my 914...there is NO way to get it out from the top.

Most front wheel drives engine/transmisions go out the bottom.

[onegammyleg]

This would fail a police examination immediately in Australia.

[Silveredwings]

Originally Posted by onegammyleg

Most front wheel drives engine/transmisions go out the bottom.

Huh. I definiately had to 'lift' the Passat engine to do the waterpump.