Comments on: Prius vs small non-hybrid car

By: etbe

etbe — Wed, 08 Oct 2008 12:11:30 +0000

Fred: The design of the car in question is not based around simply putting batteries in series (to increase the Voltage), there are also parallel sets to increase the current capacity. So removing one battery will remove a fraction of the current capacity.

Also one possible way of removing a cell from a live system (IE not using the isolator switch) would be to put a diode across it. With the diode the voltage across the battery would be about 0.6V, even at 10A that shouldn’t cause too many problems.

By: fred

fred — Wed, 08 Oct 2008 08:59:25 +0000

“A friend is creating his own electric car (replacing the engine of a small car with an electric motor). He is using a large number of small rechargeable batteries. Presumably removing one 10V battery at a time from the array would not be a great challenge, so that would be one safe way of disassembling it.”

If the rest of the circuit is complete and you disconnect ANY battery, the full voltage minus the individual cell pack (in your case, 10v) will be across the disconnected wires.

Its still just as dangerous. An understanding of basic electronics, how cars work and most importantly, reading the service manuals is adequate to remove and refit HV components in hybrid vehicles.

By: etbe

etbe — Sat, 05 Jul 2008 01:49:13 +0000

GregB: There are many factors which go into the decision of which car to buy, and everyone has their own weight that they assign to those factors. For corporate use price is a major issue. For a courier company, if the car is being driven 100,000km per annum the equation would be much different.

For luxury cars things are different again, being more expensive can be seen as a good thing.

By: GregB

GregB — Fri, 04 Jul 2008 08:26:28 +0000

(So what I was trying to say, which has been alluded to, in previous posts: different cars for different people, for different reasons..)

By: GregB

GregB — Fri, 04 Jul 2008 07:04:50 +0000

It interests me that so much effort is put into comparing Hybrid versus non-hybrid, based on price.

If prices were the only factor in purchasing any car, then surely no-one would buy a BMW, or any luxury car?

I have just purchased an ’05 Prius, and am enjoying it. It was bought for fuel economy and green-factor, knowing that hybrids are merely a stepping stone to much better technology that hasn’t been released yet.

GregB

By: etbe

etbe — Wed, 11 Jun 2008 09:56:47 +0000

Colin: Actually I’m quite familiar with electrical principles. I merely can’t find a reference for the current used in a spark plug and the duration that the current can be sustained (does it compare with the 5ms used in a defibrilator?).

I’ve just spoken to an electrician about the issues related to 500V @ 100A. The real problem with DC apparently is it’s ability to sustain an arc. With AC there is a period of zero voltage which helps in breaking an arc. Of course this means that you just have to not create the arc in the first place.

One particular issue is that of switches. A switch that is used for AC is not going to be suitable for DC of the same voltage as the arc can be sustained inside the switch. With some common configurations of solar PV on home roofs the voltage from the array of PV panels is over 300V. I know of one installation where the installer advised the home owner that if the switch connected to the solar panels was turned off while the sun was shining brightly then the switch would probably be destroyed!

A friend is creating his own electric car (replacing the engine of a small car with an electric motor). He is using a large number of small rechargeable batteries. Presumably removing one 10V battery at a time from the array would not be a great challenge, so that would be one safe way of disassembling it.