The 24v versus 12v ALWAYS sets off a great debate, so I might as well throw in my 2 euros worth. Before I get into my stride we need to clarify a couple of items. First, Australia AFAIK got a 12v system, I do not think they see mega cold conditions so that is a good example of market targeting. I am also a firm believer that if you are going to travel to remote places in a private vehicle then look at the mods/systems the Australians use, they are the masters of long distance travel IMO. Secondly Europe, you can be in serious extremes of climate within a couple of days driving so -40 in Russia easily accessible from the UK in a very short time. Toyota were going to make sure the 80 started no matter where you were, just look at the cold start facilities of the 80, despite direct injection no glow plugs needed but they were fitted anyway, idle up and variable diesel timing also aids starting, and then the 24v starter, throw in a fuel heater, all in all a package that WILL start regardless of how cold it is. 24v is a better way to get power from one point to another the volts being the 'pressure' if you like, so less current draw results in the ability to use starters with a higher Kw rating, the 24v starter has 4.5 kw as opposed to the typical 3.0kw from the 12v (diesel) versions. So without doubt the starters are more powerful, thick engine oil, with low batteries and you will still swing the engine over. Since the design of the 80 (reputedly started in 1985) everything automotive has improved, but one area that has come a long way is batteries. I have two 900 amp marine batteries in mine and yet 20 years ago for the same size they would have been perhaps 600 amps? Also parasitic draw had for awhile dropped with clocks becoming digital and so forth. Now that draw is going back up with ECU's being employed in all vehicle systems, so battery manufacturers have had to respond (look at the availability of 16 volt car batteries for example). When Toyota released the 100 what did we get....a 12v starter system, (two batteries in parallel equals 12v but doubles the amperage) the new style matrix pre heat system warming the incoming air sufficiently to help the engine start along with a different gearing on the starter dog, this means the 24v system in effect no longer required and this system is an admission by Toyota that this is the case.
For ME and I mean ME, the issue is not necessarily about reliability of the system as a whole but as I like to travel and camp in relatively remote areas, I like an element of redundancy and if a battery fails on the 24v system the car will not start, I have tried it and there is a lot of clicking and clunking but it will not swing the engine. Next, the two batteries are in parallel at ALL times except when the starter is engaged so, if a battery fails or you simply leave the lights on, it will drag the good one down, you are now stuck with TWO dead batteries, for me that is a totally unacceptable situation, so I went the 12v route.
I now have two batteries in parallel at all times except, in the event that one starts to lose power for whatever reason, left the lights on, or a faulty cell for example then the split charger will disconnect them automatically so there is always one fully charged battery. When I return to the car and find a flat battery I press a button and start the engine, the split charger will engage and recharge both batteries. As I use a 'dual sense' charger the solar panel will also charge both batteries, so the only time my batteries are not being charged is at night when the engine is off. I can at any time using the remote switch inside the car choose whether I want the batteries in parallel or separated or on 'auto', this is a great facility, if I am inclined I can force the separation of the batteries and then in the morning simply look at the battery monitor, it will indicate the charge level on both batteries, any weakness in one of them will be obvious as terminal voltage tends to fall over a few hours if a battery is on the 'way out'.
Sorry that is long winded but I have a car with a system that:
Will start on one battery.
Can jump start itself.
Is capable of isolating one battery automatically in my absence.
Has a facility to monitor/test/compare the two batteries individually.
I have an on board shower, I cannot go without a fridge as the heat messes up my insulin, plus there is other stuff that uses power. I do have another battery in the rear of the car that runs these things without impacting the cars start and run functions, I can switch that in any time I like to the cars charging system, I have also fitted a 150 amp alternator, so no worries there. Also due to my paranoia of being stranded I also have a manual car that even if all the batteries were knackered, I could roll start it and still drive to civilisation! As I pointed out this suits ME and my personal circumstances, if you never get into places where a simple battery failure can be the difference between life and death, never out of mobile phone range and so forth then leave it alone as the 24v system is great IMO.
regards
Dave
