THE PROBLEMS WITH JAPANESE ALTERNATORS FOR 4X4 USE

The most popular vehicles for 4x4 users are, in the main, fitted with Nippon Denso or Hitachi alternators usually with outputs between 55-70A. These alternators are fine for the purpose of keeping all the vehicle’s standard accessories operating - even at night, in rainy conditions and with the radio at maximum volume!

However, it appears as if the manufacturers of these vehicles, although marketing them as sturdy 4x4 and versatile modes of transport, have failed to recognize that, in Africa and other hot climes, owners like to install fridges! Thus the alternators are not designed for these applications – which may not represent the majority of course, as people in Nordic countries don’t see too much use for a fridge, but would probably be grateful for ‘de-frosters’!!

In Africa, the drivers of vehicles installed with these Japanese alternators often complain, understandably so, that their auxiliaries never appear to be fully charged – even after many hours of driving at cruising speeds. This is the case even for those lucky enough to have a 120A alternator fitted as standard – such as some of the Mitsubishi Pajeros.

These Japanese alternators have several drawbacks when attempting to ‘modify’ them to produce a little more power to keep the auxiliaries charged up:

• Their voltage regulators are usually set at 13.9V-14.1V. Most deep cycle batteries require a minimum of 14.3 and some can happily take a volt or so, more than that.
• Their bearings are not strong enough to cater for the extra power and RPM which such modifications usually require in any meaningful power upgrade
• Their diodes are also under-‘specced’ for any major improvement in power output.

So, for those of you wishing to obtain reasonable performance from your installed fridges and their supporting auxiliary batteries; I’m afraid your only option is to swap your alternator for one of the high output units (such as the Maxamp range) with voltage regulation set to match the application; with bearings capable of taking the extra RPM and loads, and diodes that can support such increased power outputs. Unfortunately, that’s the price you have to pay for keeping the Beers cold throughout your trip!

Incidentally, the Optima battery range of Yellow Top Hybrids are ideally suited for 4x4 applications where a power upgrade has been installed because they can be charged (and discharged) much faster than standard calcium deep cycle batteries.

For those of you who do not travel too much with their vehicle, and only employ it merely to get to any given destination and back; there is the solar charging option, of course.

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