300Tdi Twin alternator mount

1 x Twin Alternator Mount & Fan Belt DIY

Part Number:- GL1105, 300tdi Defender, Discovery & RRC Twin Alternator Mount – DIY

Manufacturer:- Gwyn Lewis 4×4

Fits:- 300 Tdi Defender / Discovery / RRc Engines

This kit consists of:-
1 x Alternator Mounting Kit.
1 x Fan belt, 4PK795 / 4PK803

This alternator mount comes fully welded and painting in blue

This mount allows a second alternator to be fitted to charge auxiliary batteries instead of a split charge system.

An original 300Tdi 12 volt alternator can be fitted or we can supply a high output 12 Volt 100 Amp A127i AMR5425G with 7rib 65mm pulley.
We recommend using an A127i Alternator, these have an internal cooling fan blade, an A127 Alternator has an external cooling fan blade which can fowl on the tensioner arm of our mount, an unshielded external fan blade could also be a hazard.

This mount fits in the position of the air con pump and is supplied with a fan belt.

For use in expedition vehicles or in any vehicle where you want to power auxiliary equipment using a second battery, up to more extreme use where you need to maximize charge current on winch challenge vehicles.

What you must remember is your batteries are just an electric storage tank, it’s the alternators that do the hard work, the quicker you can charge the batteries the more power you will have, even with a split charge system you still only have one alternator supplying your electrical system.

The Benefits
Two alternators using separate charging circuits are far better than a split charge system running off one alternator.
Most split charge systems are basically just a switch that automatically joins your batteries together in parallel once you start your engine and your main battery starts receiving charge.

• With a split charge ideally both batteries want to be identical, different batteries charge in different ways, that’s why ideally they should be the same type, same age and in the same condition. For example, an AGM Deep Cycle Battery like an Optima does not want to be charged alongside a regular car battery, they take charge in different ways, and a single alternator regulator cannot separate the charging needs of two different batteries simply linked together in parallel.
• A Better way to charge two batteries with only one alternator is to use a DC to DC charger, as it totally separates the main battery from the second battery. These are becoming more common with smart charge systems and special batteries. The disadvantage to this is that a DC to DC charger can only supply up to about 20amp maximum charging current whereas a second alternator can supply 100amps.
• Two alternators keep things simple, no extra control units, you have two completely separate charging circuits so different batteries are no problem at all, you could have one high cranking amp starting battery as your main with a deep cycle battery as your second for powering axillary/expedition equipment. Just let each individual alternator’s regulator determine the charging demand of each individual battery.
• You can manually link both batteries together in parallel to maximize charge current to high current draw equipment such as winches on winch challenge vehicles, this should only be done when drawing large current, charging circuits must be separate during normal use.
• By having two alternators, if one went down then you still have another to keep you going.

Wiring :-

The kit is supplied with a wiring diagram and this can be download in my Fitting Instruction.
In my opinion, earthing the alternators are very important, this is how you get a maximum charge out of your alternator, high output alternators can’t always earth properly through the bolt holes, I even earth the standard alternators as the mountings are bolted to a painted engine block and rust and corrosion over the years will cause poor earth.
You must remember the batteries are just an electric storage tank, it is the alternators that do the hard work, and the quicker you can charge the batteries the more power you will have, this is why my alternator wiring kits are very heavy duty.
Fitting a relay as a secondary ignition is important in my opinion due to you having 2 wiring circuits so it keeps everything separate.