GL 300tdi Defender, Discovery & RRC Twin Alternator Mount

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  • Regular price $199.99

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.

Weight :- 2KG

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

This alternator mount comes fully welded, but will require painting.

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 YLE10113 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.

Order a Spare Belt to suit this kit (one Belt is supplied with our Alternator Mount kit)

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 run 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, 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, a single alternators regulator cannot separate between 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, this way the second batteries charging load is handled in the same way as any other electrical accessories power demand on the main battery.
    The disadvantage to this is that a DC to DC charger can only supply up to about 20amp maximum charging current where as 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 alternators regulator determine the charging demand of each individual battery.
  • You can manually link both batteries together in parallel to maximise 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.

Battery Maintenance
An alternator in normal use will replace charge that you are using, it won’t charge your batteries up to full peak charge, to do this you need to use a specialist mains powered maintenance trickle charger that will slowly and gently charge your batteries up to peak capacity. This is particularly important with batteries like Optima Yellow tops, they will take a lot of abuse, they can be deeply drained of charge but they must be properly recharged back up to peak capacity after to avoid premature failure. This can only be done by using a slow trickle charge, an alternator cannot do this on its own, it can take a day or two to fully recharge a heavily discharged deep cycle battery using a specialist trickle charger.

Wiring :-
The kit is supplied with a wiring diagram and this can be download in my Fitting Instruction.
Earthing the alternators is very important in my opinion, this is how you get 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 a poor earth.
What you must remember is the batteries are just an electric storage tank, its the alternators that do the hard work, the quicker you can charge the batteries the more power you will have, this is why my alternator wiring kits are very heavy duty as well.
Fitting a relay as a secondary ignition is important in my opinion due to you having 2 wiring circuits so it keeps everything separate.