Land Rover D1 Custom Alternator Setup?

[benedmonson]

I recently installed dual Optima's in my 98 D1. My local off-road shop owner now suggests that I need to install a custom GM sealed brush model that at idle will provide approx. 100 amps of charge. I was also told by the expert that the alternator would provide approx. 150 amps of charge at 1500 RPM's. He has a buddy who is supposed to be an alternator genius, for $175.00 he will build me this alternator for my D1. I will be doing lots of long trips where I will be discharging my alternate battery every night by using my CPAP machine and WAECO fridge at the same time. So what would be nice is to start up my vehicle and recharge my batteries. I have installed 2 great Optima batteries and a high quality isolator just want to get the alternator right now. Does anybody have any expert opinion in this field????

 

[oonimog]

You should check the specs of the isolator carefully because many (especially the cheaper ones) have a voltage drop across them. It may not seem like much but it will keep the batteries from being fully charged and will shorten battery life. I prefer a solenoid that isolates the batteries when the engine isn't running and closes to charge both batteries when the alternater is producing juice.

To ensure you'll never be stuck with a dead starting battery, I would use it for starting only and use the aux. battery for all other nightly power needs. You could use a standard starting battery (red top Optima) for starting the engine and a deep cycle battery (blue top Optima) for your other needs.

Pete

 

[benedmonson]

The isolator is a Cole Hersee, suppose to be a high quality product. Not sure about the voltage drop on it. I do have the Red Top Optima for my starting only and a yellow top Optima for my auxillary battery.

 

[gjackson]

Ben, I'm running a similar setup (hellroaring isolator, optima red for car, yellow for house) with a stock LR alternator. At idle (diesel) I get no charge. The obvious solution to me is to use a hand throttle to up the revs when you want to stay stationary and charge.

If you go the custom alternator route, check the specs carefully. And see what can replace it if it goes out on a long trip. It sucks to rely on a piece of kit you can't replace in the field. I assume a custom GM unit could be replaced by a stock GM unit, but then you are back to no charge at idle.

How much power will the CPAP and fridge draw together?

cheers

 

[benedmonson]

Ben, I'm running a similar setup (hellroaring isolator, optima red for car, yellow for house) with a stock LR alternator. At idle (diesel) I get no charge. The obvious solution to me is to use a hand throttle to up the revs when you want to stay stationary and charge.

If you go the custom alternator route, check the specs carefully. And see what can replace it if it goes out on a long trip. It sucks to rely on a piece of kit you can't replace in the field. I assume a custom GM unit could be replaced by a stock GM unit, but then you are back to no charge at idle.

How much power will the CPAP and fridge draw together?

cheers

The fridge is the 50 Waeco that was tested in Overland Journal (was called the 40 in the test, but was actually a 50 litre) so it draws like 3 amps and the cpap draws no more than 3. So thru the night together they will draw 2-6 amps on my yellow top. As for the GM alternator it should be able to be rebuilt where ever I go I hope???

 

[Clark White]

Slightly off topic, but I am thinking of running a triple battery setup. I would have one just for starting, then two aux to run everything else (I got the idea because I found two perfect sized battery spaces in the corners of my bumper). Would that work, and would I need a custom alternator, or just a high output for that?