140amp UPGRADE alternator over the stock 80amp?

I am converting my van into a little adventure machine with a house battery.  I scored an AGM battery for the house from a local van building outfit for cheap but plan on upgrading to Lithium Ion once they drop down to the $500 range at bigger capacities in a couple years.  

I found a listing on ebay from a UK company that sells 140amp upgrade alternators and wanted to see if anyone else has gone this route and whether not they encountered any issues.  Appreciate the insight.

Diesel or petrol van? If diesel be aware that there is a vacuum pump combined with the alternator for operating the brake booster, you'd need to be sure the replacement had that or make some other arrangement for a vacuum pump.
Also you won't be using a Lithium Ion battery! What you're meaning is a Lithium Iron Phosphate battery (LiFePO4 for short; very different chemistry and charging requirements from Li Ion!)
You will have a difficult time arranging for the correct charging of the LiFePO4 battery as they need to be treated quite differently from Lead Acid batteries otherwise they will have a very short and expensive life, however you may find some product which can take the input from the alternator and regulate it to correct levels. As yet I haven't found one, at least not at a reasonable price point.
For your AGM battery you can probably just fit a voltage sensitive relay and all will be well.
Before you do any of this please do a LOT of online research into the charging and maintenance of lead acid and LiFePO4 batteries, believe me it is a huge can of worms, there's so much more to it than you'd at first think.

It is a diesel.  The alternator I found mentions direct compatibility with OEM part number:  27060-67040 80A (discontinued) which was replaced with 27060-67120 80A.  I will verify with the seller.

As for the battery, my bad on mentioning ION.  I come from a tech history and threw the Ion in there out of habit.  I will be replacing the AGM battery with a LiFePO4 down the road.

I appreciate the concern that I am not going into this wildly.  I will be using a MPPT DC-DC charger along with a solar panel to help with non-bulk phases when parked.  I have multiple local van electrical resources that have been guiding me at my phases in equipment selection and implementation.

Great, sorry I wasn't trying to be an ass I would just hate to see a forum member jump into it without the necessary knowledge.
As it happens I have not yet found a way to get ours to work the way I want it to, even the very expensive Redarc systems don't do everything I want, and do a lot of things I'd never want like Bluetooth for example.

No worries. I completely understand where you are coming from. On a side note, I'm pretty sure the 1KZ-TE engines of my vintage don't have the vacuum pump integrated with the alternator. On mine, it is located on the other side of the engine below the timing gear.

Just had a thought: at least you don't have a 3L like I have, I suspect that trying to generate 140 amps from a 3L would just about stop the vehicle moving, they're slow enough with the standard engine loading!

brewera wrote:

I will be replacing the AGM battery with a LiFePO4 down the road.

The issue with Lithium is that they draw a much bigger charge current....
... and the issue with a 140A alternator, or even an 80A, is that at idle, it will overheat and fail.So what people do is feed the alternator output into a current limiter (Sold as a BMS, as you also want to control the voltage very carefully).

My own feeling is the the important bit is 'energy in' >= 'energy out', the capacity of the battery is secondary .

Of course to drive to a location and requiring N days of power is solved by a bigger capacity, but in general even the biggest will go flat.

Incidentally, the standard battery is in a 'tube', so you could consider the space underneath that, with a metal bracket you could hang a (shallower) leisure battery there, nicely out of the way.

But not a lithium, as it would get too cold, but an 20mm odd insulation pad underneath would probably be a good idea anyway.