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Heya!
I am looking for a way to have my second truck alternator charging my lithium powerwall.
Currently I have a multiplus, a bluesolar for the solar panels, a BMV, and a CCGX setup.
Would it work if i get a second MPPT and use the alternator output as source for the MPPT?
Or what would you advise?
Cheers!
Tom
I found https://www.victronenergy.com/dc-dc-converters/buck-boost-dc-dc-converter-25a-50a
My alternator is 24V, 70A. So to use the full capacity of that alternator I guess I would need a beefier one.
Or find peace with only using 50A of it.
I want to do a similar thing. Here's what I know so far:
- The Buck Boost converter would work well, it will cope with varying voltages e.g. I have 12v vehicle, 24v house battery bank, so that's a 'boost'. It will go the other way. The advantage of this is it has vehicle on sensing in it (by vibrations), so you don't have to wire in a ignition relay. Downside is it is expensive compared to simple DC-DC converters. This is also a dumb charger, it doesn't know about lithium charging profiles, but I'm not sure that's really an issue as lithium is more forgiving to charge.
- Using an MPPT controller should work OK IF your vehicle is a greater voltage than the battery. To start working, the MPPT controller needs an input voltage at least 5V above the battery voltage. i.e. going from 24V vehicle to charge a 12V battery. I like this idea because then it uses the intelligent charging profiles.
- Another option is to use an inverter from the vehicle battery, run 120 or 230V to the 'shore power' input of a multiplus. Again then you're using the quality battery charger inside the multiplus. Inverters are cheap. And you can run a long cable without much loss. You'd need some timer relay on the vehicle ignition so you don't draw power immediately on startup. Need to wait for the vehicle to be going first.
- Could also use a dumb DC-DC converter hooked up to relays as well.
- Victron have mentioned in the forum they are working on a DC-DC battery charger for these kinds of situations. So I'm kinda waiting to see what they produce. Not much known yet.
Hope that helps!
I don't see why you can't use a second MPPT for this. In fact it is cheaper than the DC/DC chargers Victron sells.
also check this related topic. I made a post about using an diesel engine ran alternator as solar input for the mppt:
https://community.victronenergy.com/questions/34111/dc-generator-as-input-for-smartsolar-15085-1.html?childToView=36843#answer-36843
