Which MPPT Charge Controller? Which B2B?

[gianaleo]

Solar question regarding VanLife here!

We have 400ah 12v lithium Renogy batteries.
We’re aiming for 600w of solar = (200w, 12v, 16.6667a, panels x 3)
Wired in Series = 36v, 16.6667a
Wired in Parallel = 12v, 50.01a

Based on these specs, are we good to get the 100|30 Victron MPPT charge controller and wire our panels in series? Or should we go with the 100|50? From my understanding, the first number (100) is the voltage it supports up to (so 12v, 24v, 36v on the panel wouldn’t matter?) and the second number (30 or 50) is the a, and you want your panels system to be as close to but not over this number.

Any advice for a b2b for the Promaster 2500 based on these numbers would be greatly appreciated also! Something that will give us a decent charge but definitely not affect our alternator.

Thank you!

 

[snoobler]

The first number is the peak panel voltage. The second number is the CHARGE current, not panel current. The Victrons have a separate current rating for PV input.

600W/12V = 50A, so you need a 50A charge controller.

Renogy and Victron make DC-DC chargers. Additionally, this device:

LiFePO4 Battery Isolation Manager (BIM)

LiFePO4 Battery Isolation Manager (also known as the BIM) monitors voltage and connects and disconnects batteries when needed. Click here to read more!

battlebornbatteries.com

Runs the alternator at about a 50% duty cycle.

 

[Chris61]

I like the Victron150/45 and larger solar regulator as you have the option to remotely turn it on/off, very handy for some BMS's

 

[mikefitz]

We’re aiming for 600w of solar = (200w, 12v, 16.6667a, panels x 3)
Wired in Series = 36v, 16.6667a
Wired in Parallel = 12v, 50.01a

Significant error here, '12v' so called panels have a open circuit voltage of around 22 volts and a maximum power voltage around 19 volts. A 200 watt Renogy solar panel has 36 cells, typical performance will be open circuit volts 22.5 volts, at maximum power, current 10 amps and voltage 19 volts.
In series the controller will have a maximum of 45 volts and a maximum current of 10 amps at the input. With a parallel connection the values would be 22.5 volts and 20 amps.

Note that the MPPT solar controller is a power converter, takes in whatever power the panels can deliver and converts within its design limits to a voltage suitable for the battery and current it can accept.

With the Victron 100/30 you are over paneled but within the input limits. The maximum current output into the batteries will be 30 amps compared to the 40 to 50 amps (in theory) possible with a MPPT controller.
The 100/50 will convert the all the panel power to useful charging power.

There are differing opinions on the maximum power that can be taken from the alternator. Where a direct connection may work, long term reliability is a concern together with no control of charging volts and time.
Battery to battery chargers with output currents of 30 amps upwards are available with charge profiles for lithium.
There are also dual function chargers available that combine alternator charging and solar charging in one unit. This does not give as much flexibility as separate units and limits the solar input to parallel connection of panels with input maximum volts in the order of 25 volts. Renogy and others make such a unit.

Mike