Bavaria Yacht Info

Member Forums => Bavaria Yacht Help! => Topic started by: elias on December 26 2022, 08:51

Title: Adding two chargers in one pv array
Post by: elias on December 26 2022, 08:51

Merry Christmas to all !
Had anybody tried installing 2 mppt chargers ,  connected on the same pv array , for charging 2 separate batteries ?

Title: Re: Adding two chargers in one pv array
Post by: IslandAlchemy on December 26 2022, 11:32

Why not just buy a dual MPPT controller?

Title: Re: Adding two chargers in one pv array
Post by: elias on December 26 2022, 11:38

I have already 2 mppt.., is very tough for me mentally to buy a 3rd one , well if it is the only solution I will but I want to try

Title: Re: Adding two chargers in one pv array
Post by: SYJetzt on December 27 2022, 06:26

Connecting 2 mppt's on one solar array won't work! Each MPPT has to be connected to a separate PV array.
I would go with one MPPT charger to the first battery and a B2B-Charger between the first and the sencond battery.

Title: Re: Adding two chargers in one pv array
Post by: elias on December 27 2022, 13:30

Hmmm I understand , for one array one mppt . Thanks

Title: Re: Adding two chargers in one pv array
Post by: SYJetzt on December 28 2022, 07:13

I assume you are speaking from the house (service) battery and the starter battery. There is no need to charge the starter battery from a solar panel. The starter batt will be charged by the alternator sufficiently.

Title: Re: Adding two chargers in one pv array
Post by: elias on December 28 2022, 08:24

Not exactly ,I have one starter battery , one bank and recently one lifepo4 battery dedicated only to the 220v inverter  . The alternator splits with that Victron isolator (blue thing)the current to the starter and the lead acid battery bank . The mppt charges the lead acid . The new installed lifepo4 should be charged somehow too .
1. So a dc dc charger from the bank will be one solution but I would like some energy from the pv array .

Title: Re: Adding two chargers in one pv array
Post by: SYJetzt on December 28 2022, 13:24

In this case a B2B charger will work fine. There are three key features to look for the charger:
1) Output of charger should provide a dedicated characteristic for charging lithium batteries.
2) Input of charger needs a detection circuit (wake up) to start charging, if there is energy available (from solar or alternator).
3) Sufficient charging power to bring the lithium battery up to full charge in time (this is depending on your energy demands drawn from your lithium batt/Inverter and the time when additional energy is available, no matter from which source )

For example a Victron Orion should do that job well, but there are other brands on the market too. 

To provide proper function a diligent installation and setup of the charger is key.

Title: Re: Adding two chargers in one pv array
Post by: SYJetzt on December 28 2022, 13:35

forgot to mention: In this concept the existing house- and starter  battery remain unchanged. The new B2B will start charging only when additional power is available (from alternator and/or PV-array via mppt). So first your service batt (and starter batt) will be charged, and after the servicebattery is charged to full the lithium will be charged. So your service batt cannot be discharged unintentionally by the B2B-charger 

Title: Re: Adding two chargers in one pv array
Post by: elias on December 28 2022, 17:18

Did some research last days and looks that your suggestion like Victron Orion is the most appropriate for the job . Can be regulated to start and stop at certain input voltages . Thanks