I presently have a Victron 100 20 MPPT solar controller and run 160Watt portable solar panels. We have a 180ah lithium battery.
Changes this year is I am adding a second 180ah lithium battery for 360ah in total. I am also adding 2 x 100watt solar panels to the roof, for a total of 360watts solar.
My plan is to use a second Victron MPPT 100 20 solar controller to handle the 200watts on the roof and connect the positive cable from the new MPPT to the very thick red cable coming from the battery to the back of the van (running to the inverter). The original Solar controller is already wired to the cable with a circuit breaker installed. Original wiring all done by Victron Canada. 100amp breaker for inverter cable and 25amp breaker for the solar.
Are there any issues with this plan? I will then have 360watts of solar running through 2 separate Victron MPPT solar controllers and the circuit breakers and charging the batteries through the thick red cable.
Thanks! Ian
It sounds as if it would be OK as there would either be max 50A one way or 100A the other. You will need a 25A fuse or beaker to protect the new MPPT cable. There will be more voltage drop during charging from solar which may mean a slightly longer absorption period.
Thanks for the speedy feedback! Ian
Update. I have now installed the 200W rooftop panels and they seem fine attached to the Victron 100 /20 smart solar controller. I have also reconnected my 160w portable panels to my other Victron MPPT 100 / 20 smart solar controller. Both MPPT controllers are wired to the large positive cable from the lithium battery bank. It may be misleading as the batteries are at 100% or close to and when the new 200w solar are showing action on my smart phone, the portable panels are “OFF” and showing 0W. Does this make sense? Will the 2 MPPT controllers chose either the roof top panel or the portable, or can both be feeding power back to battery bank at same time?
A further thought I have had. Should I be wiring both the 200W rooftop and the 160W portable panels through the same MPPT 100 / 20?
I am a littler confused, and would appreciate any help or ideas. Maybe one the battery bank is depleted to say 60%, both solar controllers will be showing input to batteries? Thanks very much. Ian
If the battery is full or very nearly full you will often see one of the controllers taking the lead. This can be caused by tiny differences in the measured voltage. This is typical.
One way to avoid this is if they are both Bluetooth enabled controllers. You can set them up in a VE Smart Network and linking them together which should synchronise them.
Excellent reply and idea re networking. I will consider the networking idea and your point of 1 MPPT “taking the lead” makes sense. I am OK with that as when driving, only the rooftop 200W will be “live”. When camped, the portable may take the lead as it will always be in direct sun and set at 90 degrees to the sun.
Much appreciated. Ian
In experience I find that multiple SmartSolar controllers will work together just fine, especially when networked or wired to a GX device. Even different brands of charge controllers usually work together if wired properly. They are just multiple chargers charging the same battery. They will charge at the set points they are programmed too. The conflict arises when the batteries are nearly full and showing a higher, near to full, voltage. If one charger is set to charge at 14.4 and one is set to 14.2 the second one may turn off first. Or, similarly, if one is farther away and experiencing greater voltage drop, even if the charge voltages are the same it may shut off earlier.
You will lose efficiency, perhaps significantly if you run the 160 watt and the 200 watt through the same controller. You are doing it correctly using two separate controllers.
More great and positive feedback. Thank you!
Ian