Dustin Henderson
New Member
- Joined
- Nov 2, 2022
- Messages
- 17
I have a 100/40 MPPT solar charge controller that I will be installing in a pre wired for solar travel trailer.
Assume for the sake of argument use cases of 200 Watts (Serial) and eventually 400 Watts (2s2P) of paneling, if it matters. Initial install will be 200 Watts serial, outputting ~5 Amps and ~40 volts.
My intention was to splice the controller in in the same manner as the manufacturer recommends, (i.e. between POS and NEG wires already run from the roof), albeit closer to the battery compartment instead of in the interior of the travel trailer. This would eliminate additional wiring, leverage the bus bars and fuses already installed, and leave a cleaner install of less cables directly to the battery terminal. There is ample room in the under storage and battery compartments to do this and the pre wire from the roof gland has been confirmed and is conveniently located for this. (Note, There will be a disconnect between panel and SCC.)
HOWEVER, It occurred to me that the fuse natively installed for this pre wire is a 30 AMP fuse, and it is somewhat more difficult to change out given how and where it is installed.
So the question is:
How does an MPPT SCC determine Amperage output, given the relatively moderate input my panels will be providing? Would it ever try to push more than 30 AMPs?
Secondarily, Should I just go through the contortions and hassles of upgrading their 30 Amp fuse to a 40? It would be a physical challenge but is possible.
Third, should I just by pass the natively wired cable after the SCC and install my own fuse and cable directly to the battery terminals? This will start to crowd the battery compartment but could be done. (Follow up, if I go that route, should I attach the Negative cable to battery as well, or run it to ground as the pre-wire doers.)
I hope the context of the question makes sense.
Assume for the sake of argument use cases of 200 Watts (Serial) and eventually 400 Watts (2s2P) of paneling, if it matters. Initial install will be 200 Watts serial, outputting ~5 Amps and ~40 volts.
My intention was to splice the controller in in the same manner as the manufacturer recommends, (i.e. between POS and NEG wires already run from the roof), albeit closer to the battery compartment instead of in the interior of the travel trailer. This would eliminate additional wiring, leverage the bus bars and fuses already installed, and leave a cleaner install of less cables directly to the battery terminal. There is ample room in the under storage and battery compartments to do this and the pre wire from the roof gland has been confirmed and is conveniently located for this. (Note, There will be a disconnect between panel and SCC.)
HOWEVER, It occurred to me that the fuse natively installed for this pre wire is a 30 AMP fuse, and it is somewhat more difficult to change out given how and where it is installed.
So the question is:
How does an MPPT SCC determine Amperage output, given the relatively moderate input my panels will be providing? Would it ever try to push more than 30 AMPs?
Secondarily, Should I just go through the contortions and hassles of upgrading their 30 Amp fuse to a 40? It would be a physical challenge but is possible.
Third, should I just by pass the natively wired cable after the SCC and install my own fuse and cable directly to the battery terminals? This will start to crowd the battery compartment but could be done. (Follow up, if I go that route, should I attach the Negative cable to battery as well, or run it to ground as the pre-wire doers.)
I hope the context of the question makes sense.
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