Hi. I am living on a boat with an entirely off-grid system. Equipment:
9kW solar
30kWh lithium batteries
3 x MPPT 250/85
Quattro 15kVA inverter charger
Color Control GX
Honda 2.2kW portable generator
NO shore power
NOT wishing to have automatic generator start-stop
95+% of my power needs are being provided by solar. I just want to occasionally run the small portable generator in cases of prolonged lack of sun in order to top up the batteries, i.e. trickle charge of approx 1400W. This is a simple manual process, e.g. I start the generator and leave it running for, say, 3 hours to top up batteries by 4kWh - not automatic start/stop based on battery SOC.
The generator connects fine. The issue is that the generator is immediately overloaded due to either of:
1. The batteries demanding more charge than the generator can provide (generator capacity is only 2.2kW).
2. A heavy draw AC item becoming active, e.g. the water heater switching on.
I understand why (small generator cannot handle big loads) and am aware of a workaround via the settings in CCGX to limit the overall charge current such that I have been able to use the generator to charge the batteries whilst avoid it being overloaded. However.. it is a very tedious process that requires constant monitoring/adjusting of the limit in the presence of varying additional charge supply (i.e sunshine) and it does not solve the second problem, that when a heavy AC load is introduced it immediately overloads the generator which then cuts out in order to save itself, therefore I have to disconnect all such potential loads in advance.
I understand that the proper way to solve the issue is to set up an upper charge limit on the relevant AC Input such that the generator can never be asked to supply more than that amount. In my case I wish to set it at 6A. 6x230 = 1380W, so comfortably within the generator's 2200W capacity.
I see online that the recommended set-up for two AC input sources is to have the generator as Input 1 and shore/grid power as Input 2. However, the guys who installed my system did it the other way around: shore power is Input 1 and the generator is Input 2.
My question is: In my case does the allocation as to Input 1/Input 2 actually matter? It seems to me that it should not. My understanding is that the only important difference between AC Inputs 1 & 2 is that Input 1 has the higher status such that when both AC Inputs are active then AC Input is given priority, i.e. if both shore and generator power are available then under conventional set-up the inverter would use the generator whereas in my current set-up it would use the shore.
Please note that whilst I do have a connection set up for shore power (currently AC Input 1) this is not actually live. My boat is on a mooring a long way from any shore power. The connection is only there as an option in case of one day the boat being in a marina or at a boatyard for maintenance. As it stands currently the only actual AC input source I have is the generator. Therefore now (and for the foreseeable future) there can never be the situation of both AC Inputs being active.
Obviously I would prefer to stick with the current set-up (AC Input 1 as shore and AC Input 2 as generator) rather than have to re-wire the connections to the inverter. If that is deemed to be ok then I would simply set the current limit for AC Input 2 as 6A. Please let me know if there are any issues that I haven't considered.
Many thanks in advance for your advice.