First let me apologize for this long winded post. I may not be clear in my explanation. Writing clearly is not at the top of my skill set, with that said here goes.
I have four 12 Agm
in series at 66 ah each
I have a a 48 volt brushless three phase dc motor
for a kicker
50 amp continuous
I provided some images
I have two 30 watt panels and I have room to make it four panels if needed at 1.63 amps
I have 1 100 watt panel @ approximately 5.5 amps
I have at present one 48v to 12v dc converter @ 30 amps but I plan on making that two in parallel for 60 amps. Unless there are issues to prevent it.
The reason for the second converter is , the on board items such as , Bilge
pumps, wash down pump
and anchor winch
are heavy loads. (hopefully bilge
pumps not needed) After adding everything up in situations where running lights ,deck lights and bilge pumps are all active, 30 amps from a single
dc to dc converter is just barely getting by. Example : 14 amp for bilge no 1, + 5 amp bilge 2 + 6 amp marine radio
, + 4 amps deck
and running lights. Worse case scenario. 29 amps fuse blows at thirty
Note: I could not go directly to the 48 volt battery with the bilge pumps bypassing the inverter
without tapping the bank at one battery which i didn't want to do.
My house loads are negligible a Engle fridge/ freezer
runs at a 2.5 to 3 amps in most situations I doubled that to 5 amps
Three Led cabin
lights, a couple cell phone
/ tablet charges a twelve volt TV and a 12 volt hot spot router.
Other than that running lights, fore, aft deck
utility lights and one hatch
ventilation fan and a couple other small circulation fans on the bulkheads
My pumps are:
One 14 amp 3700 gph bilge pump
One 3 amp 1100 gph bilge pump
One 14 amp washdown
One 2.7 amp fresh water
All seldom used.
I have a 110v 600 watt microwave that will be seldom used that I want to put on a 48 volt 2000 watt inverter
. Turned on only when needed and I will use the microwave when docked on shore power
I have a gimbald gas bottle type coffee warmer and for cooking origo
I mention only mentioned this because no electricity involved.
Some photos: I am into this project
up to my eyeballs and it will be done one way or another.
I made the enclosure and every thing on it is twelve volt except for the microwave and that situation has changed to 110 on a inverter due to cost of 12 volt microwaves and the benefit of having a inverter for different Items even if rarely used.
So you see all my house needs that amount to anything are , emergency
pumps , fresh water pump
, anchor winch
and a inverter running a microwave a few minutes a day (maybe)
I dont see the need for another bank other than the issue of charging with solar
panels that you mentioned. The problem I see is my mismatched panels it would be better if all were identical watts and output in amps. Then my charger would need to be one that charges uphill or my panels in series up to more than 48 within the max allowed by a 48 volt charger charger . I hear series panels are not recommended. I'm not sure I understand the issue with if a main diode, fuses
and bypass diodes for each panel are being used.
I think I have a handle on the wiring aspect I have every circuit drawn out every wire numbered and and I am using double walled adheasive clear shrink connectors with solder in them on every wire connection. My wire numbers will also be covered with shrink wrap.
Now if I have two 48v to 12v thirty amp converters in parallel feeding my house panel and the 50 amp kicker
on its own dedicated fused main. Why is adding a 12 volt bank needed. I thought if I were going to add another bank it would be another 48 volt bank for more amp hours. I know the charger is the issue and to your point that charging a twelve volt bank with twelve volt panels was your main suggestion. In my mind with the addition 12 volt bank I would be going for days maybe a week or two with the 48 volt bank not being maintained (not charged per say) just not sitting there with nothing being added just losses from not being used. Its my understanding you have a percentage of loss per day if not on a float charge. I would be leaving that bank like that while charging another bank at twelve volts that will be only used for minimal loads . If they are as you said small loads why another separate 12 volt bank? I'm not arguing the point I just need to understand what your saying. You are correct I do not understand totally solar panels and different configurations .
That is why I am here.