Hello all, first time poster, long time lurker 
I’m a total solar/off grid novice by all means, no prior experience and not the most electrically knowledge, but reading lots and trying hard to understand it all.
Sorry for the long post, I have tried searching the forum and the web in general but am still unsure of some things.
We’re pretty deep into building an off grid house and studio in the Gulf Islands BC; about 3 years in to construction and getting close to done, the two buildings are about 1000sqft total, heavily insulated, slab on grade, wood construction.
Primary heat is in slab with Rinnai propane combi boilers (one for each building), and a small Jotul wood stove in the house building. We’ll be using a propane range. Main power loads will be fridge (390kwh), two HRVs (small load, not sure offhand how much), boilers (also quite small draw), lighting (all LED), and ultimately small electronics (once we’re in there will be modem, router, TV use, small device charging, etc).
It’s been a lot of work, even having contractors do most of the work, I’m doing what I can but time and to some extent skill is limited, plus making sure it’s all up to code.
I’ve hired what I can, including the off grid system. I had a reputable semi local ‘solar guy’ who’s been in the industry since at least the 80’s and done numerous other systems on island design the system and our electrician do the install (he had minimal experience with off grid, not none, but this was his biggest off grid job).
Once the system install was done (which was some time over the summer) I was pretty much on my own, no follow up support from anyone (the electrician has been helpful but isn’t all the knowledge on the subject), the designer just told me to ‘read the manuals’ which is what I’ve done. I’d hoped for more help in at least initial setup.
It is an 8wk 48v system; 24x 360w Longi panels, Magnum MS-PAE 48v inverter/charger (with remote, BMK), Magnum mini panel, Outback 80amp controllers (x2), Midnight disconnects (x2), Simpliphi 3.8kwh 48v batteries (x2). No built in backup generator, but I have a 5kw Honda for manual charging. My plan is to run an extension cord from a future on grid workshop to the house as the primary backup, it’s about 360’, an 8awg cord should work for this purpose.
I’ve run into a few problems now and am not sure what to do. I set all the settings following the various manuals, some things didn’t quite ‘line up’ but I went with the best I could do, which might be what some of the issues are.
About a week ago when I went to the site (we currently live in another house on the same property) the power had shut down overnight. I was able to reset and restart it, when I did the batteries were at 45.7v(!). I had some difficulties getting it going again, mostly just doing things in the wrong order since I’ve never done it before, and found that my generator has an issue where one leg of the 240 isn’t the right frequency… anyway, I did get it going and charging with the solar, then topping up with the generator.
Since the restart I’ve been resetting everything through the remote, now the BMK won’t give me a SOC (just says ‘Think’n’), it did give SOC before it died, and it does give the voltage, etc. now.
One of the problems I’ve run in to (and this might be part of why it got so low before it died as the SOC was inaccurate) is that the lowest AH I can set the inverter/charger to is 200ah, whereas the batteries are only 150ah total.
According to the Magnum manual it will say Think’n until the batteries have reached 100% SOC. What’s strange is it did give me a SOC before it went down, even if inaccurate it was there.
Needless to say we don’t have a lot of solar right now so I’ve been running the generator some each day.
The next issue I’ve got is when I run the generator to charge I can’t tell if/when they’re charged (no SOC). The remote display will say ‘Charging’ when I first start it, but then changes to ‘Constant Current’ (the Simpliphi batteries say to set the charger to CC/CV) and doesn’t change- admittedly I haven’t run it for more than about 30 min at a time), the Magnum manual doesn’t list that as one of the things it would display when charging... It appears to be charging properly, but I am afraid of overcharging (since it thinks it’s 200AH) so haven’t left it running too long, just enough to make sure it doesn’t die again. On the generator it will go to as high as 57v and the volts settle at 53 and some once the generator is off and it has sat for a while, by the next morning it is usually 52 and some volts.
I’m thinking the system needs a third battery, Simpliphi‘s instructions imply as much and it would solve the AH setting issue, not a cheap solution but if it’s needed it’s needed.
Without the SOC all I’ve got to go on is volts, can anyone advise what is a good range to try and keep them in?
Is it safe to just run the generator for a longer time and it shouldn't damage the batteries?
Any advice on this? I don’t want to damage anything.
Thanks for making it through the whole post.
Ben
I’m a total solar/off grid novice by all means, no prior experience and not the most electrically knowledge, but reading lots and trying hard to understand it all.
Sorry for the long post, I have tried searching the forum and the web in general but am still unsure of some things.
We’re pretty deep into building an off grid house and studio in the Gulf Islands BC; about 3 years in to construction and getting close to done, the two buildings are about 1000sqft total, heavily insulated, slab on grade, wood construction.
Primary heat is in slab with Rinnai propane combi boilers (one for each building), and a small Jotul wood stove in the house building. We’ll be using a propane range. Main power loads will be fridge (390kwh), two HRVs (small load, not sure offhand how much), boilers (also quite small draw), lighting (all LED), and ultimately small electronics (once we’re in there will be modem, router, TV use, small device charging, etc).
It’s been a lot of work, even having contractors do most of the work, I’m doing what I can but time and to some extent skill is limited, plus making sure it’s all up to code.
I’ve hired what I can, including the off grid system. I had a reputable semi local ‘solar guy’ who’s been in the industry since at least the 80’s and done numerous other systems on island design the system and our electrician do the install (he had minimal experience with off grid, not none, but this was his biggest off grid job).
Once the system install was done (which was some time over the summer) I was pretty much on my own, no follow up support from anyone (the electrician has been helpful but isn’t all the knowledge on the subject), the designer just told me to ‘read the manuals’ which is what I’ve done. I’d hoped for more help in at least initial setup.
It is an 8wk 48v system; 24x 360w Longi panels, Magnum MS-PAE 48v inverter/charger (with remote, BMK), Magnum mini panel, Outback 80amp controllers (x2), Midnight disconnects (x2), Simpliphi 3.8kwh 48v batteries (x2). No built in backup generator, but I have a 5kw Honda for manual charging. My plan is to run an extension cord from a future on grid workshop to the house as the primary backup, it’s about 360’, an 8awg cord should work for this purpose.
I’ve run into a few problems now and am not sure what to do. I set all the settings following the various manuals, some things didn’t quite ‘line up’ but I went with the best I could do, which might be what some of the issues are.
About a week ago when I went to the site (we currently live in another house on the same property) the power had shut down overnight. I was able to reset and restart it, when I did the batteries were at 45.7v(!). I had some difficulties getting it going again, mostly just doing things in the wrong order since I’ve never done it before, and found that my generator has an issue where one leg of the 240 isn’t the right frequency… anyway, I did get it going and charging with the solar, then topping up with the generator.
Since the restart I’ve been resetting everything through the remote, now the BMK won’t give me a SOC (just says ‘Think’n’), it did give SOC before it died, and it does give the voltage, etc. now.
One of the problems I’ve run in to (and this might be part of why it got so low before it died as the SOC was inaccurate) is that the lowest AH I can set the inverter/charger to is 200ah, whereas the batteries are only 150ah total.
According to the Magnum manual it will say Think’n until the batteries have reached 100% SOC. What’s strange is it did give me a SOC before it went down, even if inaccurate it was there.
Needless to say we don’t have a lot of solar right now so I’ve been running the generator some each day.
The next issue I’ve got is when I run the generator to charge I can’t tell if/when they’re charged (no SOC). The remote display will say ‘Charging’ when I first start it, but then changes to ‘Constant Current’ (the Simpliphi batteries say to set the charger to CC/CV) and doesn’t change- admittedly I haven’t run it for more than about 30 min at a time), the Magnum manual doesn’t list that as one of the things it would display when charging... It appears to be charging properly, but I am afraid of overcharging (since it thinks it’s 200AH) so haven’t left it running too long, just enough to make sure it doesn’t die again. On the generator it will go to as high as 57v and the volts settle at 53 and some once the generator is off and it has sat for a while, by the next morning it is usually 52 and some volts.
I’m thinking the system needs a third battery, Simpliphi‘s instructions imply as much and it would solve the AH setting issue, not a cheap solution but if it’s needed it’s needed.
Without the SOC all I’ve got to go on is volts, can anyone advise what is a good range to try and keep them in?
Is it safe to just run the generator for a longer time and it shouldn't damage the batteries?
Any advice on this? I don’t want to damage anything.
Thanks for making it through the whole post.
Ben
