I am putting together a 100% off grid system for a new home. Max draw in a day about 30kwh. It's in western Washington so lots of fall/winter cloud cover and due to the particular location on a north facing hill with only about an hour of direct sun in the winter months (likely from behind clouds most days). I have pretty much decided on my general set-up, but I am not sure it's going to cut it and am open to other ideas. Planning on two EG4 6500EX, eight or nine 100ah 48v batteries, probably EG4-LL or LifePower4, but maybe SOK. 24 Canadian Solar bi-facial 445W panels, that's about all I have room for in the spot that gets sun in the winter.
Due to the limited winter sun we will likely need regular automatic generator backup to recharge the batteries. I have been told not to run a small (<13kw) generator through a 6500EX by Signature Solar techs. That I can use the built in dry start but should use an external battery charger to charge safely and efficiently. Saying that inverter generators running at more than 50% produce a dirty wave which will damage the inverter. Is this true with all inverters? I had been planning on a 7000watt inverter generator, but may need to go with a 13kw, see below.
I don't understand how using an external charger would work. The said they are coming out with a 100amp charger this winter. If their new 100amp charger is 95% efficient like their smaller chargers, that's about 1 hour per battery, so 8-9 hours to charge them all. That doesn't sound great to me. Also if the 6500EX has a charge current of 120amps x2 inverters, that means it needs about 3.5 hours of sun to charge up all eight batteries, correct? So if I am getting an hour of sun in the winter I can only charge the equivalent of ~2.3 batteries, probably less on most days due to clouds? Then I would need to run the generator for another 6+ hours with a 100amp charger to charge the rest, 12+ hours if we are using energy that day. If I had the 13kw generator I would get 120amp charging as well so slightly fatser than an external charger maybe, but still not great. And I may be able to justify a 26kw generator, I see some for around $7k, so assuming I could connect that to both inverters (not sure if I can?) I could charge the batteries in about 3.5 hours . Sooo... I understand we will likely have to cut our usage, get a propane stove/dryer/fridge, but it seems like at some point in the winter, unless I get the 26kw generator (and it can charge with both inverters at once) we will have to run directly from the generator for at least part of the day, probably within a few days. Am I missing something?
Can I set things up to run directly from the generator and charge the batteries at the same time? Will the inverter do this for me? Or can I use multiple chargers at the same time on batteries that are tied together? I am starting to think I may have to have a 26kw generator unless I want the generator running for most of the day. I am open to getting 4x 6500EX, but don't think it does me much good with limited winter exposure panel space. Are there better battery charges that I can tie into the system somehow? We need this to be able to work (turn generator on/off, switch to solar, etc) when we are not there. If I went with a Sol-ark 15k (expensive...) it has 275amps of charging power, but then I would need a 30kw generator if the 50% rule applies?
There is a small chance we can have hydro power from our creek which would solve all of our problems, but permitting is unlikely. Off topic a bit, but any reason I could not hook the hydro power (converted to DC) to the solar input on the inverter?
I am open to a completely different set-up, but budget including ground mounting, generator, etc. is $30k. I am confident I can manage most of this myself, so no install fees. Please let me know if I am misunderstanding something or my assumptions are wrong. Let me know your thoughts. Thanks!
Due to the limited winter sun we will likely need regular automatic generator backup to recharge the batteries. I have been told not to run a small (<13kw) generator through a 6500EX by Signature Solar techs. That I can use the built in dry start but should use an external battery charger to charge safely and efficiently. Saying that inverter generators running at more than 50% produce a dirty wave which will damage the inverter. Is this true with all inverters? I had been planning on a 7000watt inverter generator, but may need to go with a 13kw, see below.
I don't understand how using an external charger would work. The said they are coming out with a 100amp charger this winter. If their new 100amp charger is 95% efficient like their smaller chargers, that's about 1 hour per battery, so 8-9 hours to charge them all. That doesn't sound great to me. Also if the 6500EX has a charge current of 120amps x2 inverters, that means it needs about 3.5 hours of sun to charge up all eight batteries, correct? So if I am getting an hour of sun in the winter I can only charge the equivalent of ~2.3 batteries, probably less on most days due to clouds? Then I would need to run the generator for another 6+ hours with a 100amp charger to charge the rest, 12+ hours if we are using energy that day. If I had the 13kw generator I would get 120amp charging as well so slightly fatser than an external charger maybe, but still not great. And I may be able to justify a 26kw generator, I see some for around $7k, so assuming I could connect that to both inverters (not sure if I can?) I could charge the batteries in about 3.5 hours . Sooo... I understand we will likely have to cut our usage, get a propane stove/dryer/fridge, but it seems like at some point in the winter, unless I get the 26kw generator (and it can charge with both inverters at once) we will have to run directly from the generator for at least part of the day, probably within a few days. Am I missing something?
Can I set things up to run directly from the generator and charge the batteries at the same time? Will the inverter do this for me? Or can I use multiple chargers at the same time on batteries that are tied together? I am starting to think I may have to have a 26kw generator unless I want the generator running for most of the day. I am open to getting 4x 6500EX, but don't think it does me much good with limited winter exposure panel space. Are there better battery charges that I can tie into the system somehow? We need this to be able to work (turn generator on/off, switch to solar, etc) when we are not there. If I went with a Sol-ark 15k (expensive...) it has 275amps of charging power, but then I would need a 30kw generator if the 50% rule applies?
There is a small chance we can have hydro power from our creek which would solve all of our problems, but permitting is unlikely. Off topic a bit, but any reason I could not hook the hydro power (converted to DC) to the solar input on the inverter?
I am open to a completely different set-up, but budget including ground mounting, generator, etc. is $30k. I am confident I can manage most of this myself, so no install fees. Please let me know if I am misunderstanding something or my assumptions are wrong. Let me know your thoughts. Thanks!
