[RE-wrenches] 120 Vac and 12Vdc mixed distribution system

Thu Apr 25 09:44:19 PDT 2024

Certainly the old gear was simple and probably had a better chance to 
survive a solar event, EMP, or worse. It did have to have some one like 
you (us) or Todd steering the boat. No auto-pilot for sure.

Most of my clients see the graphically based power (on-line somewhere) 
system and that is what they want. Just too easy for the spose or kids 
to see and too hard to know the difference between 12.0 and 12.8. I also 
think many do not expect to live as in the city but somewhere in between 
what Michael is saying here.

You guys have seen all of this below on similar systems. For a new 
client it can be a game changer and some peace in these weird (I think) 
times. Might be best to have both 😉😉😎😎👍

Dave Angelini Offgrid Solar
"we go where powerlines don't"
    [1]https://offgridsolar1.com/ [2]  [1]
e-mail  offgridsolar at sti.net
text 209 813 0060

On 2024-04-25 8:52 am, Michael Morningstar via RE-wrenches wrote:

> Here's a different take. Just food for thought and not necessarily a 
> suggestion. Those 1st or 2nd Gen 12V systems were/are for me the most 
> reliable and trouble free systems. I'd install one and never hear back 
> from my customer for a decade or more. I regularly see "rats nest" 
> wired 12V/Trace DR/UX hybrid systems with Arco panels that still hum 
> along. When I get asked to update these systems, assuming that the 
> power needs haven't grown much, I usually keep the voltages the same 
> (12VDC and 120VAC), sanitize the wiring, add OCPDs, Victron smart 
> shunt/Battery monitor, Victron CC and inverter, and Lead Acids or 
> AGM's. Good for another 20 years with batteries being replaced in 10. 
> With only a few exceptions, every ancient system that I have tried to 
> bring into the 21st century for my low needs off-grid pioneers has been 
> a flop. Inverters and Charge controllers that take a dump after a few 
> years, TMI with new monitor/controllers, and lots of headaches with 
> Lithium.
> 
> Now, if we're talking about a client who has just purchased a property 
> with a legacy system and wants to live like they are still in the City, 
> that's an entirely different conversation.
> 
> My own system for my full time off-grid home is 12V/120V, and I live 
> Fat! Tiny array (700Ws 4 hours a day), tiny hydro (150Ws 7 months a 
> year) 2 Rolls 21 CS-21Ps, Honda eu2000i, 12VDC Sunfrost, 12VDC device 
> charging station, 12VDC UV water disinfection (gravity spring water) on 
> a 12VDC loadcenter (SQD QO), Morningstar 300W Suresine powers an AC 
> loadcenter for lighting and most plugs) Magnum 2812 powers a loadcenter 
> that feeds bathroom and kitchen plugs. It stays off to reduce idle 
> consumption). I've never had a problem with this system in 15 years. If 
> I'm not around, or my financials are weak, replacing a piece of 
> equipment won't hurt myself or my wife. If need be, I can charge from a 
> vehicle or farm equipment. And I could pull a battery from something 
> here on the ranch in a pinch. The wiring/installation is clear and I 
> made a manual so that any decent electrician could troubleshoot and 
> make repairs should Todd Cory not be around :)
> 
> Again, I say all this to provoke a thought experiment. I've installed 
> and replaced hundreds upon hundreds of off-grid systems from pinky 
> dinky to millions and the ones that have worked the best were/are 
> either AC Hydro, old-school (pre-Xantrex) or Schneider/Discover and the 
> latter have had their share of issues.
> 
> On Thu, Apr 25, 2024 at 7:34 AM Bradley Bassett via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> I had a lot of trouble keeping QO breakers functional on a 12VDC 
> distribution system. I'd have to move them around every week or so to 
> keep a good contact on the plug in contacts. They seem to work fine on 
> a 24VDC system. I went to using MNPV or MNDC breakers instead in PV 
> combiner or other MidNite boxes. QOU breakers are fine, but I don't 
> know of any standard distribution box for them.
> 
> Brad Bassett
> Application Engineer retired
> 
> On Wed, Apr 24, 2024 at 11:42 AM Jason Szumlanski via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> 
> Hi Dave,
> 
> I appreciate the concern. It's not one of those situations. We have a 
> couple of barrier islands around here where people have set up what 
> amounts to little fish camps that are used infrequently. The islands 
> are also home to a few full-time/most-time residents and state parks. 
> Everyone knows everyone. The clients are safe and reliable. These sites 
> range from places that people paid just tens of thousands of dollars 
> decades ago all the way up to many-multi-million dollar strips of sand 
> where very wealthy people like to look out over Naples beach a couple 
> times of year from their off-grid mansions. It's pretty interesting.
> 
> I "get" why people who only take friends out a few times a year on a 
> fishing expedition want a band-aid approach. There is no reason to 
> throw $100K at a situation like this. In this case, I feel I can get 
> creative to meet the very limited 12V and 120V needs while providing a 
> reliable and long-lasting solution for around $25K and pocket enough 
> money that I want to answer their call in the future. Right now they 
> are getting by with 4 x 100W Solarland modules with a 9.6kWh battery 
> bank and a Honda EU2000. I'm certain they will be blown away with the 
> performance of whatever I propose, and happy that it is installed in a 
> safe and professional manner.
> 
> The current distribution systems look solid, each protected by a Square 
> D QO breaker panel and professionally installed. The power production 
> and delivery system is a total kludge that I feel I can fix without too 
> much risk.
> 
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
> Florida Certified Electrical Contractor EC13013208
> 
> On Wed, Apr 24, 2024 at 2:19 PM Dave Angelini Offgrid Solar via 
> RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
> 
> How about just buy an RV?
> 
> Seriously the reason Jason I am Leary is because of the experiences I 
> have had with what I call Offgrid Squalor.
> 
> Just have to be careful especially these days of druggies, people in 
> vans with no windows, ex paramilitary that went bad,
> and you get the picture.
> 
> If you know the person that is the way to keep you and your loved ones 
> safe. Money does talk sometimes and the lack can of it
> can be a warning.
> 
> Also as mentioned, these types of situations, are what gets my 
> accountant telling me if you do not charge enough,
> no one will listen to your advice.
> 
> Dave Angelini Offgrid Solar
> "we go where powerlines don't"
> [1]https://offgridsolar1.com/ [2]  [1]
> e-mail  offgridsolar at sti.net
> text 209 813 0060
> 
> On 2024-04-24 10:51 am, John Blittersdorf via RE-wrenches wrote:
> 
> Jason,
> Just using the converter works fine. They are considered a battery 
> charger or a regulated power supply. I am currently running that way 
> now with the battery cables going nowhere.  I was thinking of putting 
> the battery back in the system just for triple redundancy when my 
> inverter hits low battery cutoff voltage on a cold winter night and no 
> fuel for the generator (or it won't start).
> My Iota DLS puts out a regulated 13.4 volts up to 30 amps.
> 
> John
> 
> On Wed, Apr 24, 2024 at 8:25 AM Jason Szumlanski via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> 
> Ah ha! I didn't consider using a small 12V battery with a charger. I 
> was thinking of just using a 120V -> 12V converter to handle the DC 
> loads. Is the 12V battery really necessary, or can I just power the DC 
> loads directly with a converter? If I just have lights and fans on the 
> DC system, the load should be pretty minimal.
> 
> I could use a separate 12V battery, but I would like to eliminate that 
> cost and complexity if possible.
> 
> And yeah, I am not considering this a money making opportunity. It's 
> really just a challenge to ward off boredom from the daily grind.
> 
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
> Florida Certified Electrical Contractor EC13013208
> 
> On Wed, Apr 24, 2024 at 8:01 AM John Blittersdorf via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> Jason,
> I have a customer with the same situation except he already has a 12 V 
> VFX inverter,  He has a sunfrost fridge and other small loads with a 
> very fancy custom control board
> originally set up to handle AC and DC systems.  We are adding a lot 
> more solar and I was considering a dual battery system but the owner 
> didn't like that idea.  We are going with and Iota 12v power supply (i 
> use one at my house for my sunfrost) to power up all his DC loads and 
> will be adding a large 48 V battery bank and over 4Kw of solar using a 
> VFXR3648 directly in place of the 12V inverter.  He complained that the 
> existing inverter would not handle all his current AC loads very well.  
> My own house is fully wired for 12VDC as well as AC (lots of #10 copper 
> not being used) and I have been considering getting a small LFP 12V 
> battery to put back on by DC System. Then use the Iota as a secondary 
> charging method with some of my large stash of older modules hooked up 
> for 12V direct with C40 charge controller to recreate my original 
> system just for kicks. I'm only using DC for my Sunfrost and one 
> "emergency light" in the livingroom right now.  For your customer, a 
> small LFP 12v battery (approximately $500 or less) to replace his old 
> battery bankm and more larger ones for the new AC side with 48V 
> inverter fed by his generator or through an Iota 48 V charger ifusing a 
> smaller non charging inverter. Unlike Dave, I like these challenges. 
> Maybe thats why I never seem to make money.!!
> 
> John Blittersdorf
> offgridvermont.com [3]
> 
> On Wed, Apr 24, 2024 at 7:22 AM Jason Szumlanski via RE-wrenches 
> <re-wrenches at lists.re-wrenches.org> wrote:
> 
> Fortunately, the owner is pretty handy and is willing to live with any 
> negative consequences. That said, I want to offer him something as 
> simple and bulletproof as possible. I am walking into this with eyes 
> wide open, for sure.
> 
> Jason Szumlanski
> Principal Solar Designer | Florida Solar Design Group
> NABCEP Certified Solar Professional (PVIP)
> Florida State Certified Solar Contractor CVC56956
> Florida Certified Electrical Contractor EC13013208
> 
> On Tue, Apr 23, 2024 at 5:47 PM Dave Angelini Offgrid Solar via 
> RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
> 
> Not being helpful but I  walk away from these.  It will come back to 
> you.
> 
> Dave Angelini Offgrid Solar
> "we go where powerlines don't"
> [1]https://offgridsolar1.com/ [2]  [1]
> e-mail  offgridsolar at sti.net
> text 209 813 0060
> 
> On 2024-04-23 2:40 pm, Jason Szumlanski via RE-wrenches wrote:
> 
> I have an off-grid client who is working on replacing old equipment at 
> a cabin. He has a lot of 12 volt distribution in the house for 
> lighting, fans, and a 12 volt refrigerator. He also has 120 volt AC 
> loads that run through a separate distribution panel where the only 
> source is a 2000 Watt Honda generator. There is no inverter present. 
> The batteries are charged through a Trace C40.
> 
> He currently has a few ancient solar panels and a struggling Bank of 
> AGM batteries. It's time for an upgrade. I can easily supply enough PV 
> power for what he needs. He currently has a 9 kilowatt hour battery 
> capacity that he was happy with when the batteries operated optimally. 
> Nonetheless, I would probably future-proof him with a 10 to 15 kilowatt 
> hour LiPo to double or triple his usable capacity.
> 
> For convenience, obviously it would be nice to have an inverter to 
> eliminate or reduce the generator requirement. But he seems committed 
> to keeping his 12 volt distribution because it would be costly to 
> replace fixtures. I think he would consider replacing the 12 volt 
> refrigerator if he has an inverter.
> 
> He definitely wants LiPo batteries.
> 
> I don't like the idea of 12 volt direct from a battery plus connecting 
> an inverter to that same battery. It is going to be hard to measure and 
> monitor things.
> 
> I am thinking about using a 48 volt battery with a single phase 120 
> volt inverter, getting him to change to a 120 volt refrigerator, and 
> using a DC converter to give him somewhere in the range of 100 amps at 
> 12 volts for his existing DC lighting and fan loads. Is this a bad 
> idea? Should I stick with a 12 volt battery system? He does have a tiny 
> 12 volt pressure pump which might be an issue for the converter. I'm 
> not sure. I am a bit worried about the efficiency loss and capacity of 
> DC converters and not sure how to size it.
> 
> Jason Szumlanski
> Florida Solar Design Group
> 
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