OFF GRID POWER; various thoughts on...

[Redoverfarm]

I have been looking at some.  Most have short pedestals a couple inches that the rails mount to which allow the rails to clear the ridges of the metal panels.  Just thought I would throw this out in hopes someone would have a recommendation of type or brand.

[Dave Sparks]

We did pole mount. I have seen metal roofs with panels but have no idea what most have used. There is one guy near us with a standing seam roof and he used some special mounts that secure to the standing seams. Your roof is the typical panels that overlap, like ours,  IIRC.

I do not like using a Home roof but have used these on barn. S5 for standing seam metal. Sorry this is late! Busy with fire season and another bad drought.

https://s-5.com/products/solar-racking-systems/

[Redoverfarm]

Dave thanks for the link.

[OlJarhead]

https://www.youtube.com/watch?v=cHNELRnJ_4Y
Please pass the salt?  Battery?

If this turns out true I'll be all over it!

[Hunterscabin]

Anyone have experience with the Jackery Portable Power Station? 
Thought about going this route for the CPAP machine. Specifically on recharging. 
How long does it take to recharge with the power station's solar panels vs recharging from power source? 
Searched forum and found no other mention of this product. Certainly not trying give any push towards this item. Have not purchased it. 
Thanks

[DavidRaftery]

I have a question on grounding the neutral wire in a CB panel.

I plan on finally hooking up my 2,000 watt PSW inverter this spring. I will connect it to a standard 6 circuit AC electrical panel box. I only plan on using 3 of the circuits. I understand in normal grid tied main panels, the common leg is also connected to ground inside the panel to create an effective ground fault current path. On sub panels this is not necessary. Would there be any difference when using an inverter as the source of electrical input? Should I treat this the same as a main panel and bond the ground and neutral busses together?

Thanks for any thoughts.
Dave

[MountainDon]

It depends on whether or not the inverter has a bonded neutral or a floating neutral. If it has a bonded neutral then there should not be a second bond in the service panel. You can use one of these 3 led testers to check... Plug the tester into the inverter receptacle and see if the 2 "correct" lights illuminate. That would mean the inverter has a bonded neutral.  That tester can also be used on a generator test and of course your home.

The service panel usually has a green screw inserted into the neutral buss, which will connect to the ground thru the metal case. Remove it to remove the neutral bonding; insert to bond.


I have seen an inverter be ruined by connection to a system with a service panel neutral bond.

[OlJarhead]

Anyone have experience with the Jackery Portable Power Station?
Thought about going this route for the CPAP machine. Specifically on recharging.
How long does it take to recharge with the power station's solar panels vs recharging from power source?
Searched forum and found no other mention of this product. Certainly not trying give any push towards this item. Have not purchased it.
Thanks

Sorry I missed this! 

YES!  I use a Jackery 550 for my CPAP and can leave the heat on without issue.  It runs about 10% or less of reserve power when using the 12v adapter.  We have  Roof Top Tent on my Jeep and I use the Jackery for my CPAP and my wife uses it for her hair irons etc and we recharge it on the 12v socket at the back of the jeep when traveling.

[OlJarhead]

What's everyone's thoughts on increasing my 660AH 24vdc battery bank without drastically increasing the cost?

Don't want to add more batteries (Have 12 GCB's now @220AH ea) nor weight (816lbs now) but could use more AH's of course.

Lithium seems too much $$$ and needs to be warm to charge (not gonna charge em at 0F for example)....AGM's also seem pretty spendy (I may go that rought) but I can afford more than the $105ea for GCB's at Costco that are 210AH (used to have the 220's but they moved down to 210s for some reason).

Thanks in advance.

[DavidRaftery]

It depends on whether or not the inverter has a bonded neutral or a floating neutral. If it has a bonded neutral then there should not be a second bond in the service panel. You can use one of these 3 led testers to check... Plug the tester into the inverter receptacle and see if the 2 "correct" lights illuminate. That would mean the inverter has a bonded neutral.  That tester can also be used on a generator test and of course your home.

The service panel usually has a green screw inserted into the neutral buss, which will connect to the ground thru the metal case. Remove it to remove the neutral bonding; insert to bond.

I have seen an inverter be ruined by connection to a system with a service panel neutral bond.

Hi Don,

Thank you for the information on bonding and the testers

I looked in my Samlex user manual and it says the neutral is internally bonded to the metal chassis of the inverter. The inverter has an internal GFCI which monitors the current flow. (When in doubt, read the manual !) From the manual:

"The AC output of this inverter is available through a NEMA5-20R Self Monitoring GFCI Duplex Receptacle. The Neutral slot of this receptacle (longer rectangular slot) is internally bonded to the metal chassis of the inverter.

GFCI Tripping and Reset: If there is a leakage of 5 to 6mA due to ground fault on the load side or there is a Neutral to Ground bond on the load side, the GFCI will trip.

Caution: Do not feed the output from the GFCI receptacle to a Panel Board / Load Center where the Neutral is bonded to the Earth Ground. This will trip the GFCI."
 
I will definitely pick up one of those testers to double check my wiring.
Thanks again,
Dave

[DavidRaftery]

What's everyone's thoughts on increasing my 660AH 24vdc battery bank without drastically increasing the cost?

Don't want to add more batteries (Have 12 GCB's now @220AH ea) nor weight (816lbs now) but could use more AH's of course.

Lithium seems too much $$$ and needs to be warm to charge (not gonna charge em at 0F for example)....AGM's also seem pretty spendy (I may go that rought) but I can afford more than the $105ea for GCB's at Costco that are 210AH (used to have the 220's but they moved down to 210s for some reason).

Thanks in advance.

Cheap bastard that I am, I went with GCB's. I asked my Jeep mechanic and he got them for me at wholesale. I bought 4 Interstate GCB's 224 AH for $132 ea, with $20 core charge, 58 lbs each. I think that was 3 years ago. I hope the prices have not increased too much because I am thinking of buying another 4 of the GCB's.
Dave

[OlJarhead]

Costco tends be lower.  8 years ago I bought my 220ah GCBs at $89ea plus core....they now have 210ah GCBs ar $105ea


But I want more reserve...even 59AH more would be better...235s give me 45AH more at 24v so I'm looking at those but if I could bump that another 50 plus without spending $10k I'd do it

[MountainDon]

Caution: Do not feed the output from the GFCI receptacle to a Panel Board / Load Center where the Neutral is bonded to the Earth Ground. This will trip the GFCI."

That's good. Some inverters simply go "Phffft" and stop working forever.

[OlJarhead]

Simpliphi PHI-3.8-24-M 3.8kWh 24 Volt Lithium Ferro Phosphate Battery With Metal Case | NAZ Solar Electric (solar-electric.com)

Looking at this has me thinking.

Since it's rated at 10,000 cycles at 80%DoD if I read that right it would mean it can take a 75AH draw regularly without issue...right?  I mean, I usually see about 45-65AH overnight from last solar charging to first solar or roughly 5%-10% of my 660AH bank (which I realize is a little undersized, but I've protected it for 8 years and it's still actually doing well after the last fiasco and only drawing down to 24v under load in the cold - freezing after 8hrs without a charge).

Anyway, if I understand correctly the above Lithium option, though a lot smaller, and double cost, might actually work since there isn't an issue drawing it down even more.

Of course, there is the issue of keeping it above freezing....but maybe I can set a charge controller to NOT charge under 32F???

I have both the Morningstar MPPT45 and the Outback Flex (60 I think)....and plenty of solar with the 9 panels I have...just wondering if maybe this is an option.

Thoughts?

[MountainDon]

A friend here used BattleBorn lithium batteries in their cabin. They had no devices that would draw power when they were absent so they were able to simply pull the charge and discharge breakers to Off and leave things, usually with somewhere between 60 to 80% charge. They moved the batteries into a corner inside the cabin so they would get warmed up to above freezing before flipping the charge breakers on after arriving. That would be my plan whenever we change.

But I seem to recall you need to leave a fan running when away. That complicates things. As far as I know, there is no low-temperature cutoff setting in a Flexmax charge controller unless something new has been added. I think I have seen that some built-into-the-battery BMS systems have a low-temp cutoff, but am not certain nor any idea which it might be.

[OlJarhead]

Ya that's my concern.  I think since they can draw down a lot more than GCB's it might be fine to use a much smaller bank like this one but I do need to leave fans on in the back room to circulate the heat and keep the composter from freezing.

I suppose I could just let it freeze in the winter but that can be a problem as well (pipes freezing up) resulting in the walk of shame to the outhouse in sub freezing temps and a foot or two of snow.

If I could keep these above freezing it wouldn't be an issue and I can certainly get them there during the day when the suns out, but can't do it otherwise...unless...

You know, I have that heated back room, I could put them in there if they aren't too big...hmmm....means changing things like putting the inverter back there too but it might be worth it. 

What do you think about the AH rating vs GCB's? 

[OlJarhead]

I was doing some simple math and I think this one 86lb battery will provide more usable power and last longer than my GCB's -- like more than twice as long) and I can keep it in the room in the back where it will remain 50F or more year round.

If I moved the inverter back there as well, I have a remote switch I can put in the porch to turn on the power...I'd just have to run the charge controller and cables to the back room.

Might motivate me to put a good door on the back room and finish it too  and give me a LOT more room in my porch as well

[MountainDon]

I agree with your assessment of what lithium battery capacity could be used. The greater usable capacity of the lithium means less required total capacity when compared to flooded lead-acid batteries. We use fewer kWh of power on an average day so I believe we can get away with about half that capacity. Now I am torn between going to lithium immediately or working out the present GC-2s for another couple of years.

I will have to move them inside the cabin which will mean relocating the inverter as well and routing new cables from the CC. Doing that will also mean the entire large exterior battery enclosure can be repurposed. So bonus #1.

Bonus #2 comes in the form of lithium recharging faster from the same size PV array as the lithium cells have lower internal resistance. Bonus #3 = no more watering.

Just be sure that the battery can discharge at the rate you need for the length of time you want. That may influence the choice of one battery or two smaller capacity in parallel.

[Dave Sparks]

Hi Guy's ! Been some time.  The other problem with Lithium is that you do have recharge them !  When going from an old lead acid that has lost capacity, the extra capacity of being able to go down to 10% Soc with lithium, will take more solar or gen run time.

Not a good thing to find out in Winter Offgrid,  especially if you are not close loop charging the LFP. 
Close loop is where you save the charge time Roger?

Don,  what ever happened to Glen the moderator? Hope you and Karen are Peachy!

[OlJarhead]

Thanks guys -- I received an email from a sales rep that said I'd need THREE of those LiPo batteries.  What the??? 

Not much point then.

But he basically said with my battery bank he'd recommend going to 50% of that (so 330AH) and then seemed to have math that said 450AH of LiPo equaled 330AH of Lead....ah...no.

But didn't seem to get that I'd only be using about 40% of the AH cap on the battery when I'm at the cabin nightly (and that's likely spring and fall vs summer when I have a lot more solar production)....at about 40% nightly I can't see why I'd need THREE $2500 batteries.....

What am I missing?  Seems to me ONE of those 24v 150AH batteries should be all I need if I'm only using a max of around 60AH between sundown and sunup....specially when I set my genset to run at 24vdc under load to prevent dropping very far (lol I know, that's probably way higher than most but I don't want to replace batteries lol).

[OlJarhead]

24V 3x MULE - LiFePO4 - 360Ah - 9kWh - BigBattery.com
$3400 for this bank of 3 120AH batteries giving 360AH of Capacity of LiPo backup which HAS to be better than 660AH of lead

[OlJarhead]

I received a reply back on the SimpliFi's and it was the draw each battery can handle vs the AH rating.  So yes, I'd be fine with just one batter as long as I didn't draw more than an inverter capable of around 1500 watts.

[OlJarhead]

Chatted with a sales rep on the Big Battery store batts above and he agreed those would do what I needed and then some.  So I may go with the https://bigbattery.com/products/24v-3x-mule-lifepo4-360ah-9kwh/?utm_source=Website&utm_medium=LearnMore&utm_campaign=Analyst&utm_id=ButtonsCamp setup.

I figure it will be a little heavy getting them into the back room and I'll have to do some changes but I'll end up with MORE capacity not less (I know it sounds nuts) and no more watering, worrying lol...just have to make sure they cant be killed but it sounds like they have a cut off to protect them.

[OlJarhead]

The only problem with these is I was just told they only have 3000 to 5000 life cycles but then I was told that is at 'normal usage' lol -- come on folks.  I schooled the salesman.  He then said that was at 100% DoD.

Since I'm running more like 15 to 20% DoD I'd get 20+ years out of them. 

If so I'm doing it.

[MountainDon]

I received a reply back on the SimpliFi's and it was the draw each battery can handle vs the AH rating.  So yes, I'd be fine with just one batter as long as I didn't draw more than an inverter capable of around 1500 watts.

Yeah, I was thinking it must be the continuous discharge rate. We don't use more than about 1200 at any one time if we pay attention to what we are doing.

I've not heard of 'BigBattery".