Building new Off Grid Home in Panama

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

vtmaps wrote: »

Just to be clear... You changed the discussion from 'maximum input voltage' to 'maximum watts or current'. They are very different types of maximums, and the consequences of exceeding them are different. For example, four of these 130 watt panels in series (520 watt array) will drive a classic beyond hypervoc before the sun comes up.

--vtMaps

My error, you are correct, I was relating to what would be gong into the batteries. The panels, Helios 7T2 305W panels that I am looking at have a Vmp of 36.7 and Voc of 45.08.. Putting two in series gives double and with 3 parallel strings keeps the max input voltage well below the Classic threshold, but the current will be triple.

Also looked at Cariboocoot basic controller configuration. If I configure the six panels in the array to 3 in series and 2 parallel strings, is there still no need for circuit protection on strings?

Cheers

Ernest

niel · May 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot wrote: »

Clarifying what vtMaps said: four of them in series on a Classic 150 would be a problem. 4 * 41 Voc = 164 Volts. The controller would not be damaged, but at that point it would be shut down.

Basics of panel configurations on MPPT controller: http://forum.solar-electric.com/showthread.php?16241-Different-Panel-Configurations-on-an-MPPT-Controller

gotta correct you marc as the controller would be blown if it was to a 12v battery, for the max on a classic 150 is 150v and adding the 12v from the battery voltage used puts the max at 162v before damage occurs. at 164v it is history under that circumstance. now you could use a classic 200 or 250 to up the initial voltage abilities of the controllers for their voltage designs are 200v and 250v respectively and they will still have the hypervoc ability adding that extra safety cushion against damaging higher voltages.

the real point is to be sure you design within a controllers abilities to keep power flowing and that's for any controller. hypervoc is an insurance buffer zone against a possible rare overvoltage condition that would destroy other controllers as they don't have hypervoc.

what i said about the shutoff of power applies to all controllers operating beyond their design voltage including the classic. the difference is the classic will not be destroyed for a minor incursion into the overvoltage area whereas the other controllers out there would be toast and will not produce power permanently.

Cariboocoot · May 2013

Re: Bulding new Off Grid Home in Panama

Niel;

I was going by the OP's sig data which says XW6048. On a 48 Volt system the limit is 198 Volts.
But yes it would be too high for a 12 Volt system.

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Blackcherry04 wrote: »

Any idea how they do the roof penetrations for Solar PV racking ??

We are just getting through this discussion. I am having custom brackets made that will be screwed into the metal structure below, after which we will mount two rails on these brackets that the panels will be attached to.

When I have them in hand, have to have them made, will post pics.

Cheers

Ernest

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Not for the faint of heart. Was at the local Ferrateria (hardware/general store) in San Carlos just down the road today. There are solar panels on the shelf. My friend Peter and i were looking at them with the possibility of putting in home made solar lights here at the development. Various sizes from 100W on down with the 100W panel at $380.00 US, it goes downhill from there. Just thought I'd let you know.

Cheers

Ernest

Cariboocoot · May 2013

Re: Bulding new Off Grid Home in Panama

Panamretiree wrote: »

Not for the faint of heart. Was at the local Ferrateria (hardware/general store) in San Carlos just down the road today. There are solar panels on the shelf. My friend Peter and i were looking at them with the possibility of putting in home made solar lights here at the development. Various sizes from 100W on down with the 100W panel at $380.00 US, it goes downhill from there. Just thought I'd let you know.

Cheers

Ernest

Are you sure you're not in Canada?

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot wrote: »

Are you sure you're not in Canada?

If I was having a good rib eye or some prime rib, yes I'd definitely say I was in Canada, but alas, I cannot, I will have to be content with the fond memories of such delicacies.

Cheers

Ernest

NorthGuy · May 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot wrote: »

Are you sure you're not in Canada?

In Canada, Rona sells 85W panels for $500.

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

NorthGuy wrote: »

In Canada, Rona sells 85W panels for $500.

Time to get out of Dodge. Socialism on the rise; ergo NDP in BC, Trudeau Mania; ergo socialism, good time to head south.

$11.50 a "24", daily wear - T-shirt, shorts, no socks, don't remember where I put the coat I brought down here, and the coffee is great.

Cheers
:cool:
Ernest

Cariboocoot · May 2013

Re: Bulding new Off Grid Home in Panama

Ah, but the NDP did not win in BC!

Still, we need some sensible economic practices up here. There's just no reason for our extra-expensive everything. They talk about being environmentally friendly, but for most of the country there's zero incentive to add solar or anything of the sort. BC even put the 7% tax back on insulation, weather seal, solar, et cetera.

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot wrote: »

Ah, but the NDP did not win in BC!

Still, we need some sensible economic practices up here. There's just no reason for our extra-expensive everything. They talk about being environmentally friendly, but for most of the country there's zero incentive to add solar or anything of the sort. BC even put the 7% tax back on insulation, weather seal, solar, et cetera.

Good for BC, although just a different/same tiger with different stripes, oops, tiger would infer that there was some teeth in what they do, toothless tiger sounds better.

Unfortunate there are no incentives for alternative energy, would make people feel better when the infrastructure goes down, and it stimulates the industry by spending dollars and creating jobs. This could create a cottage industry like the landscape/gardening, someone has to maintain the systems since not everyone wants to or has the ability to maintain a solar system, batteries and all.

Down here it would be a great business opportunity because most expats that talk about solar do not fully understand the maintenance implications, they subscribe to the "maintenance" free philosophy, build it and I should be able to leave it and it will perform as it should.

Anyhow, I digress.

Cheers

Ernest

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Update on the house solar project. Roof is on, have the panel brackets being made, and putting conduit in between house and workshop (10 foot run). Getting my head wrapped around how to bring some of the monitoring equipment into the house and where. Concrete is not a forgiving beast to work with (very messy). Contacted a customs broker in Panama City too determine the import requirements and who to contact for shipping. Paperwork is never done.

The interior ceiling grid is being installed. They use metal wall studs at 12 inch spacing and support it from the roof struts (cariolas). Pics to follow.

Cheers

Ernest

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Question for the masses: The system ail be in the workshop, have a power run of about, say 35 feet. Want to run in monitoring equipment like the trimetric. Can I use the same shunt for multiple meters, or do I have to put in separate ones?

Cheers

Ernest

Cariboocoot · May 2013

Re: Bulding new Off Grid Home in Panama

Not sure why you'd want multiple meters measure the same spot.

But two different meters (or one that can read multiples such as the Pentametric or OB's Flexnet) need a shunt apiece.

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Question: Having two Classic CCs, one the 150 and one the 150 lite, with the 150 as the main controller and using the Followme function, and the CCs are charging in parallel, do you need blocking diodes on the output of each Classic? I will be installing CCT Breakers on the in and out from each controller.

Cheers

Ernest

NorthGuy · May 2013

Re: Bulding new Off Grid Home in Panama

Panamretiree wrote: »

Can I use the same shunt for multiple meters, or do I have to put in separate ones?

I don't see any problem that would prevent you from using the same shunt for several meters, except that they all will be measuring the same thing.

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot wrote: »

Not sure why you'd want multiple meters measure the same spot.

But two different meters (or one that can read multiples such as the Pentametric or OB's Flexnet) need a shunt apiece.

Want to have meters in house and workshop, but don't want to go the workshop every time I want to look at the system. Looking at the Trimetric 2025 (had similar on our boat), and want to have a similar unit in the house. Have looked at the Classic and there is a master/slave function you can set up as well as a wireless network.

Have not read the XW operation manual close enough to know if there is a master/slave function there as well.

Cheers

Ernest

Cariboocoot · May 2013

Re: Bulding new Off Grid Home in Panama

Panamretiree wrote: »

Question: Having two Classic CCs, one the 150 and one the 150 lite, with the 150 as the main controller and using the Followme function, and the CCs are charging in parallel, do you need blocking diodes on the output of each Classic? I will be installing CCT Breakers on the in and out from each controller.

Cheers

Ernest

No, you most definitely do not use blocking diodes on the output of a charge controller. They won't work if you do because they won't be able to read the battery.

niel · May 2013

Re: Bulding new Off Grid Home in Panama

no you do not need blocking diodes on each classic's output and you shouldn't need the blocking diodes on the pv strings either.

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Cariboocoot wrote: »

No, you most definitely do not use blocking diodes on the output of a charge controller. They won't work if you do because they won't be able to read the battery.

niel wrote: »

no you do not need blocking diodes on each classic's output and you shouldn't need the blocking diodes on the pv strings either.

Thanks for the replies. One more issue to cross off the list.

Also got two quotes in one reply, now if I can find out how to access certain forums such as mine without going into my profile each time, I'd really be having a good day.

Cheers

Ernest

BB. · May 2013

Re: Bulding new Off Grid Home in Panama

You mean like near the top "Thread Tools" / "Subscribe to Thread"?

You can also get emails when your thread is replied too...

-Bill

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

BB. wrote: »

You mean like near the top "Thread Tools" / "Subscribe to Thread"?

You can also get emails when your thread is replied too...

-Bill

Have tried the "Subscription Threads" under Quick Links and have had no joy yet. Will keep experimenting.

Cheers

Ernest

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Had another thought about panel arrays. Read a post by Chris Olson where he stated that he puts in solar panels to take care of the 70% (or so) days and not the perfect day(s) when such days come along. With this in mind, I am installing two small solar arrays - 6 panels on front and 6 panels on back of roof from a suggestion by niel that made perfect sense (also have two CCs that adds redundancy to the system).

Having said this and in keeping with Chris Olson's sentiments on installing panels, installing a 3rd small array with a CC for the times that Chris speaks of would seem to be a less expensive system addition than more batteries and/or operating the genset for battery charging. During the times when there is significant sun exposure down here, one could isolate an array and just use two. Any thoughts?

Just pontificating and theorizing.

Cheers

Ernest

BB. · May 2013

Re: Bulding new Off Grid Home in Panama

Adding panels--Usually a good idea (once you get above ~13-25% rate of charge--Can be a waste of money and even hard on the battery bank with very high charging currents).

Adding battery banks/strings--Less so if you are trying to stretch beyond 2-3 days of storage. If the battery bank is undersized for the present loads--A different discussion.

I like automation--If you have a "manual array" switch--Someday, somehow, it is going to be switched on the wrong day/at the wrong time...

You seem to be pretty busy for a "retired guy".

-Bill

Cariboocoot · May 2013

Re: Bulding new Off Grid Home in Panama

What you're talking about is "stationary tracking": instead of one large array aimed solar South and producing maximum power all at once the panels are divided up to lengthen the time of equivalent good sun; some easterly, some southerly, some westerly.

You really don't have to isolate any of the arrays so long as the total peak charge current remains below the maximum the battery bank will handle - which is fairly easy to do because the batteries are somewhat self-limiting and the arrays will not produce peak current simultaneously owing to facing in different directions.

westbranch · May 2013

Re: Bulding new Off Grid Home in Panama

you could get another CL150 and have Follow Me in play so that if one senses a need to go to Float they all would go to Float...

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

BB. wrote: »

You seem to be pretty busy for a "retired guy".

-Bill

Bill - you are right - for a retired fellow I am fairly busy, and sometimes have more time so I can think of stuff. Have met other Canadians living here who have the same issue(s), how did we ever get all this done and work at the same time.

One also have to have a reason to get out of bed in the morning as well. My Father told me that even though you retire, you have to have something to do. He was a mechanic, but when he retired, he started making wooden children's toys, sold them at craft fairs.

Cheers

Ernest

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

westbranch wrote: »

you could get another CL150 and have Follow Me in play so that if one senses a need to go to Float they all would go to Float...

WB - will have 2 CCs, one 150 and one 150 lite. Have read the manual for the Classic. Like the "Follow Me" function and how CCs are controlled using it. Also like that the the 150 lite can be programmed and monitored through a 150.

As I am typing this, the power has gone out for the second time this evening, hate being in the dark.

Cheers

Ernest

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Have the panel roof supports made. The panel support system will be comprised of 4" galvanized channel secured to 5-brackets that will bridge the roof corrugated design. The distance from peak to peak is 7" so I am spanning 14" with the roof bracket. There will be 5 brackets per 20'section of galvanized channel.

First picture shows the profiles of the roof bracket and 4" galvanized channel to be used.

Attachment not found.

Second Picture shows profile of roof bracket (upside down)

Attachment not found.

Third photo shows how the brackets and 4" galvanized channel will be installed on the roof. You can also see why I've had to have special brackets made for this type of roof.

Attachment not found.

Cheers

Ernest8)

Panamretiree · May 2013

Re: Bulding new Off Grid Home in Panama

Looking at finalizing the design.

First conundrum is 48V versus 24V. The battery bank will have the same power either way; 2 strings of 4-420 AH L16 batteries, or one single string of 8-420 AH L16 batteries. Watts is watts, lower current from 48V instead of 24V.

I did a daytime/night time load analysis from my initial load analysis and found that my night time loads - ~3200 kWh - would be adequately handled by 4-L16 batteries in series in a 24V configuration. This would draw the batteries down ~50% each night and not leave much for the morning when we want our coffee, eggs and toast. This lead me to the second string that would provide the requisite additional power for us in the morning. The batter bank would now only be drawn down 25% during the night, and some more in the morning until the arrays get percolating. Of course this is from an educated guess process and won't know the actuals until we get into the house and start using the system. I also think I have missed a couple of loads that will pop up in our future.

Using a 48V system there is the same power available fro a string of 8-L16 420 AH batteries. It does minimize a few connections and some components, and no need to consider upgrade in the future. I did read that the current draw in a 48V system is lower; therefore the batteries are not "shocked" with huge draws and may be better for longevity of the battery bank. I do realize that regardless of amp draw, 3100 kWh from a 24V battery bank is the same from a 48V battery bank, the only difference for a 24V system is that 2 strings of batteries are need to equate to the same power from a 48V system - straight number crunching.

Another supporting argument for a 24V system with two strings of batteries is that one string can be taken off line for maintenance, troubleshooting, etc. Have read where batteries should be taken off line and allowed to "rest" to get an accurate battery condition. Question for the Magisterium - for those completely off-grid -equalizing batteries, if what I've read is true, how does one achieve this maintenance aspect and keep the system operating if you are supposed to take the battery out of operation to do this. My take would be that you either use a genet for the maintenance period, or you have additional batteries, or strings of batteries to swap out. Just curious.

Adding a third string of 4-L16 batteries to the 24V system would only be $2K versus a 2nd string for the 48V system of $4K, something to consider.

Have a local distributor - Panama City - for the batteries. Inquired as to how "fresh" they would be. Email back indicates that all batteries brought in are within 90 days of manufacture, and they are fully charged when delivered. Will be asking for the charge sheets for SG and length of time that was needed to get to the specified SG - not too much to ask - they can only say no to the request.

AC is still not out of the question as there are spit-AC units on the market with good SEER ratings, and even 120VAC units. Awful muggy here right now, and one does need a good nights sleep to enjoy one's cerveza. Still researching this aspect of our build. 240 VAC would be required, going to look into the different settings available on the various units.

For the 24V system, I will use a Schneider XW4024. For the 48V system I have a choice, mainly because of price point, the XW4548 and the XW6048. There is only a difference of $600.00 between the XW4024 and the XW6048. Using generator support, a lot of the advantages of a larger inverter/charger/system is negated; however, the output AC current does go from 37.5A for the XW6048 to 30.9A for the XW 4548 to 27.5A for the XW4048. I imagine that generator support will be more crucial for the 24v system than the 48V system, and the setup such that the genet would operate more for the 24V system.

Both systems will have generator support. Still trying to source a good Honda genset down here.

Have decided on two arrays, one on the front of the roof, the other on the rear consisting of 6 panels each, configured with two panels in series with 3 strings into a combiner, then into two Classic controllers. I would use a Classic 150 as the master and slave a Classic lite for the second array.

This would provide approximately from each array (using the MidNite Classic String Sizing tool):

Rated PV Array Power: 1830 Watts
Anticipated Array Power @ 104F: 1717 Watts
Rated PV Array Current: 24.9 Amps
Battery Charging Current @ 28.8 V: 63.5 Amps
VMP (Maximum Power Point Voltage) : 73.4 Volts
VOC (Open Circuit Voltage): 90.16 Volts
VMP @ 75 F°: 73.8 Volts
VOC @ 75 F°: 90.4 Volts

Having two arrays will require two CCs; however, this gives me redundancy should one head south for whatever reason. Using this configuration for a 24V system with a battery bank of 840 AH (2 strings of 4-L16 420 AH batteries) has a charging requirement of 84 amps at 10%. With these two arrays there should be sufficient PV for this battery bank. I have also considered maxing out the forward array with 2 extra panels giving:

Rated PV Array Power: 2440 Watts
Anticipated Array Power @ 104F: 2290 Watts
Rated PV Array Current: 33.2 Amps
Battery Charging Current @ 28.8 V: 84.7 Amps
VMP (Maximum Power Point Voltage) : 73.4 Volts
VOC (Open Circuit Voltage): 90.16 Volts
VMP @ 75 F°: 73.8 Volts
VOC @ 75 F°: 90.4 Volts

I would do this only on the from array because it gets no shading from earl morning to late afternoon. The rear array would have the two extra panels shaded in late afternoon.

The array values for a 48V system configured as 2 panels in series and 3 parallel strings look like:

Rated PV Array Power: 1830 Watts
Anticipated Array Power @ 104F: 1717 Watts
Rated PV Array Current: 24.9 Amps
Battery Charging Current @ 57.6 V: 31.8 Amps
VMP (Maximum Power Point Voltage) : 73.4 Volts
VOC (Open Circuit Voltage): 90.16 Volts
VMP @ 75 F°: 73.8 Volts
VOC @ 75 F°: 90.4 Volts

The two arrays should be sufficient to charge a 48V battery bank consisting of 8-L16 420 AH batteries. Having 8 panels on the front roof area configured as 2 panels in series and 4 parallel strings gives the following data:

Rated PV Array Power: 2440 Watts
Anticipated Array Power @ 104F: 2290 Watts
Rated PV Array Current: 33.2 Amps
Battery Charging Current @ 57.6 V: 42.4 Amps
VMP (Maximum Power Point Voltage) : 73.4 Volts
VOC (Open Circuit Voltage): 90.16 Volts
VMP @ 75 F°: 73.8 Volts
VOC @ 75 F°: 90.4 Volts

8 panels on the front roof and 6 on the back roof, for a 48V system should be sufficient to provide adequate charging and load support during the day.

Should an upgrade to 48 V or simply installing a 48V system, array values above stay the same, but there is more room for array growth in the future. I do believe there is sufficient capacity in the array should a 3rd string of L16 batteries be required, for whatever reason, in the future. Have read on this site, build it and it will grow.

I do like the notion that a 24V system allows one to use generic electrical components for system modifications, whereas with a 48V system, it is not as straight forward.

I will be using 1/0 gauge for grounding the arrays. The grounding for the system will be 3-4 5' pieces of 1/2" rebar pounded into the ground.

I'm thinking 6 gauge wire with a 60 amp breaker from the arrays to the CCs, and #10 wire for panel to combiner. I will use #4 from the CCs to the batteries with a 100 amp breaker.

I had initially thought to use two combiner boxes, but in thinking about it, I think having a 12 place combiner box that can be split to use with two arrays is a better way to go. This also allows me to install it on the rear roof side and just running the wires from the front array over to the back. have to think about esthetics as well.

I intend to use the Scneider XW power distribution panel to tie the inverter/charger, genet, and batteries together. I have chosen this option because sourcing component availability down here is not the easiest.

I'm thinking it would be a good idea in the 24V system if each battery string had its own cct breaker to protect it from the system, or the system from it. This would be before the DC disconnect in the distribution panel.

I will be installing a Trimetric Battery Monitor, although the PentaMetric Battery monitor has some features that are interesting as well. I have used the Trimetric on our last boat.

I have looked into remote monitoring of the Classics and the XW inverter/charger and it is all possible through a wireless network. I would also consider get a second PC and dedicate it to monitoring the solar power system.

Other niceties would be individual battery monitors (voltage only) to start.

Have considered looking into wind, but know that I will need to do a wind survey of where the house is to make sure it is feasible. The times when it will be needed is during the wet season down here. if wind is feasible, will need to ensure the wind turbine design is acceptable to the development as well. Will be looking at getting "A Wind Turbine Recipe Book" (Chris Olson's recommendation). Even if I don't use a wind turbine, always nice to read and become informed on a subject that may in the future come handy. Need to source an anemometer so I can get this going this fall after we move into our house, and after we get the solar system installed and going, and in between the honey-please-help-list/projects.

Anyway, long story. I believe I have it fairly well nailed down, with the exception of the 24V versus 48V system. All constructive comments accepted. Hope I've hit a lot of the high and low points, and got into the weeds a bit.

Looking into how to import the solar system into Panama. Hope to have everything sussed out by end June so I can order the system and batteries. The mounting system for the solar panels is already on site. Will be having hold downs made for the panels.

Cheers to all.

Ernest

Building new Off Grid Home in Panama

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