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diy solar

The Electrodacus SBMS thread (SBMS0, DSSR50, etc)

i never said that anything about ohms law. but I am clearly getting anywhere from 35 to 60 amps charging the battery at 55 feet to 60 feet of 10 AWG wire with 6 250-watt used polycrystalline panels using the 3 DSSR20 digital solar charge controllers

Still no measurement of the losses... You can pass whatever amps you want but that value alone is useless to know the losses.


the voltage I just measured was 27.48, 27.58 and 27.68

Ok, now we're talking, but we need the battery voltage at that time to know the voltage drop.
 
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the battery voltage is in the previously posted picture but not at the exact same time the measurement at the 3 breakers was taken with the multimeter; when I took the measurement at the breakers was maybe an hour later out of curiosity when the DSSR20's were not charging. I would say there is about 2 feet of 10 AWG PV wire between the breakers and the DSSR20's. the battery will act as a big resistor as I understand it. but is still being charged readily to 100 percent state of charge.
i can't measure the battery voltage right now as it is not getting any charge until it uses more from the battery. charging by the DSSR20's is turned off by the SBMS0. the SBMS0 turns the DSSR20's off so the battery does not get overcharged.

when it uses 3 percent of the energy stored in the battery, then the DSSR20's will be turned on again by the SBMS0 via the small 23 AWG sense wires (solid strand cat 5 cables). the DSSR20 gives all that the sun offers up to 24 amps per DSSR20 and I have seen over 60 amps (utilizing 3 DSSR20's) in good sun.
the inverter I think is only 1/0 maybe. the second inverter is set up with 4/0 but not yet installed. waiting on delivery.
 
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pictures are poor off the cell phone. maybe I can change the color on the SBMS0 sorry people. I can blow them up on my monitor but that is another place - a different computer. see what I can do for picture resolution.
 
if you want voltage drop from panels to the breaker you would have to measure the voltage at the panel and at the breaker and measure the 55 to 60 feet of PV wire to be accurate there.
then 2 feet more to the DSSR20 of 10 AWG is minimal. then it goes through another 2 feet 10 AWG to the busbar then another then maybe 3 feet of 2 AWG wire to the main negative and positive bus bars. then 18 inches of 4/0 to the battery.
so another 4 feet of 10 AWG, then 3 feet of 2 AWG then 18 inches of 4/0 for that voltage drop calculation.

27.48 volts, 27.58 volts, and 27.68 volts was at the breaker after 55 to 60 feet of 10 AWG outside plus a Temco branch connector (maybe 15 inches long) combining the 2 panels in parallel outside at the solar panel array.
so perhaps I may have 59 to 63 feet of 10 AWG then 3 feet of 2 AWG then 18 inches of 4/0 for voltage drop and still charging the battery with 35 to 60 amps depending on the sun, with 6 used 250-watt 60 cell polycrystalline PV panels.
I will add 6 more panels to the south in a few weeks. I expect to get 100 to 120 amps charging then for a faster charge and more power to use quicker.
every connection has some resistance as well but still charging with the used 23 cent per watt solar panels!

beats the heck out of a noisy generator any day.? 65 degrees at 3:59 p.m woohoo spring is near.
 
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Your data is a bit incomplete. It would be great if you include the voltage at the solar panels. The 3 sets of panels should have equal voltage, but good to check. If possible at the same time the panel voltages are measured, current and battery voltage is also recorded. Now you'll have data that has some meaning.

Edit: Ambient temperature is also important. If possible behind the panels.
 
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Your data is a bit incomplete. It would be great if you include the voltage at the solar panels. The 3 sets of panels should have equal voltage, but good to check. If possible at the same time the panel voltages are measured, current and battery voltage is also recorded. Now you'll have data that has some meaning.

Edit: Ambient temperature is also important. If possible behind the panels.
yes if voltage drop is an issue. I know there are many missing data points. every time there is a new connection there is more resistance you would have to add all of those in as well and have more accurate wire length measurements to calculate the total voltage drop. perhaps the used 60 cell 250-watt polycrystalline panels put out more than the label says. the open-circuit voltage is not a factor, as it is the connected current and connected voltage which would have real meaning is how I understand it. as the temperature climbs, they will not do as well as solar panels prefer the cold.
I use the battery more in the nighttime to run light in the barn (A huge old 2 story 40x50 barn with 18x50 lean-to attached - this is what caught my eye when I bought the property some 25 plus years ago) and in the solar power shed etc. now there is a voltage drop of 5 extension cords(likely 150-175 feet) running a 250-watt heat lamp for the baby animals all night long from the inverter which is probably only 90 percent efficient. I also have all the battery chargers running to keep the batteries in the hand tools and diesel skidloader and diesel truck charged to use some more solar power. need the AC breaker box wired but slow as anything when you are the only one in the DIY off-grid build.
I use as much as I can when the solar is plentiful during the day.
i will make it function more efficiently with the better outside working weather just around the corner. from 25 degrees below zero 2 weeks ago to 65 degrees above zero today. that's a 90 degree Fahrenheit temperature swing. I have 90 feet of 2-inch plastic conduit (I scored for $20 dollars) I will route some wires underground and some I may put above grade at 7 feet to decrease my wire run length. the current is what charges the battery. how many amps flow at a voltage higher than the battery. LiFePO4 is liking all the amps the solar can give it at the moment.3.4 x 8 = 27.2 volts which seems to be the flat part of the curve for long life. when any cell reaches 3.55 volts for a preset time the SBMS0 turns the DSSR20's off to prevent overcharging the LiFePO4 battery. more later when I can add more real user data. ?
maybe when I get it all finished I will sell it to get away from the taxation rat race. I have 2800 secluded acres in the mountains I have also been building on for the last 21 years (My real pilgrimvalley farm). burned out 5 generators there. noisy darn things.
 
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I don't see any problem other than his SCC is rated for only (I believe) 20A. If you want to switch 400A then 20 of his SCC are required. If you have 10 kW of panels then a more suitable CC needs to be chosen. You don't have to use his SCC. Use a mppt controller and connect panels in series to reduce current and wire losses. The charge controller requires hardware to accept a shutdown signal from the bms.




Not necessarily, it all depends how the system is setup. The bms can be the first (primary) disconnect or the last resort disconnect. It it's used as the first disconnect then there will be lots of spikes. My system uses the bms as the primary disconnect. Should the bms fail to do its job then the mppt cc will limit charging voltage to a safe level.



That would be a problem. Perhaps with my mppt cc also. There is no backup plan when using his SCC.
seems like the same question/potential problem ---- as MPPT also have fets and also dc-dc converter losses with the other electronic components, Capacitors etc to break down over time, therefore, having just as likely a potential to break down so would not protect the battery either. the purpose of the SBMS0 is a BMS to protect the high-priced LiFePO4 battery from being overcharged which it does quite readily as it monitors each individual cell and shuts down the charging via small sense wires. I bought the SBMS0 to monitor and protect the DIY expensive (Lishen 272Ah cells) battery investment. at least that was the primary reason for me and I liked the 3 digit accuracy. if I understand the balancing correctly by watching his video the tiny fets just shift the charge voltage to lower charged cells vs the higher charged cells - a switching mechanism to balance the cells while charging (balances the 24-volt LifePo4 battery). - just get the 2 shunts hooked up to the positive side for the monitoring measurements of PV in and load. the DSSR20 is a very small digital solid state relay that is not a PWM or an MPPT. it sends a constant current (all that the PV panels can send) to charge the battery. I bought 4 of the DSSR20's with diversion to use the heating idea from the excess solar PV electricity generated.
I have no problem connecting 2 10 AWG PV wires for every 2 panels connected in parallel. this is easy for DIY people. the DSSR20's do not have the dc-dc converter losses as they do not use that method to charge.
i never seen any better way to protect the battery being offered up. my system will be redundant so if something goes wrong, I will be able to remedy it in relatively short order. I went through a power outage for 3-4 days due to an ice storm one winter 20 years ago (so I try to prepare for the unexpected or at least have a second way to cure the problem. propane furnaces do not work without electricity. so a properly vented propane heater not requiring electricity is the short term answer to that problem. all-electric off-grid is still the ultimate goal at the moment though.
a good carpenter fixes all his mistakes. over 45 years I made a lot of mistakes in carpentry, electrical, plumbing etc but learned to do a good job. my scientific laboratory background demands precision - something the younger generation does not want to do.
just have a Vietnam veteran tell you in no uncertain terms doing it right the first time is the main thing- doing it right the second time ain't quite the same thing --- while doing commercial roofing in college gives you the personal satisfaction to always do your best. I have worked on watertowers, powerplants, hospitals, national disease laboratories doing research etc. 2 jobs for over 40 years.

Dacian is quite knowledgeable, I think English is not his first language possibly french in Canada. but likely the most helpful after the sale vender you will find.
 
if I understand the balancing correctly by watching his video the tiny fets just shift the charge voltage to lower charged cells vs the higher charged cells - a switching mechanism to balance the cells while charging

Nop, it's a resistive balancer. Look at the datasheet of the chip (the one from TI IIRC) he used for more infos on that ;)


my system will be redundant so if something goes wrong, I will be able to remedy it in relatively short order.

Your system has no redundancy, be it on the charging side or the loads side, and personally if I put a BMS on a battery it's to not have to watch the battery myself (i.e. being a human BMS), especially since you're likely to not act quickly enough in case of a problem.


my scientific laboratory background demands precision

Then do not mistake resolution for accuracy please, the SBMS0 is far from accurate to the 3rd decimal (he actually had to do like the chargery BMS and consider anything under a certain value as 0; definitely not accurate to what resolution is displayed). Justifying the SBMS0 is great using that kind of false assumptions is what annoys me, please look at the real data instead of using assumptions. I'm not saying the SBMS0 is bad, but just that you (and some others) seems a bit too blinded and present this BMS like the next miracle based only on feelings and what you probably saw in videos instead of facts.


I have worked on watertowers, powerplants, hospitals, national disease laboratories doing research etc. 2 jobs for over 40 years.

You keep repeating your degrees, jobs, etc... but it doesn't make what you say more true or false, it just allows you to make arguments from authority.
 
Nop, it's a resistive balancer. Look at the datasheet of the chip (the one from TI IIRC) he used for more infos on that ;)




Your system has no redundancy, be it on the charging side or the loads side, and personally if I put a BMS on a battery it's to not have to watch the battery myself (i.e. being a human BMS), especially since you're likely to not act quickly enough in case of a problem.




Then do not mistake resolution for accuracy please, the SBMS0 is far from accurate to the 3rd decimal (he actually had to do like the chargery BMS and consider anything under a certain value as 0; definitely not accurate to what resolution is displayed). Justifying the SBMS0 is great using that kind of false assumptions is what annoys me, please look at the real data instead of using assumptions. I'm not saying the SBMS0 is bad, but just that you (and some others) seems a bit too blinded and present this BMS like the next miracle based only on feelings and what you probably saw in videos instead of facts.




You keep repeating your degrees, jobs, etc... but it doesn't make what you say more true or false, it just allows you to make arguments from authority.
again i do have a redundant system in the works so you are wrong on that point again. the sbms0 balances the cells while charging them. it is working as i have it assembled.
you offer no solution that is better.
what is your perfect system?
what do you use?
show some real data. real-time pictures of what solar pv system that you actually have functioning.
the dssr20 is an economical solar charge controller.
the sbms0 also functions as it is designed (a bms to protect the battery from being overcharged) without any heat issues.
show a more effective solution for the same cost.
i am sure you can not nor will you as you have nothing to show.
some people are interested in the sbms0 and dssr20 system some are not.
 
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Off-Grid Solar PV DIY using Elecrodacus SBMS0 and Electodacus DSSR20:
word police go away. the SBMS0 balances the individual cells in the 24-volt LiFePO4 battery as it charges from the DSSR20 (the digital solid state relay - which is the solar charge controller I am using in this 24-volt build), using 60 cell 250-watt used polycrystalline PV panels.
it all functions as intended.
I have 2 of the SBMS0 monitoring redundant systems currently.
i like to check on it but have had no problems ... it functions as it is designed 24 hours a day 7 days a week.
no high heat going through the SBMS0. no wires to solder either as some other brands of BMS use.
uses standard 10 AWG PV wire to the DSSR20's and onto the busbars. I also am trying some terminal blocks to combine some 10 AWG wires on the negative side wiring,
the SBMS0 has a 28 AWG ribbon cable to connect to the individual cells via a 10 pin connector(supplied).
the installer must get the current shunts and the category 5 or 6 wire to connect the sense wires to shunts.
again no big current goes through the SBMS0 - no large wires used.

you can control the inverter here also at the SBMS0 but I have not done that part yet (I have to get the switch issue in the inverter solved 1st).

when any cell reaches 3.55 volts for too long of a preset time it turns off the DSSR20 and charging stops on the battery. then when enough of the battery capacity (3 percent preset) has been utilized from the load side (inverter or direct dc wired things) the SBMS0 will turn the DSSR20's back on to charge the battery some more.
there is no real large amount of useful amp-hours above 3.55V and charging to 3.65V will only decrease the LiFePO4 battery life span.
my LiFePO4 stays around 27.2V or slightly less most of the time 26.9V right now as the sun is just starting to offer a small charge current to the battery via the 6 250-watt used polycrystalline PV panels and the 3 DSSR20's (south-facing array with panels mounted at 45 degrees).
looks like it is sunny to partly cloudy out this morning. more snow will melt and the country driveway will dry a bit more.

my current project is an off-grid DIY stationary 24-volt LiFePO4 build using inexpensive 60 cell 250-watt polycrystalline panels utilizing the Electrodacus SBMS0 and Electrodacus DSSR20's (some with diversion in the later part of the build). I also have 2 of the Electrodacus DECT16 to aid the management of some of the small control wires. each SBMS0 monitors and balances a 2P8S 16 cell Lishen LiFePO4 battery with a potential 13926.4 watt-hour capacity. I need to increase the load to the AC wiring presently.
the design is to run all the electric needs and hopefully the heating needs next winter with off-grid solar PV.

I will try to get a better cost and time to recoup the investment done in the excel spreadsheet to share in another place.?
 
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again i do have a redundant system in the works so you are wrong on that point again. the sbms0 balances the cells while charging them. it is working as i have it assembled.
you offer no solution that is better.
what is your perfect system?
what do you use?
show some real data. real-time pictures of what solar pv system that you actually have functioning.
the dssr20 is an economical solar charge controller.
the sbms0 also functions as it is designed (a bms to protect the battery from being overcharged) without any heat issues.
show a more effective solution for the same cost.
i am sure you can not nor will you as you have nothing to show.
all blow no show.
show your system on the proper forum or stop your useless banter.
some people are interested in the sbms0 and dssr20 system some are not.
an armchair commentator -- show real data of your actual results. you have nothing!

Sorry, I'm not playing "who has the biggest"... ?
 
As the person who started this thread, It is open to everyone whether they own the SBMS or not, whether they like the SBMS design model or not, so long as their participation is in good faith and on topic and not detrimental to the conversation. This is not a fan club or owners group, it is a thread for information, discussion, debate, questions, etc.

Bidule has his issues with the SBMS design model, some of these points I agree with, some I don't, and some I understand but don't fully agree with. That is okay. Actually that is good. Everyone learns more when there is a diversity of opinions.

The SBMS0--I suppose due to its unique design model, and some unorthodox design choices--seems to breed some number of true believers, evangelists almost, as well as equally absolute opponents. In my opinion, at both extremes their is a deficit of openmindedness and mental flexibility and inquisitiveness.

I hope that in this thread we can try to stick to the spirit of openness and avoid letting our opinions/beliefs calcify and harden. The SBMS0 is very unique and very unorthodox, makes some 'opinionated' design choices and (the point that doesn't get enough attention) is very flexible. So its normal and to be expected that there will be disagreement, differences of opinion, and different priorities. But lets keep it civil and respectful and openminded. Nobody should be telling anyone else to 'go away' or that their perspective doesn't matter without first hand experience.

Carry on
 
My 2c:

On the point of flexibility,
the thing with the SBMS0 is its designed particularly around Dacian's preferrred and unique model, and that model goes against a number of orthodoxies, which is a big part of what causes people to be both attracted to it and skeptical/resistant to it :).

BUT, the SBMS0 is also designed to be pretty damn flexible. You can use or appreciate the SBMS0 even if you don't subscribe to one ore more aspects or premises of Dacian's design model or the premises that underlie it. I personally am not sold on every one of his premises, I think he gets tunnel vision on particular use-cases and has a hard time understanding different use cases or different priorities.

But I still really like the SBMS0 because, his way is not the only way (and he specifically designed it to be that way). If you don't buy into the argument against mppt, don't worry, you can use MPPT. If you don't like the idea of the BMS being your first and only protection layer, set it up so that its not the only protection layer, it is at least as flexible as a Chargery or FET based BMS in this sense, arguably more so. If you could care less about 'diversion'/thermal energy storage, ignore it.. Etc etc. In most cases there are tradeoffs, but for those not sold on all of Dacian's broader design decisions (or who just have different priorities) you can still get many of the selling points without fully implementing his design. The DSSR20 is a completely optional and separate component.

On the other hand, some things are not so flexible. Want a 48V SBMS, you are shit out of luck. Want separate temperature limits for charge and discharge, again shit out of luck. Don't like the idea of the shunts on the positive side, shit out of luck. Want a fuse or switch directly on the positive main battery terminal, not going to happen without risking damage to the BMS. Want a color other than Orange/Yellow, too bad, its Dacian's favorite color ? (this last point is both meant as a joke, but is also actually true, and broadly illustrative of his design: its his project, based around his preferences, and while he is fairly responsive to community/user feedback and sometimes requests, he isn't beholden to it and isn't trying to market to the masses and seems pretty confident and happy building it the way he wants, and accepting that some people will like it and others won't). Sometimes this feels fairly inflexible but he always has his reasons, usually logical ones, even if I don't always agree with the logic, I can usually understand his thinking.
 
One of the most valid (but mitigable) criticisms of the SBMS0 default design model in my opinion is that it introduces a single point of failure. But this is also an area where I think there is a decent amount of flexibility. I believe @Airtime has considered/discussed this in the past here and on Dacian's message board.

(this is a point I would definitely be curious to learn more about / here solutions to or pros/cons of different approaches)
 
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I’m absolutely no expert on anything discussed here. Was it Lincoln who said better to read forums and be thought a fool than to comment on them and remove all doubt?

We had a grid tied system installed on our home 8 years ago (doh, moved 4 years later so that wasn’t the smartest purchase). Several micro inverters failed, so panels on the roof racks had to come off to repair/replace them. Warranty job. Didn’t look like the fellows were having a fun time up there in the snow.

No doubt Dacian designs his system and devices based on his preferences. Sounds good for off grid use with some caveats. Cable losses during peak sun. Any voltage you like so long as it’s 24. But nice if you have space for many (ground mounted- so much easier) $35 used 60 cell 250w panels. Build a smaller battery pack and dump the excess power straight into wires buried in the concrete floor. What’s not to love?

Doesn’t work for me in the city, though. Grid connected, tiny lot, no space for mounting panels on this 1908 double Dutch roof. Our electric/gas bill is under $165/month. But who knows, maybe someday, never say never, etc.

We’ve had 2 years of trouble free use with his SBMSO in our Sprinter controlling an mppt and lots of connected relays.

Folks had strong opinions about the Pinto, the Pacer, and the Vega. Atari or Coomodore. Wax Cylinder or wire recorder. Galaxy or iPhone. So it goes with technology. Great to have free thinkers in the world like Dacian.

The Pacer was pretty cool though ?
 
One of the most valid (but mitigable) criticisms of the SBMS0 default design model in my opinion is that it introduces a single point of failure. But this is also an area where I think there is a decent amount of flexibility. I believe @Airtime has considered/discussed this in the past here and on Dacian's message board.

(this is a point I would definitely be curious to learn more about / here solutions to or pros/cons of different approaches)
It only introduces a single point of failure if you choose to design your system that way. Totally up to the system designer.

Before commenting more on that, I'll just note again that I design for the BMS to have primary control of normal charging--like Cal, who I originally got that idea from. This is inverted from the more typical model of various charge controllers being primary and the BMS just as a second layer emergency disconnect.

Why? I like to have normal charging controlled by something that knows the real state of the battery at a cell level, not just based on the crude metric of pack voltage. Only the BMS knows cell voltages. Hence, I like the BMS to be in primary control in normal operation. That is one of the main reasons I like the SBMS0, since it is designed specifically for that use case.

Back to the single point of failure... you can still have multiple layers of protection even if you have the BMS in primary control of normal operation. For example:
- DC loads--I use a Victron BatteryProtect. In normal operation the BMS controls it, but it also has its own LVD if the BMS fails. Also, my fridge has it's own LVD built in, so I actually have 3 layers of protection on the fridge :).
- Inverter/Charger--in normal operation the SBMS0 controls charge enable and discharge enable. But my Victron Multiplus has its own HVD and LVD protections that will kick in if the BMS fails.
- Solar charging--here's where you do get a single point of failure if you use Dacian's default assumption of SBMS0 with DSSR and nothing else.

I ultimately decided not to go with the DSSR for my base system and instead have a Victron MPPT SCC. Two reasons:
1) I can control it from the BMS for normal operation, but it also its own protections that can kick in if the BMS fails. It gives me a second layer of protection for solar.
2) I'm not sold on the DSSR efficiency claims. Much of Dacian's arguments are from what he sees as an economic argument including for example the cost of DSSRs vs SCC amortized over a 30 year period etc. Kind of like how he argues against alternator charging in a van because diesel is way more expensive form of energy generation. Frankly I don't give a shit about either of those, I just want reliable multiple sources of charging in my van.

Once I finish the rest of my van I may yet experiment with DSSR on one of my solar panel pairs and the Victron on the other, just for my own curiosity. But my default system design is based on SBMS0 for BMS, a DIY pack, and Victron equipment for the rest. BMS in primary control, Victron protections as second layer. No big disconnect relays or FETs.
 
I have nothing against SBMS0. If I hadn't seen and purchased Chargery, SBMS0 would have been my first choice.

There's no reason to use DSSR. Is it supposed to be cheap, or cost effective? There are other options that cost less and support fault redundancy.

This 30A pwm charge controller costs just $13. Unlike the DSSR, it limits charge voltage to a safe level. In addition a relay or fet switch needs to be added at the panel for the primary overvoltage disconnect.

 
I have nothing against SBMS0. If I hadn't seen and purchased Chargery, SBMS0 would have been my first choice.

There's no reason to use DSSR. Is it supposed to be cheap, or cost effective? There are other options that cost less and support fault redundancy.

This 30A pwm charge controller costs just $13. Unlike the DSSR, it limits charge voltage to a safe level. In addition a relay or fet switch needs to be added at the panel for the primary overvoltage disconnect.

that is definitely a very cheap price for the PWM controller. nowhere in the listing does it state that I read how many watt PV array it will support? who will warranty that cheap 13 mppt? will your insurance go along with it?

I think I bought one like that 18 years ago and took it down to Bolivia South America to run a solar panel to charge the 12-volt battery in the off-grid mountain homestead. not being used anymore and was only used to charge the battery for the Toyota land cruiser and CBT diesel tractor.
Natives were skeptical of all electrical things it seems especially electric fences! haha ? I definitely was a gringo to the Bolivians.
The Mennonites and Amish I worked with were also afraid of the computer and 666. they have modernized a bit - some have others are still very strict what they allow. the local Bolivians were later all given (by socialist president Evo Morales) a small solar panel and some type of controller (never seen it) to run a light in their off-grid homes. 18 years later they have 230 volts (50 Hz I think) Electric grid running through the valley 2 wire 230 volt so I also implemented that on the mountain farm there. a whole different ballgame than 220 240 we use in the USA. seem a bit scary to me without the 3 wire and 4 wire grounded system Split Phase I was used to dealing with in the USA. We burned out 5 generators in many years of building in the mountains. gas and diesel generators are the worst. of course, it was for lead-acid batteries as I had no access to any LifePO4 if they were even being made back then.

I want to do a DIY hydroelectric there and have tons of water running through the mountain valley. slow but sure. the new pic is the extension which is attached to the Molino (mill building) which was designed for a water wheel. all used for living quarters etc presently. doing an off-grid kitchen using wood-fired stoves and ovens at the moment there. ?
we are so spoiled in the USA - but I want to get away from the taxation rat race anyway. waiting for the covid vaccine at the moment.
off-topic - sorry.
there is a 35 percent tax to bring things new into Bolivia so tools are selectively brought that are used. and new expensive things if you can find them are bought in Bolivia.
 

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I have nothing against SBMS0. If I hadn't seen and purchased Chargery, SBMS0 would have been my first choice.

There's no reason to use DSSR. Is it supposed to be cheap, or cost effective? There are other options that cost less and support fault redundancy.

This 30A pwm charge controller costs just $13. Unlike the DSSR, it limits charge voltage to a safe level. In addition a relay or fet switch needs to be added at the panel for the primary overvoltage disconnect.

the use of the Electrodacus DSSR20 is also for diversion to heat water and heat the floors of the house with the excess solar electricity generated from the Solar PV panels in the winter. the DSSR20 with diversion is cost-effective this way.

again this is an off-grid DIY build with LiFePO4 batteries stationary I will have about $10,000 invested for a 10,000 watt PV array including 20 DSSR20 charge controllers, and 4 13926.4 watt-hour LiFePO4 batteries, 2 inverters, etc.
then uncle sam will give me back $2600 so the net cost is about $7400 dollars. I think the payback period will be about 3 years from the electric and heating savings.?
it is not for everyone but I think it is a very good way to build a DIY off-grid system at a safe low voltage. ?

LiFePO4 batteries were the most expensive part of the $10,000 investment($3063.80 and $2903.19 = $5966.99 including delivery to South Dakota from alibaba.com for 64 Lishen 272Ah cells).
$5966.99/64 = $93.23 per cell average including delivery! 13926.4 x4 = 55,697.6 watt hour potential battery storage capacity.
$5966.99 divided by 55.697 kWh = $107.13 per kWh for the LiFePO4 battery storage including delivery.
Although the Lishen 272Ah cells have been reported to do 280 to 285 Ah per cell I choose to use the lower number of 272Ah.

I bought 24-volt water pumps and 24-volt water heating elements to use more solar PV-generated electricity. I have 14 DC direct-wired led lights and would like some more as no inverter is needed.
most people can install 2 panels at a time to slowly build their off-grid DIY system.
I also like the 24-volt safety factor a bit more than the 48-volt;
but I also do 48-volt in another system off-grid but not with Electrodacus SBMS0 as it is only compatible for up to 24-volt system.
cheers all, ?
 
Hi all, I've been designing a mobile solar system with ElectroDacus for a van build, and working my way up the learning curve. Since investing the time to figure it all out, I thought I would write up what I've learned into a Beginner's Guide to ElectroDacus to save others some of the trouble.

Seems like there are a lot of people on this thread who are knowledgeable on the subject, so if anyone feels like reading it over and giving feedback, I would appreciate it. I still have some sections to finish, and plan to add more pictures and example circuit diagrams. But please let me know if I've badly screwed anything up!

- Oberon
 

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