few questions about solar power....

corporal_Canada

ive had a watt meter connected to my solar setup and ive seen it peak at pumping 168 watts.. i want to plug my pc into this but the inverter starts squaking.. i believe that indicates a low battery.. so ill let solar bring my battery bank pile up to full ... and everything im pulling from the inverter hovers between 150-200 watts.. 

JRHill

@corporal_Canada , a thing to consider: Deep cycle batteries like to work. And by work I mean they bubble in excitement from the charge. And they bubble likewise from the discharge RIGHT BEFORE they get fully charged again. So a continuous day after day slight charge and the equivalent discharge is not best practice with a lead battery. I don't know of a formula except for C/2 (for you battery specs), monitoring SG and more.

On a different forum I once recommended that a person take a basic course in electrical circuits and theory. Many Community Colleges offer equivalent classes and for darned near nothing except for a book. I got ripped from that person because he is way too busy to spend his time doing something like that. And he still keeps asking the same kind of questions over time.

So even if you didn't take a class but began studying the subject on your own it would be really interesting to answer questions related to what you are learning and how  they apply. Does this though tickle anything within you?

corporal_Canada

i completely agree with you... i was linked a 12v 100ah lifepo4 battery.. priced at 10,000 or 11,000 philippine pesos. but the cheap bastard in me thought to himself.. what if i link 4x 3.2v 50ah lifepo batteries in series that only cost 1000 php each. im saving here... i will link a photo... 



yes i should take some sort of class the only thing i remember is from automobile mechanics in the military and that was in 2006... 
the only problem is not all islands in the Philippines are that good in english, perhaps some online google class ?

littleharbor2

You need a BMS for those cells. A 4s, 50 amp BMS shouldn't cost very much. Don't try to operate without it. These batteries are very sensitive to overcharging.

corporal_Canada

i am aware of the BMS bit and i actually have one, simply no idea how to connect it.. .. short term i will just get 4 of these t make a 12v .. and in the long term i want tohave 5x 12v.. so.. um... 20 of these ????4  cells linked in series and each 12v block linked in paralell (i prefer parallel to keep my life simple) and i will be buying (hopefully authentic 520 watt panels and try to grab 1000 or 1500 watts to power my pc and AC.. yes i know this means completely new mppt and new inverter... but now that i see this is working on a small scale, im going to 

yes im aware i need 14000 watts for 24 hour use of my AC and... 5x 200ah battereies... is 12000 watts

i hope im not wrong again... 

BB.

One math calcification... Watts vs Watt*Hours.

Watts are a rate--Like Miles Per Hour (50 Miles per Hour)
Watt*Hours are an amount--Like Miles driven (50 MPH * 10 Hours = 500 Miles driven)

So 5 parallel strings of 200 AH batteries =1,000 Amp*Hours

1,000 AH * 12 volt batteries (guess/example) = 12,000 Watt*Hours = 12 kWatt*hours

14,000 Watt*Hour / 12 volt bank = 1,170 AH @ 12 volts 
1,170 AH of "needed AH" * 1/0.70 typical max battery bank usage * 1/0.85 typical AC inverter eff = 1,966 @ 12 volt minimum suggested battery bank capacity
Just an example of taking actual "engineering/real life" numbers into account, and your battery bank bank is all of a sudden 2x larger (and 2x more expensive).

You should not just "jump into the middle" of purchasing and installing a solar power system without doing some basic math based on your assumed energy needs--And system requirements/efficiency/etc.

And, believe me, that when are talking about batteries that are larger than a laptop battery pack, the safety requirements and potential hazards are huge (not to say that a single failed laptop battery has not set a home on fire or even potentially taken down an aircraft when started a cargo fire).

If you choose to go down this path... Highly recommend that you do this as a paper design first. Then research the hardware needed to design and build a safe system.

Pick the wrong battery lithium chemistry--Battery Failure can start a catastrophic fire. Over charge, can start a fire, over discharge, can start a fire, short a cable--can start a fire... See a pattern here?

If you do want to still "roll your own" power system--And do more than a very small battery battery bank (or really use any lithium batteries at all)--This is something that should be done in an outside structure (such as concrete block or metal building). Not something that you would want to do in a home office/bedroom.

I debated including a Lithium Ion "fire video"--In the end, I decided to include one. Mainly to show how even small cells failing can easily propagate a fire:

https://www.youtube.com/watch?v=8nz5ijXcckI

For solar systems and DIY energy storage, highly recommend Lithium Iron Phosphate (LiFePO4) batteries or possibly newer "safer" lithium cells. This chemistry stores a bit less energy than other Lithium chemistries, but tend not to explode into flames with cell failures.

-Bill

JRHill

Thanks for posting that video, Bill.

corporal_Canada

wow, great video, and this has crossed my mind alot , i assure you and i saw these kind of fireproof containers on temu for 6-10$cad.. thinking if i put each 4 3.2v cells into 1 of these things im edging closer to a non catastrophic event... 

and also if my math is wrong about power consumption i do apologize... my AC sais 600 watts pulling.. im assuming that includes condensor and evaporator power on.. and havving the fan on the inside powered on all the time so.. the 600 watts is all that power consumed in the timespan of 1 hour.. so.. 600 watts...
as for a 12v battery.. i calculate this way and i appreciate your corrections.. 12v x 200ah.. = 2400 watts.. so.. 2400 x 5 batteries.. = 12000 watts stored assuming they are all at full capacity... to link the 4 3.2v cells i will use copper plates.. and 4 cells should create 12v...eac 12v battery will be linked using a 0 gauge precrimpled cable.. and this time i will use the correct colours... did i F up again ???

PS.. i said 200ah because im linking 4x of those 3,2v 50ah batteries in series.. and if i am correct.. (should any diety permit that).. 50ah x 4 is 200ah.. and the voltage also multiplies... 

but i defer to your preffesional knowledge,  can a 3.2v battery that size actually be 50ah ???or just another chinese BS... 

corporal_Canada

sorry, forgot to add, wont a mppt prevent overcharging ???or that bms ?? to be honest, im not sure what a bms does.. possibly it distributes the power input evenly... 

BB.

Note: 

12v x 200ah.. = 2400 watts
12v x 200ah.. = 2400 Watt*Hours (or WH)

600 watts is all that power consumed in the timespan of 1 hour.. so.. 600 watts...
600 watts is all that power consumed in the timespan of 1 hour.. so.. 600 Watt*Hours...

12v x 200ah.. = 2400 watts.. so.. 2400 x 5 batteries.. = 12000 watts 
12v x 200ah.. = 2400 Watt*Hours.. so.. 2400 WH x 5 batteries.. = 12000 Watt*Hours 

PS.. i said 200ah because im linking 4x of those 3,2v 50ah batteries in series.. and if i am correct.. (should any deity permit that).. 50ah x 4 is 200ah.. and the voltage also multiplies.

OK... diety vs deity--Getting silly there. Anyway to be vary clear... Adding cells (and batteries) in series, the voltage adds... I.e., 2 series * 12 volt batteries = 24 volt battery bank

Adding cells/batteries in parallel, the AH rating increases (5 parallel strings * 50 AH = 250 AH).

In your case--you have 4 series * 3.2 volt cells @ 50 AH giving you 12.8 volts @ 50 AH battery (a battery is technically composed of multiple cells in series or parallel or both).

You take each 12.8 volt "battery" and put 4 of them in parallel you have 4p * 50 AH @ 12.8 volts = 200 AH @ 12.8 volts

The solar MPPT controller is set to control the "overall" battery charging voltage (12.8 volts or whatever is required for your battery bank).

For a "forgiving chemistry" such as flooded cell lead acid--That is fine.

For a "high tech "unforgiving chemistry" such as Lithium Ion, you need to protect each and every cell from over voltage, under voltage, over temperature, under temperature, over current discharge, over current charging, etc... Depending on the installation/usage/climate--You may not need a BMS that "does everything"... For example, the Philippines does not get freezing weather. Your installation may not draw/charge more than XXX amps--So don't need over current protection, etc.

If you are going to "roll your own" Lithium Ion battery pack--You are responsible to ensure that it operates "safely" and potential failures are protected against (I.e., BMS, fusing/circuit breakers/etc.).

And if you are working to tech support for various "things", you need to use the correct units to avoid confusion, or somebody making the "assumption" that you typed XY, and you really intended XYZ and make the answer based on XYZ--Which may be a very "wrong" answer.

And, yes, you can get 50 amp or larger "single" cell lithium ion batteries. Is that best for your needs--I really could not say (I am not a battery engineer).

-Bill

BB.

Regarding "fire safe bags"... Remember, that Lion Ion batteries also output a tremendous amount of (very hazards) smoke & fumes.

Even if you manage to keep the "flaming materials" in the fire resistant bag--You are still left with lots of smoke and poisonous fumes... I ran across the number of 1 liter of fumes per 1 WH of Li battery capacity--I cannot find it now, but if I am anywhere near correct that for a 2,400 WH battery, would be something like 2,400 liters of fumes/smoke/etc...

I get nailed every so often for being so negative about Li Ion batteries and their possible failures. Yes, a well designed system does not fail very often--But they can fail.

Besides the "normal" stuff that comes out of a fire, one from Li Ion fires is hydrogen fluoride gas, when mixed with water (fighting the fire), makes hydrofluoric acid. If you want to scare yourself, look it up.

Even well designed and constructed large battery installations have failed (utility size). The failures are not all in "our control". And for a DIY guy getting started--It is a casual stroll in a minefield.

Utility Scale fire:
https://www.kpbs.org/news/public-safety/2024/07/05/are-lithium-ion-batteries-a-big-fire-risk-depends-what-you-compare-them-to

LH Acid from LI cell fire (lab tests):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5577247/

Do I have cell phones, computers, hand tools, solar power storage, etc. with Lithium Ion cells... Certainly. All have been failure free (so far). 

Have folks here built their own LI battery banks? Yes. Without failures--Yes as far as I know. Do we have some photos here of battery sheds/homes that have burned down from battery/Genset/fuel fires.... Yep.

What I am trying to say--Study first and make sure you have the knowledge to safely design and build your off grid solar power system. This is not something I would recommend a shade tree mechanic operation.

Our forum here is getting smaller over the years, and many of the folks that have built their own battery packs have appeared to moved on. I miss them here. But there may be better places to get actual detailed instructions on design and construction of what you are looking for. I (and others here) can give you the basics--But we don't know what you don't know--And I don't want to lead you down a path fraught with danger.

-Bill

JRHill

Three years ago when I changed over to LFP04 (SimpliPhi) I knew I couldn't have them in the outside battery box in the winter. And even if I fashioned some way to warm them I am sure we could have a few days each summer when they would be out of their comfort zone. So I set them up inside, in the crawlspace, where the temp year around stays cool +/- 10f, low humidity and pretty short cables. I had a lot of people wag their finger at me and still do.

Still I have my thoughts wander into the dreaded lithium battery failure. But it's just one more on the list of total catastrophes that could happen where we live. I'm actually more concerned with the city people who burn, lite camp fires, shoot tracers, blow tannerite and ride dirt bikes/ATVs with straight pipe exhausts during burn ban season than I am about the batteries for our solar.

corporal_Canada

dont worry about being nailed, i am here to learn and to be honest, i agree with everything....caveman part of me still says "fire BAD" I simply thought i could take he correct steps to do this correctly and safely, i have an insanely long thread on DIY solar and they are egging me on to go lifepo4.. but instead of buying 1 whole battery for 10,000 php or more. i can simply put it together myself..... the battery cells you already saw.... and i saw a 30ah for 300 php less.. but less isn't always better and to make the 4 cells into 12v... i will be using these kind of copper strips with holes in em....
as for the watts calculation ive developped a new understanding of solar power.. so for example if i have 1000 watts or wh of solar power going to the power bank. it could be immidiately consumed by the inverter since electrons travel at the speed of 2200 M/s.. so if the umm condensor turns on and has a pulling surge of 1000 watts.. the amount ofwattage that the solar panels are outputting (assuming they are at maximum capacity).. the 1000 watts or WH will be put back into the power bank.. how am i doing so far ? 

am i really wrong about the watt or wh calculation ? does 5x 200ah not equal 12000 wh total ???

and deity or diety.. thank you for the correction.. it sometimes slips your mind that i am French-Canadian and english isnt my primary language.. tbh, it is a huge struggle.. but my awsome brain powers through most of it.... 

donque je vous souhaite une bonne nuit et merci o/

BB.

Do your reading first about BMS and Li Ion batteries. It is not rocket surgery, but it does require getting everything "right" for proper and safe operation. Can you do it "safely"--Probably.

as for the watts calculation ive developed a new understanding of solar power.. so for example if i have 1000 watts or wh of solar power going to the power bank. it could be immediately consumed by the inverter since electrons travel at the speed of 2200 M/s.. 

Watts is a Rate... Yes, you can have 1,000 Watts of energy going to the power bank (again like 60 Miles per hour, or 10 Gallons per hour of flow)... Where it goes next is a combination of your DC loads (aka AC inverter's DC input) and the battery state of charge.

Watt*Hours is an amount... Like Miles Driven, or Gallons of liquid. If you have 1,000 Watts * 1 hour of time, then 1,000 Watts * 1 Hour = 1,000 Watt*Hours. 

so if the umm condenser turns on and has a pulling surge of 1000 watts.. the amount of wattage that the solar panels are outputting (assuming they are at maximum capacity).. the 1000 watts or WH will be put back into the power bank..

The actual "math" for condensers (or capacitors) is a bit more complicated. Don't worry about them here--More or less, a capacitor has little effect on the "total energy" of your system... Say you have a capacitor (or anything) that draws 1,000 Watts for 1 second--There are 3,600 seconds in an hour--So the WH=1,000Watts*/3,600 seconds per hour = 0.0003 Watt*Hours. (60 seconds per minute * 60 minutes per hour = 3,600 seconds per hour)

You are overthinking this a bit... Using Water analogies:

10 Gallons per hour from "solar array" (water source)
4 gallons per hour into "inverter" (load/water sink)
10-4=6 GPM available for "filling the bucket" (battery bank).

If your battery bank is full (bucket is full), then the 10 GPM source is only feeding 4 GPM to the source--The "extra" 6 GPM "goes nowhere" because there is nowhere for the water to flow (bucket is full, sink is only taking part of the available flow).

Batteries are "voltage sources"--The battery holds "12 volts" (or whatever) voltage regardless of the amount of current exiting (to loads) or entering (charging battery).

Solar Panels are "current sources"--The solar panel "wants to" output 10 amps to the load(s). Whether the voltage is 0 volts (short circuit) or near Vmp (I.e., 18 volts). If the load "need" less than 10 amps, the Vpanel rises up towards Voc (voltage open circuit) as current flow falls to zero volts.

Now in real life, Batteries can output only the current and voltage they are capable of... I.e., a 12 volt battery may "rest" at 12.8 volts, but under heavy load drop to 12.4 volts. And as the battery approaches "dead", the voltage falls to 10.5 volts (dead) or lower (very dead).

Similar with solar panels... Their optimum power output (power=voltage*current) rating under "full sun" will vary in voltage and current as the sun/loads vary. I.e., solar panels Vmp is the Pmp=Vmp*Imp under 1,000 W/sq meter of sun, and as the loads required less current, the Vpanel rises from Vmp (max power) to Voc (open circuit).

Finding Electricity 101 online courses will make things fit together better for you.  There are many in English, and you should be able to find them in French too (Canada, France, etc.).

And even then... It is easy to get these things confused... When I first started posting on this forum decade or so ago, even though I am "nominally" and electrical engineer--I was getting the V/A/AH/WH/Power stuff mixed up a bit until I got the posting/practice down (at least most of the time).

am i really wrong about the watt or wh calculation ? does 5x 200ah not equal 12000 wh total ???

Technically, you are incorrect. The proper statement is:

5 strings * 200 AH capacity per string = 1,000 AH of capacity.

What is not "in your statement" is the working voltage. We know that you are working with 12 volt battery bank--But it is "missing" from the Math statement:

Power = Voltage * Current = V^2/R = I^2 * R

5s * 200AH = 1,000 AH
1,000 AH * 12 volts = 12,000 Watt*Hours (here Amps * Voltage = Watts, and * Hour--Time = Watt*Hours)
5 string * 200 AH * 12 Volts = 12,000 WH

English is my only language --And I have lots of trouble with it too... Spell Check is (usually) my friend. People that can converse in multiple languages still amazes me to this day (and my wife's first language is Mandarin Chinese). Google Translate is my friend.

donque je vous souhaite une bonne nuit et merci o/
so I wish you a good night and thank you o/

I am sorry if my bit of teasing hurt your feelings. I was all intended to be in good humor.
Je suis désolé si mes taquineries vous ont blessé. J'étais censé être de bonne humeur.

Take care,
-Bill

corporal_Canada

i apologize if my question is "basic" im simply trying to understand the surge "pull" of the power demanding  portion of the AC for example.. lets say it is 1000 watts surge.. i imagine i need that amount of power available inside the poer bank... and it is istantly "refilled" yes the water analogy works for me... just as imperial measurements work for you over yonder...... as for hurt feelings.. i really hope i was built thicker than that, and i tried any form of spellcheck, im certain my pc would commit sepuku (japanese suicide) ad google translate is a far stretch from being perfect.. and whatever happened to "thesaurus" ?? that was handy... 
and i your asian wife has adjusted to life in Cali over the years... entirely different mindset... 

however before i rush into a 20 lifepo4 cell system for the power bank, i will only try out 4 ..just a 12v battery to begin with and adjust to having something more delicate


please take care, thank you for sticking with me this far... 

BB.

Having a text conversation without body language--Joking around can be easy to miss-read.

"Surge" is nothing "special" in the math--It is just more Watts for a few seconds to (for example) start a motor.

So--You just need to look at it as another specification point. Surge can be difficult to accurately measure. A surge may last for a fraction of a second, while most "simple" meters measure once a second or similar.

And surge can be highly variable. A standard window A/C unit may draw 45 Amps for a 1/10 of a second. And a "newer style" "inverter" based A/C may draw 600 Watts "surge" and 600 Watts "running". Inverter A/C motors have very little surge (there are "soft start" motors too... Not "zero surge", but less than 45 Amps (45 Amps * 120 VAC =  5,400 VA/Watts max surge).

Induction motors are "difficult" for smaller off grid systems... They have "high surge" current, which places a heavy demand on the AC Inverter, which also places a heavy demand on the battery bank. The "better" inverters will brown out a bit but support the heavy AC current spike for a few AC cycles... The less expensive inverters may shut down and never start the heavy motor load. The typical AC inverter is usually rated for 2x its Watts rating (I.e., a 1,000 Watt inverter will usually be rated to support 2,000 Watts for a few seconds to a few minutes).

For the battery bank--The DC wiring and Battery bank need to be able to support that high surge current too... For example:

1,000 Watts running / 12 VDC = 83.3 Amps DC battery bank load
2,000 Watts surge / 12 VDC = 167 smps for a few seconds to a few minutes

A typical Li Ion battery bank will support around 50% to 100% of its AH rating for max current:

200 AH * 0.50 = 100 Amps Max current for most batteries
200 AH * 1.00 = 200 Amps max current for some batteries

Another issue we have not really discussed is battery bank voltage. Typically we use 12 VDC or 24 VDC or 48 VDC for our home battery bank voltages.se

For smaller systems (around 1,200 to 1,800 Watts max continuous) we use 12 VDC as the minimum battery bank voltage. For around 2,400 to 3,600 Watt or larger inverters, we tend to use 48 VDC. As you can see from the equations:

Power = Voltage * Current
Current = Power / Voltage

The higher the AC inverter's power rating, the more current it draws... For various reasons, low voltage DC is "difficult" to wire up to carry high current. So for larger AC inverters, we tend to use a higher voltage battery bank (24 VDC or 48 VDC) to keep the copper wiring to a reasonable size. Also, because of voltage drop, it is difficult/expensive to send 12 VDC more than 10 feet without spending a lot of $$$ to keep the voltage drop in the wiring low enough... Typically for 12 VDC, a maximum of 0.5--- I.e., a discharged battery supplying high current at 11.5 volts - 0.5 volts = 11 volts at the load--At 2x surge current, 1.0 volt drop means 11.5 volts - 1.0 volts = 10.5 volts at inverter's DC input. 10.5 VDC most inverters shutdown as 10.5 volts is assumed to be a "dead" battery.

The problem with 24 and 48 VDC batteries is there are more cells in series--And more per cell voltage, means more  per cell voltage sense wires for the BMS.

You can buy 4,000 Watt or larger "12 volt" AC inverters--But it is generally not a great idea.

And why you need to do a paper design of your system and "know your loads"--You want to design the system to support your loads/energy needs. Generally, you cannot "grow" a smaller 12 VDC battery into a "big" 12 VDC system. The limitations for DC wiring and heavy currents make this difficult and expensive...

-Bill

corporal_Canada

omg, i made a mistake, another forum site convinced me that the AH is accumulative if you link batteries in series.. but its just the voltage.. and the WH adds together, now i finally understand why you kept reposting the same thing over andover, i apologize, i was lead astray... or i misread..  

BB.

It does take time, using the system+meters+etc., and using the math to finally "get" how it all works together.

Because Watts and Watt*Hours always "add"--It is why I tend to use W/WH to do the paper system design. They are "complete units" in that "energy/power" wise, it fully describes what you are working with.

And when finally getting down to system components, it is simply dividing Watt*Hours by volts (240 VAC for house hold loads, 12 VDC for "12 volt" battery banks to get the Amp*Hours of storage). And even then, sometimes batteries are rated in Watt*Hours instead (or in addition to) Amp*Hours...

Power = Voltage * Current
Current = Power / Voltage
Energy = Voltage * Current * Hours (time)
Current * Hours = Amp*Hours = Energy (Watt*Hours) / Voltage

Say you have some 100 AH 12 volt batteries--Exactly 4 of them.

In parallel:

4 * 100 AH = 400 AH (at 12 volts)
Energy = V*I*H = 12 volts * 400 AH = 4,800 Watt*Hours (V*A*H)

In series:

4 * 12 volts (100 AH batteries) = 48 Volt battery bank (at 100 AH string)
Energy = 48 Volts * 100 AH = 4,800 WH of energy storage

This shows that you don't get extra energy appearing anywhere when you use AH and Voltage correctly for parallel and/or series connections of batteries. And why using Watt*Hours is easier to keep straight when working with 120/240 VAC for house wiring (via an AC inverter) and a battery bank at 12/24/48 Volts (for DC powered devices) in a "mixed" load system.

-Bill

corporal_Canada

thank you... i know all this, however the other forums said something different so i thought i was learning something new... 
would you recommend that i buy 4 cells of 3.2v and link them in serires for only 4000 php or buy a 12v lifepo battery in a plastic casing and MAYBE has a bms inside... that will cost 10,000 php and above.../

?
your advice is always accepted.. 

BB.

I don't have enough knowledge to really suggest which is better (and safer) for you... You need to get all of the information and answers from the Mfg. "...maybe has a BMS inside..." is not "good enough" to make any decision.

Yes, people have build and used "naked" LiFePO4" cells (without BMS) by "monitoring the per cell voltages" and manually balancing the cells if/when they got out of balance (and the whole issue of "top" vs "bottom" balancing, etc.). And save the cost/complexity of adding a BMS.

Li Ion cells have a good reputation for not "going out of balance" very fast/often. Top balancing is when you get the cells 100% full and have their resting voltages equal (this lets you set the charger to the max voltage for all 4 cells in series, then it is safe to "assume" that each cell is within its proper operational voltage).

Bottom balancing is taking cells to near zero state of charge and balancing the cells. This is done for applications that take the bank to near zero state of charge (drones, model race cars, etc.). This allows the owner to "know" the 4 cell battery voltage and per cell voltages are still within specifications/discharged voltage limits.

An example of the decisions that you need to make--And I cannot make those for you.

-Bill

corporal_Canada

already have a 4s bms. a little 1 inch rectangle with a mess of wires going about it... 
i am here to learn but the socialist part of me naturally wants to save money.. however if you think a prebuilt lifepo4 battery is ideal, well not much i can say or do to argue with you

BB.

I am not saying one way or another...

Do your research first. All of those EVs, toys, computers, phones, etc. that are catching fire have been "professionally" designed and built. And yet they still are doing fire works. It is possible that your eventual design and installation will be safer than some off the shelf battery+BMS system.

Just because the "battery system" has been built into a nice plastic box does not mean that this is a "better" system.

Here is, what appears to be, a well built Li Ion battery:

https://www.youtube.com/watch?v=x2Tllo3_Bhw

Note that the mfg. has improved their design based on customer/YouTube reviews (in this case, they were using soldered lugs and leads, and updated to crimped wire connections--Which is an improvement.

However, this battery fails the disconnect battery from charging if below ~50F. The BMS chosen by the Mfg. is either poorly implemented, improperly spec'ed (vague temperature function specifications), or "broken" from factory. The BMS may also be using "generic" FET devices (no markings). Sometimes that is a bad sign (grey market components) or the BMS company "erased" the component markings to make "cloning" of the hardware by others more difficult.

My two cents... Aluminum bus bars (apparently aluminium from video review)--Aluminium is a poor choice until correct alloys, plating, use of anti-corrosion grease per connection, use of starlock washers or similar to "cut through" aluminium surface corrosion. Nylock nuts do not work if the threaded post/stud/bolt threaded portion actually extends a 1.5+ threads beyond the Nylon bushing inside the nut. In this case, there are other locking nuts that may work on the shorter studs--But that becomes problematic because of the thick aluminum(?) bus bars and adding a starlock washer may make the studs "too short" for proper bolt up.

And my whole warning about fire from Lithium Ion... The battery construction is by the manufacturer. The best you can do is buy from a known good/responsible manufacturer and a "fire resistant" Lithium Chemistry (such as LiFePO4 lithium iron phosphate).

Using Fiber Tape to hold the cells together--I am not sure is a great idea. Typically (from what little I know) use metal clamps to hold the cells "compressed". Tape and glues tend to degrade over time and temperature.

Don't even know if the battery case is built from flame resistant plastics--And no UL/NRTL marks. The CE mark is (from what I have seen before) is ambiguous as to what it means (typically not UL, but a mfg's declaration that they comply with European requirements--No third party Listing/Ongoing inspections typically).

So--Here we are--An apparently responsible Li Ion battery manufacturer that has yet to "master" the "safe/reliable" construction of a "black box" based battery.

And my "warning"... These are opinions based on a random Youtube video review. I do not know what the bus bars are (copper, aluminium, plated aluminium, or whatever).

If you bought good quality cells (prismatic in this case), and used copper vs aluminum bus bars, and had a BMS that actually functioned correctly, you can do better.

A quick example of the issues that even the "experts" can get tripped up--Especially "new companies" and "new to them" products.

Hopefully somebody here can give you some names and links to quality components they have used.

-Bill

corporal_Canada

agreed, i prefer copper and thank you so kindly for spelling aluminium correctly, i appreciate the effort, thus far of all the 12v lifepo battery sellers that ive asked for a photo of the inside, only 1 complied, i did see 4 cells and something that appeared to be a bms of sorts... the petite bms i have is branded as Daly but its authenticity is about as likely as buying Air Jordans from China, just saying

here, see for yourself biggguy... 

corporal_Canada

i would like to test my current setup with 3 new additions a better inverter and naturally a better (authentic) mppt, 3 REAL 500 watt solar panels.. id would like to power the AC... i hope im not going about this the wrong way.. ... AC claims 600 watts. i believe the condensor/evaporator power surge + the big fan on the inside is calculated and it averages out to 600 watts per hour... .. my 2x12v 50ah batteries technically have 1200 wh stored in them if the solar panels are doing their job.. so that can handle the surge i just mentioned.. and the rest will be refilled by the solar panels.. still learning here so.. im learning with what ive got....
all advice is welcome

corporal_Canada

sorry forgot to mention i believe the AC power surge is roughly 1kw

BB.

You might want to see if you can purchase "solar powered" A/C (or mini-split) system instead. 

There are not a lot of them out there, but it could be an interesting fit... There are ones that run directly off of solar panels (no batteries)--Basically you get cooling when the sun is up.

You may also find a hybrid system that uses solar panels+Batteries+Grid Power too... This article (just an FYI--I know nothing about this web site) mentions a few different brands:

https://www.hvac.com/expert-advice/solar-powered-air-conditioners/

-Bill

corporal_Canada

yes, i have seen those pop up all over alibaba, yet i noticed most ofd them are scams and some sort of land connection... im trying tpo start my solar based life somewhow.. maybe with 3 x 500-700 watt panels , bigger mppt, inverter, i can beging to go throug all the stages of weening ?? off those scary outlets in the wall.. heck my pc ONLY stays connected to the inverter and the power bank uses solar between 0800 and 1400.. the rest i just charge the power bank with some sort of chinese "smart" charger... its the only way that i can safely touch parts of my computer without getting zapped maybe with 3 hefty panels and more battery capacity i can run the AC AND my beloved pc 24/7... yeah im weird and lobve downloading all the time. but yes i have seen AC units with solar panels .. but naturally im skeptical at its authenticity

corporal_Canada

question, can i not make my own solar powered AC ? at least i can be certain that it works.... portable AC ( the type that doesnt go into a window) only 8000 php.. i believe i only need 500-700 watts solar panel for it.. 1 battery.. 1 inverter and mppt.. am i missing something ???

BB.

There have been companies that have sold AC inverters that support direct connection from solar array to DC inverter input.

https://windandsolar.com/suntaqe-150-modified-sine/

Note that a "typical" 12 VDC inverter "expects" 10.5 to 16.0 volts or so... The solar array will output less than 10.5 volts in morning/evening, and can exceed 16 volts in the middle of the day--A "standard" AC inverter will shut down if outside the 10.5 to 16.0 VDC operating range (which a typical "12 VDC" solar array will do during a "normal day").

MW&S appears to have an intermediate device to "condition" the solar array voltage to better match the AC inverter's DC input range (and some other "output" states that can reset an AC inverter when needed).

An "issue" with powering 120/240 VAC devices (motors, Air Conditioners, etc.) is that they expect to have 120 VAC @ 60 Hz or 230 VAC @ 50 Hz... When the load exceeds the AC solar panel power (such as sun rise and sun set), the standard AC inverter will "collapse the solar panel voltage, P=V*I, so V goes way down, P goes way down) and the AC inverter shuts down. 

Of course, now the load has no AC power, the AC inverter restarts, the AC load starts again, and takes more Watts than the solar array can output, AC power turns off, etc... For something like a refrigerator or A/C unit, constantly "shutting down and restarting" is very hard on the motor and (probably) the electronics.

(my guess) is that the actual "solar A/C" system does use an AC inverter--However it is a special type called a VFD--Variable Frequency Drive. Basically, the VFD can figure out how many Watts the solar array is outputting (morning, noon, evening) and it will only run the compressor at a speed (RPM) that does not exceed the solar array output Watts. I.e., if the sunlight is low (morning/evening/poor weather), the VFD outputs less than 50/60 Hz (1/2 the frequency of less?) and simply the A/C has lower cooling capacity when there is not enough sun.

The VFDs are also used on water pumps--The pump runs slower in the morning/evening, and faster during the middle of the day. Works well because a water pump can run slower when there is not enough solar power without issues (same with a VFD equipped A/C unit).

With "modern" electronics, there are many wild and wonderful things that can be done... But is there a "market" for these "new" systems--Many times, it is more complicated than just "bolting" an off the shelf part (like an AC inverter) into an A/C system and have it work.

-Bill

corporal_Canada

always wondered about those solar AC's, unless im wrong, dont solar setups kinda need a battery as a middleman ??? or do they just use a small pack of 18680 cells duct taped together ??? and as a Canadian i aprove of duct tape
i remember you mentioning that Russia has mentioned they want Alaska back ??? why ??? no worries i heard that a missile landed in Poland and even Russia said "oh sh!t" dont want to p!ss off the country that invented the most advanced tank on earth, you see Poland has been waiting for Russia to give it a dirty look since ww2,  and God help the country that will shoulder the Kelbasa onslought, and no this isnt racist, i believe  i have slavic ancestry and apperantly 1% Nigerian ????
anyhoo, the cheapest AC i can find with the unit AND the solar panels included is 500$US, if you can find better, im listening otherwise im building it myself...