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Re: Are chemical reactions involved in charging and discharging Lithium Ion batteries?
The question I have is if there is a chemical reaction which can be interpreted as oxidation, bonding or whatever at the molecular level, what is actually happening at the atomic level, where electrons are shared between shells of atoms forming bonds within the valiencis of the host atoms. In order for something to attach, there needs to be a covalent bond https://en.m.wikipedia.org/wiki/Covalent_bond or free spaces within a shell/shells to which other atoms can attach and share the respective electrons within the valiencies, to provide a bond. Take for example salt, an essential to the human diet, it is composed of sodium and chloride, both in and of themselves are poisonous but in combination, through covalent bonding they are not..
Do I accept it at face value, or look deeper?
Do I accept it at face value, or look deeper?
mcgivor
1
Re: make sky blue chinese mppt cc
reply to comment #2 above: NO. There are no external connectors for recording stats & I don't see labeled connectors on the circuit board to support that. There are a 2 unstuffed 4 pin locations on my 30A unit that look like a connector would fit - but I have not yet traced out circuit to see where they connect. Quick glance suggests space for 2 optoisolators connected to a non-Reference designator silkscreen rectangle. That shape could fit a double stacked LED or a 3.5MM jack. Can't do anything unless Firmware supports it... Maybe future boards will have locations stuffed & firmware support ?
Re: make sky blue chinese mppt cc
I had wondered about the software versions for this unit. Perhaps this was why they were willing to sell me a 40A unit shipped from US for only $67. Won't be able to see the software version till next June.
Re: make sky blue chinese mppt cc
PLEASE: Everyone who leaves comment good or bad list the FIRMWARE VERSION. It should be number in lower right corner of LCD when first power up. I just bought 30A unit from Seller MakeSkyBlue on eBay - received unit 11 December 2018 - and it is version 113. Yesterday I read that newest firmware is V117 on units purchased from seller MakeSkyBlue via AliExpress. Based on variety of reviews I read here, and others on net, the hardware might be OK, but various versions of firmware seem to have problems. It would be great to know if newer versions solved any problems. Also, whether firmware could be updated. The AliExpress MakeSkyBlue webpage states that the circuit board changed between V116 & V117. It would be nice to know what changes were made.
Re: Solar panels to battery charge.
I find the Iota chargers sold by our hosts adequate for bulk charging. They lack some features (notably fully adjustable voltages etc) found in more expensive chargers, but do the job of occasional bulk charge, with solar finishing to the extent sun is available.
The main advantages to higher bank voltage is fewer parallel strings to keep balanced, and lower operating currents for a given charge/discharge wattage. 3kw inverter at 12v is 250a, with surge capability of maybe 2x that, needing heavy wiring to handle safely.
Generally speaking, mppt won't really be a "game changer" vs properly designed pwm. The difference will be mainly seen in cool/cold and breezy climates where the higher Vmp of panels can be utilized by mppt. In hot climates, mppt could actually be worse, as they need some voltage headroom (often ~20%) to buck down to charging voltage.
6-7yrs for T105s cycled daily in an 8 parallel string setup sounds optimistic to me, but if you're getting 4-5yrs now, who knows?
The main advantages to higher bank voltage is fewer parallel strings to keep balanced, and lower operating currents for a given charge/discharge wattage. 3kw inverter at 12v is 250a, with surge capability of maybe 2x that, needing heavy wiring to handle safely.
Generally speaking, mppt won't really be a "game changer" vs properly designed pwm. The difference will be mainly seen in cool/cold and breezy climates where the higher Vmp of panels can be utilized by mppt. In hot climates, mppt could actually be worse, as they need some voltage headroom (often ~20%) to buck down to charging voltage.
6-7yrs for T105s cycled daily in an 8 parallel string setup sounds optimistic to me, but if you're getting 4-5yrs now, who knows?
Estragon
1
Re: Solar panels to battery charge.
mike95490 I am aware how Mppt's work I can present it with 12/24/36/48v of PV input and it will convert as need to match output charging I would like to keep them under 70 input utilization to be safe and not over work them that is why I go two of them. Keep in mind that they are installed but not connected yet. I am still useing the tristars, and there is a lot of wasted energy useing the PWMTristars. When I switch over the the MPPTs I should gane better harvesting from the solar panels in any voltage configuration. I was getting 4 to 5 years out of costco 6v battires. This is the first time I am going with the T105's so I was hope/expecting to get a few more years out of them since they should be a better battery like 6 or 7 years.
cptmiker
1
Re: New to solar and this site and a little problem to solve with my generator
a 3 phase voltage stabilizer is going to be pretty pricey. You are likely better off getting the generator serviced to spec, and widen the acceptance window on the inverter
https://www.ashleyedisonuk.com/voltage-stabilisers-660/
https://www.ashleyedisonuk.com/voltage-stabilisers-660/
Re: Emergency Lighting and Data Power in an Off Grid System
Dave has a point, I just got them to recommission a repaired 5KVA Standby generator which has Voltage and Hertz on the low side. We are running it at 3KVA at the moment to prevent it tripping while we wait for the new generator, the half dead generator is extremely mission critical at the moment.
Although at the moment the boardwalk lighting, outdoor WiFi and cameras seem like a nice to have addition, they would also become mission critical as soon as they are installed, so putting them on the old batteries (which brings in charging problems) may be a bad idea.
What is your opinion on battery bank fusing, personally I like the Red Spot HRC Bakelite fuse carriers with 200A fuses which can also be used as a last resort battery disconnect when sparks are flying in the DC DB board and a safety disconnect when working on the batteries.
Although at the moment the boardwalk lighting, outdoor WiFi and cameras seem like a nice to have addition, they would also become mission critical as soon as they are installed, so putting them on the old batteries (which brings in charging problems) may be a bad idea.
What is your opinion on battery bank fusing, personally I like the Red Spot HRC Bakelite fuse carriers with 200A fuses which can also be used as a last resort battery disconnect when sparks are flying in the DC DB board and a safety disconnect when working on the batteries.
Re: Solar panels to battery charge.
battery bank 16 t105 at 225amp hour each configure to 12v =1800amp hours
Battery
8 strings
225x8 = 1800x12 = 21,600 watt hours
total usage per day estimated at 2,766 watt hr per day
if Satellite box are left on 24/7 then usage would be 5,626 watt hr per day.
Solar panels are a total of 1,600 watt hr at 88.96amps x4hr per day average 6400 watt hr per day at 355.84 amps per 4 hour charge time
( note ) Seligman AZ is an average of 6hr per day good sun. so if I calculated by 6hr it would be 9600 watt hours at 533.76 amps for a 6 hour day. backup generator to run on low output days. and to run other high useage appliances like wash and dryer etc. they are never used without the generator.
""Assumes perfect condition and max output""
guessing loss of 20 % efficiency on average leaves
5120 watt hr per day harvest at 71.168 amp per hour at 4 hr per day
So I am not sure why going to 24 or 48v would be that much better aside from efficiency gains and significant cost of hardware. If money was no object I would gladly upgrade solar panels higher capacity battery's to reduce the strings. I'm not knocking anyone or anything and very much appreciate the feed back. But money is an issue to make conversion and I am trying to work with what I have. is this realy that bad. Is 4 to 4.5 years a reasonable time for battery's?
On a side note what would you recomend for a battery charger to run off the generator on bad days?
cptmiker
1
Re: Solar panels to battery charge.
You need to understand how a MPPT controller works. 12V or 48V, it's the same wattage ,
Currently, you are under paneled for the amount of batteries you have. However, you must not be loading them down too much, if you are getting 4.5 years out of a bank of T-105s
Re-arranging the panels to be a series string instead of parallel might cost you a couple hours and a few cables, I don't understand how it could be a higher expense than that. A 2Kw inverter for 24v or 48v should be about the same cost. More than a 12V, but you can find some higher efficiency units than you can get with 12V
Currently, you are under paneled for the amount of batteries you have. However, you must not be loading them down too much, if you are getting 4.5 years out of a bank of T-105s
Re-arranging the panels to be a series string instead of parallel might cost you a couple hours and a few cables, I don't understand how it could be a higher expense than that. A 2Kw inverter for 24v or 48v should be about the same cost. More than a 12V, but you can find some higher efficiency units than you can get with 12V