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Post by Dave on Feb 20, 2022 21:06:15 GMT -5
SO today with only 100 Amp/hr to replace, why will my chargers take so long? Yesterday they took the whole 7 hours...from 8 to 3...to reach float. Something not right here? I expect the bank recharged in 2 hours tops.
Just guessing from a distance – If your system is on – your solar panels are spending all day powering your home – running the PC – pumps – TV – fridge – whatever – just to be on my system consumes wattage
Only the left over charges your batteries
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Post by Deleted on Feb 21, 2022 14:47:24 GMT -5
Correct, but if 80amps is available why does it take to long to reach float?
On my German PMW charger it would reach from 80% to 100% in 30 minutes every day.
On my Dutch MPPT charger it takes all day to go from 80% to 100%. Sure the loads are bigger but so the the amps available to it.
DO you know anything about the VIctron BMV 712? DO you monitor your power use at home? For example we used 111 amphr last night.
SHalom
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Post by Dave on Feb 21, 2022 15:25:04 GMT -5
DO you know anything about the VIctron BMV 712? - NO DO you monitor your power use at home? - YES = For example we woke up today to so we ran the generator for coffee, microwave, and toaster over Our little face meter is the face of a battery that fills with black as the charge increases So my family knows the difference between and the brink of They understand when NOT to run the microwave or coffee pot They understand when to power down - as we do every night and they understand how much power we have for breakfast Right now I am 34 months on my batteries $90x6 = $720 divided by 34 = $21 a month electric bill - solar is not freeAlso my batteries are sitting on the floor of an unheated building My cheap batteries are toast - need replacement Since October - if we are all here and it is all lit up TV Stero etc - a ran the generator 2-hr before bed Feb - the temp went sub-zero (-22F) one morning (-17F) the next - many mornings near 0F Furnaces ran nonstop - the generater came on at dark It is still cold - winter So right now my electric bill = $21 + gas for the generator and I have a fuel saver generator - and about 4 others in various states of repair Will be thking about replacements again this spring and I will go cheap again - maybe just 6v golf cart GC2s again - Sam's Club and the stratagy again = the idea of an affordable replacement in the future when I have less money - or for my family after I am gone - they can always upgrade
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Post by Deleted on Feb 22, 2022 15:53:22 GMT -5
I have thought of using your idea of replacing with cheap batteries
as I have discovered we consume 100 amps each night running the NiFe to almost dead flat.
Its hard to figure battery capacity.
Have today a voltage of 27 after using 80 amps, so the system is not flat today? Why is that?
I get the impression is depends upon the load on your battery, not just V verses A.
My batteries are suppose to last for 35 years, and if they do I will be happy.
I am currently predicting 200 amp hr storage.
200 - 87 /200 = 73 % SOC.
Yesterday my calculation went to 20% , today its 70%...??
Weird.
I do not use a generator, we have plenty of sunshine here. I play to have more panels. currently we have 4100 watts to draw from. On a typical sunny day that's over 20,000 watts of power.
More than enough. My problem is my battery storage, never know what it is.
Love you smilee face to indicate battery voltage. Nice. I need something like that.
SHalom
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Post by Dave on Feb 22, 2022 19:21:55 GMT -5
Its hard to figure battery capacity. And the solution = whatever your needs are x 3 Plan for 3 days of no sun – and still not hit bottom
This makes the professional install $$$$$$$$$
I have the minimum and know it and my family plays the count your wattage game We have a hands on – manual system -
I get the impression is depends upon the load on your battery, not just V verses A. Correct – the math amps x volts = wattage (Ohms Law) does not work in real life
This is Not Ohm's Law - RSD Academy
The reason why it does not hold up in real life (solar math) = the resistance of the battery itself My batteries are not in a temperature controlled room – they are at the mercy of the weather – they were old and tired and (-22F) + (-17F) for a week in a row really hurt them – not a surprise – I had previously wondered if they would last all winter
My batteries are suppose to last for 35 years, and if they do I will be happy. Doubt it
My 2 cents – I have done it both ways – a long bank in series and multiple banks of 6 in parallel Usually all connections are group together at one end – at that point when the sun is up – it is hot and all the meters in the system thinks it hot – but downstream in a long series battery bank – is reality the same
Each battery has its own resistance (R) – in series the entire system is limited by the weakest link Charge comes in – bat A has R + bat B has R + bat C has R and that last battery in the chain – gets less than bat A – yet all the system is metered from bat A
Experience In battery series ABCDEGHIJKLMNOP – which batteries die first Answer ABC – because they boil more often and NOP because they are underpowered
In battery series ABCDEGHIJKLMNOP – what happens if bat H has an issue bats I-P suffer and could be damaged – but all you know is that you have a storage issue – bat A measures good
Today – even the manufactures of the batteries do not recommend series more than 3 x 12v
My neighbors system – 24 bats – NOT a series of 12 :::::::::::: But 4 groups of 6 bats at 12v to = his 24v system I ::: + ::: ::: + :::
Each group of 6 is metered and can be isolated from the whole His plan – my paraphrase – identify and locate battery heath better in the future only replace 6 bats at a time
I do not use a generator, we have plenty of sunshine here. I play to have more panels. currently we have 4100 watts to draw from. On a typical sunny day that's over 20,000 watts of power. More than enough. My problem is my battery storage, never know what it is.
I don’t understand your math (google) battery bank to solar panel wattage ratio 1:1 ratio - Ideally, no matter your application, the 1:1 ratio is a good rule to follow,
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Post by Deleted on Feb 23, 2022 5:17:03 GMT -5
You have a strange explanation. If you hook up 20 cells in series, like this, the string gets charged evenly, though from experience, the ones close to the negative and positive ends get more charging than the others, this is due to the wiring process mainly. Each connection is never perfect. If I followed your math, I need 20 solar panels. Currently I have only 14 of them. NiFe does last 35 years, the manufacturers say this. Edison batteries last longer than this. The video E=I/r+R was OK, I suspect the internal resistance changes as the load increases or the current removed increases, so measuring battery capacity is hard. Shalom
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Post by Dave on Feb 23, 2022 5:51:35 GMT -5
If you hook up 20 cells in series, like this, the string gets charged evenly, though from experience, the ones close to the negative and positive ends get more charging than the others,
DUH
1- everyone has 2 6v batteries in series – then sets of 2 in parallel - 24 bats = 12 sets of 2 ::::::::::::
2 - the string gets charged evenly – no it does not
3- though from experience, the ones close to the negative and positive ends get more charging than the others
That is what I said – you think it strange
In this thread – long ago – I posted the manufactures recommendation against long string battery banks The current recommendation = no more than 3 in a sting (1 front + 1 middle + 1 back) 2 6v batteries in series – then sets of 2 in parallel - 6 bats = 3 sets of 2 :::
Neighbor has 2 (6 bat sets) in series = 24v :::+:::
Neighbor has 2 sets of (2(6 bat sets)) in parallel to service his home :::+::: :::+::: 24 bat total = 4 sets of 6 bats
3 - though from experience, the ones close to the negative and positive ends get more charging than the others
Turning 1 pos end into 4 and turning 1 neg end into 4 reducing the middle bats from 20 to 4
Spread change and discharge more evenly Since each bank of 6 is individually metered – you know where the problem is (1 of 6 NOT 1 of 24) A bank of 6 – can be replaced as a single unit
This is the trend here – new installs – the plan I have for me
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Post by Deleted on Feb 23, 2022 14:52:32 GMT -5
That is an interesting idea Dave. You say three bats in series, 2V+2V+2V=6Volt bank. You are using Lead Acid. You forget in each cell are dozens of plates in parallel already. I have a 1.2 V NiFe KOH cell. If I hook up three, I get 1.2+1.2+1.2 = 3.6 V Each cell is massive and large, 500amp hour. I suppose one could have purchased what your saying. Makes sense. Now I don't get you saying series can't go past 3....? When you apply 33Volt across this end, all the voltage must run down into each cell, otherwise the circuit is broken. Yes I agree not all cells are equally charged due to each R value is slightly different R1 R2 R3.....R19, R20, so in practice the cells closest to the postive end and the negative end receive more current than the ones in the middle. I experience this weekly when topping up the water loss. However you can series up more than 3. Your problem with parallel is if one battery has R1 and the other R2, the lower R value drags the storage capacity down to its level, so both batteries must be identical, near impossible to achieve. AN opposite problem with solar panels, if a string has one panel at 300W and another panel at 200 W, the 300W panel is reduced to 200W, so your string is only 400W, not the expected 500W. So if your battery in parallel has one at 200Amp/hr and the other at 150Amp/hr storage, the weaker one pulls down the better one, so the total storage is 300AMp/hr, not 350AMp/hr. Question: how do you monitor your banks in parallel for those that are not playing the game? Eg in series it is unnecessary, 490 Amp/hr + 480 Amp/hr + 475 Amp/hr .... up to the last of the 20 in series, I still get 100% maximum from each cell, despite some being slightly less charged than others. I would get 24Volt and in theory 500 amp/hr. ANother problem for you is getting 200 amp/hr of useful battery. To keep the Lead Acid above 90% SOC, keeping chemistry healthy, requires you to have 2000 Amp/hr of storage. With you 6 cells in 4 parallel, say 200 amp/hr each (eg neighbour) :::+::: :::+::: 24 bat total = 4 sets of 6 bats Hmm? You only achieve 400AMp/hr at 24 Volt, not enough. To achieve 2000 amp hr, you need 10 sets in parallel. The cost for these 60 batteries at say 300 each is $18,000 and they only last 3 to 10 years. With mine, I have 20 in series, and I get 200 amp hr of daily use, cycling from 100 % SOC down to 20% SOC every day, these batteries cost me $9000 delivered, and will last for 35 years minimum, possibly up to 50 years. SHalom
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Post by Dave on Feb 23, 2022 15:23:07 GMT -5
This is the only solar battery arrangment I have ever seen Exceptions - but not 12v bats all I have ever seen = are 2 6v bats in series = 12v Solar is 12v or 24v or 48v standard A 12v bank = 6 - 6v bats (this is all I have) A 24v bank = 2 12v banks in series To increase 12v bank = multiple 12v banks in parallel To increase 24v bank = muntiple 24v banks in parallel My neighbors arrangement :::+::: :::+::: when the time comes - the 6 weakest bats can be pulled out of the 24 and replaced by 1 new 6 bat bank -------------- :::+::: :::+::: 24 bat total = 4 sets of 6 bats Hmm? You only achieve 400AMp/hr at 24 Volt, not enoughI give you A You change it into B and comment about the error of your own BHow does your image represent everyone has 2 6v batteries in series – then sets of 2 in parallel
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Post by Deleted on Feb 23, 2022 16:04:24 GMT -5
OK fair enough, and what is the total amp/hr storage of your friends / your neighbor's battery bank?
Mine in theory is 500 amp/hr but in practice is 200 amp/hr available.
Today I have 50% SOC and used 100 Amp last night, so the maths is correct
200-100/200= 50% SOC. The voltage is currently 27 V.
SHalom
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Post by Dave on Feb 26, 2022 23:15:40 GMT -5
OK fair enough, and what is the total amp/hr storage of your friends / your neighbor's battery bank?
I emailed this exact quote to my neighbor
Not sure how many watts of panels he has – but he has 24 Trojan T105 @ 225 amp/hr We estimate the he has 5400 (2700)total amp/hr storage - as configured
Mine in theory is 500 amp/hr but in practice is 200 amp/hr available.
My neighbors Trojan T105 are rate as @25 Amps 447 min @75 Amps 115 min 5-Hr Rate 185 amp/hr 10-Hr Rate 207 amp/hr 20-Hr Rate 225 amp/hr 100-Hr Rate 250 amp/hr
I must explain – his system is much larger than I have told you He has 3 windmills and is grid tie – and receives a check each month for energy sold
He calculates his system at 129600 watt hours (Wh)
Everyone here calculates their system in wattage – DIY Solar Packages are sold by wattage Wattage necessary to run your home x 3 (overkill to outlast a storm) My previous package was 5000 watts @ 2520 amp/hr stortage My current package is 800 watts @ 225amp/hr storage
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Post by Dave on Feb 27, 2022 7:32:59 GMT -5
Additionally – my neighbor and I – both have a more independent subsystems not dependent on our main solar package
Example – outside of my house solar - I have other 3 separate battery systems + 3 sets of solar yard lights used indoors
Inside the house I have 2 – 12v RV LP furnaces – one at each end of the house Each 12v furnace has a 12v marine style trolling battery + an 8amp automotive bat charger Sun up – we charge the trolling bats Sun down – we can use the 8amp charger as needed Light off – bed time – the furance runs totally off the trolling bats
In the barn and bathroom ( outhouse ) we have solar lights you would put in your yard Sun down – lights on – until about 2 am or so
All my electronics are behind the bathroom then a work bench then the back side of the chicken coop This area has several RV 12v led lights + 2 of my neighbors old T105s + a 75 watt solar panel
My neighbor also has his well pump slaved to a solar panel Sun up = pumping water – slow and steady
My neighbor also has a remote operated motor driven gate It has its own solar panel and small bat
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Post by Dave on Feb 27, 2022 12:21:06 GMT -5
Please tell us exactly what type of batteries you have And how you have them arranged
I am guessing that you have TN500 – which is a 1.2v battery @ 500 amp/hrs Then you have 20 of them in a series to make 24v – but you still only have 500 amp/hr
And you paid 10K for this?
Neighbor has 24 Trojan T105 – which is a 6v @ 225 amp/hr 2 together = 12v @ 225 amp/hr X 3 to make a 6 bat bank = 675 amp/hr X 4 banks of 6 = 2700 amp/hr (I was wrong to say 5400 – my bad)
Trojan T105 @ $200 x 24 = $4800
I have off the shelf golf cart batteries 6v @ 75 amp/hr 2 together = 12v @ 75 amp/hr X 3 to make a 6 bat bank = 225 amp/hr
My bats were $90 x 6 = $720
I am guessing that you have TN500 – which is a 1.2v battery @ 500 amp/hrs Then you have 20 of them in a series to make 24v – but you still only have 500 amp/hr And you are limited to 80% discharge an already you are hovering at 50%
So you are trying to charge faster – which drives the line voltage higher 33vs sometimes you say in this thread – which just cause your batteries to gas – increasing maintenance
So your real problem is that your giant storage bank is not as large as you think if it is all limited to 500 amp/hrs discharge rate
Here we have a lot more storage capability – we limit ourselves to a 20% discharge because of our increased storage capacity – we never draw more our batteries down more than 20% – NO to little maintenance –
The tradeoff is life span
My current package is 800 watts @ 225amp/hr storage Correction My current package is 800 watts @ less than detectable storage – same as dead And we are generator dependent after dark And we start the generator these days always for coffee and microwave (breakfast for us)
Bats lasted 34 months – I just spent my money on a new car But spring I’ll be replacing my batteries – might upgrade – but will not go expensive – or move away from maintenance free (I have girls)
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Post by Deleted on Feb 27, 2022 15:51:01 GMT -5
Wow is very interesting listening to you and the prices are so different in our country.
At work we purchase gold buggy batteries, made from the USA too, and some are 6V and some are 8V if I remember, I have used some, because we blew them up after only 12 months of use. And we paid $5000 for them, not sure how many, 6 I think, that 6 in series making a 36 volt system. We have 2 buggies, so that is about $400 each for them. Yours are so much cheaper in the USA, so lucky are you !!!
So you are paying $700 every 3 years for your battery maintenance?
Your neighbour has a massive system !!!!
I paid $9000 for 20 batteries in series, in theory 500amp hour each. They weigh 35Kg each and are made of Nickel Iron using KOH electrolyte.
I reckon after 12 months they are probably around 300 amp hr. Since I upgraded the system with 3 Smart MPPT controllers, they all reached float by 11 am, for the first time ever.So now my batteries are not overcharged.
I suspect a better performance from now on. I can refill them after 5 years with new KOH and get my 500 or 400 amp/hr back, which will be nice.
Overcharging Ni-Fe does not hurt them. They liked to be worked hard. SO daily they go to 70% SOC and sometimes to 20% SOC. Not something you can do with Lead Acid batteries.
Let's say they last the minimum of 32 years and factor in 4 changes of KOH costing us $200 each time, so that 9800/32 = 300 per year.
And if they last 48 years, that 10200/50 = 210 per year.
And if they last 72 years, 10,800 /72 = 150 per year.
You are paying roughly 230 per year to maintain your system.
If the end of time for the world was to work so you could purchase right through it, than I would agree your system is best/ cheapest. But my understanding like with COVID for example, many of us who dare to be different will not be allowed to buy or sell, so we are stuck with what we have until they eventually impose the death penalty on us for being different to them. So I decided to purchase Ni-Fe because it has a long age of life.
I note your battery temps get to below zero, and Ni-Fe does not work too well at 0 degrees Celcius (32 F) so you might be better off sticking with Lead Acid.
I just also purchased some more solar panels, to get sunshine at 6 am right on sunrise, to help battery health from night time use. We get plenty of sunshine here, so lucky are we to have this option.
Shalom
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Post by Dave on Feb 27, 2022 17:24:49 GMT -5
You are paying roughly 230 per year to maintain your system. True statement – this would be a little less than $20 a month – I calculate $21 a month The goal is to beat that price next time around But as TESLA changes the world – battery technology will in prove and come down in cost Tesla cars are everywhere here – we live from exit 15 to exit 49 on Interstate 25 – exit 11 is our shopping center, it has an 8 station EV America station to charge VWs, BMWs, Nissans, Toyotas and across the street is a Tesla supercharge center at the truck stop and Wendy’s That truck stop says it has a Tesla Semi charge station coming soon (sign has been up a year) We have been looking to buy a car – I test drove a Nissan leaf – and I sat in a Tesla Model 3 If I can find an old used up Nissan leaf for <5K I might buy it I could afford the Tesla – but NOT the insurance that goes with it Right now in El Paso County – Pueblo, Colorado – exit 94-104 on Interstate 25 – the people voted down a nuclear reactor – the same money will be spent to install solar panels on new construction and commercial buildings + free panels to home owners My point – batteries will more available Batteries from used EVs – Leafs and Prius are measured in KW/Hrs FYI – I just bought a new car from an auto auction It was the first time my daughters hear a real auctioneer jabber away – fun I saw 2 different Prius sell for less than $1000 – body damage (I was very tempted) I am blessed – and I know itHere in Colorado the best car I ever owned was a 2000 Jeep Cherokee XJ I loved that car – it would go anywhere – 24” of snow / mud – anywhere I also had a Chevy 4x4 and would brag that when my Chevy got stuck – my much smaller jeep would go pull it out I have been car shopping – looked at all types and prices – before I decided I went to an auto auction Had no idea what to expect – we home school, so I made the girls look up the book values of 15 cars that we thought we might like. Of that 15 – the prettiest car on the lot was a 2008 Subaru Outback – showroom clean inside and out It was the second car in the door – the auctioneer stated the dealer says it has a slipping transmission Wham – bam – Bang it sold for $850 before I even was up to speed. Few cars later – Grey 2010 Nissan Murano – book value 4-8K – I bid $2500 it sold for $2550 Few cars later – Pretty Red 2012 Toyota Sequoia – book 8-12K – I bid 2900 it sold for 3K By now I am think I am so stupid – these were clean enough cars for 3K Eventually – last minute entry – 2000 Jeep Cherokee XJ – I could not stop myself and took it home for $1950 - $2550 to get it off the lot - fees + tax + tax - and there is the tax The scary auction part – popping the hood after you pay for the car Oil everywhere – I mean everywhere – and lots of it I took it to my mechanic and as soon as he saw the engine compartment he said – no worries happens a lot on these cars – notorious for valve cover gasket leaking at the pulley end and the belt throws the oil everywhere Valve cover gasket and 2 rear shocks $450 2 rear struts for the rear hatch $60 We have about 1000 miles on it and – everyone likes our new car
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