Solar Power

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glalt
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Re: Solar Power

Post by glalt » March 11, 2020, 1:09 pm

fhorst wrote:
March 10, 2020, 11:34 am
Good news and bad news..

I'll start with the bad news.
My 16 * 12v 200Ah lead-acid batteries are fried, dead, no longer to be used. they appear to be fully charged and after 4 hours.... voltages below 8 volt. Empty.
Farewell 126.000 THB... :cry: :cry: Welcome 1000kg old lead... :mrgreen:

That is what happen when the crappy EASUN MPPT inverter charged the batteries at 78 volts!!
(My 3 x new Revo II 3.2kw MPPT inverters work perfect!!)

Good news, you won't believe how cheap lifepo4 is these days!!
I was amazed. maybe positive effect from Corona, to high stock??

Lifepo4 (lithium) is safer then lead, do exploding gasses !!
Also, it does not have big issues with the Thai temperature. 40, 50 degrees, no real problem!
Besides that is is now even cheaper then lead-acid, lifetime is + 2000 cycles, compared to + 500 from lead acid.
And those are real cycles, discharge 95%, without problems!!

I've looked into Lithium when i bought the lead-acid last year februari, price was minimal 2.5 times higher.
now... $43 for 152Ah, and under $83 for 280Ah!!

I've bought 32 * 152AH (3.2v) for $ 1602
3.2v 152Ah LiFePo4 Battery for $ 43.00 (MOQ=1)
This price was including DDP transport. (all costs, including tax, paid!!)

they look really impressive, are well matched (same voltage 3.29v = 70%)
(pictures of the batteries, somehow I can't get photo's inside) (edit.. found it!)
https://ibb.co/gJCPK3q
https://ibb.co/QcxHCVw

Maybe ill add in the future one set (16 * for 48v system) of 280Ah (only $82.67, MOQ=4)

on an other forum (diysolarforum.com) I found the perfect guide on how to order Chinese batteries (thanks ghostwriter66)

The BMS I ordered (not yet arrived) give me full insight (Bluetooth app) what is happening with the batteries.
After the expensive malfunction of the EASUN, i like to stay on top to know what is happening.
It can do 100A charging, 300A discharge and balance the cells with 1A (if needed)
I bought from Aliexpress, $120.70

Building is really easy, it takes less then 30 minutes to setup, and light to handle!!
(my lead acid are 70 kh each.. one lifepo4 cell is 3 kg)

Will Prowse, a known youtube "guru" explains all about it in [urlhttps://www.youtube.com/watch?v=wyP_dgWz8pY&lis ... 583gq0OAyi] his video's (this is playlist for DIY lithium[/url]
Sorry to hear about your lead acid batteries. I use EPsolar tracer charge controllers. They have since been updated with EPever tracer charge controllers. I have three of the old models and two of the new models. I like the remote meters that are optional. I keep a close eye on them and they do indeed convert extra voltage to amps, thus MPPT. The old originals are more than seven years old and have been totally trouble free. I use pure sine wave GAIA inverters. I really don't trust the hybrids. Simple things for a simple minded guy.

I started out with four AGM sealed batteries. They lasted about five years. Disappointing for such expensive batteries. I bought them because I kept them in the house. They were replaced with four six volt golf cart batteries that are kept outside. Both my main systems are twelve volt mainly because so many DC devices run on twelve volts.

Two 12 volt deep cycle lead acid batteries are original. I think they are getting weaker. A few weeks ago I did something the experts say not to do. I used a pair of jumper cables and hooked those two battery banks together. So far everything is working great and both banks are balanced. The FB deep cycle 125 AH are over seven years old. I am very careful not to discharge them below fifty percent.

That's an amazing price for the Lithium batteries. Since I am happy with my lead acid batteries, I'm a little hesitant to change over when necessary. I worry about my existing charge controllers charging Lithium batteries. They can be damaged if not charged properly.



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fhorst
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Re: Solar Power

Post by fhorst » March 19, 2020, 9:35 am

glalt wrote:
March 11, 2020, 1:09 pm
Two 12 volt deep cycle lead acid batteries are original. I think they are getting weaker. A few weeks ago I did something the experts say not to do. I used a pair of jumper cables and hooked those two battery banks together. So far everything is working great and both banks are balanced. The FB deep cycle 125 AH are over seven years old. I am very careful not to discharge them below fifty percent.

That's an amazing price for the Lithium batteries. Since I am happy with my lead acid batteries, I'm a little hesitant to change over when necessary. I worry about my existing charge controllers charging Lithium batteries. They can be damaged if not charged properly.
Start with the last.....

"They can be damaged if not charged properly."
555

Joke, yes??

The + 125.000 THB Lead-acid got damaged as they where not charged properly
:D

Voltage range of lead acid 12 Volt batteries is 10.5 as lowest voltage, (lower and they get severe damage) and 16v as maximum charge (short, few hours, equalising phase)

Lifepo4 have min 2.5, max 4.2v.
For a 12v battery, that is minimal 10 volt, max 16.8 volts.
Quite a larger tolerance!!

There is one big difference.
In a lead acid battery, the 6 cells balance eachother.
Lifepo4 does not, that's why it needs BMS.

There are many scary stories about lithium battery explode and other things.
Lifepo4 is NOT the same!!

In fact, you can penetrate it, cut it, smash it, put it in a fire...Still Safe!

No explosion, no exploding gasses.

Lifepo4 are almost the ideal battery.
Except we always want lighter, smaller, cheaper, and faster charge and discharge possible.
With a charge rate of max C1 (the same capacity in one hour) it's fast. Better is C0.5.
That is charge a 150ah in 2 hours!

Discharge normally now is C1, there are C2 and 3.
Compared to a starter battery.. the CCA is about C5 But charging.. C0.1
And.. at high discharge rate, lead acid loses much of its stored capacity.
Fast discharge 100Ah give you about 70Ah.
Fast discharge lifepo4? Stay the same :-)

Anyways... I get carried away..
Lifepo4 are less sensitive to charging then lead acid, and wrong charging is potentially less dangerous.

Yes, you can overcharge lifepo4. Normally charging goes perfectly with 99% of all the lead acid chargers. While lead acid loses power "fast" and it needs tickle charge, lifepo4 do not.
(Only little bit)

With long term continuous tickle charge, you will damage the lifepo4.

Easy trick if you have the lifepo4 full all the time, is to give them small discharge.
That can be a small ligh bulb, or small resistor
Your charger should be able to tell you how many watts it uses during tickle. (A few)
Discharge about the same, and it is perfectly safe to use the lead acid charger for Lifepo4.

For solar... That is what we talk about here..
It's the same if you have your battery only for backup.
Lifepo4 charger stop when the batteries are fully charged.
Lead acid almost stop, move to floating charge.

And that's easy!
As most solar controllers give you the option to set your own battery, and own settings.
Lifepo4 is fully charged at 3.65, is 14.6v
Set the floating between 14 and 14.5 , problem fixed.
That easy.

While lifepo4 can do much more cycle then lead acid, full charge and discharge does shorten this cycles.
Tesla does a nice trick.
They charge to 80 or 90% and discharge till 10 or 20% with this setting, they can guarantee 10 years, 3500 cycle!

And it is easy to copy this.
Lower max charging, higher max discharge :-)
Yes, you use 80% but almost twice as long.

Now reaction to your first part..
Whole! 7 years!
That is really long time for lead acid!
I am impressed.
I like to know your storage location (cool inside the house? Or hot Thailand outside?) And if you really used them every day. (= Discharge at night, charge during day)
7 years is 2500 days/ cycles!!

If they are used mostly for unstable grid, and where mostly fully charged, 7 years is still long time, just not that spectacular.

Battery decades.
We all do :D
And with age comes less power.
They just can not hold that much capacity any more.
In fact, normally 15% of the power you put into a new lead acid battery is converted to heat.
When they get older, that number rises.
When you disconnect them from the charge, also no tickle, they self discharge at a much higher rate then they used to do. This self discharge is also heat. (Energy can not come from nothing or real disappear)

Simple test is to disconnect for a week after fully charged. At start measure the voltage a few hours after charging, it should be close to 12.7 volt.
After 7 days doing nothing, no connection for discharge, the voltage still should be 12.7.
After a month 12.6 (90%) or 12.5.
12.4v is about 80%.

Older battery discharge faster, up to a rate that they look fully charged, but are discharged in a matter of hours (with low wattage used)

You have old and new.
What happens now is that after disconnect from the charger, the new batteries are (re) charging the old ones, trying to compensate it's self discharge.
The old ones simply cannot hold on to it, and lose the new energy fast.
This way the new batteries are constantly discharged.
Your inverter might stop at 10.5 volts discharge, the old battery does not!
And it will continue drawing energy from the new batteries.
Those where already low, low enough to trigger the safety discharge stop from the Inverter.
Now they become below 10.5 and getting damaged.
Each day a little more.

Connect old and new battery together is not advisable for this reason.

Even when they don't discharge down to the dangerous 10.5 volt, they will continuously discharge the newer batteries.

It looks like you are adding more Ah, and for short time discharge, you do.

Leave the batteries without additional charge...
Not only the old one discharge fast, also the new.

For solar, power is "free", and easy to forget that a watt lost can not be used.

If you would place them on grid tied charger,and place a watt meter...
You will clearly see the difference!

After charging the new batteries keep their charge for many months.
The old? Hours? ,Days?? few weeks? A month?

Most solar owners have enough batteries to have them 2 days without (much) sun, and change the batteries when they are no longer capable of giving energy the whole night.

My dead batteries, 3200Ah on 12v... 38.400watt
Can do about 4 hours @ 500 watt discharge.
From the +38kw, they have 2kw left.
If I don't use any energy, they self discharge fast.
In a day they go from 12.7 to 11 volt

If I add new batteries, then they look to be good again... But they are still dead.
All I would see is the new batteries trying to keep up the appearance :-)

Connect old and new is bad for this reason.
The old, even when they are 7 years.., should be able to provide you with enough power.
If they no longer can... They are defective, depleted, no longer economical usable.
Unless they have sentiment value.
Then add as much as you need to keep up the appearance :D
If it can't be done, it never happened..

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fhorst
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Re: Solar Power

Post by fhorst » March 19, 2020, 10:05 am

It as already a long post..

Better split in 2.

As lifepo4 advocate... ( I really do like them!)...
Many people think they can not combine lead acid and lifepo4.

It's not advised for 1 simple reason.
Lifepo4, once charged to full, charging should stop.
Unlike lead acid, that tickle charges.

Lead acid kind of continuous tickle charges the lifepo4 after they are both fully charged, and there is no load, no discharge.

In solar system, if you only have for backup unstable grid, that will be a problem.
If you use your stored power at night, there is no problem.

Actually it is the same like using lead acid battery charger on lifepo4.
It will work perfectly, but you need to add small discharge.
10 watts is normally enough.
(Depending on the size of your lifepo4 batteries.
10w is good for 150ah)

The self discharge rate of the lead acid probably is higher then adding that 10W load to lifepo4.

As there is continuous charge from the lead acid to the lifepo4, the continuous discharge will prevent overcharge of the lifepo4 battery

In theory, as the lifepo4 have lower internal resistance, and slightly higher voltage, they will discharge first at night. Also charge first with solar power.
The effect is that the lead acid battery, who does not like to be discharged (a lot) practically stays full, and the lifepo4 takes most of the load.
Only during longer times of clouds and rain, the lead acid really need to do it's job.

This way the combination prolongs the lead acid life cycle a lot. Really a lot.

A new lead acid battery that is constantly tickle charge to full, and stored in the best temperature range (15-20 Celcius) can last 10-15 maybe 20 years.
After that, even while it is never really used, it is still dead.

Lifepo4 you can charge (70%) , charge up to 70% every 2 or 3 years, have between 0.5 and 40 degrees, and after 20 years it's practically as good as new.

I have not tried any of the above.
But did a lot of research on this topic.
If my lead acid batteries would not be dead, but possible could be recovered, I am planning on having this combination.

My 32*152Ah, 14 KW usable storage is little to low storage for those rainy days.
My setup needs to have 20ah to do 5 rainy days
And if I want to use energy like it is sunny day, even 30ah.

If the 16*200ah can hold their charge again, that problem is fixed :-)
(I'll try to fix them with de-sulphation pulses)
It's a long shot, hail Mary, wishful thinking.
Hard to say goodbye to +125.000 THB so fast.
I was hoping to be able to use them at least 4, possible even 7 or 8 years.
But... Defective product charging 12v at 19.5v will kill any battery. Defective product doesn't listen to my planning on using them longer then the 10 days or took to destroy them.
](*,) ](*,) :snide:
If it can't be done, it never happened..

glalt
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Re: Solar Power

Post by glalt » March 19, 2020, 10:56 am

My systems are stand alone. I do have double the recommended panels to charge the battery banks. On a sunny day the banks are fully charged by about 11:00 AM. By the next morning the voltage is about 12.3 - 12.4 volts. During charging my meters show about 14.2-14.5 volts when fully charged and the setting is for flooded batteries. With my double capacity panels, the batteries fully charge even during cloudy or rainy days. I have no idea how long they will hold a charge but as long as things keep working well I don't care. Once in a while I check them with a hydrometer. I keep expecting to find a dead cell, but not yet. I think one major problem for some systems is sulfation and then being overly discharged caused by not being fully charged. The lead acid deep cycle batteries are not cheap so I keep an eye on the voltage in the mornings.

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fhorst
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Re: Solar Power

Post by fhorst » March 25, 2020, 9:18 pm

Thumbs up as feedback is not (yet) possible in this forum.
I agree, lead acid can last long as long it isn't discharged too much.

My system was designed to discharge about 30% at night, nothing more, and indeed be charged in the morning again.
As lead-acid don't like heat, it even had personal air conditioning in that room.... just to keep the batteries happy.
The lead acid deep cycle batteries are not cheap, $4500 investment was big enough to have 500 dollar protection :-)
It was designed to last 5 to 8 years....
Sadly... EASUN.. and POEF!! Not even 1 year,

the 32 x 152Ah lifepo4 have arrived and they are new and at rated capacity.
I've used "https://s.click.aliexpress.com/e/_rIkLxb" this 150W Battery capacity tester
As it was charged to 3.35v, it wasn't fully charged. still, 146.7 Ah... not bad :-)

Today I've ordered 16x 152 extra, giving me 48 x 152Ah cells at nominal 3.2v that's about 23Kwh...
that whole, or at least 22kwh can be used, over and over again for many many years with my usage + 10)
total costs where $ 2450 for the cells (I bought at Haomi https://bit.ly/2Qi-Lifepo4)
and the BMS for $120

The total capacity is higher then I originally intended to use for the deep cycle, smaller, lighter, more cycles and even cheaper...
plus that lead acid have only 70% efficiency, lifepo4 does 95-99%!!

Yes, I'm sad i lost my $ 4500,- investment, but at the end.. I'm better off,

If only the lifepo4 where this low price last year..... :?
If it can't be done, it never happened..

glalt
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Re: Solar Power

Post by glalt » March 26, 2020, 10:14 am

I have no reserve power. As mentioned the voltage in the mornings is 12.3 to 12.4 volts. I have an isolated 10 AMP circuit in my electrical panel with a double throw switch. Down is the grid power and up is the battery bank. It runs the refrigerator, freezer, small appliances and lights. The battery bank is not strong enough to run overnight but works OK when the sun is shining. I normally don't bother. The electric grid here stinks and I didn't go solar to save any money. I just want to have electricity when the grid is down. (Often).

Have you tried one of those little pulse chargers to try to save your lead acid batteries? It would be worth a test on just one battery. You never know. If the batteries got hot and the fluid all evaporated, they are likely ruined.

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fhorst
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Re: Solar Power

Post by fhorst » June 5, 2020, 1:18 pm

Sorry for the late reply..

Yes, I've tried the pulse chargers and special pulse generators.
Both bought and DIY from schematic on the web.

Sadly, no positive results. (For 200ah it can take 4 weeks to see results)

I'm now going to try the Epson salt solution.
Maybe that helps.

Otherwise they are sold as old lead.

I hope to revive them, for my father in law to use with pump.

We just bought 2 panels for him, and I have 2000 watt inverter left over (24v)

My Lifepo4 is going strong
I order some extra due to low prices and I want to run my crypto miner rig 24/7.
It uses about 1000 watt and makes 90 USD per month.
( Bitcoin stuff)

Now 736Ah, at 51.2v, 37.5 kWh
Solar is upgraded to 13kw. (41 panels)

Next step is to fine tune the Inverters, for airflow, cooling and noise.
And connect the 6.5kw generator for emergency.
It's autostart and dual fuel (LPG and gasoline) (both DIY, but easy to do)

Ow Yes, and make baffle box for it :-)
If it can't be done, it never happened..

glalt
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Joined: January 14, 2007, 10:35 am
Location: Nong Hin, Loei

Re: Solar Power

Post by glalt » June 5, 2020, 3:54 pm

We have gone from a 5,000 watt gasoline generator running a 1 HP submersible water pump to a solar DC submersible pump. She uses it to irrigate her fruit trees. That pump runs off 3 solar panels. The system is now running every day working at filling that dried up farm pond.

The other farm was using a Kubota tak tak to run a water pump. Irrigating rice takes a lot of water and it had to run 24 hours a day. She got tired of hauling diesel fuel every day. That larger solar system uses 6 340 watt solar panels. The pump works well when the sun is shining and stops at dark or when it rains. No batteries for either system.

During the drought here, the water table dropped and the Kubota powered pump lost suction. The bigger system is working now to fill up the pumped dry farm pond.

JR
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Re: Solar Power

Post by JR » June 16, 2020, 9:57 pm

fhorst. I see you are closing in on my 15kw system. :-)

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