Battery gravity doesn’t look good

Simonbr2

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I setup my solar about a month ago and I’ve been slowly learning. I seem to have a strange problem that I can’t wrap my head around.

i have a hydrometer and refractometer to test my batteries and both are in the recharge area constantly. This morning I ran my generator and let my inverter/charger do a full charge on my batteries. It went from bulk to absorption then full. My MPPT also showed full charge. Checked the battery with the refractometer and it still shows the same. I’ve attached some pictures. Any ideas?
 

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fratermus

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Checked the battery with the refractometer and it still shows the same
The same as what? Is this off-grid or is the Abso also charging from shore power?

I understand these are Interstate 903-S, and I think tall batteries have an increased vulnerability to electrolyte stratification. So you could be seeing weak acid at the top where sampling occurs. A vigorous EQ session (>=15v, see below) might help stir things up.

Although Interstate documentation is infamously absent, there is some chatter that the battery is made by U.S. Battery. if so, this could be relevant info. If I were charging these off-grid I might implement the guidelines as:

* Absorption 14.7v for three hours (the max Abs duration of the controller, IIRC), at which point acceptance should be =<12.6A for the 420Ah bank
* Float thereafter at 13.0v
* EQ: 15.3v for 1-3 hours monthly after normal full charge

Let us know what you find out.
 

Simonbr2

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The same as what? Is this off-grid or is the Abso also charging from shore power?

I understand these are Interstate 903-S, and I think tall batteries have an increased vulnerability to electrolyte stratification. So you could be seeing weak acid at the top where sampling occurs. A vigorous EQ session (>=15v, see below) might help stir things up.

Although Interstate documentation is infamously absent, there is some chatter that the battery is made by U.S. Battery. if so, this could be relevant info. If I were charging these off-grid I might implement the guidelines as:

* Absorption 14.7v for three hours (the max Abs duration of the controller, IIRC), at which point acceptance should be =<12.6A for the 420Ah bank
* Float thereafter at 13.0v
* EQ: 15.3v for 1-3 hours monthly after normal full charge

Let us know what you find out.

what I meant by the same is that the level in the refractometer did not change after using the abso in charge mode. I was told the charger is just a basic charger and will not perform the correct charge for solar systems. Not sure if that’s correct.

The system is 100% off grid and the generator is connected to the abso.

This Monday I changed the MPPT from 30a to 40a, it’s been raining since then and today is the first sunny day. I verified the gravity of my batteries today upon arival to camp and they are now lower then the 1.10 level.

Is this really accurate, I thought the gravity told you the true voltage or the battery, my system is still working and my dc fridge still running. If I would truly have bellow 1.10 would the battery still run items? In which charge state does the gravity change? Bulk, abs/boost or float or all of them?

i haven’t tried to change the charge settings yet because I wanted to swap my MPPT and allow the sun to come out so by tomorrow morning i thinks that’s my next step. I’ve also included the default settings image.
 

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Tecnodave

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Your batteries are in desperate need of an equilization. I would not trust what the EPever is telling you, they are not accurate. I much prefer true float type hydrometer but your refractometer is all you need and it tells the story. You are way undercharged.....

Most battery chargers are set up for automobile batteries and as such can not do a proper charge on FLA batteries, especially not true deep cycle large format batteries. I had EPsolar Tracers and disposed of them as they would not fully charge my Interstate L-16 batteries, mine were early units with generic settings for car batteries but not user settable settings.

I will confirm that tall batteries do have a problem with stratification but i have a solution that works well for that, a turkey baster, a large plastic one, use one to stir up the acid before sampling for the refractometer. I got much more accurate readings stirring things up before reading

I can confirm that Interstate Large format batteries are manufactured by U.S.Battery ( Came from inside the company)

Get the data sheet from U.S. Battery, dont even ask Interstate, you will only get the sales rep. I have access to the company on a local level where i can access the battery techs.

This is my go to hydrometer:


I don't think that there is any significant differences in spectrometers

When you equalize don't stop when bubbling begins, it needs to be vigorous bubbling, strive for 1.265 with no more than .020 deviations between cells, .010 is better

david
 

Simonbr2

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Your batteries are in desperate need of an equilization. I would not trust what the EPever is telling you, they are not accurate. I much prefer true float type hydrometer but your refractometer is all you need and it tells the story. You are way undercharged.....

Most battery chargers are set up for automobile batteries and as such can not do a proper charge on FLA batteries, especially not true deep cycle large format batteries. I had EPsolar Tracers and disposed of them as they would not fully charge my Interstate L-16 batteries, mine were early units with generic settings for car batteries but not user settable settings.

I will confirm that tall batteries do have a problem with stratification but i have a solution that works well for that, a turkey baster, a large plastic one, use one to stir up the acid before sampling for the refractometer. I got much more accurate readings stirring things up before reading

I can confirm that Interstate Large format batteries are manufactured by U.S.Battery ( Came from inside the company)

Get the data sheet from U.S. Battery, dont even ask Interstate, you will only get the sales rep. I have access to the company on a local level where i can access the battery techs.

This is my go to hydrometer:


I don't think that there is any significant differences in spectrometers

When you equalize don't stop when bubbling begins, it needs to be vigorous bubbling, strive for 1.265 with no more than .020 deviations between cells, .010 is better

david
Awesome information thank you. I’ll try to find a turkey baster at camp and maybe even give the cells a rocking to mix up the acid.

im trying to change the settings on the MPPT but getting errors. I wanted to confirm I am doing this correct.

when trying to change the equalization to 15.3 I’m getting an error, I’m guessing this is because the charge limit is set to 15.0 so I would have to move that to 15.3 also

same goes for the float setting , trying to set at 13.0 gives me an error. I’m guessing I have to change the “boost reconnect charging voltage” but not sure what value I should use.

once all is set and it does the charge tomorrow, is there a way to force the equalizer mode and is this even a good idea?
 

Tecnodave

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I do not have any offshore controllers or other electronics in my system, my controller is by far the most advanced unit available and any setting you want can be entered so i cant advise you about that, get the U.S. Battery data sheet and set your charger to those settings. As i said the EPsolar, renamed EPever could not charge my Flooded Lead Acid cells. I sold them off and have a good controller now

Bulk charge 14.7
Adsorb 14.7 60 minutes minimum 90 minutes better
Float 13.5
Equalization 15.7
Maximum sustained charge rate 40 amps

It will take more than 1 charge cycle to get your batteries back to where they should be

this data is for the generic “traction battery” these are sold for floor sweeper use.

My settings are different as i have true solar duty Rolls-Surette S-530 L-16 batteries and they differ somewhat as they are manufactured differently than a traction battery

Just a note, my battery set came out the door at Rolls-Surette on July 19, 2005......THATS 26 YEARS!!
.they are still in use.....still at 1.265 across the set with no more than .010 difference......that is maintaince not deferred....

My backup set are Interstate (U.S.Battery) L-16 which i bought in 2001.....still in use....thats 20 years

These are NOT PARALLED, each set has its own Classic 150 with WBjr and Bogart Tri Metric
still at full capacity and at 1.280 s.g. e.q. 32.00 volts......these are traction batteries! not solar batteries

My solar controllers are MidNite Classic 150’s.....with WBjr’s and ......Bogart Engineering Tri-Metric 2025 battery monitors..............just a tad bit more expensive and way,way,way more programmable than EPneverreliable or most anything else out there.

My EPSolar controllers proved that they are not capable of true solar batteries, they were sold as is where is with a full 30/30 warranty. 30 seconds, 30 feet.

All my systems are nominal 24 volts....
I eq at 31.5 volts for 90 minutes, rest 30 minutes, record results.

Get the data sheet for your battery, there are many options in manufacturing that will affect the charge parameters

Eon’s ago i did a stint at Alaska Husky Battery in Fairbanks Alaska, i learned just a bit there.
 

Simonbr2

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I’ve configured the settings from the us battery data sheet but also needed to change some disconnect and reconnect parameters to be able to make the changes. Does the display voltage and amperage on the mt50, bellow the battery level and smiley face, show what is being sent to the battery or is it a reading of the current battery state?
 

Simonbr2

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The reason I’m asking is because the MPPT is currently in eq stage with my new settings, the Mt50 is showing 13.2v 23.9a. I don’t understand how the charge controller can do the eq when the voltage is not at the required voltage 15.3v. The way I see it is that the battery should charge up to 14.7 before moving into other charge states. I’m not sure if the mt50 is showing me the actual voltage or what is being currently pushed into the battery.
 

Tecnodave

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I can comment on the batteries but i have no little to no experience with asian made electronics, I bought 2 EPsolar Tracers, when they trashed my batteries i disposed of them and bought all high quality controllers and chargers that are fully programmable and do not refer to generic types for setting. I therefore cannot comment on settings for a particular controller, I can tell you what the battery manufacturers state.

The display on the Tracer only shows what is put into the battery and what is taken from the battery from the output terminal of the tracer.....IF YOU HAVE ANY CONNECTIONS DIRECTLY TO THE BATTERY THE TRACER CANNOT “SEE” that current.

A true battery state of charge indicator MUST have a current shunt right at the battery where it can measure TOTAL CURRENT both into the battery and out of the battery......IT must also measure the voltage right at the battery

The original TRUE STATE OF CHARGE monitor is the BOGART ENGINEERING TRI-METRIC, Victron makes one that does this but it only works with a full VICTRON system, if you have equipment from others in the mix the Victron will have non accurate information.

In any case the true state of charge is read by a hydrometer or a refractometer.

WHAT IS PAINFULLY OBVIOUS TO ME.......You do not have a proper charger that is capable of doing a full equalization charge, The charger should not be in eq before the Bulk phase has finished. Go back and do bulk or Adsorb phase until each battery hits its terminal voltage......then move on to e.q. phase

Even though i do have high quality controllers and chargers, i verify the voltage and amperage settings with an external device that is specialized to that purpose, Personally all my meters are FLUKE or others in the same quality range, that can be calibrated by a calibration laboratory to NIST standards. My choice FLUKE 87V NIST......about $500.00, i use several Fluke 77 IV DVOM ($360) as my bench meter but i verify that against the 87V which is verified by a Fluke lab standard.

It is not a simple proposition to simply charge up a battery to recover from a very low s.g. reading. For now only believe your refractometer, they basically cannot go out of calibration unless you smash the device hard enough to not be able to see the scale. Yours has a built in calibration set point with the “water” line at the very bottom. To verify get some good quality distilled water that has very low T.D.S. (total dissolved solids) such as Arrowhead Puritas and check your refractometer with that. it should read 0.0 , the water line on your refractometer, but unless really abused, its fairly impossible for them to be not accurate.

The meter readings in the Tracers are “approximate guesses“ as they are not taken right at the battery terminals , not to be relied on....

For now.....with the units that you do have in possession do keep charging those batteries with no load on them, only use the refractometer and do get, beg, borrow , i cant suggest “steal” a reliable voltmeter and verify the voltage at the Tracer terminals, I think that you will find that the tracer readings are WAG’s......wild assed guesses....
 

fratermus

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I thought the gravity told you the true voltage or the battery

The specific gravity tells you about state of charge. Watching the density change over time can also tell us something about state of health.

im trying to change the settings on the MPPT but getting errors.

Parameter errors mean the input violates other settings. See this list which puts them in rising voltage order, or the manual.


Does the display voltage and amperage on the mt50, bellow the battery level and smiley face, show what is being sent to the battery or is it a reading of the current battery state?

It's the voltage being read on the controller's battery output terminals. This can be different than battery voltage if wires are undersized for the length/current. The bigger AN models have voltage sensing wire inputs to get a better read on Vbatt under such conditions.

Measuring battery voltage at the battery with a multimeter would help clear up the question.


I don’t understand how the charge controller can do the eq when the voltage is not at the required voltage 15.3v.

What does it look like when a controller tries to EQ an undercharged bank? What mode should show on the controller?

If voltage is still rising I'll guess the controller is trying to drag teh batt up to Veq. If we were doing it manually we'd:

  1. charge fully
  2. then EQ
 

chrisski

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I’ve only had to equalize once, and the was for specific gravities being off.

I turned on the SCC in full sunlight when my 1000 watts of panels could deliver up to 45 amps to my 12 volt 458 ah batteries. They started to bubble pretty quickly. My plan was to measure every hour until specific gravity was the same, but on my first measurement at hour one they had equalized.

Based off what I did, I’d ask a couple of things And these may have been answered, but I missed it.

First what is the size of the batttery bank in AH? I see its 12 volts, but I did not see the AH rating.

How many amps was your SCC pushing in equalization? You mentioned lower volts than equalization read which tells me there may have not been enough amps to get the equalization voltage you need.

I’m thinking if the SCC is fine, then there may not be enough power from the solar panels to the batteries to start equalization.

I also believe in a better hydrometer. I found my Deka in the local autoparts store.
 

Simonbr2

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I’ve only had to equalize once, and the was for specific gravities being off.

I turned on the SCC in full sunlight when my 1000 watts of panels could deliver up to 45 amps to my 12 volt 458 ah batteries. They started to bubble pretty quickly. My plan was to measure every hour until specific gravity was the same, but on my first measurement at hour one they had equalized.

Based off what I did, I’d ask a couple of things And these may have been answered, but I missed it.

First what is the size of the batttery bank in AH? I see its 12 volts, but I did not see the AH rating.

How many amps was your SCC pushing in equalization? You mentioned lower volts than equalization read which tells me there may have not been enough amps to get the equalization voltage you need.

I’m thinking if the SCC is fine, then there may not be enough power from the solar panels to the batteries to start equalization.

I also believe in a better hydrometer. I found my Deka in the local autoparts store.
hello chrissky

I have 2x 6v interstate in series, 420aH. The volts and amps during eq was 13.2v 23.9a. About and hour ago I installed a shunt and connected all negatives to the p- side of the shunt and now I’m getting better readings during load and charge on the new meter.

Once I reconnected the scc is now in boost. I do have a hydrometer and refractometer. I am using the refractometer to verify the gravity.

i left for the beach for the next hour or so and the Volta had increased to 13.5, maybe it’s playing catch up. From what I understand, I have my boost set to 14.7 volts so the scc should be pushing 40amps at varying voltage until it gets close to the 14.7 which then starts to decrease the amps
 
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chrisski

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The average golf cart battery is about 210 ah, so I’m guessing you have two huge 6 volt batteries, at 420 ah or two normal batteries at 210 ah at 12 volts.

My 12 volt Trojans float at 13.6 volts and equalize at 16.2 volts. At some point above 15 volts is when the batteries get enough voltage to start bubbling. Without this, the batteries are just not equalizing.

You mentioned 14.7 volts. My batteries’ absorption voltage is 14.7. That’s what I charge them at. No equalization will occur at that point. 14.7 is the voltage amps get pushed into my battery bank. I’ve installed moire panels and I can now hit the 60 amp charge limit. Still when I do, there’s no equalization until the voltage goes up and the batteries start bubbling. The sound is almost like standing by a creek or brook.

If both batteries weren’t working in equalization mode, I’d try to hook up one at a time. With this though, the charge controller would need to be able to do 6 volts.

I don’t know why the volts don’t go up to as high as needed for equalization for you. May be the charge controller, or perhaps the battery is that dead.
 

Simonbr2

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The average golf cart battery is about 210 ah, so I’m guessing you have two huge 6 volt batteries, at 420 ah or two normal batteries at 210 ah at 12 volts.

My 12 volt Trojans float at 13.6 volts and equalize at 16.2 volts. At some point above 15 volts is when the batteries get enough voltage to start bubbling. Without this, the batteries are just not equalizing.

You mentioned 14.7 volts. My batteries’ absorption voltage is 14.7. That’s what I charge them at. No equalization will occur at that point. 14.7 is the voltage amps get pushed into my battery bank. I’ve installed moire panels and I can now hit the 60 amp charge limit. Still when I do, there’s no equalization until the voltage goes up and the batteries start bubbling. The sound is almost like standing by a creek or brook.

If both batteries weren’t working in equalization mode, I’d try to hook up one at a time. With this though, the charge controller would need to be able to do 6 volts.

I don’t know why the volts don’t go up to as high as needed for equalization for you. May be the charge controller, or perhaps the battery is that dead.
They are 903-s 6v 420ah each. Volts are up to 13.8v on the MPPT and 3.4v mesures at the battery. Still not sure why it’s in the boost mode if they are not charged up yet. I do have a dc fridge connected and running, I know having a load on the battery changes the voltage, I’m thinking that’s why I am not seeing g the higher voltage.
Wouldnt forcing a bulk charge, full 40a, be what the battery needs if it’s just at 3.8v?
 

chrisski

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I don’t know about your inverter charger or the boost mode you mentioned. To me, to equalize, the voltage needs to go up to whatever the spec sheet says for the 903-s 6 volt battery equalization is. It will probably list the voltage for two in series for 12 volts, if not just multiply voltage by two. For a flooded lead acid battery, I think this will be real close to 16.2 volts.

If your charger won’t let you reach that voltage, than I’m not sure these batteries will eqaulize.

My battery 458 ah bank is about the same size as yours and is still hungry for it full load of 60 amps while it’s charging. The only boost mode I know of is some car chargers will push 40 amps into the tiny 64 ah batteries in hopes of recovering cells, but our batteries are seven times that size and can easily take the 40 amps. When I looked at this boost mode for my car batteries, I got mixed results about whether it works. Mostly came down to with the new construction of the lead 90% of the dead batteries stay dead after this boost mode. A few decades ago, when batteries were not as well constructed, they could be saved by. A boost mode.

When I did equalization, although I could have pushed 45 amps, I’m not sure how many amps were pushed at 16.2 volts. I think reaching a that equalization voltage is more important than amps pushed.
 

Tecnodave

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They are 903-s 6v 420ah each. Volts are up to 13.8v on the MPPT and 3.4v mesures at the battery. Still not sure why it’s in the boost mode if they are not charged up yet. I do have a dc fridge connected and running, I know having a load on the battery changes the voltage, I’m thinking that’s why I am not seeing g the higher voltage.
Wouldnt forcing a bulk charge, full 40a, be what the battery needs if it’s just at 3.8v?
Do read the manual for your DC fridge.......they work on a range of voltage and a equalization just might be out of range for the DC controller in the fridge, It would be best if the frig is powered from another source. My Grape Solar DC fridges with the Colku Compressor with electronic drivers will operate on 10-15 volts or 20-30 volts, that requires me to power the frig from alternate source when i equalize a battery set. The electronic drivers can be damaged by eq. voltages......information supplied directly by engineering staff at Grape Solar.....
 

chrisski

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That is true. I remove all DC circuit breakers during equalization. Other items can be damaged like rumor is CO2 detectors don’t like that high voltage.
 

Tecnodave

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@chrisski

golf cart batteries are called GC-2, they are 180-235 a.h.

what the OP has are generically called L-16 batteries 360-450 a.h.

They are traction batteries....golf carts use 6 batteries for 36 volts
OR 6 ea GC-8 4 cell golf cart battery for 48 volt carts

L-16’s as traction batteries are used for big store floor sweepers in a 12 volt system
other companies build solar specific L-16 for solar use.....different chemestry and different plate structure specific for solar use....EXAMPLE.......Rolls-Surette S-530, S-550. & L16, other players in the real solar battery market....Crown, Trojan <and i missed DEKA>
 

chrisski

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L-16’s as traction batteries are used for big store floor sweepers in a 12 volt system
other companies build solar specific L-16 for solar use.....different chemestry and different plate structure specific for solar use....EXAMPLE.......Rolls-Surette S-530, S-550. & L16, other players in the real solar battery market....Crown, Trojan <and i missed DEKA>
So if the chemistry is different, is there even an equalization mode? If there is what would the equalization voltage be? I did not see a spec sheet for a Interstate 903-S.
 

Tecnodave

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L-16 are build differently by different manufacturers, The solar ones are only built by a few companies that specialize in it.

Interstate is NOT a battery builder, they are a battery marketer, they put their labels on batteries that have been manufactured....

Interstate L-16 traction batteries are manufactured for them by U.S. Battery, go to the U.S. Battery website and get the data sheet for the L-16 traction batteries, U.S. Battery does market a solar specific version and Interstate did market that battery but it is not in my current catalog

I have one set of 4 Rolls-Surette S-530 solar batteries and one set of Interstate branded traction batteries,

They are NOT connected in parallel during normal use, I have two separate systems that can be connected easily.
On the rare occasion that i use huge amounts of power i do switch them in parallel to run large loads as my MagnaSine 4kw. inverter can draw over 200 amps sustained.

The required charge parameters are enough different for each set that i have several controllers and chargers in my setup so that each battery gets the charge profile as specified by that battery’s manufacturer for that specific battery.
 
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