Battery question equalization

rake1

I have had my surrette 530 batteries (2- 6 volts in series) 400 amp hours, for about 6 months now and they are working perfect. I checked them with my hydrometer and they are in the green approx (12.25). I watered them and they took next to nothing so all is well with them. My question is should I equalize these batteries? Surrette suggests to equalize twice a year, My problem is my charger is an automatic charger and shuts down long before I can hit 15.5 volts for equalization. Can I disconnect my panels which are 18 volt and hook them up direct to the batteries to equalize these. ( this is a 12 volt system). If not how else can I do this?

vtmaps

Re: Battery question equalization

rake1 wrote: »

I watered them and they took next to nothing so all is well with them.

That's not necessarily good. If you're doing it right they should take some water after 6 months. I think SG of 1.225 is a bit low. Stirring the electrolyte with a good equalization is important.

rake1 wrote: »

Can I disconnect my panels which are 18 volt and hook them up direct to the batteries to equalize these. ( this is a 12 volt system).

Yes. But you must stick around and monitor voltage, and especially temperature.

--vtMaps

Vic

Re: Battery question equalization

Hi rake1,

12.5 green implies that the Hydrometer that you are using may not be the most accurate type to use. Id you could find a glass float style Hydro at an Auto Parts store, you may get more reliable readings ... just guessing. 1.250 SG is not quite high enough if the temperature is 25 degrees C (77F) nominal.

Using "almost NO water" in 6 mo may well be an indciation that these battries are being undercharged, unless they are not being cycled very deeply.

You should really have a charger that has settable Absorption voltage and timed Absorption , and can do EQ as well. Sounds like you may not have such a charger.

Furthermore, 15.5 volts is the absolute minimum speced by Surrette for EQs.

YES, you can connect the PV modules to the battery -- through a circuit breaker -- to do a carefully-monitored EQ. You should try to keep the battery currents below about 22 Amps when the EQ voltage is approached/reached. The EQ voltage should really be temperature compensated, but you may be the manual PWMer of the charge voltage for this PV direct EQ. It is worth trying though.

Good Luck, Vic

Cariboocoot

Re: Battery question equalization

Couple of things.
First, just to be picky, the specific gravity would be 1.225 not 12.25. I say this because on a 12 Volt system it's too easy to get the decimal point in the wrong place and confuse Voltage with SG. By the way an SG of 1.225 is low by about 0.050.

Now, what have you got for a charge controller? As above the SG seems a bit low for "full charge" and the issue of doing an EQ is another matter. 15.5 may not be possible but is any Voltage above 15? Does it have an equalization function? This is important because as vtMaps said with direct panel connection you'd have to watch the Voltage all the while, which is a pain. You would not want the panels to push the Voltage all the way up to Vmp so you'd be turning things on and off yourself, which is the charge controller's job.

BB.

Re: Battery question equalization

My guess--You are not fully charging the battery bank.

Assuming your hydrometer is accurate (and temperature corrected), you are only charging to ~75% state of charge. Ideally, you should be charging to >~90% State of Charge at least a couple times a week (>~1.250 SG) (or at least every 5-10 days--as suggested by some other folks).

Add that you are not using next to no water every 6 months--I would suggest your batteries are not being properly/fully recharged.

I would go back and review the Bulk/Absorb/Float voltage set points, and any timers/charge termination settings (hours of absorb, ending amp setting, etc.).

Nominally, you should be looking at absorb times in the range of 2-6 hours (depending on a lot of stuff) and a charging voltage of ~14.5 to 14.8 volts at 77F).

You may need to add a few tenths of a volt (at a time) and try absorb times in the 4-6 hour range (absorb is the time the battery reaches and is head at the "charging voltage set point).

And, you could connect the solar array directly to the battery bank and perform an "uncontrolled" charging--if you are careful.

Careful meaning:

• don't connect solar panels "backwards" (dead short, dead solar panels) when bypassing controller
• monitor battery temperature (if it gets >~115F, stop charging until bank cools down).
• When you are truly equalizing, the charging current should be around 2.5 to 5% rate of charge
• Measure the specific gravity of each cell every 30-60 minutes. When the SG stops rising in all cells, then the battery is equalized (Surrett probably recommends 1 hour of equalization every X months--that is fine, they know more about their batteries than I do).
• Note that "true" equalization only occures when the battery (on average) is fully charged (most cells are near maximim SG of ~1.265).
• Log the temperature corrected SG Readings of each cell. The maximum SG reading as the end of this process is your 100% SOC.
• I would also monitor the voltage of each cell/battery. You are looking for differences, a battery that reads low or high voltage relative to the other(s) may indicate problems somewhere in the bank.
• If you don't have one, I would suggest an inexpensive DC Current Clamp meter to help you measure current during "uncontrolled charging" and over all debugging/monitoring the health of your system.

My initial guesses.

-Bill

rake1

Re: Battery question equalization

The hydrometer is one with the glass float I have to confess that when I tested this morning It was in the green so I just made a close guess at the SG. My Panels will put out 18 amps Max on a good day so I will not reach the 22amps mentioned by Vic.My setting for charging are 14.8 bulk and 13.7 float so I believe that is high enough. My Xantxex C40 does the bulk of the work and those setting mentioned are what I have it set at. I also have a Tristar 60 for my wind turbine which is set just above the C40 Both I believe are capable of equalization but my manual is at my camp. Also this is at my camp so it is used each weekend for two sometimes three days. My panels only put out 18amps so I always charge with my charger until the c40 hits absorb and the light is flashing telling me so. It will then stay in absorb for 1 hour then go into float it is always a sold green when I return and my trimetric meter is showing usually 14.1 to 14.7. And if windy 15 and dumping from the wind turbine. On a weekend I probably use 130amp hr out of the batteries so they are not being drained down to bad. I have never seen my battery voltage drop below 12.3 on the trimetric. One thing that does concern me is as example when I enter the camp and batteries are at 14.5 within 1/2 an hour drawing 10amp they go to 12.4 but then just stay they for hours on end. They have done this since new so I just assumed that is the nature of the batteries. I think I have answered all questions please fell free to add your comments.
PS I do have a DC clamp meter and use it regularly.

Cariboocoot

Re: Battery question equalization

I think I see two problems and they are somewhat related.
The first is that you aren't getting near the kind of charge current that would normally be sought for 400 Amp hours of batteries. The second is that your only maintaining Absorb Voltage for an hour.

Any chance you can Bulk with a generator early on and then extend the Absorb as long as possible and see how long it takes before the current drops below 2-3 percent (12 Amps)?

Under the circumstances some EQ time might be a good idea.

Out of curiosity, what have you got for panels? I'd be expecting about 700 Watts but somehow I think it's more like 300?

rake1

Re: Battery question equalization

Coot you are right I only have 260 watts and I know that is not enough, that is why I charge to the absorb stage before leaving the camp. My charger puts in 25 amps which is only 6% not the 10 % I would like. But on most days I wait till the sun is up good then start the generator so I have the 18amp from the array plus the 25amp from the charger. Today I was putting in at times 42amps as measured with my clamp meter at the positive and negative jump wire. Once it hits the absorb stage the c40 starts cutting the amps big time so more panel wouldn't help me. I could set my C40 up to a higher voltage, that would keep it in bulk a lot longer but I think 14.8 is already pretty high isn't it? I checked today when I was getting 42amps and batteries were only bubbling slightly a bubble every 4or 5 seconds.

Cariboocoot

Re: Battery question equalization

42 Amps is good, but it might be better to push that kind of current to them with the generator before the sun gets on the panels then let the panels take over and finish the charging. The whole idea behind the charge rate is to get the batteries bulked and through Absorb before you run out of sun in one day. This can be a problem if there's not enough panel or not enough sun.

Not sure what Surrette recommends for Absorb Voltage on those batteries, but some here have found a higher Voltage works better for them. I think I'd try to get the Absorb time extended first. I'm not familiar with the settings on the C40 but it appears to be fixed at 1 hour. This doesn't seem adequate to me. Perhaps you could turn the Float Voltage level up to maximum and see if that helps (chances are you won't have many hours of sunlight available to maintain such a level anyway).

rake1

Re: Battery question equalization

Wouldn't I be better off turning up the bulk setting that way It would stay in bulk longer? I think the batteries must be getting charged sufficient because the battery charger starts cutting amp a little time before the c40 goes into full absorb. The charger has no relation to the C40 as it is connected direct to the batteries. As mentioned the reading on the trimetric when I return to the camp are always 14.1 to as high as 15.1 so doesn't that indicate that the float is set correctly.

Cariboocoot

Re: Battery question equalization

Okay, what we'd like to see as a charge function:
Bulk: as much current as practical to bring the batteries up to Absorb Voltage as quickly as possible.
Absorb: hold at Absorb Voltage until charging is complete (current drops low).
Float: maintain slightly elevated Voltage against varying loads as long as sun permits.

Unfortunately Xantrex doesn't work that way, and their terminology is different.

If you raise the Bulk Voltage it will to a higher Absorb Voltage and then stay at that Voltage for 1 hour. This isn't the same as extending the amount of time the Voltage is held up. If you alter the Float to a high level then the Voltage should go to the Bulk (Absorb) set point, drop a little bit to the Float set point after an hour, then stay there until the panels can't maintain that level. In other words what we're trying to accomplish is not a higher Voltage but a longer time at the high Voltage (or as near as the Float setting can get).

Or you could buy a different charge controller.

Vic

Re: Battery question equalization

Hi rake1,

First, do your chargers -- C-40 and others -- use Temperature Compensation on charge voltages?

Believe that the C-40 has very limited range of voltage settings, It is quite possible that the Float V on this CC cannot be set above 55 V, or even less for FLAs.

And, if your Hydrometer is not calibrated with numerical SG readings, it should be thrown away when you find one otr, better yet two Hydros that are glass tube/glass float types that have NO colors, and real numbers. Hydros are very inexpensive, and batteries, not so much.

Have seen many battery banks ruined by C-nn "CC"s. Have never used one myself, but many of the neighbor's banks have been ruined by them (IMHO).

Make certain that you DO use a Batt Temp Sensor on all charge sources.

Surrette Flooded Battery Manual is on this page:
http://support.rollsbattery.com/support/solutions/articles/654-battery-user-manual-flooded-agm

Surrette still recommends 14.4 V Absorb, and about 13.16 V Float BUT, these voltages MUST be temperature compensated.

And as Marc (Coot) mentioned it appears that the batteries need more TIME in Absorb.

Agree with Coot, perhaps an even more advanced CC, which allows setting voltages to 0.1 V, uses more standard terminology, and allows setting actual Absorption TIME would do you and the batteries much better.

Sorry for the attitude ... but .. Good Luck, Vic

rake1

Re: Battery question equalization

First, do your chargers -- C-40 and others -- use Temperature Compensation on charge voltages? Yes Both are temp compensated.
Dam I just got rid of a CC that I couldn't adjust at all and bought this one 4 months ago because I could adjust the bulk and float.
But I don't think I can change the absorb time but will email the company see if there is any way to change this setting. Maybe it can be done
with software update. I am wondering if I changed my ts-60 from the wind turbine to the solar panels and used the C40 for the wind if that would get me any further ahead.
I know the ts-60 can be changed with my laptop because I have done it before just not sure what the absorb time is on it. Have to do some reading on this idea and again send some emails
to see if this will work. thanks guys.

gww1

Re: Battery question equalization

I am sorry to break into this thread but I have a ts60 morningstar that I want to use for a dumpload controller on my battery bank to control some wind turbines.

Where can I buy a temp sense controller for it?

I am using two outback controllers with temp sense for solar and I want to set the ts60 a little higher to cover the extreem though I don't think it will happen often.

I can't set the voltage higher on the ts60 when the outbacks are temp compensated.

Sorry for the interupt.
gww

PS sorry, I don't know how I missed it but I found a temp senser on naws.

BB.

Re: Battery question equalization

Hi GWW,

Yep, right there, next to the $26.00 price tag.

MorningStar certainly makes their profits on the "little extras" (temp sensor, LCD Meter, Computer Interfaces)...

-Bill

rake1

Re: Battery question equalization

Here is what I found on line for my C40 see below
So should I move the pointer to 15v then do an equalization? It will then equalize at 16v is that OK??
It will automaticly shut off after two hours.
TheC-Series
offers either manual or automatic triggering of
the equalization charging process. Equalization charging is
the deliberate process of charging a battery (or battery bank)
at a high voltage for a set period of time to remix the
electrolyte and destratify the internal plates. Equalize
charging helps to remove sulfate buildup on the battery plates
and balances the charge of individual cells.
Equalization charging holds the voltage
above the BULK
setting for 2 hours by 1 volt for 12-volt systems, 2 volts for
24-volt systems, and 4 volts for 48-volt systems.
The default setting for this feature is MANUAL
. Automatic
equalization is enabled by moving the jumper located on the
right side of the circuit board above the reset switch to the
appropriate AUTO pin set.

gww1

Re: Battery question equalization

Bill
As does outback, always something more to buy to make it work and none of it cheep.
Thanks
gww

rake1

Re: Battery question equalization

Any thoughts guys

rake1 wrote: »

Here is what I found on line for my C40 see below
So should I move the pointer to 15v then do an equalization? It will then equalize at 16v is that OK??
It will automaticly shut off after two hours.
TheC-Series
offers either manual or automatic triggering of
the equalization charging process. Equalization charging is
the deliberate process of charging a battery (or battery bank)
at a high voltage for a set period of time to remix the
electrolyte and destratify the internal plates. Equalize
charging helps to remove sulfate buildup on the battery plates
and balances the charge of individual cells.
Equalization charging holds the voltage
above the BULK
setting for 2 hours by 1 volt for 12-volt systems, 2 volts for
24-volt systems, and 4 volts for 48-volt systems.
The default setting for this feature is MANUAL
. Automatic
equalization is enabled by moving the jumper located on the
right side of the circuit board above the reset switch to the
appropriate AUTO pin set.

BB.

Re: Battery question equalization

Assuming your hydrometer is accurate, you need to charge the battery bank more than it has been so far. So, you only option is to move the charge controller up to 15.0 volts and see what happens. Monitor the battery voltage with an accurate meter and see if it ever does hit 15.0 volts and plateaus (hold 15 volt for two hours). With such a small array, it is possible that it will not get there and hold.

Assuming the charge controller does finish the absorb cycle, measure the specific gravity then start the equalize cycle. If all goes OK, you should see the specific gravity continue to climb (measure the temperature SG ever hour and log all the cells). At the point the SG stops rising in all, then stop the equalization--there is nonthing more to do (or stop pressing the equalize button). Monitor the battery temperature and stop equalizing/charging if it gets over ~115F.

Some folks have found that it can take a few months of this heavy (higher voltage) charging to bring Surretts back to full SG readings.

Note that many inverters have high voltage cutoff set to >~15.0 volts... So you may find that you need to have the loads turned off during the higher voltage charging.

-Bill

rake1

Re: Battery question equalization

Attachment not found.Bill can you answer this for me, if my batteries are not getting the full charge I thought they were. Why is my 3 stage charger also reducing amperage at about the same time as the CC hits absorb. The charger puts in 25amps then just before the CC hits absorb the charger starts reducing amps. Isn't that a good indication that the batteries are getting a full charge? Keeping in mind they did this same procedure since new. This is the Hydrometer I have I am not trying to debate your facts just trying to get a better understanding. Thanks

BB.

Re: Battery question equalization

The "gold standard" is using the hydrometer to measure temperature corrected specific gravity (you can measure resting voltage of the battery bank as an alternative--3 or more hours of no charging/discharging current).

For a typical battery bank, 1.225 SG is not full charge but only ~75% SOC. But, you will not know if your battery bank is achieving full charge or not until you attempt to charge it until the SG stops rising... At that point, those logged readings are "full charge". Normally, a declining "full charge" specific gravity (over the years) indicates that the sulfur has been locked into hardened crystals of lead sulfate (or sulfation of the battery).

The battery is not "full" when the the voltage hits the charging set point and the current starts to decline. It is "approximately" fully charged when the battery is held at a "reasonable" set point voltage and the current declines to 1-2% of the bank's 20 Hour AH rating (i.e., a 100 AH battery declines to ~1-2 amps of charging current at 14.5-14.8 volts or so at 77F).

Equalization is the intentional over charging of a battery (over charging the 100% full cells) while using the "leakage current" to continue charging the one or more series connected cells that are not at 100 SOC (at ~2.5 to 5% of battery's AH capacity or 2.5 to 5 amps at ~15-16 volts). And when the low cells stop rising, they are fully charged too.

Some vendors say to equalize a bank every 1-few months, others say to equalize when the cells are out of balance by 0.015 to 0.030 SG or greater... Your choice what to do (based on your vendor's recommendations).

If your hydrometer is accurate--Then it seems to be indicating that your battery is not fully charged. If you are not holding absorb voltage for ~2-4+ hours after significant discharging (say at least 10-20% discharge), then you are probably not fully recharging the bank ("full" in this case is >90% SOC--Not a "hard" charge to exactly 100% SOC every day--that should be reserved for equalization day).

Anyway--What is your present charging profile (i.e.., hit 14.8 volts and hold for X hours at ~77F) and what is your temperature corrected specific gravity at that point.

You may wish to purchase another good quality glass hydrometer to make some comparision readings (a modified saying--A man with one hydrometer knows exactly the SG; a man with two hydrometers never knows his exact SG :roll:). And make sure to rinse out the hydrometer with distilled water a couple times before use and after use. The gunk from the battery cells can collect inside the hydrometer and cause the float to stick.

Anyway--That is my understanding of what you have said so far (and I certainly may have made errors and/or poor assumptions--my wife and kids are always telling I am not perfect :p).

-Bill

rake1

Re: Battery question equalization

I posted a pic of my hydrometer in previous post it is glass but not an expensive one. My charge profile is I charge with 25 amps min until the charger reduces voltage to what the sun is putting out that day then I turn it off. Example sun is putting out say 10 amps once the charger is below the sun output it is running for nothing so I shut it off. This is always at the absorb point set with the CC that is about 14.7 volts. It then continues to get the 10amps gradually reducing to next to nothing all with in 1 hour then goes to float which is set at 13.5v. So I guess what you are telling be is even though I am in absorb and the CC goes into float I haven't been in absorb long enough correct? That I understand, But here is the two things that confuse me, one my trimetric is always reading 14.1 to 15 volts when I come back to the camp. And two and more confussing why is my 3 stage charger shutting off saying the batteries are full very shortly after this goes into the absorb stag?

PS I usually measure the SG on last day and temp in the camp is probably 70 F for two days but the batteries would be less than that as it take a few days to reach room temp. To be honest I have never checked the bat temp but will from now on.
I can only assume that they may be 10 degrees below the camp temp.

BB.

Re: Battery question equalization

What is your three stage charger (is this the AC charger and not the Xantrex is it?).

Your hydrometer appears to be a very reasonable unit (I don't do batteries, so I cannot comment on various brands/usage from my experience--just what I read here).

The Battery Voltage and Charging Current both can be used to estimate how well your batteries are charging (i.e., what is the charging voltage and current near the end of the charging cycle--i.e., is it 14.8 volts and less than 2% of the bank AH capacity?).

But--I am, more or less focused on your specific gravity measurements. If accurate, 1.225 should be around 75% state of charge (or a sulfated battery bank, or an inaccurate hydrometer).

Holding Absorb for ~1 hour for a battery that has been only cycled slightly--It is probably OK. If the battery has been deeply cycled, I would guess that you should be looking at 2-4 hours minimum of absorb time (with 14.5-14.8 volt absorb setting).

How much water have your batteries been using (ideally, refill with distilled water every ~two months)? If you have not been needing to add much water in 6 months, it could indicate under charging (again--this is variable, the new Trojan RE batteries, from what I have read, use significantly less water).

Lots of variables here. Hope I am being clear and helpful. :-)

-Bill "arm chair quarterback" B. :roll:

Vic

Re: Battery question equalization

rake1 wrote: »

The hydrometer is one with the glass float I have to confess that when I tested this morning It was in the green so I just made a close guess at the SG.

rake1,

Thanks for the photo of your Hydrometer, BUT the descriptive label obscures the image to the point that it is impossible (at least for me) to see if there are numbers on the scale or only colors.

IMHO, if you can find a Hydrometer that does NOT make judgements for you about the condition of your expensive batts it would be best ie, without ANY colors.

Try an Auto Supply store, like Napa Auto to see if you can find a glass float/glass tube with only NUMBERS for the SG reading ... guessing is not good, and the range of values of SG seems quite wide, within the green range.

ANY battery that has been chronically undercharged will require a protracted period to recover, often at higher charge voltages and EQ voltages than normal. IMHO Surrettes are no different than others in this respect. Surrettes seem to require lower charge voltages when PV arrays of reasonable size recharge them --14.4 V for a 12 V system - 57.6 for a 48 V system. Others like some Trojan, US Batt and others seem to want 15 V/60V, all IMHO.

Trying to use an "Automatic Charger" is usually not a good choice for recharging RE batteries, unless it is designed for RE use. Perhaps an IOTA or similar charger might be OK, but many of these lack a Remote battery Temp Sensor, etc.

Rake, when your bank gets back into shape, the Foat voltage is quite a bit too high. Right now, since you seem to be undercharging the bank, having Vf too high just continues charging (a bit), so is not a big problem. Opinions, Vic

rake1

Re: Battery question equalization

Vic it does have # on it I just didn't pay as close attention to it as I should have when I read it. I will get another reading next weekend and will now take a lot more care when reading it. Bill the charger is an ac charger I run of my gen and it will put out 25 amps, but most time I will wait for the sun then start the gen that way I am putting in 25 plus the sun which could be as high as 43amps depending on the day. My batteries (400ah) don't get drained real low about 30%, 125 to 150 ah over the weekend if no sun at all. At the end of two days and no sun the 25amps only will bring the batteries up to absorb in just over two hours. Once it hits close to absorb the charger is next to useless little or no amps coming out of it or it shuts off say fully charged. Because it is saying full and turning it's self off I was happy thinking full charge. now the panels can keep it at float for the rest of the week. But I must admit even with 42 amps going in these batteries do very little gassing only the occasional bubble.
Bill I am not sure what voltage is going in while the 25 amps are charging, I never thought to look at that. I do have a button on the charger I can push but was always more concerned with the amps.
I added water for the first time this weekend not because they were low just because I thought I should they were down very little water. Maybe one full hydrometer in each cell. And these as you know are large batteries.

BB.

Re: Battery question equalization

The charging system should be current limited until your absorb voltage set point is hit... At that point, the chargers will hold the voltage and the battery will slowly decrease the amount of current it allows to flow it (the voltage of the battery rises as specific gravity numbers go up)... Until at "full charge" basically all of the current is being turned into heat and hydrogen+oxygen gases.

If you are not seeing much gasing, then that would be an indication that you are probably under ~90% SOC--Gassing voltage should be around 14.3 volts at room temperature (ref 12 volt battery)--I think.

The battery should have a "fair amount" of fizzing when fully charged (sort of like fresh can of soda pop just opened). You don't want a rolling boil.

If you have an accurate volt meter, you might check the battery voltage right on the terminals. Long/smaller gauge wiring can "trick" the chargers with excessive wiring harness voltage drop. For a 12 volt battery, I would suggest 0.05 to 0.10 is the maximum "ideal" voltage drop back to the charger (unless you are using remote voltage sense leads).

-Bill

Vic

Re: Battery question equalization

rake1,

As noted before, the little/no water useage is a strong indication that the batteries are not getting fully charged.


Almost all of the bubbling occurs during the Absorption stage. This bubbling is part of fully recharging the batteries (for FLAs). It help mix the electrolyte, which has a tendency to have the heavier acid sink to the bottom of the cells. This mixing is very important. Ideally, batteries shoud be fully recharged several times per week, in general.

The automatic charger could well be hurting your batteries by not allowing a full recharge during cloudy weather. If you have enough solar power to finish charging the batteries after the Auto charger shuts off, then this should not be a problem.

As BB Bill noted above, you would want to see an Ending Current into the batteries while in Absorb of 1-2% of capacity. This would be about 4-8 Amps. On the Surrette banks here the EA value is about 1.2% of actual 20 Hour Capacity. Your target value will be a bit different, and this value is somewhat sensitive to the battery temperature.

Measuring and recording the SG o each cell in the battery logbook is important for future reference. These measurements should be taken when you know tha bank is fully charged.

EQing these batteries soon may help their general health (know that this is the subject of the Thread!). A Minimum EQ Voltage, according to Surrette is 15.5 V, or a bit higher, for these batteries.

Thanks for the added info on your Hydrometer, it is good that it has numbers. Good Luck, Vic

rake1

Re: Battery question equalization

Yea not much gassing and the charger is hooked direct to the batteries, and my Klein Clamp meter shows the same reading as my trimetric meter. What voltage and amp should I be at in absorb? I know now I am at like 2 or 3 amps once I hit absorb on my c40 CC. I am going to equalize next weekend using the c-40 at 16v for two hours see what my reading are then.(c40 Xantrex) only equalizes for two hours at a time. Just saw you previous post
In absorb I am at about 3 amp but will check again on the weekend now that I know a lot more LOL. In absorb will the batteries still gas at say 5 amps?
What do you suggest as an alternative CC? One that I can adjust the time in absorb?

Vic

Re: Battery question equalization

Hi rake,

Good that the Trimetric reads the same as the Klein, and that you have the Trimetric, that can measure the actual current that is charging the batteries.

OK, Gassing will become more vigorous later in Absorption. Getting down to about 2-3 Amps should be sufficient for Absorption. Howerer, this current needs to be at an Absorb voltage that is high enough to do the finishing charge.

You have said that the C40 has a RTS installed, and that you are Absorbing at 14.8 V, IIRC. The things that do not seem to add up are the little water use, your DOD, and the Vabs.

When you read the battery voltage from your DMM or Trimetric, do you notice that the voltage IS temp compensated ? That is, if you know that the battery bank is cool, do you notice that the Absorption V is raised to above the setting in the C40?

One thing that can happen with systems in remote areas is Rodents eating wires and cables. A neighbor's system, near me has had the RTS cable eaten through several times by Mice or RATS. If you notice no temp compensation in Absorb, you may want to try to verify that the RTS is connected, and that the cable is intact. Believe that these RTSes have a nominal resistance across two pins of the plug of about 10,000 Ohms at about 75 degrees F. This Resistance will vary with temperature, and believe that the R decreases with rising temp (?).


When you get to the camp, hope that you can measure and temp comp SG readings for each cell of the battery bank, and record these - when the bank is fully charged.

Regarding the C40. I have little respect for them. Have seen them break, but the user did not know it, and this has ruined more than one battery bank in the local area. IMHO a C40 can do a marginally adequate job. BUT in the days of expensive batteries, spending even more than the cost of a C40 to get a CC that has settable voltages and times for charging and EQing will be much better for the batteries, and for you to be able to intrepret what is happening. Decoding the Morse of flashing LEDs is not easy for everyone. Your Trimetric does help you know what is happening, though.

For your system, perhaps the new Rogue CC that is due in a couple of months might be a giant step up ... (I forget the amount of PV you have -- a Signature line would help remind us of just what IS your system hardware).

EQing at 16V should be fine, just watch the temps of the bank (this should not be an issue in two hours), and watch the SGs. Normally, personally monitoring an EQ is the best thing to do. But think that this is the first EQ for the bank. Later EQs may not need to be two hours in duration.

I am biased against the Cnn line of CCs, but they do work for some. Realize that you do not have a huge system, where the extra cost of a high-end MPPT CC would be small, but the C- CCs seem a bit limited these days. Just opinions, Vic

rake1

Re: Battery question equalization

The c40 has an RTS brand new so I can only assume it is working, only way to tell is to check the voltage of the battery while this is in absorb stage correct if it is higher than the bulk setting than it is working? Remember I do not have an absorb setting I can change. I know the tristar is working because it was dumping voltage at 14.8 volts. Once I installed the Rts It wouldn't dump until 15.2v when cold.When I return I will get all new accurate readings not just close like the last time,these will be cold reading as the camp will be 0 degrees Celsius. I will try to get the batteries drained down enough to get my charger delivering 25amps while cold and check the voltage to see if the c40 temp compensation is working. I will EQ also if I have the sun then I will also get reading before I leave when batteries are close to room temp.
As mentioned earlier I send emails to Xantrex and Morningstar about the cc here is what I found
the c40 1 hour absorb and no changing it period.
The TS60 well if you can understand this reply than please explain. I was thinking about using the ts60 for solar and moving the c40 to the wind turbine thinking the ts60 may do a better job with the solar charging. here is the reply I do know what MS view is and have used it in the past.

With the TS PWM, absorption time is controlled by the transition to float duty cycle. This can be adjusted using MSView software available at no charge on the morningstarcorp.com website. You'll also need a serial connection to a PC.

Here's a Tech note on this subject:

Transition to the float stage is based on the PWM regulation duty cycle. The duty cycle is derived from a square waveform and the percentage of time - out of each complete cycle - when current is allowed to flow. Current is regulated by opening and closing the PV-battery circuit -- the essence of a series charge controller. A 50% duty cycle means that current is flowing, and interrupted for, half of the cycle. Our controllers pulse with a frequency of 300 Hz, so each cycle lasts 1/300th of a second. By varying the duty cycle, we can control the average current going into the battery so that the regulation voltage is maintained but not exceeded. As the battery reaches full charge at a particular voltage, it will require less and less current to maintain that voltage and the duty cycle will decrease. The duty cycle will approach zero %, but will never actually get there because losses and battery self-discharge require at least some current to maintain regulation voltage. A Morningstar PWM controller's float transition algorithm waits for the duty cycle to reach 30% or less before starting a one hour timer. When the timer expires, the controller moves from absorption to float voltage. A 30% duty cycle simply means that 30% of AVAILABLE charging current is allowed to pass. Duty cycle is the best measure we have to determine how deep a battery may be in regulation. Factors affecting the accuracy of this method include: 1. Reduced radiation and current. With less available charge current, the duty cycle will inevitably be higher making the transition to float more difficult; 2. Load on the battery. Loads on the battery drain current from the battery which causes a higher duty cycle. If the load is large enough (greater than the amount of solar current ) it can pull the controller into 100% duty cycle and out of absorption - into bulk charging; 3. Aging batteries. Old batteries tend to absorb more current at regulation, keeping duty cycle high. Sulfation leads to higher internal resistance, and more energy loss in the form of heat, which leads to excessive water loss."

Vic

Re: Battery question equalization

Hi rake1,

First, thanks for the signature, it does help, had forgotten about the Turbine and the TS-60.

Yes, an easy way to tell if the RTS on a given charger is working is to wait until it is in a charge stage where IT is regulating the voltage, Absorb is probably the easiest for this test (called Bulk Voltage on C40(?)). If the batteries are fairly cool, you can use the Trimetric or your DMM to measure the battery voltage compared to the voltage you have set . WIth cool batts, the regulated voltage would be higher than the setting on the C40. Believe that the C40 does not temp compensate the EQ voltage - guessing.

Good that you will make careful measurements on SGs (and record them) when you return to the camp.

Regarding little water use on the batts. It IS possible that given the light use of these farily new batteries, mostly in cool/cold months, that you are really getting the batts charged enough. This is given that your target Bulk V is 14.8 V (a lil bit high), the weekend nature of batt use, and the fairly low Ending Current that you see near the end of what would normally be called Absorb.

We will be looking for the report on your next return from the camp. Good Luck! Vic