I need help

BB.

Re: I need help

A quick summary of terms:

• Bulk=Maximum current until the battery achieves 80%-90% State of Charge (near full). Note; battery voltage during this time may be less than 57.9 volts.
• Absorb=Battery is 80-90% full and at ~57.9 volts (held by battery charge). Battery starts to take less current (~2-6+ hours of falling current).
• Float=Battery is fully charge, cut back voltage to prevent "overcharging" and "boiling away water". After absorb has been reached, fall back to float voltage until battery energy is used by load--then start the whole cycle over again.

Note, for solar and generator powered battery banks, when the battery bank is being used daily, there is little need for "float" as sun will go down and/or you will turn the genset off (waste of fuel).

If you are gone for several months, you may change the absorb time down to 2 hours or less so the battery bank is kept at float and not overcharged (when the home is shut down).

The above is not written in stone--different terms and charging algorithms are sometimes used. And everyone seems to have their "own favorite" charging setup (and may change it between summer and winter seasons).

Your big concern is to

1. Conserve power. Especially useful if you have less sun and are trying to save genset fuel;
2. Monitor battery bank and insure that it is charged >90% State of Charge once or twice a week, at least;
3. That you think about load reduction/genset use the next day if you fall below 75% State of Charge;
4. That you probably should start the genset if you are at 50% or below (don't go hear often);
5. Immediately cut loads/start genset if you are at 20% State of Charge or less--To prevent imminent battery bank damage;
6. Equalize around once a month and/or if Specific Gravity differences between cells are >0.030 (suggestions, opinions can differ).

-Bill

hillbilly

Re: I need help

The following is a cut and paste job, from one of Surrette's bullitins about charging and discharging for Off Grid systems. For your consideration, HTH:


Consideration of application of use is important and will affect how the charge
regime that should be used. In most alternative energy applications, maximum
charge application is only available for 6-8 hrs. Meaning, the majority of charging
has to be completed during this time frame to avoid reliance on an auxiliary
generator further reduction in the battery’s state of charge (SOC). Consideration
has to be given also to whether the system is grid tied for back up power or stand
alone.
Off Grid Systems
Off grid systems generally consist of solar PV panels and a battery bank. With
these components the following voltage settings are recommended:
Charge Stage Volts
(48V)
Min – Mean – Max
Absorb / Bulk 57.6 – 58.8 - 60
Equalization 61.6 – 63.2 – 64.0
Float 52.8 – 53.2 - 53.5

When a voltage setting is chosen the length of time the bank is being held at
constant voltage is to be considered. If only a short absorption time is possible
then the voltages settings should be at the higher levels. If a long absorption
time is possible then the voltages should be lowered.
For example with a large PV array, small battery bank and minimal loads the
lower settings should be chosen if it is apparent the battery bank can be held at
the bulk/ absorption voltage for a minimum of fours hours. When the battery
bank is put through the first 10 normal cycles the specific gravity (SG) of a pilot
cell should check and recorded and if the bank is receiving full charge each cycle
the SG should be slightly increasing as the battery gasses and loses water due
to overcharge. Please refer to bulletin 609, Voltages, Specific Gravity and State
of Charge for further info on determining cycle depth and full charge.
If the battery bank is large in relation to the PV array (C/20 min) and loads are
large then the batteries will require a higher voltage setting. Also the battery
should be cycled deeply (i.e. to 50%) before starting an auxiliary charge source
such as a generator. Once every three months the bank should be discharged to
the low voltage set point before starting the generator. This is usually dependent
on the cut-off of the inverter which is usually 11 volts on a 12V system. The
batteries are designed to be cycled and a deeper discharge forces electrolyte
deeper into the active plate material and helps open up fresh reaction sites. With
large battery to PV systems, it is imperative that the battery bank is returned to
100% SOC once every 30 days. Full charge can be determined by charge
acceptance, which is ~2% of capacity at 100% SOC

solargirl

Re: I need help

Another question, Have you heard of or used the battery life saver, A desulfator device.
we have one on the batteries now, I don't know if it is even worth putting on a new set. or is it? I haven't noticed any difference since we put it on the Surrettes, maybe 3 months ago.

Solargirl

hillbilly

Re: I need help

The verdict is generally not overly enthusiastic regarding de-sulfators, but they probably can't hurt. I'd say if you want to help your batteries out I'd go more with a "corrective Equalize" charging, not fun but might help depending how badly those batteries were sulfated. Another bit from Surrette:


Corrective Equalization - Method
Corrective Equalization can take a very long time depending on the degree of sulfation. It is not recommended to equalize with a generator as some generators produce low grade AC that is not properly filtered by the inverter. This is especially true at higher voltages.
1. If you have hydrocaps remove during equalization.
2. Set charging controls to the highest voltage allowable by the charge controller (inverter). If the bank is severely sulfated or available current is very limited, charge control can be removed or by-passed. Temperature should be monitored very, very closely and keep below 125ºF.
3. Charge at a low DC current (5 A per 100 AH of battery capacity). If grid power is not available use solar panels or a good DC source when possible. At high voltages, charging with generator can be difficult and hard on the inverter.
4. Once an hour, measure and record the specific gravity and temperature of a test cell. If the temperature rises above 115ºF (46ºC) and approaches 125ºF (52ºC) remove the batteries from charge. (For temperature measurement choose a center cell, if applicable).
5. If severely sulfated, it may take many hours for the specific gravity to rise.
6. Once the specific gravity begins to rise the bank voltage will most likely drop or the charging current will increase. The charging current may need to be lowered if temperature approaches 125ºF (46ºC). If the charge controller was by passed, it should now be used or put back in line.
7. Continue measuring the specific gravity until 1.265 is reached.
8. Charge for another 3 hours. Add water to maintain the electrolyte above the plates.
9. Allow bank to cool and check and record the specific gravity of each cell. The gravities should be 1.265 ± 0.005 or lower. Check the cell electrolyte levels and add water IF necessary.
To avoid this situation it is recommended that a specific gravity reading of one pilot cell is measured and recorded on a regular basis when it is thought that the bank is fully charged. The measurement should be compared to previous readings. If the measurement is lower than the previous reading a longer absorption time and higher voltage setting should be used. Note as stated above, the longer the absorption time and the higher the bulk voltage, the more water will be consumed but less equalization will be required. Note: the specific gravity should rise as the cells use water. Look for trends in the specific gravity over a period of time and make very small adjustments as necessary.
Caution: If you have HYDROCAPS, remove during equalization.
Pulse Charging
Pulse charging, has shown, that banks do not get as severely sulfated as ones with traditional 3 step charging when subjected to the same undercharge conditions. Pulse charging will lower the degree of sulfation but it will not eliminate the need for a controlled, preventive equalization. The benefit of pulse charging, is the bank will need less overcharge and hence less maintenance.

solargirl

Re: I need help

Hello all

Got my batteries in thursday, we didn't have time to move the charge controller yet, and the cables from the batteries to the inverter were to short, we made due with what we had , and I have ordered the longer cables, should be here tuesday. I checked all the cells with the hydrometer today, after charging today 50% of them are 1250 which is fair according to the hydometer, so should I equalize these batteries or just charge easy with the inverter? I didn't receive any charging instructions with the batteries, I will call the company on monday, I don't even know how much I can discharge them, I know not to discharge them past 50%, should I just try to keep them fully charged all the time?

They are crown forklight batteries, I will look back on the previous posts and see if there is an answer there.

Thanks for all the help

icarus

Re: I need help

You can't equalize until the are fully charged as EQ is a deliberate over charge.

I would get them all to 100% soc with a hydrometer as soon as possible, even using the genny if you have to. Leaving them sit partially charged is a recipe for short life.

Tony

solargirl

Re: I need help

Ok I have the generator on now.

hillbilly

Re: I need help

Crown should have some specific instructions for installing a new set of batteries, all the other info that I had posted to you was from Surrette batteries... which I would guess to be similar. Each manufacturer seems to have their own suggestions on exactly what charging parameters, and how to initially charge a set of new batteries, and while pretty similar they do vary a bit. I would follow this to the letter, that way if you have any problems you can tell the dealer and manufacturer how you followed their directions. I would also recommend starting out with good records of all the SG levels and voltage levels (while at rest, with no charging or discharging for 12-24hours), thus you can compare those later on if you seem to be having any further issues.
Good luck

BB.

Re: I need help

Charging them to 90% state of charge is fine too... And if you have enough sun, let the solar take it the last amount to full.

Certainly, charging to 100% state of charge and an equalization (once an hour, when equalizing until no cell changes specific gravity any further)--then log the readings. This will be your ideal full charge and you will compare down the road when checking the state of charge of your bank (and whether or not equalization is required or can help).

That last 10% of charging (90-100%) is not very efficient--so you should avoid using your genset to recharge the bank to 100% every few days (such as during the winter). As long as you get >90%--call that "full charge" for day to day use.

Approximately once a month check the specific gravity of your cells and see if they are out of balance by 0.030 or more -- then equalize.

Try to run your bank in the 75%-90% range and you should be pretty happy. Running lower (to 50% SOC) is not going to be a huge problem--but get it above >75% within the next day (solar or genset) or so.

-Bill

niel

Re: I need help

"Certainly, charging to 100% state of charge and an equalization (once an hour, when equalizing until no cell changes specific gravity any further)--then log the readings. This will be your ideal full charge and you will compare down the road when checking the state of charge of your bank (and whether or not equalization is required or can help)."

this thought wasn't completed, but i'll say that batteries have to reach 100% soc or full charge every so often or sulfation will set in. eqing needs to be far less often than 100% soc full charge needs to be.

solargirl

Re: I need help

Crown didn't send me any paperwork other then warranty info.

solargirl

Re: I need help

Thanks Guys

I will keep the generator on for a few hours tonight, then I will start in the morning with the hydrometer and record each cell , and get them all charged properly.

hillbilly

Re: I need help

So I checked the Crown battery website http://www.crownbattery.com/?page=support and didn't find much specific to new batteries other than this:
Newly purchased batteries require a full charge before use
New batteries need to be cycled several times (20 - 50 cycles, depending on type) before reaching full capacity. Usage should be limited during this period.

There was some other helpful info there regarding care and maintinence and charging routines that's probably worth a quick peck too.

solargirl

Re: I need help

Hello All,

Well I have my system all wired in and batteries are working great.. Here is my question , At night when no power is coming in from the panels or generator, should my charge controller register any volts? It does 3.4 sometimes 3.0. (IN)

I wonder if it was wired correctly, panels to combiner box/circut breakers for each panel, then to the charge controller, then batteries, back to inverter. Should I have a circut breaker before the charge controller?

Thanks
Solargirl

niel

Re: I need help

this might sound stupid, but try disconnecting one or both of the pv leads to see if this makes it go to 0v. try this with the genny leads as well.

solargirl

Re: I need help

Thanks I'll do it tomorrow, I also got my Kill A Watt meter, The TV/satellite box is the problem I think, 353 watts per hour I can't believe it takes that much, it is LCD I thought they didn't take alot of power, computer 120 watts, blower on woodstove 23 watts, Refrigerator 150 watts when it is running and 08 watts just sitting there. then lights.

Thanks to all of you for your help

Solargirl

icarus

Re: I need help

Put the TV and the Sat box on outlet strips so you can shut the OFF when they are OFF. (Most Sat boxes draw ~35 watts on or off).
Consider a Paddle/ceiling fan which moves more air is quieter, for 1/3 the power. Also consider a sterling engine stove top fan, or a thermo-electric stove top fan. Move to a lap top, would drop power use to ~50 watts.

Tony

BB.

Re: I need help

If this is an Outback FM series charge controller (perhaps the older FX series will do it too)--If I recall correctly, they sometimes will read a few volts on the solar panel input. There is nothing wrong if that happens as long as the FM charge controller is "sleeping" and not trying to charge the battery bank (I think there is a firmware fix for "turning on" at night).

I am not connected with Outback in anyway--just some items I have read about here before.

-Bill

Solar Guppy

Re: I need help

BB, first post the inverter is listed as a trace 4048, which means is an SW4048, not an Outback

Looks like the loads have been found

BB.

Re: I need help

solargirl wrote: »

At night when no power is coming in from the panels or generator, should my charge controller register any volts? It does 3.4 sometimes 3.0. (IN)

I wonder if it was wired correctly, panels to combiner box/circut breakers for each panel, then to the charge controller, then batteries, back to inverter. Should I have a circut breaker before the charge controller?

Solar Guppy, my assumption is the question was about a Solar Charge Controller rather than the Trace Inverter Charger...

To me, it appears the question is about the input voltage reading non-zero from the solar panels at night (and I did not see what solar charge controller Solar Girl was using--at least in this thread).

To Solar Girl, if your question is should there be a circuit breaker in the solar panel to solar charge controller circuit... Generally not. If you have more than two parallel strings of solar panels, then there should be breakers/fuses in the panel combiner boxes to protect the panels from short circuits. Solar PV Panels have very little excess short circuit capacity and even if there is a short, nothing bad should happen (no fires in the wiring and such). Breakers/fuses are there to protect the wiring and devices from catching fire--not to protect the device from damage in the event it somehow draws too much current internally.

The Solar Charge Controller (assuming panels and wiring are sized correctly to the solar charge controller itself) does not need its own solar panel breaker on its input.

However, there should be a fuse/breaker near the battery bank to the solar charge controller's battery output connection. The battery is a huge source of current and any shorts in the controller or the wiring should be protected by a fuse/breaker near the battery to prevent wiring/device fires caused by large amounts of current from a shorted battery bank.

-Bill

solargirl

Re: I need help

Thankyou Bill,

Sorry I didn't phase the question very well, But you did answer it, I do need to have a disconnect/breaker from the charge controller to batteries.
I do have a main disconnect from the batteries to the 4048 inverter.'

Solargirl

solargirl

Re: I need help

Hello all and thanks for the helpful info,

I have just recieved the new Xantrex 6048 inverter and am waiting for a electrician friend of mine to put it in, all is going well , so far so good with the new batteries, seems like they use a lot more water then the old surrettes did, or maybe I am just paying more attention this time.

BB.

Re: I need help

You may be approaching "over charging" your battery bank too... No water use a too much water use are both (usually) not good things.

If you are getting the water levels down to near the plate tops every month--That is probably too much charging... Look at reducing the Bulk/Absorb voltage a couple 1/10's of a volt and see if that reduces your water use to a more reasonable level.

If you are equalizing the battery "often" (more often than 2-12 times a year)--that may be an issue too. Normally, you should only equalize when the battery Specific Gravity is more than 0.030 from low to high cell... And only equalize until all cells stop rising SG (30-60 minutes between measurements).

If the tops of your batteries are getting wet--Also look at some sort of water miser caps. You do not want to lose electrolyte trough misting either (to high of charge rate/voltage/equalization causing too much "fizzing" in battery).

On the other hand, everything may be perfectly OK--How much is "a lot more water" for XXX AH battery bank...

-Bill

solargirl

Re: I need help

Hi BB

Yes I do notice sometimes the tops of the batteries are damp. I will have to pay more attention to how many times I am adding to the batteries, I will start writing it down on the calendar.


Thanks

BB.

Re: I need help

If the top of the batteries are damp--You may be overfilling too...

The recommendation is to 1) check that the plates are covered, 2) do the "heavy/equalization" charging, 3) then fill up the battery--maybe 1/2 way or a bit more...

If you fill a cold battery to the base of the slotted tube (or whatever your battery has) when cold and not charging--it is possible that the added gas from charging (aka bubbles) plus the increase heat of warmed water--That the levels approach the top of the vent slot and now starts forcing electrolyte out the top of the battery (like forcing water up a straw).

You really want to avoid "pumping" electrolyte out on the top of the battery bank. You are not only losing water (which you can replace), you are also losing sulfuric acid--which you are not supposed to replace.

-Bill