Author Topic: Battery equalizing (Read 4218 times)

steamboat · « **on:** January 28, 2007, 08:35:27 PM »

We have 24 T-105's 6 volt batteries that serve as our power system. They are charged by the Honda 6500 generator partnered by a Trace 24/40 generator. The batteries are in real need of equalizing; they will hold a charge for only so long before the voltage plummets. We have been told that once part of the battery is rendered useless by lack of equalizing it is lost forever. Can we do better than that?

Moved to proper section.

wpowokal · « **Reply #1 on:** January 28, 2007, 05:43:10 PM »

Steamboat have a read here,

http://www.sandia.gov/pv/docs/BattIntro.htm

and here,

http://www.homepower.com/magazine/downloads_batteries.cfm

Do you use a good quality hydrometer to check state of charge? How old are they? What voltage do you float them at? My answer to your question is yes & no, possibly redeamable but much more info is required. But in the mean time give them around 6 hours at 30+ volts or proportion of depending on your system voltage, I assume T105's are flouded lead acid here.

Most batteries don't die they are murdered.

allan down under

Walter · « **Reply #2 on:** January 28, 2007, 05:54:09 PM »

Yeah you can, equalize them.

At the end of a charge your full pack voltage should be 174 V at room temp.

To equalize the pack increase the voltage to 180V and keep a close eye on things. The batteries should gas a litle bit but not violently. Wait for current to drop off to say 3A (depending on battery age and condition). Use a timer. This should take no longer than about a tenth of the time for the bulk charge.

Ungrounded Lightning Rod · « **Reply #3 on:** January 28, 2007, 10:37:21 PM »

How long have they been like this.

If a short time equalizing will fix 'em.

If many months the ones that were low will have sulfated. Then equalizing will only help somewhat - although if they haven't gone to the second stage of sulfation repeated equalization may bring them back some more.

Ungrounded Lightning Rod · « **Reply #4 on:** January 28, 2007, 10:39:26 PM »

and as wpowokal points out: Checking the specific gravity will tell you if they're really out of equalization or if something else is wrong.

Flux · « **Reply #5 on:** January 29, 2007, 02:34:29 AM »

You don't give much information about age or system volts or much else.

If they are old then you will probably have no chance. If not very old and badly abused then again you may not save many.

Check sg with the hydrometer as others have suggested. You may have to deal with them individually or in pairs for 12v. Probably the equipment that has got them in a mess may not be able to sort it out.

I am inclined to suspect that it is too late to do much, but still worth a try.

You can play with desulphators, EDTA and all the other time wasting things but if good old fashioned equalising up to about 8v doesn't work then you might as well cut your losses.

Flux

steamboat · « **Reply #6 on:** January 29, 2007, 03:42:58 AM »

The system is about 6 years old and was charged for the last 5.5 years with a honda 3500 generator which does not have a lot of possibilites to really send a good punch for the batteries. I doon't think that the battereis were equalized at all in the past two years, at least. The water levels are monitored regularly and they are kept in a basement. There are 24 of them, wired in a series of 4 for 24 volts. the inverter is a trace 24/40. there are all kinds of setting on the inverter to equalize, need to review manual for them. I know that the inverter lets only a certain amount of amps come in from the new generator [6500 honda] because the batteries were'trained ' to a lesser input for the old generator. Had to figure all of this out when the new generstor came since it wouldn't charge very much until I changed some of the values. Now it will charge for as long as desired but the amp input drops off steadily after an hour or two when it perceives that the batteries are full. A good charge lasts about 24 hours then values can plummet to 22 volts or so after that time span. Can tell you specific charging values set on inverter if needed.

The house system is a good one that was designed and installed when the house was set up [ a modular cape] The friggy is an electric one!! an Amama with bottom freezer that actually does quite well in terms of comsumption. Heavy equipment such as dishwasher, washer and dryer run when batteries are being charged anyway. Water pumping is done with a DC pump wired directly to the batteries. It pulls water from a 1200 gallon tank buried on the hillside which is fed by a pump 750 down in the well [1525 depth] and this is down directly off the generator on the 240 side.

I'd hate to think that the batteries are too far gone but welcome any suggestions and am compliling the responses for review. Thank you.

wdyasq · « **Reply #7 on:** January 29, 2007, 05:00:12 AM »

"A good charge lasts about 24 hours then values can plummet to 22 volts or so after that time span. Can tell you specific charging values set on inverter if needed."

It may also be you are 'using too much of the battery'. FLA (Flooded Lead Acid) batteries do not do well if deeply discharged. Once batteries are 'overworked' a few times they loose capacity fast.

Ron

Flux · « **Reply #8 on:** January 29, 2007, 06:15:16 AM »

If you have cycled those batteries much I suspect you have had most of their life,

If you don't have a hydrometer, try to disconnect each string at a time so that you can look at the volts after standing for a few hours.

Any large variation in the cells of each string will indicate the sick ones.

For now you may be able to get all the sick ones into one string and concentrate on them while you use the rest.

When fully charged and left standing for a few hours you should see about 6.4v per cell.

Any below 6 will be very sick and may be draining the rest.

It sounds as though you have little facility to charge the things to a good equalising voltage of at least 30V per string.

Most inverter battery chargers perform poorly from small generators. You must somehow manage to keep the charging current up by altering the settings or something to get up to that voltage.

Watch the individual cells in each string, a bad one will not respond and will drive the rest high. Any cells that refuse to respond fairly quickly should be dealt with individually but you don't seem to have means to do this.

Equalising should be done often enough to keep cells in step, when left too long you need a crude 6v unregulated battery charger that can keep amps into the sick battery long enough to see if it will respond.

Anything that will not make 6v on a long charge will have shorted cells.

You may end up with 3 good strings if you are lucky, but luck never comes my way.

Get that hydrometer as soon as you can and monitor the sg at least once a month and work on any slow cells.

Flux

Flux · « **Reply #9 on:** January 29, 2007, 06:16:09 AM »

If you have cycled those batteries much I suspect you have had most of their life,

If you don't have a hydrometer, try to disconnect each string at a time so that you can look at the volts after standing for a few hours.

Any large variation in the cells of each string will indicate the sick ones.

For now you may be able to get all the sick ones into one string and concentrate on them while you use the rest.

When fully charged and left standing for a few hours you should see about 6.4v per cell.

Any below 6 will be very sick and may be draining the rest.

It sounds as though you have little facility to charge the things to a good equalising voltage of at least 30V per string.

Most inverter battery chargers perform poorly from small generators. You must somehow manage to keep the charging current up by altering the settings or something to get up to that voltage.

Watch the individual cells in each string, a bad one will not respond and will drive the rest high. Any cells that refuse to respond fairly quickly should be dealt with individually but you don't seem to have means to do this.

Equalising should be done often enough to keep cells in step, when left too long you need a crude 6v unregulated battery charger that can keep amps into the sick battery long enough to see if it will respond.

Anything that will not make 6v on a long charge will have shorted cells.

You may end up with 3 good strings if you are lucky, but luck never comes my way.

Get that hydrometer as soon as you can and monitor the sg at least once a month and work on any slow cells.

Flux

wpowokal · « **Reply #10 on:** January 29, 2007, 07:23:42 AM »

As always good advice is worth re-reading, sorry Flux it begged to be said.

allan

wpowokal · « **Reply #11 on:** January 29, 2007, 08:06:54 AM »

One point none of us have mentioned yet, are the cable connections clean and tight?

allan down under

Flux · « **Reply #12 on:** January 29, 2007, 08:12:20 AM »

Good point, after 6 years of abuse some basic maintenance is likely to be needed.

Flux

wooferhound · « **Reply #13 on:** January 29, 2007, 08:33:39 AM »

How about some Battery information ?

Trojan company site with links to Battery care

http://www.trojan-battery.com/Tech-Support/BatteryMaintenance.aspx

Do and don't Battery Table

http://www.batteryuniversity.com/partone-21.htm

Batteries the heart of a back-up power system

http://www.oasismontana.com/batteries.html

The care & feeding of solar batteries

http://www.backwoodshome.com/articles2/yago95.html

Lots of Links to Battery information pages, check out the first link FAQ

http://www.uuhome.de/william.darden/index.htm

Battery Tutorial

http://www.batterystuff.com/tutorial_battery.html

I seem to remember DanB doing a detailed story about Battery care, but I cant find it.

wooferhound · « **Reply #14 on:** January 29, 2007, 08:52:36 AM »

I just accidentally found this Old very detailed battery Manuel .PDF

http://www.rebelwolf.com/downloads/BattMan.pdf

SparWeb · « **Reply #15 on:** January 29, 2007, 12:45:26 PM »

Ron! There are horse-lovers on this site! I must cover my eyes! That graphic in you sig will get you censored!

wdyasq · « **Reply #16 on:** January 30, 2007, 05:53:58 AM »

Good thing - only enough to feed 1/2 dogs.

Ron

wpowokal · « **Reply #17 on:** January 30, 2007, 06:50:11 AM »

Steamboat, for all the coments so far we do not know if the system you have was your's from the begining and you were not empowered with enough knowledge to adequatly care for it,or you purchased the property/instalation.

From your scant description of loads I suspect you are placing a heavy draw on your system, and maybe not fully replacing the amp hours drawn out. The bore alone would have a sizable pump, if you would care to share with us your loads we may be able to assist with enpowering you with the knowledge to better manage your instalation in the future.

I too run a 24V system and my largest daily draw so far this summer has been 23Kw, now that's some 1150 Ah, which takes some replacing. But I run a comercial instalation( cool room and processing plant) so accept such loads. My batery system is 5200 Ah but that draw is just over the 20% ideal depth of discharge (DOD), but of course there is incomming power during part of that 24 hour period.

Unfortunatly many people who make the move to renewable energy withdraw when the first set of batteries need replacing, often after they(the bateries) have been murdered because the owner was not empowered with enough knowledge to adequatly care for the package.

The challenge, should you accept, is too pick our colective brains/experience to have an enjoyable renewable energy future.

allan down under

steamboat · « **Reply #18 on:** January 30, 2007, 05:20:48 PM »

I will try to answer as much as I can. The system was brand new when we moved in, so was the house.

The water system was set up to be a separate draw on purpose because of the nature of the well. Well pump, 1.5 hp, down 725 feet is wired 240 with a 240 breaker [dedicated] in the basement that needs closing for pumping to begin. There also is a switch [120v]that opens/buzzes when the float in the storage tank indicates that the water level has dropped. This we keep snapped off in the panel box until we suspect that we need to pump. Pumping is the only thing the generator is asked to do because of the tremendous amount of power to turn over the pump.So, wiring, switches, breakers are all separate from the batteries because of the power needed and the unreliable level of the batteries and the harm that can come from an underpowered water pump at that depth. There are two inverters in the basement that eventually will be used in sync when the solar panels go up. Posts for them are in the ground- 16' well drilling rods half buried.

Water comes into the tank at about 7 gallons a minute and so the generator runs about 60-80 minutes a week. We plan to keep this system separate from household power until we're absolutely sure the batteries have enough oompapa to do the job. One can only dream of the cost of getting a truck up here in the middle of the winter to pull 725 feet of threaded rod to fix a pump that is about 6' long and weighs how much?

The batteries actually worked quite well for several years so the load seemed balanced with the input and capacity. It's only in the past few years when we did not equalize that they began to act up. A lot of thought went into the system's design and we had the help of an electical engineer who was in the solar system business to get it right. What happened was human error and the results are predictable. Clear as that.

I will get to the rest of your questions later but wanted to clear up about the water system needs.

steamboat

Gary D · « **Reply #19 on:** January 31, 2007, 06:43:51 AM »

Hi Steamboat, is the inverter you use now a Trace/Zantrex plus 4000 watt/24 volt? If so, it can pass thru 60 amps A.C. and at the same time have the capability of up to 110 amps charging(if my reading is correct). Is your Generator rated/capable of 6500 watts at 110/120 volts, or half that? You should be able to jump/adjust the charging amps significantly over the other generator.

Perhaps you need to get your bulk phase totally up, and give a good equalizing several times? It will mean more genny run time, but perhaps save the battery bank. Carefully check each battery in each string to see how they are responding voltage wise, hopefully they may outgass some sulfate off the plates. May not be worth my 2 cents...Take this with a grain of salt, be carefull. Batteries can be nasty, it only takes one bad experience to make you respect them! Gary D.

Gary D · « **Reply #20 on:** January 31, 2007, 07:06:20 AM »

The spec's came from this site, if this is the correct inverter, maybe I missread something... Gary D.

http://store.altenergystore.com/Inverters/Off-Grid-No-Utility-Needs-Batteries/3000-to-5500-Watts/c60
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Author Topic: Battery equalizing (Read 4218 times)