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Forum Index : Solar : Bubbling AGM

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Wombat

Regular Member

Joined: 27/05/2011
Location: Australia
Posts: 72
Posted: 06:40am 01 Jun 2011
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Well... Hello to all out there.
Now that I have my first post out of the way in the "For Sale" section, I would like to know if anyone has come upon this problem...

I have 6x 12V/240AH/10HR AGM valve regulated batterys wired in series (1440AH@12V/10HR), alot :-) Don't put your tongue on this! They are wired for balance, ie same resistance cabling per battery.

I did borrow a charger (15A) for them, used metering, (current was low, 1 maybe 2A) but was very concerned when I noticed bubbling.
Two batterys bubble alot while the other four do not.

There ratings are : Cycle Use 14.4-15
: Standby Use 13.6-13.8V
: Initial current less than 72.0A

I did borrow a charger (15A) for them, use metering and set the charger for 13.7V (current was low, 1 maybe 2A) but was very concerned when I noticed bubbling. I worry that two batterys have a problem.

I have left these batterys hooked together for nearly 6 months and currently have a unloaded voltage of 12.82V.

I don't think I should attempt desulfating them being AGM's... but would like to see them all up and running.

Oh, I currently only have a small 4A unregulated 6/12V charger and a 2KVA Honda generator with 8A 12VDC output. A bit sad I know, but we have to start somewhere :-)

Can someone suggest a good programmable charger for them? UPS style?
Any and all assistance/feedback would be most welcome...

Thanks Russ.

P.S. What is the difference between Cycle and Standby use? Thanks again.
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 11:59am 01 Jun 2011
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Hi Wombat

Your batteries are in parallel not series as you state. You should separate them to read each voltage on its own as it sounds to me that you may have faulty cells in the two that are bubbling. Do use a desulphator as you don't tell us the history of the batteries. your small charger and desulphator across each individually to start with and then combine them as a bank when the overnight standing voltage is equal on all batteries within .1 / .2 volts once you have them all the same and reconnected leave the desulphator in place all the time as it saves boiling the hell out of them all the time with equalization charging. You can equalize every couple of weeks but not more.

What are you using them for? could you add a solar panel or two?

Cycle use is when you are using some of the power stored in the case of a power system and standby is where the batteries are kept floating at the recommended voltage ready for use. This float state will require a equalization charge every so often or a desulphator connected all the time to keep them healthy.

All the best

Bob
Foolin Around
 
Wombat

Regular Member

Joined: 27/05/2011
Location: Australia
Posts: 72
Posted: 01:03am 02 Jun 2011
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Hi bob,

Yes, they are paralleled, silly me, haha.

These batterys came from a data centre about 16 months ago. When I got then home, the first thing I did was check each battery for there standing voltage.
They varied in sets of 3. ie 2x 12.92, 2x 12.91, 2x 12.88.

It appears they were hooked in pairs as the tops of 3 have some light paint splatter on them. 1 from each group.

I borrowed a charger, set it for 13.7V and charged then in pairs overnight. It was a 3 stage charger and I monitored the current and voltage. Current was low, and they would switch to float charge. Using a 1000w 12v torch across each set to drain some power for a short time, then recharge again until they were all reading within 0.1V of each other.
I didn't notice any bubbling at the time.

Wanting little or no resistance, I made up a bunch of 50mm cables hooked them in PARALLEL and went overseas.

Well... I'm back, and hooked the charger across the whole bank. About 5min in, I noticed the bubbling! Quickly turned off the charger and started twiddling my thumbs. Oh, and I had to return the charger. How sad!

I do have a battery desulphator and checker (Jaycar kits KC5479 & KC5482) which I am running on my old car battery for about 2 weeks now with little or no improvement. Has anyone got/use these units? Are they any good? I have seen the little units some of you guys have on your banks and they appear to work quite well.

Anyway.... I will disconnect the bank and check the standing voltages again, and take it from there.

Fingers crossed. (haven't lossed one yet! haha) Russ.
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 02:22am 02 Jun 2011
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Hi Wombat

I have one of those Jaycar units as well and found them to be just better than useful, the ones I use on the battery bank is an infinitum unit and have desulphated some seriously buggered batteries with it but the jaycar one is still on my car only because I am to lazy to pull it off.

The thing with desuplhating is it takes time it cannot be done in a couple of days, I have found with seriously sulphated batteries it can take three months to bring them back.

All the best
Bob
Foolin Around
 
mac46

Guru

Joined: 07/02/2008
Location: United States
Posts: 412
Posted: 04:18am 02 Jun 2011
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Wombat,

Listen to VK4AYQ crefully, he has helped me out with problem batteries, Charge them individually first...then after you get equal voltage...you can start hooking them together. This sounds to simple to make any diffeance, but it makes a huge differance, You'll find the problem batteries this way, and keep them separated until you have confidence that they have recovered, otherwise they will drag down the rest of the bank.
Good luck with them.

....Mac46
I'm just a farmer
 
Wombat

Regular Member

Joined: 27/05/2011
Location: Australia
Posts: 72
Posted: 09:07am 02 Jun 2011
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Thanks for the reply's Bob & Mac.

Bob, do you drive your car with the desulphator attached? How curious!

I am worried that my desulphator will damage the charger I attach to a battery with voltage spikes. Am I worrying without cause? I do this at times...

6 hours separated and all still at 12.82V.

I would like to buy (Arr.. expensive!) or build a good charger. A 3 stage min, fully programmable to 50A would be nice. (Have a MT-2132 18+18V 16.6A Sec Parallel toroid waiting for use) May have to settle for 15A, or 30A if I use 2

So... charge them individually. What max voltage should I be looking for? 15 or 13.8V? 15 me thinks...
Tomorrow I will hook up my little 4A charger to one battery and see what it does.
Hope the voltage doesn't get too high.

Oh... and I do hope to build some solar panels soon... and a small wind Gen. (have some bits already, but that's another story...)

Time to jump "with joy?" in the deep end... Russ
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 12:20pm 02 Jun 2011
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Hi Wombat

I leave the desulphator on all the time as they work best as the battery is being charged.
Fancy battery chargers are a waste of money in my opinion, unless they are a programmable float controller left on the battery permanently, a 3 to four amp charger is ideal to desulphate the battery after the process is started, as to many amps strips the remaining active material of the plates and leads to further degrading of the battery. Your 18 x 18 toroid may be a bit high as it will have a output of close to 24 volts and high amps is only useful if you are working the batteries,

All the best

Bob
Foolin Around
 
Wombat

Regular Member

Joined: 27/05/2011
Location: Australia
Posts: 72
Posted: 08:56am 04 Jun 2011
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Hi VK4AYQ.

It's 2 days now and all batterys are still reading 12.82V.
So I think it's time to rejoin the 4 good batterys and charge them with the desulphator attached as suggested.

I'll try to keep the voltage at 13.7V max.

And now have some 24V panels I can hook up when I get a controller.

Thanks for all your help, Russ

??Maybe this post should be under "Other"
as batterys aren't really solar??Edited by Wombat 2011-06-05
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 10:13am 04 Jun 2011
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Hi Wombat

Aim for 13.8 to 14.2 volt bracket as this is the best range for charging 12 volt batteries.

Bob
Foolin Around
 
rgormley
Senior Member

Joined: 22/02/2006
Location: Australia
Posts: 245
Posted: 11:32am 04 Jun 2011
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small hijack here...
Hey bob whats a charge,float,equalize volt for 24v SLA bank?

Cheers,
Richard
 
Wombat

Regular Member

Joined: 27/05/2011
Location: Australia
Posts: 72
Posted: 01:02pm 05 Jun 2011
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I have 4X 12/240AH/10HR AGM batterys in parallel on a 4A charger, volt meter, Amp meter, and the Jaycar desulphator connected.
Stats to date:

TIME VOLTS: AMPS: ZAPPER:

11.30 12.86 0.91 53.4
11.35 12.88 0.95 53.4
11.40 12.90 0.94 53.3
11.45 12.92 0.88 53.2
11.50 12.93 0.93 53.1
11.55 12.94 0.95 53.1
12.00 12.95 0.92 53.1
12.30 13.00 0.90 53.1
01.00 13.04 0.83 53.2
02.30 13.09 0.91 53.4
03.30 13.12 0.93 53.5
04.30 13.14 0.90 53.5
06.00 13.15 0.83 53.6
07.30 13.17 0.86 53.7
10.30 13.19 0.88 53.7

Voltage is rising nicely, if slowly.
Current stable at 0.9A.
Concern with the desulphator, as this should be going down.
This reading is from the meter terminals of the desulphator.
Any ideas?

I will turn it off now, and start again when I can keep a eye on it.

Russ
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 04:14pm 05 Jun 2011
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Hi Richard

This is a table for various battery types, based on a 12 volt, for 24 and 48 just multiply by 2 and 4,

I put this in this way as it may be handy to all of us running different battery voltages.


Battery Type- Fast Float
Gel U.S.A 14.0 13.7
A.G.M. 1 14.1 13.4
A.G.M. 2 14.6 13.7
Sealed Lead Acid14.4 13.6
Gel Euro- 14.4 13.8
Open Lead Acid- 14.8 13.3
Calcium- 15.1 13.6
De-Sulphation 15.5 for 4 hrs

Hi Wombat

The desulphator draws a small amount of current to run itself, and also it takes a small current to maintain float voltage that is above standing voltage, and also as it slowly converts sulphate back to acid that takes a small amount of energy as well, all these add up to a small current draw this is common to all batteries as they are not a perfect unity power storage, on my battery bank it takes 5 amps 24 / 7 to maintain float voltage and I notice that in the cold weather now it is a bit more.

Over all on battery systems I have found by rule of thumb that it takes a ratio of 1.33 to 1 to allow for losses in circuit battery and inverters, so it is wise to remember this when estimating what you can do with a battery bank.

I leave the desulphators on mine all the time to keep them in top condition with out to much high voltage desulphation as this is when you loose electrolyte to gassing, and with a SLA or gell cell it isn't easy to replace the water lost and can cause premature battery demise.

Remember the makers dont want the battery to last as long as possible only long enough to make you happy to buy another one of their batteries, I think that half the batteries replaced could be coaxed to last much longer with sensible management.

All the best

Bob
Foolin Around
 
rgormley
Senior Member

Joined: 22/02/2006
Location: Australia
Posts: 245
Posted: 12:28am 06 Jun 2011
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Thanks Bob!

...Richard
 
Wombat

Regular Member

Joined: 27/05/2011
Location: Australia
Posts: 72
Posted: 12:04pm 06 Jun 2011
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Hi VK4AYQ. (ham radio callsign?)

Thanks for the battery type listing. We keep a copy on hand for when needed.

I've seen an image of your battery bank somewhere here in a posting.. very nice... massive even. I really need to double, even triple my bank for my usage.
A turbine in in the pipes eventually...

I would like a 1.5 - 2.0
kva UPS style inverter for home use and 12V power for accessories. Actual power required? not sure... I think my place is a bit power hungry. I do have a small 240v watt meter that should be put to more use!

Yes, I understand that the desulphator draws from the connected battery.
It looks like it's going to take a long time to get these back up to scratch.

Last night I left the desulphator running without the charger to keep things moving
and turned the charger back on @ 4.00pm this afternoon.

TIME: VOLTS: AMPS: ZAPPER:
4.00 12.78 0.00 52.4 Readings before I turned the charger back on.
4.30 12.93 0.95 53.0
5.00 12.98 0.92 53.2
6.30 13.05 0.88 53.4
7.00 13.08 0.86 53.5
8.00 13.10 0.82 53.6
9.00 13.12 0.84 53.6
10.00 13.14 0.85 53.6

So far, so good
Tonight I will hook the charger to the desulphators charger terminals and off the battery terminals, to hopefully NOT take power from the batterys.

Russ
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 12:22pm 06 Jun 2011
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Hi Russ

yes a call sign but not doing much at the moment as moved the shack out of the house to a new room in the shed, but not finished, hope to have the 432 Mhz and 144 Mhz antenna up in a couple of weeks, been buzy with other things, building a new shed removing carrots that interfere with air flow on the turbines and fitting some neo's to a LG and F&P rotors.

battery bank 24 volt 4000 AH ex government lighting back up system was past use by date but the desulphators have brought them back from extermination.

bringing the batteries back up is a slow process, mine took over three months to 80 percent and have slowly improved from there over the past year, I am running eight on the whole lot but will get another four when funds allow to balance the whole bank.

Be patient and rush in slowly as it will take time.

All the best

Bob
Foolin Around
 
Wombat

Regular Member

Joined: 27/05/2011
Location: Australia
Posts: 72
Posted: 06:26am 10 Jun 2011
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Giday Bob.

Well it's been a couple of days now and I'm only reading 13.2V with desulphator connected, running 24/7.

I was wondering if my Dual Tracking Power Supply could help. It can output up to 6A.
Would the desulphator hurt the Power Supply? I would hate to damage an expensive piece of equipment!

Thanks. Impatient Russ
 
VK4AYQ
Guru

Joined: 02/12/2009
Location: Australia
Posts: 2539
Posted: 10:30am 10 Jun 2011
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Hi Russ

If you use your power supply put a ferrite bead in the power line to the battery that will stop high impulse feedback to the power supply, also long leads helps a bit, but the best I found is a elcheepo 4 amp battery charger for $20.

All the best

Bob
Foolin Around
 
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