lost capacacity

wellbuilt

Hi all , I'm having a problem with my off grid system . 
 Over the winter my battery's have lost  capacity  
 I left here in november on a bad solar note .
 I checked my water a and soc and I was above 80% I figured . 
 Water was filled up 2 weeks before and the battery's where very close when i checked them . 
 I was here in January and every thing seemed fine voltage was att 100 %charge we ran some heat and lights and left within a few hours
 now I went to camp last night every thing seemed ok . 
Soc was at 100% and it was cloudy and raining I turned up the heat and lights and my battery voltage dropped to 12.3 in 20 min . 
Normaly I could run all night before I hit 12.3
 I ran a charger for 5 hrs @ 10 amps and the voltage came up but today the battery's died in 20 min .
 The voltage on the solar controler went up this morning but I'm only getting 2 amps at 14.8 volts , I Normly see 13.6 float at 1.5/2 amps
 if I turn my loads on 4 10 watt lights a pro sine 300 watt inverter with 20 watt tv ,the solar amps jump up to 
 10 amps+  
I have a 40amp tracer mppt CC 2 solar panels 140 watt and a 80 watt in series for 220 watts .
 The battery charger is a 30 amp 10  amp manual  automotive charger a only ran it for a few day in the last 2 years .
 Last November I was running it for 1/12 to 2 hrs at 30 amps and 11/2 hr at 10 amps .
 There wasn't much sun for 2 weeks. 
 The battery's are 2 sams club gc215 ah 6volt for a 12 volt system . 
   What do you all think is going on 
  Thanks in advance for the help john

wellbuilt

I checked the battery's and my acid level was up at the top , the soc was 12.75 for 4 cells and the center cells on both battery's was 12.72 ? 
 I always figured 12.75 was a good reading .
 The plates in side the battery's look like new for as far as I can see .
 I pulled the fuse on the charge controler before I checked the battery's 
 maybe there is a problem with the inverter ? Burning to much power . 
  The battery's are cold , I have them in a box and run air in the bottom and out the top . 
 There looked like there was some acid around the caps from charging     (Few drops with mist) 
 the battery's have some bubbles now . 

Estragon

A couple of thoughts

- roughly how cold were the batteries?
- can you check the specific gravity?
- how long after you pulled the fuse on the controller did you check voltage?

BB.

I guess 12.75 is really 1.275 sg for battery?

Estragon

That makes sense. Should have occured to me that it would be tough to get individual cell voltages on a GC battery.

wellbuilt

Oops yes 1.275   
 The  batteries have been cold for months since November . 
 They are inside  a trailer in a box vented to the out side . 
 I would think they would be 20/30 o
 all winter .
 When I pulled the fuse I turned on some Lites and tv and the voltage dropped from 14.6/7/8 at 1.5 /. 2 amp to 12. 3 
  In 20 mins .
 The battery's are only 2 seasons old.
The SG is 1.275 on the outside cells on both battery's and the center cells are a 1.72 
 seems good to me. 
 now my volts are down to 13.6 @ 1 amp .( this is the norm when in float this time of day when it's sunny )
 The controler has been flashing float all day even a 14.6 volts witch I have never seen before? 
 I really never had to run the genarator except the last week here in the snow .
 The trailer heat was running on and off all night but with running the genarator @ 30 amps for 2 hrs and 10 amps for 4 hr we had enough power all night with12.3 volts left at resting .
 It is possible the battery's were not 100% charged but I started with 12.3 volts on the last day here and charged for 4 hours . 
 If the batteries where left not fully charged chould they sit in the cold  dormant till now? 
 Don't most people keep there batteries in unheated space? 
  What do I check ? 
 I have a good morning star Pwm controler I could parallel the panels and try a charger controler .
  I could try new battery's ?  Maybe I killed the battery ? 
  
 Would the SG be that high if the batteries where no good . 
 

Estragon

The SG sounds okay so I doubt the batteries are bad. I'm assuming the charge controller was on and panels were unshaded and not snow covered over the winter?

One possibility if the batteries were partly charged is they may have frozen. Fully charged they're okay to ~70 below. Fully discharged they're plain water and will freeze at 32f. Partly charged they freeze somewhere in between depending on SOC. Do any parts of the battery feel warm to the touch when charging? Do you see any sort of bulging in cases?

As long as they don't freeze, being cold is good as it slows sulfation.

14.6 absorb charge sounds a bit low for 20°f batteries. Does the controller have remote temp sensor and is it set to do temp compensation? I don't think this is the problem, but worth checking anyway.

The apparent capacity of the batteries will be lower at lower temps. At 20f the capacity might be around 2/3 -3/4 normal so around 145 - 160 ah for yours. That would account for some loss of capacity, but not for pulling capacity down 50% or so with a couple amp load in 20mins.

wellbuilt

They look new , no bulges    , No hot spots ,  they could of had snow over them ? 
 But there were plenty of sunny days after the storm in November to clear the snow , 
 the wind blows  here 20/30 knots I don't think that would hold snow for long . 
 Plus we did not have much snow this year and it had been warmer then most years . 
 The absorb charge was up to 14.8/9 for a hour or so . 
 I am not seeing any real amps from the CC unless there is a load .
 I was getting 10 amps plus under load when I kill the power from the batteries ,  it seams like I'm going into float? 
 Of coarse my SG was at 1.275 so I should really just be at float ? 
   I'm so confused .

wellbuilt

Here is a pic of my batterie charger and system , the battery's are in the wooden box

wellbuilt

I would think I should be able to get some power in the batterie with the charger ?
 When charging the amps go down wile the volts go up so we are putting out power 
  I would use the charger if I ran low on power . 
 Last year it was used for 2 weeks in November 
 the year before I never even plugged it in . 

Estragon

It does seem like you're getting to float, and SG confirms.

If the batteries were sulfated, they would behave a lot like what you're seeing. They would get up to absorb voltage (faster than normal) and amps drop off fast. They wouldn't really be charged much though because of the hardened sulfate covering the plates, so they would discharge fast under load. The SGs are okay though, so the sulfate is in solution where it belongs, not stuck to plates.

My panels have a problem with snow, especially warm sticky snow, but I also have a problem with shading around xmas. If snow sticks and hardens in the shade then, it stays for weeks or months, even with wind.

If yours were okay in January though, that probably isn't the problem.

It might be worth separating the two batteries and let them sit apart for a couple of hours and then check voltages? Maybe one battery has a bad cell?

westbranch

When dealing with  cold climate storage of FLA  batteries with solar charging to keep them up,  it is wise to raise the ABSORB time limit from the ~ 2hrs to 3 or 4 based on observation of the SGs after each charge..as well as raising the ABSORB voltage if you don't have a Temperature adjusted charger.. it is all specific to how cold it is and the condition of the battery...

wellbuilt

Estr , wouldn't I see the sulfat on the plates when I looked down thru the fill caps?
 I think the battery's where 12.3 under load  screw gun chargers phone chargers and a light , 
 so no load would rebound to 12.4 ' then I ran a charger for 4 hrs I started with 30 amps for the first hr or so then 10 amps for 2/3 hrs ,I did notice the voltage looked low to me but on a10 amp charge the volts don't get that high.
 Could we have killed the batteries buy over charging .? 
 They never felt hot or even warm , and the water level never dropped much ,  I would add about 12 oz of water 3 times a year . 
To day the water mite be 1/8" lower then in November. 
 Should I drag the batteries home and charge them with a 6 volt charger for a few days ? 
 I have 230 watt panels a little more then 5% charging  do you think we have been under charging. For 2 years and they died a sudden death  in a week .
 Can the battery give off power when frozen ?
 I do get wind thru my vent it mite iced up at night. 
 

Photowhit

If they have been sitting in float for 4 months they may have become stratified, it would be good to do an equalizing charge on them. It will mix the electrolyte and perhaps sluff off hardened sulfates and recombine some others that might be stubborn.

I think you are over estimating your solar array, a 140 watt panel and a 80 watt panel in series on a mppt charge controller will likely be the equivalent of a 160 watt array. 

wellbuilt

West branch
 the batteries are in the back of a trailer that is heated but the batteries are in a box vented to the out side the the CC is in the heated side , but we can't get the temp above 50o inside any way 
 there is some
kind of temp sender on the unit and there is a temp adjustment that can be made but I don't know what the adjustment would be ?
 There is no real absorb voltage on the tracer controler that I can set .
there is a way to fake the setting and fool the controler into thinking it's warmer  Or cooler . 
  Any thoughts ?
 

westbranch

Sounds like you do need to take them home and get a full charge on them , deplete with a known load for X hours to ~ 12.4 and then recharge and observe/ record the SGs at each step

wellbuilt

Photowhit should the panels be wired differently for  more power . 
The panels have been working ok till now . 
 Maybe the lack of power killed them , I did not really use much power so I was ok the first year . 
 Last year we where ther longer into the season and the heat would run more as it got colder 
 I think the blower took 3 amps at  12 volt . 
 Could I do a eq charge with the charger above in the pic , or do I need to take them home and use a better charger.

Estragon

Taking them home probably not a bad idea, if only to warm them up and give them a good charge. If you can eq them too that might help too. There is a possibility the calibration of your hydrometer is off and the SGs aren't correct. It wouldn't hurt to take it too and check it with a known SG liquid.

I don't know if you can see sulfate. The fill holes are pretty small and it's hard to see much.

With 140w and 80w panels, you may be better off with the PWM controller. The difference in power is probably too wide to take advantage of MPPT. The PWM controller may also have lower self-consumption.

wellbuilt

Estr 
 The batteries look brand spanken new .
 The inside is shinny   Metal  No trace of rust or white powder .
The hydrometer is a good one and I've been using ti for the life of this system . 
 If the battery's are low it gives me a low reading . 
The sg has always stayed close since day one . 
But I will just buy a new meter and check that.
 I guess the best thing to do is just buy 2 new battery's and replace then so I 
can have power wile I'm fooling with the old battery's . 
 I need battery's at the house any way , so I'll spring for 4 shinny  new gc 215 to compleat a 24 volt string . 
 My 40 amp  CC has a eq charge every 28 days done  automatically . 
 I missed that in the manual when I set it up 2 years ago . 
  If the battery froze will they come back ? 
 I read on line that 12.3 volt battery wouldn't   Freeze till -16 and that is the voltage I had now . 
  
 
 

westbranch

how many panels  at ? watts are you going to use to start... you don't want to kill that new set right away...   you will need 215 * 5% = ~ 11Amps @ 24V for a safe slow charge, 22A would be much netter..

Estragon

-16 sounds about right. In my experience they don't really freeze at a certain temp like pure water would. They get kind of slushy for a bit until they get cold enough to freeze solid. Don't ask how I know this :-(

Getting to the slushy stage doesn't appear to cause permanent damage. If they get to the solid stage though, bad things can happen.

The bad SG reading idea is a bit of a long shot. The meter is probably ok. Just trying to rule things out. Having a spare isn't such a bad idea anyway.

wellbuilt

If the water and acid separate  in the battery is the water or acid on top .?
The hydrometer draws from the top , could the water freeze on the bottom ? 
 I wonder if the battery's could of  froze on our last day , before I starting charging them for the end of the year . 
 The charging wasn't really looking good the volts stayed low 13 .4 and the amps were also low . 
 Normally as my charging amps go down volts end up around 14.9 when I finish charging . 
  
 Westbranch 
 I don't really have a big plan just yet , I'm thinking I want to buy one string of the same Bach and age .
 I may end up with 4 8 or 12 gc 215 buy summer .
 I'm sure it would be better to buy all the batteries at one time , but I can't keep them charged .
 Then swap out my old gc215 for 2 new gc215 so I could get some fishing done at camp.
Then bring the old batteries home and get them charged up in the garaged (not very warm in there).
 The 2 extra battery's will just be charged once a week .
 If the old batteries charge up and work that would be fine ,I'll drop them in the trailer and use them . 
 The 4 new battery's will stay home on float for 6  weeks or so at that time I will add 4 more gc215 and a inverter charger.
 I will charge with the genarator for a few weeks until I get solar panels and CC hooked up .
  I'm thinking my 40 amp mppt is not working 100% until now it has not given me a problem 
most of the time in the am I would have 12.5v under load .
 
 

BB.

Water& water ice is much less dense and will float on the concentrated sulfuric acid.

- Bill

wellbuilt

Would it be safe to say if the water should be on top of the acid and my sg reading is 1.275 in the top1/2 " or so , 
 and the plates look shinny new with no white in any cells . 
 No hot spots on the battery bank , the battery's should be good . 
 All the cell were bubbling at the same rate . 

Estragon

If the SG reading is accurate the battery shouldn't freeze without temps much lower than you got.

Stratified electrolyte with stronger, denser acid on the bottom can happen to any FLA battery, but is more of a problem with tall batteries like L16s.

wellbuilt

Estragon , If the acid is stronger on the bottom my SG reading is drawn off the top sooooo
  Idon't think the acid could be  separated ?
 I'm beginning to think my battery are not the problem . 
  I. did have a problem with the blower motor last year where the motor was rusted and tight and was not turning freely but after a squirt of oil 'it was spinning good . 
 Maybe the motor dropped the battery's from full power under load to 12.3 v because it is bound up ( a few mice in there ?) 
 when I turned off power I started the genarator so I never really checked the standing voltage .
 In the  morning the sun was up early and the cc was reading 14.5 so I did not get a good standing voltage reading. 
 I did put a 80 watt load on the system 4 lights inverter /tv and the power did dip down to 12.3 in half an hour . 
  When I took my SG reading in the after noon , I turned the solar array off  and ran the lights and radio for 1/2 hour 
  maybe I was getting a good reading because there was   Surface charge Still on the battery .

Estragon

I don't think there is a problem with acid stratification. As well as not being as much of an issue with golf cart shape, you said all cells were bubbling equally. The bubbling is what mixes the acid up. The fact they all bubble well also makes it less likely you have a bad cell, whether because of freezing, defect or whatever.

A stuck motor could definitely be the problem. Locked rotor amps will be several times normal running amps.

If checking SOC with a voltage check, surface charge could be an issue, so getting a resting voltage is important. Checking with SG is different. You're checking the strength of the acid, which doesn't have a surface charge issue. I usually turn charging off before doing a SG check only so the bubbling stops before opening caps. Batteries make me nervous enough as it is without them burping acid at me.

wellbuilt

Ok some  New information 
 I talked to Renogy the people that sell the controler .
 It seem like they sold me a bum charge controler , the tec guy was telling me that some of the controllers would not go into bulk charge , the voltage would just stay at 13.6 13.7 13. 9 14 volts or what ever . 
 I never really had a draw on the battery's So float was enough power to keep me going .
  The charger would kick in when the sun was out , and I was drawing power from the battery's.
  When we where there with the inverter on and radio playing we would draw 40 watts or so but the controler would start to bulk charge and give me 8/10 amps in good sun . This is why I had no power problem .
The last few weeks we where there the sun was going down early it was cloudy and we had the battery's down to 12.2 volt in the am .
sooooooooo  be a good off grider I was  turn off the battery switch  during the day to save power
and In turn the controler never went into bulk charge. 
  Renogy doesn't care if they are selling junk ,  there  Products only have to last for a year and the warranty is up .
 They would give me a new charge controler in the first 12 months. 
 But I have had the unit for 18 months soooo they want to sell me a new  controler at full price .

wellbuilt

The question is if the battery's where left  at 12.4 volts for 4 month  at 20o on float when the sun was out and the panels where not snow covered 
  Will they charge back up , and be  serviceable . 

westbranch

Will they charge back up , and be  serviceable ?.The best (only?) way is to haul them home and charge them and use them and make sure the solar is charging the batts...
Look at what I posted in #20, still applies and I would recommend a better CC with a good warranty... 

eg. MidNite KID (MPPT) or BRAT (PWM) or some of the MorningStar units

wellbuilt

That's what I will do , I have a 20 amp sun saver  cc to try for now . 
 And I will get some power on them  
 thanks every one for the replies ,  you all have been a great help .