battery, your thoughts-help

gww1

Re: battery, your thoughts-help

vic
I was using bts but unhooked it cause there is no good place to put it and it was making the fm80 and mx60 not play well together. I discussed this with outback tec before unhooking. No plates are showing but it is time for water. There is not as much room as one would think for water and a charge affects it more then I would have thought. I got home at the end of the 5th hour of absorb and the battery was only accepting 3 ac-amps. I figure this transulates to about 6 dc amps. The sears clamp meter showed the case to be about 77 degrees. I spot checked my normally highest cell and my normally lowest. The sg's were 1.160 and 1.150 respectively. I tried to put night time loads on it but left the charger in the inverter on and apparently this setting is conflicked cause the grid was carrying my loads this morning. I left the loads on grid but turned the inverter charger off. It should go through another charge cycle and long absorb if we get sun. The batteries were bubbleing pretty hard during absorb. I can observe it one more time in the middle of the day today and then I will be gone till sunday.
Thankyou for your comments.
gww

Blackcherry04

Re: battery, your thoughts-help

gww1 wrote: »

I got home at the end of the 5th hour of absorb and the battery was only accepting 3 ac-amps. I figure this transulates to about 6 dc amps. The sears clamp meter showed the case to be about 77 degrees. I spot checked my normally highest cell and my normally lowest. The sg's were 1.160 and 1.150 respectively.

Sounds like your heading over the abyss if those SG's are correct after 5 hrs of absorb.

gww1

Re: battery, your thoughts-help

Blackcherry04
Considering that 1.170 is considered 100 percent dead per the charge pamplet that came with the batteries, I would say you are right. However I had called the battery rep and he was insitant that I just go by voltage. It was sitting at 52.8 this morning. I am about to equalize and am hopefull that I can bring the sg level back up. It does say on the charging pamplet that it is impossible to fully charge the battery with out equlizing. I came here due to fear of my actions, whether from advice or not, might be destructive.
Thanks
gww

Blackcherry04

Re: battery, your thoughts-help

Is that Voltage (52.8 ) resting without any charging source ?? Here is the problem, you could have that voltage with one square inch of plate. I don't know your hydrometer, but your heading the wrong direction.

NorthGuy

Re: battery, your thoughts-help

gww1 wrote: »

It does say on the charging pamplet that it is impossible to fully charge the battery with out equlizing.

Is this available for the download somewhere?

High resting voltage is a sign of stratification. I supposed to have 50.5V, but when my batteries were stratified, I got 51.5V. Cannot check it now because batteries are never resting, but 52.8V would indicate severe stratification.

Stratification means all the acid has sunk to the bottom. As a result, you have sort of 2 batteries in parallel - the bottom part with highly concentrated electrolyte (which gives you these high resting voltages), and the top with very mild electrolyte. Because of the concentration difference, the top part operates at lower voltages and the bottom at higher voltages. When you charge, the voltage may be high enough to charge the top part, but not the bottom part, so most of the charge goes to the top part. When you discharge, the voltage might be too high to discharge the top part, but ok to discharge the bottom part. So, mostly the bottom part gets discharged. If it goes on for a long time, the bottom part gets sulphated because of deficit charging while the top part gets corroded because of overcharge.

Therefore, you have to mix the electrolyte to stop these effects. You probably do not need to do this every day, but once a month seems to be too rare to me. However, I'm not an expert in batteries.

The fork-lift battery charging is different from RE in that they have one more phase at the end. During this phase, the current is kept constant, but the voltager rises as high as it can go, sometimes as high as 68V. This produces lots of bubbling and mixes the electrolyte. If your batteries were used with a forklift charger, they would get this mixing every day. Perhaps, your rep only has experience with these chargers, but not with RE. For these chargers, his advice sounds reasonable.

In RE there are only two ways to get mixing - stronger absorptions and regular equalizations. If your absorptions are mild, you would need frequent equalizations - once a week or so. If your absoptions are strong, you can get away with less frequent equalizations, or without equalizations at all. Week absorptions and monthly equalizations doesn't seem to be enough.

If your rep promises that he replaces the battery if it sulphates (with all expenses paid) then I don't see anything wrong with doing as he says. Otherwise, it looks completely insane to me.

Blackcherry04

Re: battery, your thoughts-help

North , you hit the nail right in the head with your explanation. At least he has a grid connection to pull himself out.

gww1

Re: battery, your thoughts-help

Hey guys
Thanks for the comments. I am on a new path now. I took Vic's advice and called the battery maker.

They gave me the phone number of Tim Becker (hope I got that right) for me to talk to.

My new plan is to absorb at 61 volts.

The type of charging mentioned below was discussed and I explained that my controller would only use what amps I had availible and use them to drive the battery to a spicific voltage and then would cut back what ever amps it had to to hold that voltage. He thought I should absorb at 61 volts daily and eq would hold that voltage or a little higher for 3 or so extra hours. Two hours at 61 volts and watch the amps and heat at that time to see what adjustments may need to be made. I may not have compleetly understood but he left the door open if I have more questions. He thinks the batteries are new enough that no permanate damage has been done. He thinks it would have took about a year to have really started to affect the batteries.

He thinks the cells were somewhat further apart and that most of my spot checking should be on my lowest cell which is how I was handling it. His view was they could be taken to 43.2 under load say 20 amp and if the draw was less that could be raised a little cause a lower draw could take the actual voltage a bit lower using the same voltage. I don't believe they liked shallow discharging as well as getting close to the 80 dischare pretty regular. To me this fits the 46 volt cutt off close enough, maby a bit more in emergencys.

Ending with a voltage 2.6 or a little above is what would be the ideal voltage to stop at on a daily basis but as you say the plugin charger ragulates current to get to that spicific voltage, we regulate current after reaching voltage. I am going to start at 61 volts for absorb. I couldn't watch it today so I put it on the grid and set the absorb for 2 hours and will check the sg's sunday when I get home. I am running no loads yet. I have my fingers crossed that I am going in the right direction although I will feel much better when I can babysit and watch the amps and heat for a while when making more adjustments. He thought I would be safe to about 110 degreesthe way I am measuring.

I should not have needed vic to tell me to call the battery makers but I am glad he did as well as glad for all the comments from you guys.
Thanks
gww.

PS Not having instant internet access could have made me sit on my hands too long and given me real damage, if I do dodge this bullet. Something to think about.

gww1

Re: battery, your thoughts-help

northguy
You ask about the pamplet and where to get it. Believe me, it is not much. My last post probly has as many words in it as the pamplet.

Single sheet that came with the battery.
cheers
gww

gww1

Re: battery, your thoughts-help

I am also glad coot had me raise the absorb to 58 volts. Trying that and seeing minimal differance made me very receptive to the 61 volts being contimplated and shows coots first instint for 60 volts was very close to right on. I can see it now :
Coot: "grasshopper you are fast to learn slow."
gww: "yes master"
cheers
gww

westbranch

Re: battery, your thoughts-help

Her is a short read on a fellow poster that had a similar problem... low SG, different battery than your but same problem, too low a charge V and time IIRC.

http://forum.solar-electric.com/showthread.php?14333-Specific-Gravity/page6

Blackcherry04

Re: battery, your thoughts-help

It's good you got to talk with someone that knows your battery. Since you have grid, I'd get it up to absorb voltage as early as you can in the morning up to 61 V with your Inverter. That will give you all day on the PV to gen enough hours in absorb. It's winter now and makes it harder to get it done.

gww1

Re: battery, your thoughts-help

northguy
Thank you for the link

Blackcherry

I belive that may be the answer short term although I will probly just see what happens with no load and soler and then see where I am at.

It would seem to be counter productive to discharge the batteries and then charge them again from the grid. Alright for training batteries but not a long term goal. On days I don't run loads it would seem that letting the solar bring the batteries through bulk and then lengthening the absorb with the grid would use much less grid power.

I really would like to get the batteries working off the solar even if I had to reduce loads and/or add solar/wind. I know the time constraints of daylight may make this impossible but I would like to work towards that.

I do realize that all bets are off till I get the batteries stableized. I am charging purly from grid for the last two days and solar be dammed.

When I figure out what the battery takes, I wan't to upkeep them with as little grid power as posible.
I don't know enough yet to have anything but a general goal for now.
Thanks
gww

Blackcherry04

Re: battery, your thoughts-help

I got you, I thought you were cycling them. I hope your plan works for you.

gww1

Re: battery, your thoughts-help

I got you too, I intend to cycle them when I can watch them and have a bit of sun. Right now I turned off the load and just charged from the grid. I was running loads while charging also. After I check the sg's from this charge and if I think things are going in the right direction I am going to add the night time loads but turn them off before daylight and see what happens. I should get to absorb earlier even at the higher voltage setting. I then am going to watch the absorb current going to the batteries looking for the low point. Then check the sg's. If I am not getting improvement due to not enough absorb time, If I can't be there I will do as you say, if I can be there I will add to the end. I really believe I have enough solar to get to absorb and hold it long enough but if wrong I will have to do more. I was reaching and holding for a couple hours the old absorb voltage with my loads on. I am hoping the higher voltage and reduced loads will be enough but I haven't done it yet to know.

Thanks
gww

Ken Marsh

Re: battery, your thoughts-help

As C Coot stated, In the long term you want to reduce usage, particularly battery exercise.
We have the same problem, Just too much usage for any reasonable solar system.

And we have the house heat/cool/DHW on the system too.
The solar panels run every thing fine when there is sun or even partly cloudy.
When there is no sun, it is back on grid. I am not not anal about being off grid.
As near as I can figure from Trojan battery life data, I can buy a KwHr off the grid
for about the same $ and maybe a little less that cycling a KwHr through the battery.
Bill (BB) has posted on this. Thanks again Bill.
The battery will run everything for hours but it is expensive to do so.

Blackcherry04

Re: battery, your thoughts-help

I was going to buy a Forklift battery from a National company ( not GB ), before they would take the order, they wanted me to talk to their local service manager. After 30 minutes on the phone and hearing all he was telling me, I decided that a forklift battery was not something I was willing to live with. The voltage drop under load and the re-charging regimen was more than I could to deal with. They do last a long time, but probably not for everyone.

NorthGuy

Re: battery, your thoughts-help

Blackcherry04 wrote: »

I was going to buy a Forklift battery from a National company ( not GB ), before they would take the order, they wanted me to talk to their local service manager. After 30 minutes on the phone and hearing all he was telling me, I decided that a forklift battery was not something I was willing to live with. The voltage drop under load and the re-charging regimen was more than I could to deal with. They do last a long time, but probably not for everyone.

So true. I believe the batteries that I have are essentially the same as forklift, but with higher price tag. I cannot even begin to tell how hard are they to deal with. I managed to design some sort of charging regime which is somehow acceptable, but I'm not sure they're going to last for as long as I hoped for. It would be easier somewhere in Arizona, but not in the North.

Would you give us more details on what this guy told you?

Blackcherry04

Re: battery, your thoughts-help

NorthGuy wrote: »

So true. I believe the batteries that I have are essentially the same as forklift, but with higher price tag. I cannot even begin to tell how hard are they to deal with. I managed to design some sort of charging regime which is somehow acceptable, but I'm not sure they're going to last for as long as I hoped for. It would be easier somewhere in Arizona, but not in the North.

Would you give us more details on what this guy told you?

Pretty much what you already know. That the time and current in RE PV is just not there to be able to keep it charged and the SG 's up and keep stratification from taking over. That without enough current over time I wouldn't be happy with it. He also talked about that they were slow to supply high amp output to a load, something I had not thought about.

Cariboocoot

Re: battery, your thoughts-help

Blackcherry04 wrote: »

Pretty much what you already know. That the time and current in RE PV is just not there to be able to keep it charged and the SG 's up and keep stratification from taking over. That without enough current over time I wouldn't be happy with it. He also talked about that they were slow to supply high amp output to a load, something I had not thought about.

This is what you'd expect from a deep cycle battery as opposed to an automotive type. It's just that when you get to forklift size with its 80% DOD ability the factors go into crazy land. Fine if you can plug them in to a 'proper' charger over night, but a bit of a pain in the anatomy if all you've got to work with is four hours of sunshine producing a bell curve of available power.

Ken Marsh

Re: battery, your thoughts-help

NorthGuy wrote: »

So true. I believe the batteries that I have are essentially the same as forklift, but with higher price tag. I cannot even begin to tell how hard are they to deal with. I managed to design some sort of charging regime which is somehow acceptable, but I'm not sure they're going to last for as long as I hoped for. It would be easier somewhere in Arizona, but not in the North.

I doubt that you went wrong with the Industrial Trojans.
I was considering using them next time we need batteries.
We have a HUP battery at our cabin.
It is different from a L16.
It will start heavy loads like a half hp submerged pump at 80% DOD.
Of course we don't want to discharge a L16 that much
but but the L16s have a hard time starting the pump at 50% DOD, everything considered.

NorthGuy

Re: battery, your thoughts-help

Ken Marsh wrote: »

I doubt that you went wrong with the Industrial Trojans.
I was considering using them next time we need batteries.

Trojans are monsters. They require long absorptions all right. Last one was 6 hours 40 minutes. This is very typical. That could've been Ok, giving potential longevity etc.

But! I also charge them at 64V because at lower voltages the absorptions would be longer, much longer. This does require extra energy, which is not always readily available, and adds to the cost.

I would say that the batteries are defective, but according to Trojan support they're perfectly normal.

Are they going to last with such charging? I don't know. The warranty conditions are such that there's no chance to ever get the replacement. So, I'm sort of in a limbo.

The loads are not a problem. They can still support my loads when 80% discharged. However, my highest loads are 3-4kW, which is not much for 673AH@48V bank.

gww1

Re: battery, your thoughts-help

A small update. I again talked to tim baker (I did have his name wrong earlier). I put the battery to a 20 hour absorb. Last night I tryed to run off them and they dropped the loadquite early. The drop point was 46 volts for 18 min. I went out and the voltage was 50.4. I put the loads on the battery again and when I went out this morning they were droped again. The battery was almost 52 volts.

Its had to figure what that means as the turbine had put 900 watts into the battery. I let the loads and divertion loads come back on line when the batteries hit 57 volts for half an hour. I hit absorb at ten am. I had raised the absorb voltage to 61 volts for four hours.

I do have some issues to address. One is even when I have the absorb set for 4 hours on the mx60 charge controller it quits putting anything out and says full battery and the fm 80 can only keep the volts to about 56 volts on its own. I went and tried to force the mx to bulk and it keeps going back to full batteries.

The mx60 doesnt have a log that allows me to see how long it had absorbed but the fm 80 says 2 hours. I shut the divertion load off and the fm80 is keeping it in absorb and running loads at last look for 3 hours so far. It goes to absorb a bit latter then the mx60 but I am sure the mx could not have absorbed for 4 hours as it was only 1:30.

I checked the sg on my lowest cell at the 3 hour absorb mark and It was 1.275.

Tim believes I am on the right track and that the sg's will level out and that I should keep my monthly EQ's to 4 hours or less and that this will get me there. He believes I need to set my load cut off point to 44 volts if I want to get through my load spike/surges. I looked at the fm80 low voltage for the night and it was 47.something.

For better or worse I am going to try 44 volts and see what happens cause I can't keep my loads going and the battery seems to bounce back after dropping them. Time will tell if I am on the right track or not. I really need to figure the mx60 thing out.

I added a bit under 1 1/2 gallons of water after the absorb.

Any comments are welcome and I thank those who have helped before.
gww

westbranch

Re: battery, your thoughts-help

Just read the parallel thread and I hate to say this but you will likely never solve this problem of getting a full charge if you keep changing more than one parameter at the same time. When you do this you can NOT tell for certain which factor is doing what.

I see your objective as "getting the battery fully charged" after a specific load has been applied and then "recharged" and depleted and recharged...(repeat as necessary) Once you have consistent results, then add your opportunity load, iin the mean time run that DHW tank on the grid. You need to figure out how to get the MX and FM working smoothly together then use the EXCESS for DHW, until you get a full charge you do not have excess power to use, though it may seem like it

Hope this helps
cheers

gww1

Re: battery, your thoughts-help

Westbranch
I understand what you are saying, however I am retired and as stupid as it sounds, I stand out by the system almost 24/7. I really think that now that the voltages are more correct I am getting closer to the answer. I could have made a mistake yesterday with the charging but I was there to shut the hot water heater down so I could get my target of four hours of absorb. I think I am getting the batteries charged now. I do believe that when you think that I am maby making $2.00 per day that I may be crazy but it is still cheeper then most things I could be doing now that the solar is payed for. If I check tonight and find I got 3 hours absorb, I believe I will have got the mx60 to do what I want and made plenty of hot water and got the battery close to full, a very small adjustment will bring me home. That is of course If I am happy with daily sg 1.275 on a 1.285 battery. I will know more after more cycleing and the next EQ.

Thanks
gww

Blackcherry04

Re: battery, your thoughts-help

That is of course If I am happy with daily sg 1.275 on a 1.285 battery.

I am not so sure that is where you have to be or want to be everyday. It's a spot that you always want to be within striking distance to and the Constant that you always know the health of your battery. Slipping away overtime where you cannot get back is where the danger is.

North Guy has a couple posts here that shows how he manages his battery bank, that is a similar battery to yours. He is using it and he's able to bring it back to it's highest level when he wants. You may or may not want to utilize a regimen like this , but it works. He can tell you how The SG's relate to his SOC levels.

http://forum.solar-electric.com/showthread.php?18601-Absorption-Time

westbranch

Re: battery, your thoughts-help

No worries Mate, retired here too. All I wanted to point out is with a brand new battery (that you have to learn about) and 2 almost/sort of cooperating CC's and an opportunity load you are manually playing with can lead to a 'Whaz that?' situation.

You will just need to up that SG reading IMO.

gww1

Re: battery, your thoughts-help

Thanks guys

Will have to read later. going home and no internet. I will comment/ update at my next oppertunity.
thanks
gww

gww1

Re: battery, your thoughts-help

Blackcherry
I read the thread you posted,
thanks
gww

Westbranch,
The charge controllers are working well now. Once I put the minimum absorb time in it is not going to full battery. It is allowing the long absorbs now.


Update: I am still hunting so have not caught the end of the absorb to check the sg. I checked two of my traditionally low cells at the one hour and 38 minute mark. They were 1.270 and 1.278 respectively. I am getting 3 to 3.5 hours of absorb daily. My low voltage per night on the charge controller is 47.5 but the sitting voltage is 49. volts with my loads on. I hit 58 volts with about 12000 watts through the cc's. If charging a battery from 50% to 80% is usually done with one amp replaced for one amp removed and the last portion is much more and after reaching absorb it is taking between 900 to 1200 watts to hold it, can I assume that my loads durring no sunlight are somewhere in the same neighborhood?

The charging and sg's have been the same for the last three days. I think the cells could be closer then they are but mostly everything has smoothed out and I am happy with how it is working. As soon as I charge one time with zero loads where I can watch where the end amps come in I believe I will be able to not be manually disconnecting the loads during charging. I think now that I might survive with a 2-3 hour absorb and will get more during the summer longer hours. We have had three days of decent sun. I believe when the clouds come I am going to let the battery run till disconnect and let the software controll the charging with the settings I have and see where I end up. I think that as long as I watch the sg's and EQ once a month I might be set about right but time will tell.

Anyway, my update, your thoughts?
Thanks
gww

westbranch

Re: battery, your thoughts-help

58 volts with about 12000 watts through the cc's.

Well that works out to > 200Amps, not bad

In post 53 you were using and Absorb of 61V, is that still the same?

if so after reaching absorb it is taking between 900 to 1200 watts to hold it

would work out to ~ 15 to 20 amps.

Watt

Re: battery, your thoughts-help

Hello Gww1,

Been reading through your thread and it appears you are getting grips on those cells. Congrats.

Looking at your pictures, the battery looks be the size of a 510ah at 6hr / 800ah at 20hr rate battery. Just curious if that is correct and if so, what is the 6hr rate of that battery. If I'm wrong, what are the 6hr and 20hr if you don't mind.

I've been battling forklift batteries for a while and really like their dependability and forgiveness. One thing I have found that is a little disappointing is Peukert's law and the Peukert's constant these batteries have. Can be viewed here http://batteryuniversity.com/_img/content/runtime1.jpg . With the rates I asked about, you can calculate a near number ( better if the manufacture were to give you that number ) to use in daily use and recharge AH'ers. That battery, if it's 800ah@20hrs may only 500ah in a 6hr consumption scheme. In the end you may only be able to remove 22 or 25kwh from it before you need to remove the load and recharge. What I mean by that is depending on the load current required of the battery, say 60A for 10hrs , you may only get ~600ah and be near dead. A 100a load for 4.5hrs would be 450ah and be near dead. That would be around 17.25KWH from the bank. According to http://gbindustrialbattery.com/Battery_Options/AH_Ratings.html ,as you mentioned you bought yours there, may give an accurate indication of your sustained capacity above what I understand.

Here is a 850ah@6hr / 1340ah@20hr 48v battery, http://i261.photobucket.com/albums/ii74/Chevy_l88/20130813_014253_zps8b62e159.jpg not new but larger than the one you have pictured ( far as I can tell ). It has a Peukert constant of near 1.6 and has a darn scary low KWH usage before a recharge is needed. With the loads you describe, it appears you may be right in saying " you wish you would have bought a larger battery bank ". You may need larger capacity.

Recharging my forklift batteries seem to be very predictable. When the planets align, haha, I charge my batteries with as much current as I can throw at them until I reach 58v. I do compensate for temperature so in the winter, the voltage can reach 60v for bulk and summers are bit lower than 58v. For absorb, I stick with just a volt or so lower than EQ and have timed several cycles by measuring the SG at hour intervals until the SG did not rise for 30 or so minutes and used the previous time as the absorb time. Then went to float of 54v or so. I read where this had been mentioned and only want to back up the fact that this worked for me. When I did the voltage based charging, I had a tough time realizing what was going into the batteries themselves during charge vs what was a load. I can now do charges based on finish rate and Soc. My 48v battery seemed to stay fairly balanced with a 38A finish rate.

One area that was always tough for me was trying to manage the battery while the loads were present and ever changing. Just because the voltage was met, didn't mean the battery was happy. The balance of the system was with the purchase of the add on component to the Classic, the Whiz Bang Jr. and the Magnum ME-BMK / Magnum remote for the magnum inverter. Those two have lifted the ever increasing burden from my shoulders. Just saying that voltage alone is not a true indicator.

With all this considered, the daily production may very well not be enough to sustain the loads and charge the battery depending on how quick or slow the batteries were depleted. I didn't read were you have a KWH meter of some sort to keep up with your usage and charge. If I missed that, please excuse this babbling....

To sum all the above, depending on your load ( AH draw from batteries ) you may or may not have a 800ah capacity to base your KWH usage on. A sustained 40A for 20 hours is ~38kwh. But, 100A for 4.5hr would only be ~21.6KWH or ~57% of the 40A usage capacity. Also, as far as what voltage to terminate your usage at and recharge... To me, I base my usage off of battery temperature. The warmer the battery, the higher the cut off voltage is and the cooler the battery, the lower the cutoff voltage but rarely do I cut off lower than 44vdc under load no matter the current usage. I had my inverter set to connect based on 44vdc if that voltage was hit for more than 10 sec. I now have the battery monitor which is set for 40% Soc. The manufacture suggests a cut off of 42vdc but I like to go a bit higher as the general consensus is to raise battery life by not allowing the battery to get about 77*f or lower than 40 to 50% DOD. I also try to weigh this against charge/discharge cycles as that too adds to or decreases battery longevity. One other point is that if a short/incomplete charge is considered a cycle, I want to get the most back into the battery as possible before my solar quits producing. So, as deep a cycle as I'm comfortable with to a charged state seems optimal to me. A large battery set makes since and a not quite big enough battery makes since to be recipe for disaster.

Also, your batteries best charge efficiency probably has not been reached yet. After it ages, you will loose efficiency. Consider this as you calculate your KWH productions.

Best wishes
Mike