Battery voltage high, but SoC low?!?

[miahallen]

None of this makes any sense. The Mate3 displays SOC but ONLY if you have a FlexNet DC in the system. Do you have one? If you don't, you can't believe anything the Mate3 tells you about SOC. Replacing the Mate3 does not affect the FlexNet DC (assuming you have one).

Lots of assumptions here because I don't know what you got there. But even if you do have a FNDC, it needs to be calibrated. And it sounds like you got your LBCO set way too high. And it sounds like your charge controllers are not even set properly.

Details. Lots of them needed.

You are correct in your assumption that the system includes the FlexNet DC (I believe they come with all FP-1 systems which is why I didn't specify). The FlexNet DC is what was off calibration and now it should be much closer to true.

I'm happy to provide more details, but I don't know which ones are needed.

I'm a bit bummed russ has not returned to respond to my claim that the stickies include conflicting details about safe SOC cycles. What is safe? 20%, 50%, 80%?

There is a common misconception that you cannot cycle batteries below 50% DoD or it will ruin them. This is totally and blatantly false for real deep-cycle batteries. They can regularly be discharged to 80% DoD and it doesn't hurt them one bit. And in fact, it makes them more efficient on charging.

here - http://www.solarpaneltalk.com/showth...ng-Gen-Support

[ChrisOlson]

Nowhere here did you read 65% to 75% was OK - 80% is the limit for that type of OK - you are pushing it and giving up your battery life. What happens in lousy weather?

Those Trojan's can be discharged to 80% DoD, absolutely no problem. 50% DoD is normal with them for off-grid systems to achieve a balance of best efficiency vs kWh stored over their life. The more shallow you discharge them, the more cycles you get. But their efficiency drops and you get LESS kWh stored over their useful life vs input energy. They are a 6-7 year battery on 50% DoD cycling duty.

The problem here is understanding the system, and the settings. Trojan keeps constantly fiddling with SG in their batteries, but the P-AC's are their latest high-capacity L16's with 1.280 electrolyte. Proper absorb voltage is 2.47VPC (59.2V on a 48V system). EQ voltage should be set to 2.58VPC and Float is 2.20VPC.

Step #1 - verify that all your charge controllers are set to those values for each charge stage.

Step #2 - verify that the inverter/charger is set to those values for each charge stage.

Now, you need to charge your batteries. That means absorbing them at 59.2V until you get a SG reading of 1.275-1.285 on every cell. Ignore the timers in the FM80's and keep absorbing them until you get that SG. At this time, assuming you have a FNDC, it should show around 8.4 amps going to the batteries at 59.2V.

Congratulations - your batteries are now at 100% SOC.

Now you need to refer to the manual for the FNDC and sync it. And also verify that you have the ah capacity set to 420, discharge rate at 20, discharge floor at 50, Peukert Number at 1.25, and the auto sync setting to 9 @ 59V. There's a whole bunch of other settings in it too, that should be gone over and verified that they're correct. Since the FP-1 is all factory wired, we'll assume the shunt is not wired backwards. But with Outback's quality control as of late, anything is possible. The next few hours will tell.

Now watch your system under load. The Mate3 should be showing SOC at 100% initially, then drop gradually as the battery discharges. It should show net amps being used from the battery. If it shows net amps going INTO the battery with no incoming power from FM80, then the shunt is backwards. Contact Outback Tech Support and tell them your FP-1 is f&*ked up and you want somebody on the phone that can tell you how to fix it. Mary Raub no longer works in Outback Tech Support and she was the last one that I knew that actually knew what was going on there. So good luck with that.

Take note of amp-hours used from the battery as it discharges. When it shows 100ah used, the SOC should show 76% +/- Peukert compensation, which will be very small for loads less than 1,000-1,100 watts. If you don't get those numbers then something is wrong and you need to contact Outback Tech Support and tell them it don't work.

I'm more a Schneider Electric guy and I only work with Outback systems when other off-grid folks I know can't figure them out. I usually can't figure them out either and end up having to control a strong urge to smash the Mate3 with a 16oz ball peen hammer. But getting the bank to verified 100% SOC and syncing the FNDC SHOULD "fix" it.

[ChrisOlson]

I'm a bit bummed russ has not returned to respond to my claim that the stickies include conflicting details about safe SOC cycles. What is safe? 20%, 50%, 80%?

80% DoD is safe. You won't hurt them at all. 50% DoD is ideal to get the best return for your dollar on those particular batteries. 60-75% on a regular basis won't hurt anything as long as you deep discharge them once a month or so. 20% is too shallow. They'll die a young death at 20% DoD because they are high SG electrolyte batteries and you'll sulfate the bottoms of the grids if you don't work them hard enough and keep them turned over and stirred up.

[russ]

I'm a bit bummed russ has not returned to respond to my claim that the stickies include conflicting details about safe SOC cycles. What is safe? 20%, 50%, 80%?

Be more than a bit bummed - you bought BS without reading it all I suppose. The 80% means you get to use 20% of the battery capacity.

[ChrisOlson]

I think there is some confusion between SOC and DoD. 80% SOC is the same as 20% DoD. Since every RE battery monitor I have seen uses SOC, we should probably "standardize" on that.

Don't understand why it takes a month to get a hydrometer. Go to the auto parts house and get one and test those batteries. Got a neighbor 22 miles to the east of us that has those same identical batteries, except he has 16 of 'em. He bought them in October and he called me up in February when we got home and said his brand new batteries were getting charged during the day but they were going dead halfway thru the night and his generator was running all the time. His battery dealer had given him some salt pills or some frickin' thing that he claimed would "fix" them. He was smart enough to call me up and ask if I had ever heard of such a thing. I told him I had, but don't do it.

He don't have enough solar to fix all of them. So he brought 8 of them over here and I hooked them up parallel with our Surrettes with jumper cables and absorbed the piss out of them at 2.58VPC for two weeks. With only half on his system he had enough solar to fix the other 8. They been fine ever since. I'll bet a $10 bill those batteries sat around in a warehouse for six months before he got them. So I'm kind of familiar with those batteries. I think they're pretty good batteries and I wouldn't mind having a bank of them instead of what we got

[inetdog]

80% DoD is safe. You won't hurt them at all. 50% DoD is ideal to get the best return for your dollar on those particular batteries. 60-75% on a regular basis won't hurt anything as long as you deep discharge them once a month or so. 20% is too shallow. They'll die a young death at 20% DoD because they are high SG electrolyte batteries and you'll sulfate the bottoms of the grids if you don't work them hard enough and keep them turned over and stirred up.

Chris, I am having a problem making sense of this, so maybe you can help me out.
1. I know that for some batteries, particularly those you have, you advocate a lot deeper discharge than the generalized common wisdom, so I am interpreting all of your comments through that lens.
2. I get that 20% DOD (taking the battery no lower than 80% SOC) is in your opinion too shallow for longest, most cost efficient battery life.
3. I get that you feel that with the proper batteries and the proper recharging and maintenance occasional 80% DOD (20% SOC) is safe. And that 50% DOD/SOC (one point) is optimal for return on investment. (Not that you should kick in more loads to get there but that you should use smaller battery banks relative to your load, which you can do since you have multiple generators to handle recharging.)
4. What I do not get, based on #3 above, is why you say that going deeper than 50% (say to 60-75% DOD) is OK as long as you go even deeper than that occasionally. That looks a lot like you switched from DOD to SOC in midstream.

[miahallen]

Those Trojan's can be discharged to 80% DoD, absolutely no problem. 50% DoD is normal with them for off-grid systems to achieve a balance of best efficiency vs kWh stored over their life. The more shallow you discharge them, the more cycles you get. But their efficiency drops and you get LESS kWh stored over their useful life vs input energy. They are a 6-7 year battery on 50% DoD cycling duty.

The problem here is understanding the system, and the settings. Trojan keeps constantly fiddling with SG in their batteries, but the P-AC's are their latest high-capacity L16's with 1.280 electrolyte. Proper absorb voltage is 2.47VPC (59.2V on a 48V system). EQ voltage should be set to 2.58VPC and Float is 2.20VPC.

Step #1 - verify that all your charge controllers are set to those values for each charge stage.

Step #2 - verify that the inverter/charger is set to those values for each charge stage.

Now, you need to charge your batteries. That means absorbing them at 59.2V until you get a SG reading of 1.275-1.285 on every cell. Ignore the timers in the FM80's and keep absorbing them until you get that SG. At this time, assuming you have a FNDC, it should show around 8.4 amps going to the batteries at 59.2V.

Congratulations - your batteries are now at 100% SOC.

Now you need to refer to the manual for the FNDC and sync it. And also verify that you have the ah capacity set to 420, discharge rate at 20, discharge floor at 50, Peukert Number at 1.25, and the auto sync setting to 9 @ 59V. There's a whole bunch of other settings in it too, that should be gone over and verified that they're correct. Since the FP-1 is all factory wired, we'll assume the shunt is not wired backwards. But with Outback's quality control as of late, anything is possible. The next few hours will tell.

Now watch your system under load. The Mate3 should be showing SOC at 100% initially, then drop gradually as the battery discharges. It should show net amps being used from the battery. If it shows net amps going INTO the battery with no incoming power from FM80, then the shunt is backwards. Contact Outback Tech Support and tell them your FP-1 is f&*ked up and you want somebody on the phone that can tell you how to fix it. Mary Raub no longer works in Outback Tech Support and she was the last one that I knew that actually knew what was going on there. So good luck with that.

Take note of amp-hours used from the battery as it discharges. When it shows 100ah used, the SOC should show 76% +/- Peukert compensation, which will be very small for loads less than 1,000-1,100 watts. If you don't get those numbers then something is wrong and you need to contact Outback Tech Support and tell them it don't work.

I'm more a Schneider Electric guy and I only work with Outback systems when other off-grid folks I know can't figure them out. I usually can't figure them out either and end up having to control a strong urge to smash the Mate3 with a 16oz ball peen hammer. But getting the bank to verified 100% SOC and syncing the FNDC SHOULD "fix" it.

Chris...thanks a million for your very comprehensive response, I really appreciate it! I will do my best to follow the steps you've outlined and report back

Be more than a bit bummed - you bought BS without reading it all I suppose. The 80% means you get to use 20% of the battery capacity.

russ...you seem to be at odds with the sticky I linked, and with what ChrisOlson has stated in this thread:

80% DoD is safe. You won't hurt them at all. 50% DoD is ideal to get the best return for your dollar on those particular batteries. 60-75% on a regular basis won't hurt anything as long as you deep discharge them once a month or so. 20% is too shallow. They'll die a young death at 20% DoD because they are high SG electrolyte batteries and you'll sulfate the bottoms of the grids if you don't work them hard enough and keep them turned over and stirred up.

russ - with all due respect, are you disagreeing with ChrisOlsen's statement about "80% DoD is safe"? 80% DoD = "Depth of Discharge" correct? If I used 80% DoD, the resulting SoC would be 20% right...so I would be using 80% of my capacity if I am understanding this correctly. If Chris is correct (as stated below) than I think I'm straight on things.

I think there is some confusion between SOC and DoD. 80% SOC is the same as 20% DoD. Since every RE battery monitor I have seen uses SOC, we should probably "standardize" on that.

Don't understand why it takes a month to get a hydrometer. Go to the auto parts house and get one and test those batteries...

I just moved to Belize and sourcing typical things that I took for granted in the states has proven to be difficult, this is a 3rd world country after all. I ordered a hydrometer on Amazon, and I have a friend bringing it to me next month...that explains the delay I mentioned. However, there is a pretty well equipped auto parts store I recently discovered, and I have not looked for a hydrometer there, so I will go check. Thanks for the suggestion.

[russ]

russ - with all due respect, are you disagreeing with ChrisOlsen's statement about "80% DoD is safe"? 80% DoD = "Depth of Discharge" correct? If I used 80% DoD, the resulting SoC would be 20% right...so I would be using 80% of my capacity if I am understanding this correctly. If Chris is correct (as stated below) than I think I'm straight on things.

You would be using 20% of the battery capacity - Chris is an old hand at this - he knows what to do and he does it what is required. For the other 99% of the population it is very aggressive and you will most likely make a mess of it.

[ChrisOlson]

That looks a lot like you switched from DOD to SOC in midstream.

Yes, I certainly did. What I meant to say is that discharging to 60-75% SOC is perfectly OK as long as you discharge deeper once in awhile. Dammit. Thanks for correcting that.

I was impressed with those L16P-AC's. After I got those 8 brought back to life for the neighbor I threw the breakers off on my battery combiner and ran our system just on those 8 batteries for one day so I could measure their amp-hour capacity with my battery monitor. Holy crap, did they hang tough on discharge and hold the voltage up under load even at 50%! And they're more efficient than the Surrettes on absorb charging, and they can be absorbed at lower voltage than the Surrettes require. The neighbor said he got them $275 apiece. I gave them a big thumbs up after I ran them on a full cycle as healthy batteries. If I needed batteries I'd drop the cash on them in the blink of an eye instead of what we got.

[ChrisOlson]

I just moved to Belize and sourcing typical things that I took for granted in the states has proven to be difficult, this is a 3rd world country after all. I ordered a hydrometer on Amazon, and I have a friend bringing it to me next month...that explains the delay I mentioned. However, there is a pretty well equipped auto parts store I recently discovered, and I have not looked for a hydrometer there, so I will go check. Thanks for the suggestion.

OMG - we were down there last winter. It was our favorite spot in the whole Caribbean. If you go to the service dept at the marina on Ambergris Caye they got a hydrometer there. Of course, if somebody wandered in off the street, not a yacht owner, and asked them to use their hydrometer you'd probably get a few weird looks.

[paulcheung]

I just moved to Belize and sourcing typical things that I took for granted in the states has proven to be difficult, this is a 3rd world country after all. I ordered a hydrometer on Amazon, and I have a friend bringing it to me next month...that explains the delay I mentioned. However, there is a pretty well equipped auto parts store I recently discovered, and I have not looked for a hydrometer there, so I will go check. Thanks for the suggestion.

If you can't find the hydrometer in the auto part shop. It should be able to find it on the auto battery dealers. As third world like Jamaica, they have them in the battery shop.

Cheers

[paulcheung]

80% DoD is safe. You won't hurt them at all. 50% DoD is ideal to get the best return for your dollar on those particular batteries. 60-75% on a regular basis won't hurt anything as long as you deep discharge them once a month or so. 20% is too shallow. They'll die a young death at 20% DoD because they are high SG electrolyte batteries and you'll sulfate the bottoms of the grids if you don't work them hard enough and keep them turned over and stirred up.

That is the same concepts like the generator, I bought a 40KVA three phase generator about 20 years back, it come with a letter with bold writing on it said I should make sure it will run it at least 75 % capacity load once a month or it will get lazy and not function properly. I have to modify an electrical water heater with double size element and connected to a 600 gallon water tank to make sure it run one hour at 75% load monthly.

[ChrisOlson]

@miahallen,

Not really pertaining to your battery problem, but just curious. You got a new Mate3 out of the deal and wondered if you have it set up to upload to Outback's OPTICSre "cloud" server? The two folks up here that got them won't do it because they don't trust it. I've been waiting to hear some feedback from somebody that is using that to see how it works. This is a little video clip on it that Outback Power has put out:

IF it works (which is doubtful with Outback's record on implementing this stuff), in theory you should be able to call Outback Tech Support and have a technician in Arlington log into your system and check configurations, and configure it for you if necessary. Schneider Electric is doing this with their ComBox all the time now, but the ComBox is standalone and does not require a "cloud" server, so it can be remotely accessed over secure VPN. Outback is basically playing catchup because Schneider and MidNite Solar are pretty much kicking their ass on remote monitoring and configuration of systems. I'd love to play with one of the Outback systems connected to OPTICSre and see "what it's got under the hood".

[ChrisOlson]

That is the same concepts like the generator, I bought a 40KVA three phase generator about 20 years back, it come with a letter with bold writing on it said I should make sure it will run it at least 75 % capacity load once a month or it will get lazy and not function properly. I have to modify an electrical water heater with double size element and connected to a 600 gallon water tank to make sure it run one hour at 75% load monthly.

<grin> Yep - seen too many people buy diesels and baby them, and they end up with plugged injector tips and stuck top piston rings because they didn't put enough load on 'em.

[Sunking]

Chris I was beginning to wonder and worry you took up drugs or drinking.