BatteryMinder

JRHillJRHill Registered Users Posts: 10 ✭✭
I've been off grid for 10+ years. I've maintained, I've logged, I've been there and done it.

The thorn is batteries. The 1st set (Trojan RE-16's) when I was learning lasted 5 years, and that was stretching the life. The next and current set is a bank of RE16-B's on a 48vdc system. They're are starting to show age.

The difference between the first and current bank is the absorb. I didn't have it right the first time. Now the batteries are performing but not so much this year - they are falling off quickly. Yes, I check SGs/water and log them but its obvious that they are on a downhill slide.

Lest another $2.5k+ hit I looked at the BatteryMinder. I bought two for small 12 vdc stuff and I'm curious about that and collection info. But for a big bank, 48 vdc, I'm curious. Is this snake oil? They have a 48 vdc desulfator for 8 in series. Can anyone confirm it works? These are not golf cart batteries but the big 'uns.

Best,
JR

(for context, we are completely off grid. From Oct through Feb we need a backup genset. It is controlled via the Outback Mate3 and charges at the 2 min < 49.6 battery voltage thru the stages,)

Comments

  • EstragonEstragon Registered Users Posts: 3,834 ✭✭✭✭✭
    I vote snake oil, but sounds like you probably already know there's a trade-off between longer/higher absorb, and risk of sulfation.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • JRHillJRHill Registered Users Posts: 10 ✭✭
    Well, I have an experiment running. I have two identical and age/usage OEM 12v batteries, originally tied parallel, out of the JD410j backhoe receiving the desulfication now, not before. One of the two was failing to hold a charge or deliver starting amps to start the critter and hence the other didn't deliver either. After replacement I have a reasonable field battery and the other one that would normally be returned for core. After replacing them I threw both on separate chargers for a day (no BatterMinder) or so then disconnected and let them sit. A simple voltage check showed one with good voltage and the other well down.

    Since I bought two of the 12vdc Batteryminders I am rotating them around three different batteries on a daily basis (but not over night anymore since the two chargers plus our normal loads really hit the Trojans hard). The 3rd is the same class battery but from the wood mill - with much less service life but a sealed 12v.

    I'll follow up with results. My initial take is that even if the BatteryMinder technology works (to whatever degree) on a stand alone 12vdc batteries, can it really re/condition/improve on a full bank of 8xRE16's? That's a lot of plates for the little box. I talked on the phone with a tech at BatteryMinder and he said "no problem." I am not so much into the response. To me, and I'm not a chemist, this is suspect. I know that as the batteries age the plates break down. That residual either builds up at the bottom of the batteries in whatever form or is reabsorbed into the electrolyte. The elements of electrolyte maybe can be reabsorbed. But the elements of the plates? I don't think so, hence the experiment.

    But here is my other thought: So what if plate sediment is building up? If I can eliminate or minimize the sulfation and the normal break down of the plates happens, can I extend the life span?
  • BB.BB. Super Moderators, Administrators Posts: 29,321 admin
    I have a few Battery Minders that sit on cars that are not driven much... And they seem to do well to keep the car batteries floated, and not using any water.

    I have used "cheap" float controllers (1 amp @ 12 volt), and they gassed the batteries and exposed the plates pretty quickly (within a few months). And one of the float chargers, I connected to a dead battery (so I could start the car and replace the battery), and the next morning, the top of the 'brick' was off the charge controller. The "heavy" 1+ amp current for over night was enough for the device to blow its top (it was still working--Just very hot).

    From the rejuvenator charger discussion, it sounds like even a "good rejuvenator" cannot recover much better than 50% - 70% of old batteries.

    https://www.candlepowerforums.com/vb/showthread.php?384605-Rejuvinator-Lead-Acid-(Gel-Cell-)-on-Kick-starter

    There are many different ways that batteries can fail... Which ones can be resurrected, don't know until you try.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • JRHillJRHill Registered Users Posts: 10 ✭✭
    edited July 23 #5
    One 6/8 amp battery charger that I've had for a bizzion years just went up in smoke. It was connected to the least of the backhoe batteries. They  (BatteryMinder) would probably say that I didn't use "their charger." Nope, I don't buy it.

    Stay away from this unless you have batteries and controllers  to spare.

    But, interestingly, the battery voltages are up. And these have been charged with the same equipment. we'll see how bthey look after a few days resting.

    The reason is this on the big bank: The outback controller is great but the source of a bunch of RF noise. The OB inverter probably as well ( I don't have the eqmt to segregate the noise). All I have to do is get away from any conductors by 25' and I can get a reliable radio signal. But if the BatteryMinder causes a problem with the panel controller or inverter due to unexpected RF then I am suspicious of conditioning the 48v bank.
  • JRHillJRHill Registered Users Posts: 10 ✭✭
    Estragon said:
    .... there's a trade-off between longer/higher absorb, and risk of sulfation.
    This is curious to me. I have occasional deep draws to 65% and regular full charges to 100% per SGs. This is the best I can do to keep the batteries exercised and keep things stirred up. But to get to 100% it takes the absorb cycle and a long one at that: like 4 to 5 hrs. But I've not seen nor can I understand how hitting the batteries with an absorb, a long one or not, leads to more sulfation than other less monitored approaches like a bulk and then to float? I just don't understand this reasoning. And how can you get the batteries charged without the absorb?

    Can you point me to something I can study and digest to get a better understanding of your point?

    Thanks in advance,
    Jim
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,551 ✭✭✭✭✭
    What does "falling off quickly"  mean?  What is your EQ schedule?
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • EstragonEstragon Registered Users Posts: 3,834 ✭✭✭✭✭
    Hitting the bank with a longer and/or higher voltage absorb isn't going to increase sulfation, it's going to prevent it.  IMHO, the trade-off to doing so is water loss and grid corrosion.  Either (sulfation or corrosion) can be life ending for the bank, so the objective is to keep both at bay for as long as possible, hence the balance.  Absorb too little, risk sulfation, too much, corrosion.

    If it's taking a 5hr absorb on a regular basis to get to "full",  I'd have to question the definition of "full".  Is it SG, end-amps, or ?

    Bulk (constant current, voltage rising) stage charging gets you to ~80-85% charged.  Sulfation will harden pretty slowly (weeks-months) at that SOC.  Absorb (current dropping, voltage constant) gets you to near "full".  On a new bank, "full" might be current at Vabs ~1% of C.  On an older bank, "full" might be more like 2%.  My 5yr old L16s generally hit ~1% in <2hrs absorb.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,551 ✭✭✭✭✭
    One problem I have observed over the years with many "people" is they are afraid of doing a good long EQ if it is needed. 
    Sometimes I have tried to help them and it has helped, sometimes, it is too late! Time for new batteries.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • JRHillJRHill Registered Users Posts: 10 ✭✭
    What does "falling off quickly"  mean?  What is your EQ schedule?
    That's a great question. For me, falling off is the bank's inability to hold the SOC over night. My loads are light and fairly consistent but when I see morning lows increasing I have to do something.

    At the last battery swap out I realized that if I bumped the Absorb time+ and the Voltage a little bit - my gosh they performed, And not just when new but into the 3rd year about like new. My adjusted technique was to bump the voltage slightly up and extend the absorb two 2 hrs for a total of 5hrs. Checking SGs it really worked out like mini-EQs. It kept the SGs between cells much better but at the expense of some distilled water. Eh, so what? And I wasn't hitting the batteries with a big hammer per the calendar but only when they needed it which was RARE for the for the first three years. "Hitting" meaning the SG between cells was to far off so needed a heavy, degrading yet hard, extended sync charge.

    So, the answer is I EQ on diversity of SGs between cells and not on a calendar schedule.
  • JRHillJRHill Registered Users Posts: 10 ✭✭
    Estragon said:
    Hitting the bank with a longer and/or higher voltage absorb isn't going to increase sulfation, it's going to prevent it.  IMHO, the trade-off to doing so is water loss and grid corrosion.  Either (sulfation or corrosion) can be life ending for the bank, so the objective is to keep both at bay for as long as possible, hence the balance.  Absorb too little, risk sulfation, too much, corrosion.

    If it's taking a 5hr absorb on a regular basis to get to "full",  I'd have to question the definition of "full".  Is it SG, end-amps, or ?

    Bulk (constant current, voltage rising) stage charging gets you to ~80-85% charged.  Sulfation will harden pretty slowly (weeks-months) at that SOC.  Absorb (current dropping, voltage constant) gets you to near "full".  On a new bank, "full" might be current at Vabs ~1% of C.  On an older bank, "full" might be more like 2%.  My 5yr old L16s generally hit ~1% in <2hrs absorb.
    I don't have day and night systems. That is an interesting approach which sounds good albeit more complex for the wife, etc.. So in my case all the wall warts and trivial loads just get consumed in the inverter overhead. The two deep freezes and the fridge are key, but also are the TV and its satellite modem, internet satellite modem and the few LED lights at night. The freezers and fridge are why I don't let the inverter go to sleep - never.

    {If it's taking a 5hr absorb on a regular basis to get to "full",  I'd have to question the definition of "full"} Full is SG readings. The battery monitor shunts are good for real time but the SGs are the reality.

    {Is it SG, end-amps} I quit doing end amps. I tried to tune this but, I can't recall now, but it screwed up other things. As it is now if the batter voltage gets below 49,6, it fires the generator. bThe end amps didn't seem to give me much at the end of the day after the absorb, if it completed.


  • JRHillJRHill Registered Users Posts: 10 ✭✭
    Estragon said:
    Hitting the bank with a longer and/or higher voltage absorb isn't going to increase sulfation, it's going to prevent it.  IMHO, the trade-off to doing so is water loss and grid corrosion.  Either (sulfation or corrosion) can be life ending for the bank, so the objective is to keep both at bay for as long as possible, hence the balance.  Absorb too little, risk sulfation, too much, corrosion.

    If it's taking a 5hr absorb on a regular basis to get to "full",  I'd have to question the definition of "full".  Is it SG, end-amps, or ?

    Bulk (constant current, voltage rising) stage charging gets you to ~80-85% charged.  Sulfation will harden pretty slowly (weeks-months) at that SOC.  Absorb (current dropping, voltage constant) gets you to near "full".  On a new bank, "full" might be current at Vabs ~1% of C.  On an older bank, "full" might be more like 2%.  My 5yr old L16s generally hit ~1% in <2hrs absorb.
    Hmm, You've got me thinking. I DO have two systems. One is the main and the other is completely separated with its own batteries (48v bank of golf cart Trojans powering the Grundfoss SQF12 well pump). It doesn't run at night and then only for showers. It's batteries are always full even with garden, livestock tanks, etc - but thats always during the day DURING THE SUMMER. The panels supply more than it uses at free flow so, hmm. But its well pit is 40 ft away from the main bank. That's a lot of wire and a heavy transfer switch and another morning chore, and to reverse it. But interesting thought....
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,551 ✭✭✭✭✭
    These bats should get an 8 year life, smart carbon. I have a few clients with them and they are close.
    You are EQ ing at about 65V right? Full is 1.280 right?
    Sounds to me  you are starting a genset too high at 49.6v. Are the batteries really being cycled to 50% ever?
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • JRHillJRHill Registered Users Posts: 10 ✭✭
    These bats should get an 8 year life, smart carbon. I have a few clients with them and they are close.
    You are EQ ing at about 65V right? Full is 1.280 right?
    Sounds to me  you are starting a genset too high at 49.6v. Are the batteries really being cycled to 50% ever?
    I have the EQ set for 64.8 for 2 hours and check the SGs to make sure they are full and extend if necessary. As for the generator start I only rarely see the AGS fire it up in the summer as the panels are sufficient. But in the winter/short sun season it fires daily. I run the batteries down to 50-55% and then give them a full charge monthly.
     
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,551 ✭✭✭✭✭
    49.6V  under a load is more than 55% Soc BTW. Batteries need to be used!  Have you load tested the bank? 

    What makes you think holding Soc overnight is a problem? Batteries discharge with loads. Have your loads increased?  What is your kwh number overnight?

    Not trying to be a pain but trying to understand why 2 banks are "falling off" in 10 years. Seems too short of life.
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • JRHillJRHill Registered Users Posts: 10 ✭✭
    49.6V  under a load is more than 55% Soc BTW. Batteries need to be used!  Have you load tested the bank? 

    What makes you think holding Soc overnight is a problem? Batteries discharge with loads. Have your loads increased?  What is your kwh number overnight?

    Not trying to be a pain but trying to understand why 2 banks are "falling off" in 10 years. Seems too short of life.
    Dave, I appreciate your input, no pain at all.

    When I said falling off I meant that I seem to be in the BEGINNING of a change of performance. Last summer the system rarely dropped below 80% by the AM. This year it falls below 80% regularly but only to 76%, occasional 72%. loads have not changed. This set is definitely holding up better than the first bank. BTW the first bank were RE16-As and the current bank are the Bs.

    To answer the Kwh overnight, the panels lost direct sunlight slightly before 5pm yesterday and the batteries were at 100%. By 7p, all incoming charge was gone and the batteries had dropped to 96% at 51.2v. By morning, 8a, they were at 77% @ 50,2v. Over night I consumed 3.97Kwh. I have a FNDC with shunts so the measured current in and out are close. I reset the FNDC a few weeks back after battery maintenance and EQing so it shouldn't have drifted too far at this point. 

    BTW, related to the BatteryMinder, if anyone is interested: of the two large back hoe batteries is definitely shot. Despite continued charging/conditioning for several days it would quickly drop back 10-11vdc after removing it from the charger/Batteryminder. The second seems yet serviceable so we'll see. Ditto for the garden tractor size battery on my 'ol Kubota B7100. it was suffering greatly and had the charger/BatteryMinder on it for a week and the same for the JD Buck. I read a few reviews from folks that left the BatteryMinder working for weeks and had good results. Obviously they are grid connected and can operate electrical loads in that fashion....
  • EstragonEstragon Registered Users Posts: 3,834 ✭✭✭✭✭
    May not be relevant in your case, but something to keep in mind, is that apparent capacity can be a moving target depending on temperature.

    My bank is cool/cold in late winter, with only ~60% apparent capacity vs rated.  Even now, it's about 90% at ~17°C.  The meter SOC % may or may not account for the temp affect on apparent capacity.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,551 ✭✭✭✭✭
    edited August 11 #18
    JR, sounds pretty logical to me. Even if the temp is not accounted for the battery monitor is a good way to measure AH. Kind of a waste for Soc but another tool in the box.
    You sound like normal to me with 4kwh overnight. I just think you need to occasionally use more, especially during summer to get the battery use to a 50% deep cycle. This is why air conditioning is a great way to cycle a battery during summer. A resistance heater in winter on a large solar array (the large array can charge to full quickly) does the same thing but most of us have no trouble cycling in winter ;)
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

  • JRHillJRHill Registered Users Posts: 10 ✭✭
    Thanks guys. My Outback stuff does have the temp sensor on the bank and I can confirm it is doing its job. Estragon, thx and, BTW, the batts were at 95f at the time measured.

    Dave, in previous times I used various means to deep draw the batteries but your point is are taken. I'll take them deeper. My wife flips out when she sees the red LED. She correlates that to me not doing my job. I'm sure no one else goes through this... 

    Winter. From the end of Oct through mid Feb we have little or no solar due to the canyon sides. Though this time we are on the generator when the batteries draw down.  Auto starts 1 or 2x/day until spring. That's the way it is and nothing to improve on it. So I rely on conditioning batteries in the days with light in the summer. I can't do anything in low light days....

    It would seem that I am not exercising the bank enough. I will correct that. Once per month is not enough and I may not be taking them deep enough.

    Best,
    Jim
  • Dave AngeliniDave Angelini Solar Expert Posts: 4,551 ✭✭✭✭✭
    Mine is from a very German family, you can imagine the mix here. Items go on the list and I cross them off complete or not. :o
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
     http://members.sti.net/offgridsolar/
    E-mail [email protected]

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