Need Help Picking Battery Bank

andyrud · August 2015

Hi guys,
I need some advise! My 6 Trojan 2 volt 1100 amphour batteries are pretty well shot. I am really pi$$ed that they are only just 5 years old and are sulfated. I have to replace them with something soon. The off grid system is powering a weekend cabin 6 miles in on dirt roads. I am thinking about replacing them with lithium ion batteries. I know they are expensive but I can handle the cost. I have read that they don’t have to be as big, amphour wise because they can be discharged deeper than Fl acid batteries. BUT I don’t know enough about them to make an informed decision. This is where you guys come in!
In the summer my system rarely goes below 50 % DOD. In the winter my system rarely goes below 60 % DOD. A rare event would be 75%.
My system is as follows:
6- 24 volt panels that equal about 1500 watts.
Midnight solar controller
Trimetric Battery Monitor
Magnasine 2812 invertor- 2800watts- 12 volts
Given the previous information, what would you guys do? Also, any recommendations on what lithium ion manufacturer to use?
Thanks in advance,
Andy R

Vic · August 2015

Hi Andy,

Have nothing to offer, regarding Li batteries.

In general Trojan RE batteries like a fairly high Absorb voltage. What have you been using for Vabs?

Have you tried EQing your Trojan batteries? Perhaps, really, have you tried EQing the snot out of them? If you are ready to toss them, you have nothing to lose, but some time ...

FWIW, Vic

inetdog · August 2015

Lithium might be well suited to a weekend cabin, since you could draw the batteries down fairly low without worrying about damage and then recharge them as slowly as you want as long as it is before the next weekend.
They have the advantage that they tolerate Partial State Of Charge (PSOC) operation quite well and do not have the suflation risk that is part of the lead-acid chemistry.
if you go this way, be sure not to charge the Li batteries above 80% on a routine basis, as that increases their degradation just sitting there.

andyrud · August 2015

inetdog wrote: »

Lithium might be well suited to a weekend cabin, since you could draw the batteries down fairly low without worrying about damage and then recharge them as slowly as you want as long as it is before the next weekend.
They have the advantage that they tolerate Partial State Of Charge (PSOC) operation quite well and do not have the suflation risk that is part of the lead-acid chemistry.
if you go this way, be sure not to charge the Li batteries above 80% on a routine basis, as that increases their degradation just sitting there.

Are you saying that they will last much longer if you only charge them to 80 percent capacity? Never read that anywhere, thanks for that!

andyrud · August 2015

Vic wrote: »

Hi Andy,

Have nothing to offer, regarding Li batteries.

In general Trojan RE batteries like a fairly high Absorb voltage. What have you been using for Vabs?

Have you tried EQing your Trojan batteries? Perhaps, really, have you tried EQing the snot out of them? If you are ready to toss them, you have nothing to lose, but some time ...

FWIW, Vic

I just did EQ them for an hour and a half and it helped a little. Next time I go to the cabin I will EQ them for 2 or 3 hours.

Photowhit · August 2015

Are you measuring the Specific Gravity when equalizing?

andyrud · August 2015

Photowhit wrote: »

Are you measuring the Specific Gravity when equalizing?

No I did not.

BB. · August 2015

If you do not have one, get a good hydrometer, log each cell's reading, and rinse it out with a couple shots of distilled water after you are done using it for the day.

-Bill

PNjunction · August 2015

andyrud wrote: »

I have read that they dont have to be as big, amphour wise because they can be discharged deeper than Fl acid batteries. BUT I dont know enough about them to make an informed decision. This is where you guys come in!

Basically what I'd say is if you are interested in lifepo4, do NOT make a wholesale swapout until you get some experience behind you. Start with something small, like a simple 4-cell / 12v system so you can read, watch and learn to decide if you REALLY need lithium (lifepo4 in this case).

The reason I say this is that we all recommend "learner batteries" to those just starting out. In your case switching chemistries like this is starting out all over again to a point, since there is a different mindset than there is with lead. PSOC operations is just one of them.

In a way, saying this is akin to me not recommending a beginning user start out with 6 Trojan 2 volt 1100 amphour batteries ! Instead, a learner battery is used to learn the ropes beforehand.

If you are good at flooded lead-acid maintenance, then *maybe* you might want to consider trying your hand at high-quality pure-lead AGM instead. There are techniques to get the most out of them - and unfortunately most agm users are too conservative and UNDERcharge them on a regular basis. Nearly half or less the IR of flooded. Meaning faster charge. Conventional agm's (not pure lead) have about twice the charge current capability of flooded, and for pure lead, much higher than conventional. Handy for gennies and areas of poor solar-insolation.

That being said, the major lifepo4 players are GBS, Winston, and CALB. GBS is convenient for the new user just from a safety standpoint of providing 2-cent pieces of plastic for terminal covers, where the others have you make up your own covering sheets.

Anyway, as much as I like Lifepo4, I am not a cheerleader. There are other options you may want to consider, especially if you are already skilled at lead-acid maintenance.

Dave Angelini · August 2015

You probably would damage any battery so pick the cheapest. Did not have a hydrometer and cycled too deeply. 5 years was pretty good.

Vic · August 2015

andyrud wrote: »

I just did EQ them for an hour and a half and it helped a little. Next time I go to the cabin I will EQ them for 2 or 3 hours.

Hi Andy,

OK, since this EQ did something positive for your battery bank, try EQing more.

QUESTIONS:
What is your Absorption voltage setting?
Are you using a Remote Temp Sensor on all of your charge sources?
How often are you MEASURING your SGs with your Hydrometer?
How often are you EQing, and how is that you decide when it is time to EQ?
What is your EQ voltage, and it the EQ voltage temp compensated?
What is your Absorb time, or Ending Amps?
How is it that you are determining the DOD percentages stated in the first post in this Thread?

Some of these questions have been asked before ...

Again, before abandoning your present battery bank, let's try to see if you can improve things with the current bank.

Thanks, Vic

BB. · August 2015

I agree the above posters--Since you sort of have a working system... Measure/study/get best practices going on this bank.

Once you understand everything that you can adjust/change and have the bank charging/operating the best it can--You can always choose to replace it in the near (or farther) future.

It is also possible that you only have one bad/weak cell--You might replace the one and get some more years on the rest of the bank. Checking voltage across each cell (charging/discharging/resting) and specific gravity (log readings)--This will help you see what is happening. At this point, everyone is just guessing

With a series bank--The bank's overall performance is pretty much limited by its weakest link.

-Bill

softdown · August 2015

De-sulfators have a lot of fans and a lot of non-fans. So far, they let me get six instead of five years out of my car batteries. Might be worth trying. It can take a couple weeks to properly do the procedure....though it is very easy to do.

andyrud · August 2015

Vic wrote: »

Hi Andy,

OK, since this EQ did something positive for your battery bank, try EQing more.

QUESTIONS:
What is your Absorption voltage setting?
Are you using a Remote Temp Sensor on all of your charge sources?
How often are you MEASURING your SGs with your Hydrometer?
How often are you EQing, and how is that you decide when it is time to EQ?
What is your EQ voltage, and it the EQ voltage temp compensated?
What is your Absorb time, or Ending Amps?
How is it that you are determining the DOD percentages stated in the first post in this Thread?

Some of these questions have been asked before ...

Again, before abandoning your present battery bank, let's try to see if you can improve things with the current bank.

Thanks, Vic

Hi Vic and thanks for the reply. I don't have most of the info you requested here at home. Remote Temp sensor, yes I use one. I don't usually measure specific gravity, Usually just let the system work. I have a hydrometer and use it sometimes but rarely. I almost never EQ because the Trojan manual said they do not recommend EQ unless there is a problem, now there is a problem. EQ voltage is set to 15.5 volts. That is what the original manual said to set it at. BUT in the new manual I read on line it says EQ at 16.2 volts. ABsorb time is set at minimun 2 hours, maximum 5 hours, I don't recall what the absorb voltage is set at. DOD is determined by reading the readout of my Trimetric Battery Monitor that uses a shunt.

Andy R

Mountain Don · August 2015

andyrud wrote: »

I almost never EQ because the Trojan manual said they do not recommend EQ unless there is a problem

Specifically Trojan states, "Trojan only recommends equalizing when low or wide ranging specific gravity (+/- .015) are detected after fully charging a battery. " That's why we recommend owning and using a good hydrometer.

Photowhit · August 2015

andyrud wrote: »

I almost never EQ because the Trojan manual said they do not recommend EQ unless there is a problem, now there is a problem. EQ voltage is set to 15.5 volts. That is what the original manual said to set it at. BUT in the new manual I read on line it says EQ at 16.2 volts.

Yeah, well Trojan is also stating the Equalizing will extend the life of your battery, and claims, in this recent video, that they recommend equalizing every 30 days!

https://www.youtube.com/watch?v=jCl5klSF4tE

softdown · August 2015

I thought the more advanced/expensive charge controllers had a default setting of equalizing batteries every month. That is what I heard of the Outback FM80 anyway.

Outback equipment is pretty well vaunted. But I have to say that their manuals do not seem user friendly. I need a bolt of courage to try to change the settings on my MATE. Even then, I find it generally confusing.

I was not able to find a setting for equalizing. Apparently they call it something else. Sorry to, sort of, change the subject.

EDIT: Well...unable to get it to permanently accept a YES to an equalization mode. Pressed the YES button a dozen different times. Says I have to be in AC in mode? I find programming this thing to be, at best, extremely confusing.

So.....the default setting is NOT for an equalization mode. And it does not want to let me set an equalization mode.

My equipment came with five manuals. This has not helped at all.

Vic · August 2015

andyrud wrote: »

Hi Vic and thanks for the reply. I don't have most of the info you requested here at home. Remote Temp sensor, yes I use one. I don't usually measure specific gravity, Usually just let the system work. I have a hydrometer and use it sometimes but rarely. I almost never EQ because the Trojan manual said they do not recommend EQ unless there is a problem, now there is a problem. EQ voltage is set to 15.5 volts. That is what the original manual said to set it at. BUT in the new manual I read on line it says EQ at 16.2 volts. ABsorb time is set at minimun 2 hours, maximum 5 hours, I don't recall what the absorb voltage is set at. DOD is determined by reading the readout of my Trimetric Battery Monitor that uses a shunt.

Andy R

Hi Andy, Thanks for the detailed reply.

First, if your Classic shows Absorb Min and Max times, it is really time to Update the Firmware, as these attributes date back a number of years, and the Classic performance has been enhanced, in steps with FW updates.

Did Trojan note the Target SG for THE batteries that you are using? Trojan did increase the electrolyte SG, three-or-so years ago, for RE batteries, to 1.277, but the target for your batteries may be a bit lower. Would expect that an increase in battery electrolyte SG would increase the speced EQ voltage a bit. This may be the reason for a slightly higher EQ voltage in recent User Guides, vs older ones ... My guess is, that 15.5 V is a bit on the low side for EQ, if the fill SG in Andy's batteries is 1.277.

One huge advantage in using Flooded batteries, is the ability to actually MEASURE the SG (and therefore the sufficiency of Charge parameters). Using a Hydrometer is quick, easy, and yields accurate results when done correctly.

Batteries that are fully charged regularly and EQed when needed really are not plagued by heavy Sulfation.

Believe that you may well be able to recover your batteries, with some additional EQing, perhaps, HEAVY EQing. You will want to watch that the batteries do not get too warm/hot, and stop any EQ with the nominal battery temperature is abouve about 110 F.

IMO, the EQ voltage should be Temperature Compensated -- it is far better if the Classic does this automatically, vs needing to do this manually as a long EQ progresses.

It is just my opinion, but, Battery Monitors, in general, are ONLY a rough approximation of what IS the actual SOC (or DOD) of a battery. The Hydrometer is THE real gauge of SOC, and sufficiency of the battery Charge parameters set in the chargers.

The Classic has a useful accessory available -- the WhizBang Jr -- that allows termination of the Absorb stage, based upon the actual charge current going into the battery. The WBjr, with an appropriate Shunt can be a great benefit in regularly fully-charging your batteries:
http://www.solar-electric.com/invert...se-module.html

Here is a good Shunt:
http://www.solar-electric.com/batter...lar-shunt.html

Please check your Absorption voltage setting (Vabs), it should be temperature compensated at --5mV/C per cell. Try using a value in the middle of the Trojan-recommended range, or even higher, until you get on top of more full Capacity for the batteries.

FWIW, Good Luck, Thanks, VIc

Photowhit · August 2015

softdown wrote: »

I thought the more advanced/expensive charge controllers had a default setting of equalizing batteries every month.

Almost all charge controllers have monthly equalizing option built in, Simple 20 year old charge controllers did! Trace C60 and Pulse P250 did...

I always seperate equalizing into 2 catagories, A maintenance equalize, monthly usually mixes the electrolyte preventing stratification and 'cleans' sulfation from the plates. Then corrective equalizing, when batteries have become unbalanced, one or more cell is considerably different from the others, usually from becoming sulfated. This requires monitoring of the cells specific gravity and measuring every hour until there is no increase over a 2 hour period. This can take quite a while, and from the array may be over a couple days. I think someone with a Rolls bank did this over 4 days! I would worry about other issues if it was that prolonged.

softdown · August 2015

Thanks...that is what I thought. Yet...when I found the Equalization mode, it was set to NO. I pressed the YES button a dozen different times...including prolonged pressing. It would not recognize my attempts to make it Equalize automatically. Thought this was strange. It kept saying it could only be done with "AC in." I may surmise that this is a different setting than the main one. A setting for equalizing via a genset?

Again...I usually get perfect scores on reading comprehension. Yet I find their User Manuals to be quite user Unfriendly. Having five different manuals is a constant source of consternation. Kind of like having five different calculus textbooks....

Adding to the slight frustration, I badly need to get many things done before winter. Last winter, the average temp inside was 45 F. Interesting but one year of camping was enough.

Photowhit wrote: »

Almost all charge controllers have monthly equalizing option built in, Simple 20 year old charge controllers did! Trace C60 and Pulse P250 did...

I always seperate equalizing into 2 catagories, A maintenance equalize, monthly usually mixes the electrolyte preventing stratification and 'cleans' sulfation from the plates. Then corrective equalizing, when batteries have become unbalanced, one or more cell is considerably different from the others, usually from becoming sulfated. This requires monitoring of the cells specific gravity and measuring every hour until there is no increase over a 2 hour period. This can take quite a while, and from the array may be over a couple days. I think someone with a Rolls bank did this over 4 days! I would worry about other issues if it was that prolonged.

Vic · August 2015

softdown wrote: »

Thanks...that is what I thought. Yet...when I found the Equalization mode, it was set to NO. I pressed the YES button a dozen different times...including prolonged pressing. It would not recognize my attempts to make it Equalize automatically. Thought this was strange. It kept saying it could only be done with "AC in." I may surmise that this is a different setting than the main one. A setting for equalizing via a genset?

Again...I usually get perfect scores on reading comprehension. Yet I find their User Manuals to be quite user Unfriendly. Having five different manuals is a constant source of consternation. Kind of like having five different calculus textbooks....

sd,

This EQ setting in the Mate, must be for the Inverter/Charger.

You should be able to do an EQ from your FM CC. The Charge or Charger Menu on the CC should allow you to set the EQ voltage. The EQ Time should be in an Advanced Menu, or similar, and perhaps a different menu to initiate the EQ.

Your batteries should be fully-charged before starting an EQ.

Look in the manual for your CC for instructions on EQing ... these are straightforward. I have not used any FM CCs, yet.

Vic

Mountain Don · August 2015

My memory could very well be wrong, but I thought the Mate could only be used to start an EQ using the connected FX inverter/charger and incoming AC like from a generator. To start an EQ using the PV and FM charge controller you had to start using the controls on the FM. ??? I'd have to check my old manuals on the FM as it has been a while since I have had one.

Dave Angelini · August 2015

Mountain Don wrote: »

My memory could very well be wrong, but I thought the Mate could only be used to start an EQ using the connected FX inverter/charger and incoming AC like from a generator. To start an EQ using the PV and FM charge controller you had to start using the controls on the FM. ??? I'd have to check my old manuals on the FM as it has been a while since I have had one.

The FM controllers can all run EQ by themselves. They do not make it simple to keep the uninformed out. To me it is like someone who wants program an EQ. It can be dangerous to do this unattended .I can see programming a reminder but with 2 insurance visits to structure fires on another persons installation, I just do not like unattended generator or EQ's
How busy is your life to take the risk?

BB. · August 2015

Not to put any words into Dave's mouth...

My understanding is--Remember that EQ is "controlled" over charging of your Lead Acid Battery bank. If you have a shorted or open cell, or low electrolyte levels (exposed plates), etc... This controlled over charging can overheat batteries (or cells) and/or if low electrolyte levels/hot batteries (weather, other issues)--Such "automatic" EQ cycles can cause a battery bank to catch fire (in rare/worst case situations).

Since, at the very least, you need to inspect and maintain the battery bank at least once per month--Do your inspection/maintenance first (battery/cell voltage logging, specific gravity logging, refiling with distilled water as needed, checking for cells that are over/under bubbling, etc.)--Then manually equalize--Monitoring voltages/temperatures/specific gravity of "low cells"/etc. for the next 1-3 hours or so (as needed).

That way, if problems develop, you will catch them/fix them before something really bad happens.

Automatic EQ will work--Until it does not.

At least--That is my non-expert opinion on what "basic" battery bank maintenance/equalization would look like.

-Bill

softdown · August 2015

I see...thanks so much guys. This makes perfect sense. I thought off grid solar only had 101 challenges. Turns out to have 102.

Mountain Don · August 2015

Dave Angelini wrote: »

The FM controllers can all run EQ by themselves.

Thanks for clearing that up. I almost never run EQ through the charge controller. My reason is that, for better or for worse, I have a gasoline fueled generator. It needs exercise every so often. So, I almost always use it for doing an EQ via the (VFX3524M) inverter/charger. I seldom need the generator for actual charging. I suppose I could simplify my life by selling it.

Dave Angelini · August 2015

Mountain Don wrote: »

Thanks for clearing that up. I almost never run EQ through the charge controller. My reason is that, for better or for worse, I have a gasoline fueled generator. It needs exercise every so often. So, I almost always use it for doing an EQ via the (VFX3524M) inverter/charger. I seldom need the generator for actual charging. I suppose I could simplify my life by selling it.

You are welcome Don. Personally I would use the generator for something else. I think it is far better on the battery to use DC from the charge controller for EQ. Use the beast to run some Christmas lights or a pump.
Challenge # 103 in Colorado is to not add water before an EQ. It can make a mess and if you want your battery installation look almost new 10 years later, take care of your battery as a valued part of your home.

Photowhit · August 2015

Just for another opinion, I know those old charge controllers had equalizing settings because I used them in my 17 years of having system 15 or so now running my home, I haven't seen the need or worried about the charge controller doing a monthly equalizing. This does NOT exempt you from checking the battery fluid levels and SG monthly, or more often in heavy use of for forklift batteries. The maintenance equalizing is NOT the same as a corrective equalizing which may take many hours, it is usually 1 or 2 hours of slight over charging. I feel I have had very good service life from my batteries. I have had no fear about my batteries catching fire or exploding, I feel that is not a very realistic situation for a reasonable well maintained system. even a system venting huge amounts of hydrogen would need a catalyst for an explosion...

added; In modern charge controllers a temperature sensor will turn off the equalizing if the battery become to warm/hot, making this even safer.

Dave Angelini · August 2015

Photowhit wrote: »

Just for another opinion, I know those old charge controllers had equalizing settings because I used them in my 17 years of having system 15 or so now running my home, I haven't seen the need or worried about the charge controller doing a monthly equalizing. This does NOT exempt you from checking the battery fluid levels and SG monthly, or more often in heavy use of for forklift batteries. The maintenance equalizing is NOT the same as a corrective equalizing which may take many hours, it is usually 1 or 2 hours of slight over charging. I feel I have had very good service life from my batteries. I have had no fear about my batteries catching fire or exploding, I feel that is not a very realistic situation for a reasonable well maintained system. even a system venting huge amounts of hydrogen would need a catalyst for an explosion...

added; In modern charge controllers a temperature sensor will turn off the equalizing if the battery become to warm/hot, making this even safer.

If the temp sensor is not working the charger will default to internal and not sense battery temperature. That was the case in the fire the insurance company sent me to. It was an Outback FM that the sticky taped on sensor fell off the side of the battery. I really like doing failure analysis but I do not like seeing the damage. There is always a chance of a perfect storm and so some fear is a good thing.

softdown · August 2015

The temp sensor fell off the battery. Should have been lying right next to it then. With other batteries in the area, I might expect the temp sensor to still be in the close area.

Dave Angelini wrote: »

If the temp sensor is not working the charger will default to internal and not sense battery temperature. That was the case in the fire the insurance company sent me to. It was an Outback FM that the sticky taped on sensor fell off the side of the battery. I really like doing failure analysis but I do not like seeing the damage. There is always a chance of a perfect storm and so some fear is a good thing.

lkruper · August 2015

Dave Angelini wrote: »

If the temp sensor is not working the charger will default to internal and not sense battery temperature. That was the case in the fire the insurance company sent me to. It was an Outback FM that the sticky taped on sensor fell off the side of the battery. I really like doing failure analysis but I do not like seeing the damage. There is always a chance of a perfect storm and so some fear is a good thing.

Is a fire more likely when a charger is trying to compensate with a probe that is not measuring the temperature properly than a charger that does not have a probe at all?

Need Help Picking Battery Bank

Comments

Categories