Equalization

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Davidwfong
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Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Equalization

Post by Davidwfong »

Good day,
System, FM80, 4 x 275w panels (2 sets of 2 in parallel) 4 x Rolls S6 L16 HC batteries ( set up as 12v 890ah) new in March 2020.

My first need for and attempt to equalize the batteries ( full sun) did not produce specific gravity levels within manufactures range after 4 hours. Variation between cells .03 with 4 of 12 cells below 1.260 others between 1.260 and 1.270.

Eq voltage set at 15.6 and process started with batteries on floating. Current started 25amps but after 4 minutes had decreased to 10 amps.
and stayed less than 10 amps.

Is the eq process working correctly , should output amps be so low on eq charge, manufacture recommended much higher amps?

Any suggestions???
Thank you
raysun
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My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
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Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Equalization

Post by raysun »

EQ is a constant voltage charging phase, and will vary current to maintain the voltage setpoint. Typically, the current is fairly low, as the battery should be fully charged before EQ, and the cells below full charge are the only ones accepting appreciable current.

EQ can take a very long time, in some conditions, 24 hours or more. EQ on solar is problematic, unless the EQ time is short, and the solar exposure long.

I assume the EQ voltage set is in accordance with the battery manufacturers specifications. If so, then EQ needs to run until the sub-optimal cells reach full-charge specific gravity.

*EDIT*
Rolls recommends 15.8V for EQ.
Measure the actual voltage at the battery terminals to confirm the chargers are achieving that voltage. If not, they may need calibrating.

Rolls recommends 2.5H EQ time, checking water levels half way through.
I suspect 2.5H is the target for a "normal, healthy" battery. One that has spent a good deal of time not fully charged, or hasn't received regular EQ charging, may take a good deal longer for the cells to achieve full-charge SG.

It might be useful to give Rolls a call and describe the situation.
provo
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My RE system: Sixteen Evergreen EC-120
(4 strings, total 1920W)
Eight Rolls S-550 (2 strings, total ~800Ah @ 24V)
One FM80
One VFXR3524A
Hub 10
Mate3s
FNDC and Trimetric
Honda EU3000is generator
Location: Sierra foothills

Re: Equalization

Post by provo »

raysun wrote: Wed Nov 18, 2020 9:54 am
Typically, the current is fairly low, as the battery should be fully charged before EQ
Were your batteries fully charged before you attempted an EQ? How have you been doing your absorb stages (voltage and time), and how many times have they been through a full charge cycle (bulk, absorb, and float?) How far are you discharging them before charging again?

A 12V pack at 890Ah would like around 1100W of charging power. That will always be a challenge for an 1100W nominal array. I would think a generator would be needed to run an EQ.
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Thank you very much!

Batteries were fully charged at float stage before equalization attempt. Rolls manual recommends equalization voltage at 15.6-15.9 and starting at lower end.

Batteries installed new 275 days ago, used on approx 240 days and not used at all intermittently for 1-5 days at a time for a total of 35 no use days,
monthly specific gravity checks did not indicate a specific gravity level below 1.262 or a variation between high and low cells of .03 ( Rolls recommends equalization when variation between cells reaches .025-.030) until now. Now for the first time 2 cells are at 1.240 and 1 at 1.250 ( in different batteries) while the others are 1.262 -1.272 at float stage at 5 degrees C.

Bulk and absorb volts set at 15.0 and float at 13.5 ( as per Rolls) and are temp compensated. Absorb time is 4.7h and end amps 17.

Daily DOD is mostly around 6-10% occasionally 12-15% at night time

Recharging is every day or 2 as only 1-2 hours of sun is required to go to float stage, if there are three days without sun I will stop using batteries and run generator until there is Sun and it recharges to float stage before using again.

Looking at the log, by far most days absorb cycle is on for well less than an hour with amp hours usually less than 100.

If the low current I observed while equalizing is ok and a longer equalization time is required, is it ok to continue to equalize whenever sun is available say over a period of 2-3 days while not using the batteries during this time? I would continue to monitor the specific gravity of low cells and water levels during this time.

Thank you
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Would it be better to equalize each string of 2 batteries separately?
raysun
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Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Equalization

Post by raysun »

Davidwfong wrote: Wed Nov 18, 2020 2:22 pm Would it be better to equalize each string of 2 batteries separately?
Not necessarily. The chemical reaction is driven by the over voltage, and unless there are problems with the interconnect cables, all monoblocks (and the cells they contain) should see the proper amount.

IME, batteries, especially high capacity batteries, that are lightly used and subsequently lightly charged, suffer from "lack of exercise". Since charging is the opportunity to stir up the electrolyte to prevent stratification, and to provide enough chemical reaction force to reverse sulfation, it might be beneficial to set the charging parameters nearer the upper limits than the lower limits.
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Thank you for your suggestion.. will do

I was focused on extending battery life via low DOD as per manufactures data graph in DOD vs number of cycles.

Given your comment on light use and light charging being a negative lack of exercise

And given that my Outback starts charging in bulk at low amps early in morning and reaches float well before mid morning

Would it be better for my batteries to either or both of

1. To wait until closer to midday and full sun to start charging thereby charging consistently at higher amps?

2. Use my batteries for a 2-3 nights (deeper DOD) and then charge in full midday sun?

Thank you for your patients with a newbie!
raysun
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Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Equalization

Post by raysun »

Davidwfong wrote: Wed Nov 18, 2020 4:45 pm Thank you for your suggestion.. will do

I was focused on extending battery life via low DOD as per manufactures data graph in DOD vs number of cycles.

Given your comment on light use and light charging being a negative lack of exercise

And given that my Outback starts charging in bulk at low amps early in morning and reaches float well before mid morning

Would it be better for my batteries to either or both of

1. To wait until closer to midday and full sun to start charging thereby charging consistently at higher amps?

2. Use my batteries for a 2-3 nights (deeper DOD) and then charge in full midday sun?

Thank you for your patients with a newbie!
Having an abundance of resources is a good problem to have. I wouldn't try for any extraordinary charging cycles. Most of we off-grid folks are fairly attuned to a daily charging cycle, the solar charge controllers expect and support it, so best to let the system "do its thing".

If, during the normal course of charging, the electrolyte is bubbling at a fairly good rate, the electrolyte is getting stirred up, and the chemical reactions are occurring. Keeping an eye on SG variance in the cells is the best thing to do for long term health. A periodic Equalization charge should get cells back in line, as needed.

Folks who faithfully attend to that routine regularly report very long battery life. Its not unusual for 12-15 year service life on well maintained batteries.

There will be an inevitable loss of capacity over time, but that big battery and light use will scarcely notice.

Your profile doesn't mention an inverter, and the electrical system could well be all 12V DC (a real "old school" throwback), but I assume 120V AC is being used via an inverter. What wattage/model is in the system?
provo
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My RE system: Sixteen Evergreen EC-120
(4 strings, total 1920W)
Eight Rolls S-550 (2 strings, total ~800Ah @ 24V)
One FM80
One VFXR3524A
Hub 10
Mate3s
FNDC and Trimetric
Honda EU3000is generator
Location: Sierra foothills

Re: Equalization

Post by provo »

How do you keep your batteries charged in cloudy weather? Assuming you have a generator for those periods of low sun for several days, there's no reason not to use the generator for EQ's, as rarely as they're needed. With your small(ish) array for your battery size, you may be undercharging seasonally unless you use a generator to assist.

Do you have a battery monitor of any type to keep track of amp-hours in and out of your battery and state-of-charge (SOC)?
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Thank you
Would you please recommend a battery monitor?
raysun
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Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Equalization

Post by raysun »

Davidwfong wrote: Fri Nov 27, 2020 10:41 am Thank you
Would you please recommend a battery monitor?
A good quality, relatively inexpensive battery monitor is the Victron BMV7xx series. All have the same measuring precision and functions. The BMV700 is the basic monitor. The BMV712 adds Bluetooth connectivity which enables access by the Victron connect smartphone app, which has a rich interface, historical (trend) reporting, and remote configuration.

For a rock-bottom price in a battery monitor, there are several Victron Chinese clones on Amazon or eBay for as little as $20. The quality will vary, so caveat emptor.
Last edited by raysun on Fri Nov 27, 2020 10:56 am, edited 1 time in total.
provo
Forum Czar
Posts: 630
Joined: Thu Jul 27, 2006 4:34 pm
My RE system: Sixteen Evergreen EC-120
(4 strings, total 1920W)
Eight Rolls S-550 (2 strings, total ~800Ah @ 24V)
One FM80
One VFXR3524A
Hub 10
Mate3s
FNDC and Trimetric
Honda EU3000is generator
Location: Sierra foothills

Re: Equalization

Post by provo »

Davidwfong wrote: Fri Nov 27, 2020 10:41 am
Would you please recommend a battery monitor?
Like Raysun says above, you don't mention an inverter. In fact, it would be great if you would flesh out your profile -- use Raysun's and my profiles as examples of the level of detail.

If the only piece of Outback you have is a single FM80, the Outback FlexNet DC battery monitor might be overkill. Victron makes a decent one in that case.

If you had an Outback inverter, and maybe an Outback Mate3s also, the Flexnet DC would round out your system nicely :grin: !
raysun
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My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Equalization

Post by raysun »

provo wrote: Fri Nov 27, 2020 10:55 am
Davidwfong wrote: Fri Nov 27, 2020 10:41 am
Would you please recommend a battery monitor?
Like Raysun says above, you don't mention an inverter. In fact, it would be great if you would flesh out your profile -- use Raysun's and my profiles as examples of the level of detail.

If the only piece of Outback you have is a single FM80, the Outback FlexNet DC battery monitor might be overkill. Victron makes a decent one in that case.

If you had an Outback inverter, and maybe an Outback Mate3s also, the Flexnet DC would round out your system nicely :grin: !
I second this advice. A more complete profile helps us help you.

The Outback Flexnet DC is most effective in an all Outback system.
SandyP
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Re: Equalization

Post by SandyP »

raysun wrote: Fri Nov 27, 2020 10:54 am A good quality, relatively inexpensive battery monitor is the Victron BMV7xx series. All have the same measuring precision and functions. The BMV700 is the basic monitor. The BMV712 adds Bluetooth connectivity which enables access by the Victron connect smartphone app, which has a rich interface, historical (trend) reporting, and remote configuration.

For a rock-bottom price in a battery monitor, there are several Victron Chinese clones on Amazon or eBay for as little as $20. The quality will vary, so caveat emptor.
With an additional cable and a computer you can also log the data with the Victron BMV
bmv.jpg
-------------------------
http://spwebcam.myddns.me/
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Again- thank you so very much people, is so comforting to get such excellent, expert and independent advice!
I have added a little more info to my profile.

I have been building a system without enough knowledge under changing conditions ie. part time cabin to full time use.

I decided to splurge on 2K$ batteries (bought 4 instead of 2 to get longer life and just in case my load increased in the future)

Now told I l need more panels, another FM80, a Magnum inverter/charger and controller so proper voltages for charging and equalization, 15.9v eq and (15.0v bulk/absorb, 13.5 float at 25 degrees C ) can be programmed and must have battery temperature compensation) and a 5K generator - ie. 8K$ to properly maintain my 2K$ batteries:(

My load usage is low ie. 500-1kwh/day but now have many cloudy days so I understand I need to be able to charge batteries from gen.

I have a couple of questions.

1. Is there a decent programable charger out there that would do the job instead of having to buy my an expensive inverter/charger? As I have 2 inverters now.
I looked but can’t find and at this point I have concluded a Magnum ME 2012 with the ME-RC50 controller is my best (only) solution?

2. With such low usage should I split my battery bank in two and use each half alternately, say monthly?

Any other advice would be most welcome!

Thank you
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Again- thank you so very much people, is so comforting to get such excellent, expert and independent advice!
I have added a little more info to my profile.

I have been building a system without enough knowledge under changing conditions ie. part time cabin to full time use.

I decided to splurge on 2K$ batteries (bought 4 instead of 2 to get longer life and just in case my load increased in the future)

Now told I l need more panels, another FM80, a Magnum inverter/charger and controller so proper voltages for charging and equalization, 15.9v eq and (15.0v bulk/absorb, 13.5 float at 25 degrees C ) can be programmed and must have battery temperature compensation) and a 5K generator - ie. 8K$ to properly maintain my 2K$ batteries:(

My load usage is low ie. .5 -1kwh/day but now have many cloudy days so I understand I need to be able to charge batteries from gen. Especially for eq.

I have a couple of questions.

1. Is there a decent programable charger out there that would do the job instead of having to buy my an expensive inverter/charger? As I have 2 inverters now.
I looked but can’t find and at this point I have concluded a Magnum ME 2012 with the ME-RC50 controller is my best (only) solution?

2. With such low usage should I split my battery bank in two and use each half alternately, say monthly?

Any other advice would be most welcome!

Thank you
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Another question if I may:

I have been monitoring battery specific gravity with a refraction type tool that is supposed to have temp compensation.

Recently I left the tool outside (where my batteries are located) all night - around 0C (32F) and found when I used it in the morning the readings were different ( by .02 units) than if I had stored it indoors at 22C. Should the tool be stored at the same temp as the batteries?
raysun
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Re: Equalization

Post by raysun »

The diffraction hydrometers (refractometers) have a good deal of thermal mass, and will adjust the temperature of the electrolyte sample after about 30 seconds for an accurate reading.

Most refractometers are calibrated to a specific temperature, like 20°C, and if stored at a different temperature may require recalibration before use. A reagent with a SG near the expected sample SG should be used. Do not calibrate to 0 (zero) with distilled water for example.
Davidwfong
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Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Thank you Raysun for info on refractometer

Would you, or anyone have ideas on my other 2 questions in previous post ie

1. Is there a programable charger available suitable to charge my batteries?


2. Because of low discharge levels and subsequent low recharging should I split and alternately use my battery bank?

Thank you
raysun
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My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Equalization

Post by raysun »

Davidwfong wrote: Thu Dec 10, 2020 7:27 am Thank you Raysun for info on refractometer

Would you, or anyone have ideas on my other 2 questions in previous post ie

1. Is there a programable charger available suitable to charge my batteries?

Do you mean an AC charger? Something other than the FM80? What type of inverter is in the system (if any)? Does it have a charger function.

2. Because of low discharge levels and subsequent low recharging should I split and alternately use my battery bank?
What's the average daily discharge in Amp Hours? Is the battery fully recharged daily?

Thank you
Davidwfong
Forum Member
Posts: 11
Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

My average daily discharge is between 50 to 100 amp hours never exceeding 125. It is not recharged ever day but I do not allow battery voltage to go below 12.3 at which point I switch to generator power.

This time of year it is cloudy most days so I have been using a gas generator, and wait for sun to recharge batteries or l use a commercial non- programable battery charger to charge the batteries with my generator occasionally.

I have an inexpensive inverter without a charger which I am happy with.

I have been told I need to buy an expensive Magnum inverter/charger because it is programable and has temperature compensation like my FM80 and therefore I would be able to charge my batteries properly when there is no sun.

Because I do not need another inverter have been looking for a programable stand alone charger that will provide temperature compensation.... without success.

Now I am wondering if I can use my generator with either a commercial grade, simple converter or a battery charger to provide power directly into my FM80 ( therefore not needing a another programable charger) as it would treat this power as if it was coming from the solar array.
I understand that I would need to disconnect my array input and that the power provided must be within the specs for the FM80.

For example would a 24voltdc 50 amp charger work?

In summary, is there a way to provide the FM80 with an alternate power supply ( other than solar) on cloudy days or at nights so it can provide the programming and temperature correction to charge the batteries properly. Also. As the power was coming from a generator I could provide equalization for as long as required.

Thank you again for all you kind support.
raysun
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My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Equalization

Post by raysun »

Davidwfong wrote: Wed Dec 16, 2020 9:35 am My average daily discharge is between 50 to 100 amp hours never exceeding 125. It is not recharged ever day but I do not allow battery voltage to go below 12.3 at which point I switch to generator power.

This time of year it is cloudy most days so I have been using a gas generator, and wait for sun to recharge batteries or l use a commercial non- programable battery charger to charge the batteries with my generator occasionally.

I have an inexpensive inverter without a charger which I am happy with.

I have been told I need to buy an expensive Magnum inverter/charger because it is programable and has temperature compensation like my FM80 and therefore I would be able to charge my batteries properly when there is no sun.

Because I do not need another inverter have been looking for a programable stand alone charger that will provide temperature compensation.... without success.

Now I am wondering if I can use my generator with either a commercial grade, simple converter or a battery charger to provide power directly into my FM80 ( therefore not needing a another programable charger) as it would treat this power as if it was coming from the solar array.
I understand that I would need to disconnect my array input and that the power provided must be within the specs for the FM80.

For example would a 24voltdc 50 amp charger work?

In summary, is there a way to provide the FM80 with an alternate power supply ( other than solar) on cloudy days or at nights so it can provide the programming and temperature correction to charge the batteries properly. Also. As the power was coming from a generator I could provide equalization for as long as required.

Thank you again for all you kind support.
I'm not sure about other AC chargers, but the Noco Genius series has temperature compensation built in. They are fully automatic.

I don't recommend driving the Charge Controller from a power supply. IIRC, OB specifies against doing so, and it likely voids the warranty.
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Re: Equalization

Post by JRHill »

raysun wrote: Wed Nov 18, 2020 2:45 pmIME, batteries, especially high capacity batteries, that are lightly used and subsequently lightly charged, suffer from "lack of exercise". Since charging is the opportunity to stir up the electrolyte to prevent stratification, and to provide enough chemical reaction force to reverse sulfation, it might be beneficial to set the charging parameters nearer the upper limits than the lower limits.
I couldn't agree with the above more enthusiastically. I reached end-of-life early for my first bank because I undercharged them as in too short a bulk cycle. I was afraid of cooking them to death. Not from voltage but in terms of time. Wrong.

My second bank didn't last any longer even after correcting for the absorb time but they did perform better. I am convinced it is because our our usage habits. In the summer I can hit them with as much as the FM80 can put out with <3kw of hot panels. That's the best I can do with my system. But discharge? Rarely do we use much more than 5kWh in a day. My light draw is even worse in the winter and aggravated by only genset recharging at roughly 2.4kW in. No EQ helps with under utilizing a very capable bank of L16 Trojans.

Anyway, in the 10+ years this is my conclusion and this is one main reason I went with the SimpliPhi batteries. They just don't care about light charging and discharging in the same way as lead acid batteries. I'm hoping time will proove me correct this time.
Davidwfong
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Joined: Tue Nov 17, 2020 8:58 am
My RE system: FM80,
4x 275 watt panels
4x Rolls S6 L16 HC (445ah)

Re: Equalization

Post by Davidwfong »

Thanks again
The NOCO people told me their chargers are only suitable for up to 500ah, mine are 890 ah.

Given the problem of light use and light recharging of my 890ah bank. Would it be reasonable to split the bank into 2 banks with 445 ah each and just use one bank for a month or two then alternate with the other bank, so each bank would get deeper discharge and higher recharging?
provo
Forum Czar
Posts: 630
Joined: Thu Jul 27, 2006 4:34 pm
My RE system: Sixteen Evergreen EC-120
(4 strings, total 1920W)
Eight Rolls S-550 (2 strings, total ~800Ah @ 24V)
One FM80
One VFXR3524A
Hub 10
Mate3s
FNDC and Trimetric
Honda EU3000is generator
Location: Sierra foothills

Re: Equalization

Post by provo »

Davidwfong wrote: Mon Jan 04, 2021 4:56 pm
Given the problem of light use and light recharging of my 890ah bank. Would it be reasonable to split the bank into 2 banks with 445 ah each and just use one bank for a month or two then alternate with the other bank, so each bank would get deeper discharge and higher recharging?
Take a look at this thread from a year ago, titled "One String instead of Two"

viewtopic.php?f=17&t=14789&p=69653#p69653

for some reason it opens in the middle of the thread -- scroll up to the start to read it all...
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