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Battery talk (A place to discuss any and all battery technologies where the discussion may not fit into other topic areas) => Lead Acid (Sealed and flooded) => Topic started by: qrper on August 15, 2019, 01:04:29 PM

Title: A tech talk with a US battery guy
Post by: qrper on August 15, 2019, 01:04:29 PM
Gang...

I dropped a un-holy amount of money of these new L16HC US Batteries. I scoured the 'net looking for information on the proper way to charge them. Of course US Battery has some guide lines, but frankly, they don't set well with a solar electric charger.

So, I spent 45 minute on the phone with a battery tech from the factory. The factory guide lines (on their website) for the 3 stage charger isn't quite right for solar.
Here, in a nut shell, is what he told me.

Bulk charge to 2.45 V per cell. For my 48 V nominal battery bank that's 58.8 V
Then hold that voltage (Absorb) until the current drops to 3% of the amp/hr capacity of the battery.
To make this simple I'll only use one of the strings of batteries. So 442 amp/hrs at 3% is a hair over 13 A.

I explained that I can't hold the current steady because it is constantly changing do to clouds, dust, birds, etc, and the controller only allows me to adjust the voltage and time.

He said that I should then hold the absorb voltage at 2.45 V per cell for 2 to 3 hours.

US Battery doesn't recognize a 'float voltage' as a stage. However he said I should set, if possible, a float voltage of 2.1V per cell (52.1V)

A new LC16HC will have a specific gravity of at least 1.270. After the first dozen cycles, that should go to 1.275 to 1.280. Equalize the battery at least once per month to 61.2 V (2.55 V per cell) for at least 1 hour. As the battery ages, the equalization time will need to be extended to as long as 3 hours.

I hope this helps with the US Battery users.

mike
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 15, 2019, 02:14:54 PM
Quote from: qrper on August 15, 2019, 01:04:29 PM
Gang...

   ...   I explained that I can't hold the current steady because it is constantly changing do to clouds, dust, birds, etc, and the controller only allows me to adjust the voltage and time.

He said that I should then hold the absorb voltage at 2.45 V per cell for 2 to 3 hours.

I hope this helps with the US Battery users.
mike

Hi Mike,  Thanks for the US B Solar charging info.

Will add one point,  or so;
The Ending Amps (current)  is controlled by the Acceptance of the battery.   As long as there is sufficient Solar input to maintain the compensated Absorb voltage,  the EA value is primarily due to battery Acceptance (there will be some current Jitter,  which can have a considerable effect on when the Classic will end Absorb).

For our old-ish battery banks here,   the ideal EA value changes,   depending upon DOD of the battery in the previous discharge,   and also (apparently),    the charge Rate at which the battery was recharged (or,  probably the average recharge Rate).

Perhaps,   a Rate-Of-Change in EA  could be a more predictable method for using EA to end Absorb   ...(?).

FWIW,   probably trying to put too-fine a point on this pin.   73  Thanks,   Vic
Title: Re: A tech talk with a US battery guy
Post by: boB on August 15, 2019, 02:41:51 PM
As far as Absorb time stopping because of clouds, etc, that is typically OK...

Over the course of the day, it should accumulate those hours of Absorb even though it took longer than those hours to accumulate the time at Absorb.

The bit of jitter while being close to the 3 amp ending specification can be a problem.

I thought I made a software change to help that ?  Vic... Can you remind me if I did that ?  All it would have done would be to require a certain amount of time (seconds) before the ending amps timer was reset due to the sudden spike of current over the ending amps setting.

I seem to remember thinking about that at least...   :)

boB
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 15, 2019, 03:43:37 PM
Quote from: boB on August 15, 2019, 02:41:51 PM

   ...   I thought I made a software change to help that ?  Vic... Can you remind me if I did that ?  All it would have done would be to require a certain amount of time (seconds) before the ending amps timer was reset due to the sudden spike of current over the ending amps setting.

I seem to remember thinking about that at least...   :)

boB

Hi boB,

You DID  change the Classic FW to reduce the Jitter,  just after the WBjr began shipping.   It  was a large help.

AND,  you had wondered out-loud in a Thread,   about 18 months ago,   about changing the EA function,   as it approaches the set EA,  BUT,  have read nothing of any such change in the Classic FW.

On the systems here,  the EA value rattles around,   and,   as one is watching and waiting for EA to end,   on the MNGP,  we see about 0.8 Amps of total variation in a period of 30 seconds,   or so  ...   this is with a constant load on the inverters.  As  we  are waiting for the EA value to stop its descent.  The Jitter can make a 30,  or so minute difference in the Absorb duration.

Of course,   there is an additional factor that comes into play when nearing the set EA value.  This is voltage drop in the cable and breaker that connects the Classic to the battery.   With opportunity loads,  such as A/Cs  that cycle,   our systems can see about 1 Amp of EA current twix one A/C running and not.   YES,   this is too much drop in that connection.

Some of the above apparent voltage drop,  is due to noise from the venerable SW+ inverters,   and some appears to be from the Classic,  itself,   and there  bound to be the jitter caused from the Classic maintain its Absorb voltage.   Had wondered if running STC String Vmps of 106 V,  increases this Classic Vout jitter,   vs a bit more reasonable Vin to the Classic   --   85-ish volts would seem ideal for most FLA-based systems   ...

A communication box that could report Sense Lead-measured actual battery voltage should nearly eliminate Absorb voltage variation from voltage drop in the Classic battery connection.    And so on.

Some day I will probably try to shut off the A/Cs when the set EA is approached.  This would help reduce the cycling load variations in measured EA.

BTW,   the single Classic on this system  --  S/N 3677,  went into service in about 2011 (and was a pristine Refurb,  at that).   All of the SW+ inverters are in their 14th year of service.   Had wondered,  it the capacitors on the Vbattery inputs have gotten worked-to-death,  and perhaps need replacing.

The above is not a huge deal. The Classic (and KID,  too), are by far the best CCs available.  The WBjr has been a very useful and inexpensive addition to all of our systems   ...   we all just always want MONE !!

Had wondered about adding back-to-back SuperCaps across the Shunt sense leads to try to calm some jitter,   realizing that a 500 A Shunt is very low Z.

Had looked for boB's  thoughts about reducing EA end uncertainty,   but could not find it,  yet.

Thanks boB,   for all that you do for us,   and being present on the Forum.   73,  Vic
Title: Re: A tech talk with a US battery guy
Post by: qrper on August 16, 2019, 11:04:19 AM


   ...  I thought I made a software change to help that ?  Vic... Can you remind me if I did that ?  All it would have done would be to require a certain amount of time (seconds) before the ending amps timer was reset due to the sudden spike of current over the ending amps setting.

I seem to remember thinking about that at least...   :)

boB



Ah... people that code are on a different plain. I'm still trying to get the silly LED to blink  on my ardunio.

The conversation with the guy at US battery was somewhat unusual. I would have thought that a company after the AE business would be a bit more on top of photovoltaic installations. Perhaps they are, perhaps this tech wasn't quite up to speed.

I told him I'd figure I'd use the Trojan L16 charging specs and he told me that wasn't a good idea as (surprise!) their, US Battery, paste is much better than the other guys. Therefore the charging curves are different.

I talked to a tech person at Midnite solar about the end of charge amps and he suggested 8.4 A. The batteries seem to be happy, I did my first EQ on them yesterday, and had a nice boil of the electrolyte.

Mike
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 16, 2019, 11:28:16 AM
Hi Mike,

I believe that the US B-suggested 3% of C for the EA value is too high for daily cyclic use,  unless the batteries are taken to an SOC around 50%.  This is generally considered to be too low for long battery life.   So,  do agree with the MN Tech,   about 1% of C,  is a good place to start,  especially for a very young battery bank.   Just watch the WBjr battery charge current.  When it really does stop decreasing,   this is about the right point as the EA setpoint.   Of course,   use your good Hydrometer (Refractometer),   to confirm.

Standard charging recommendations from most battery manufacturers are for Grid-charged systems,   and assume a Constant Current Bulk,   which Solar-charged systems would have trouble doing (in any reasonable amount of time).

Some of the battery specs,   like FLA battery efficiencies,   appear to be (roughly)  valid only when the battery is completely discharged  --  0% SOC,   and should be lower for our off-grid systems that see an average DOD of about 80%,  or so ...

Believe that for most battery vendors,   off-grid,  Solar-charged systems are still a fairly small part of their sales.   IMO,  L-16 HC batteries are often considered to have a target market for "floor scrubbers".   Perhaps also finding a large market,  powering in-store carts for disabled shoppers,   etc.    Assume that  off-grid is not a large segment,   yet,   ...   who knows ...  But  L-16 HCs  are true Deep Cycle batteries.

FWIW,   all,   IMO,   73   Vic
Title: Re: A tech talk with a US battery guy
Post by: qrper on August 16, 2019, 11:39:02 AM
Hi, Vic,

The "L" in the L16 is for the Lincoln model 16 floor scrubber.

It appears that every battery company in the country sells a 'L16' of some sort. I know that Trojan was really pushing their products for AE. The tech I talked to at US battery mentioned that Trojan was purchased by an investment group. That's bad news... been there and got the T-shirt. Apparently (and I don't know where he's getting his info) the group hasn't found a buyer yet. Buy low, flip it and make some $$$.

Have you had any experience with the large forklift batteries? I've kicked the idea around several times. New is out of the question. Re-conditioned? Boy... when I was a Trojan battery dealer, the owner of the distribution center all told me, "only the rich can afford to buy cheap batteries.'

Mike
Title: Re: A tech talk with a US battery guy
Post by: boB on August 16, 2019, 01:23:52 PM
Quote from: qrper on August 16, 2019, 11:39:02 AM
Hi, Vic,

The "L" in the L16 is for the Lincoln model 16 floor scrubber.

Mike

I had never heard that before.
Title: Re: A tech talk with a US battery guy
Post by: ClassicCrazy on August 16, 2019, 09:59:23 PM
Quote from: qrper on August 16, 2019, 11:39:02 AM
Hi, Vic,

The "L" in the L16 is for the Lincoln model 16 floor scrubber.

It appears that every battery company in the country sells a 'L16' of some sort. I know that Trojan was really pushing their products for AE. The tech I talked to at US battery mentioned that Trojan was purchased by an investment group. That's bad news... been there and got the T-shirt. Apparently (and I don't know where he's getting his info) the group hasn't found a buyer yet. Buy low, flip it and make some $$$.

Have you had any experience with the large forklift batteries? I've kicked the idea around several times. New is out of the question. Re-conditioned? Boy... when I was a Trojan battery dealer, the owner of the distribution center all told me, "only the rich can afford to buy cheap batteries.'

Mike
Our local battery supplier says the forlift batteries are the best - they are made to be cycled heavily daily and sort of abused so do really well on solar systems. He deals East Penn Deka . I was at his shop once and he was refurbishing battery packs by load testing each cell , the using cells from different packs with the same discharge characteristics. They  had huge load testers there. The difference between some of the forklift packs was that some have all the interconnects welded  on each cell ( at least I mean permanently connected ) . The ones he often gets for people with solar systems the cells have studs so they can be individually lifted out of the metal case for transporting and moving around the pack.  Also he said that the cells that on the forklift packs that usually fail first are the ones in the center where they get hotter and less cooling.

I know a couple people who have these forklift battery packs and they have been happy with them. Like all battery packs they need regular maintenance and a few deeper cycles every so often to keep the electrolyte from stratifying .

Larry
Title: Re: A tech talk with a US battery guy
Post by: qrper on August 17, 2019, 10:16:37 AM
Larry,

That's interesting about the center cells going bad from heat.

Before I purchased the US batteries for the installation, I had considered a forklift battery. Issues on how to get it from there to here as well has once I got it, how was I going to move it kept me from pulling the trigger. I thought about getting 12 V batteries (they were lighter ) and putting four in series.
I've seen 12 V @ 250 Ah used forklift batteries for about $900. Two Trojan T125s would be 12 V@240 Ah. Why the difference in price when you're talking apples to apples in Ah capacity. Would the difference in service life be the key?

I worked at Republic Steel and we used large 48 V 2500 Ah batteries in our transfer carts. There were two of them in parallel. A lead-acid battery in those carts had a death sentence!

We'd run'em until someone had to get a forklift and push the dead cart to a charger. You couldn't check water or add water to the cells without removing the top of the cart, a nasty dirty job, so it was rarely done. Those batteries lasted a bit over a  year before they were toast.


mike.
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 17, 2019, 07:31:18 PM
Hi Mike,  not much time right now,   but,  here is a Thread on another Forum,   regarding REfurb Forklift batts:

http://www.outbackpower.com/forum/viewtopic.php?f=17&t=14158

Had thought about a new FL battery when one of the main banks here goes south  --  they are in their 14th year of service ...

73,  Later,  Vic
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 21, 2019, 07:03:09 PM
Hi Mike,

While  we have had very good luck with Surrette batteries (4KS25P & even S530s)  --  all of these batteries have been in service for more than 13.5 years  --   the replacement cost for a 48 V bank,  is now about $18 K (with shipping and CA Sales TAX [at 9.75%]) per bank.   New forklift batteries seem fairly attractive   ...

But,  of course,   forklift (FL)  batteries are designed for a very different task,   as you know.

For a given AH Capacity they generally have fewer plates in parallel,  per battery,   which can often mean poorer surge current capability,   vs more traditional deep-cycle batteries.

They have higher SG electrolyte (often,  at 1.285,  or higher),   which shortens life,   and would generally necessitate higher charge and EQ voltages,  which can upset some inverters,  especially with cold batteries,  in EQ.

Because Capacity in a small volume is important for FLs,  there usually a small electrolyte Reserve space above the plates,   and,  often less space below the plates for shed plate debris.  This usually equates to more frequent checking/adding water,  in the first case,   and probable shorter battery life in the second,  when compared to premium deep-cycle batteries.

IMO,  why go to the bother of dealing with transporting,  unloading,   and placing  FL batteries that have cells that have often been beaten nearly to death,   and might only survive a few additional years of service for you  ...

If we were to try a FL battery,   would probably do as you noted --  specify four 12 V batteries,   each of which (in our case)  would only be about 1,000 pounds.   And  each 12 V battery would be able to rid itself of internal heat much better than would a 48 V FL battery,  with cells tightly-packed in a steel can.

We are hoping that the existing large banks will go some more years,   before we need to make that decision.

Just opinions,    FWIW,   73  Vic
Title: Re: A tech talk with a US battery guy
Post by: ClassicCrazy on August 21, 2019, 10:26:25 PM
Just to be clear  - the people I know who use fork lift type battery packs got them new. The dealer who reconditioned packs was doing it for forklifts . I wouldn't buy a reconditioned forklift pack.

Larry
Title: Re: A tech talk with a US battery guy
Post by: bee88man on August 22, 2019, 09:45:01 AM
As for FL battery having more heat in cente cells issuer, it is a factor of depth and durtion of discharge...for a solar application it may not be the same as in a real fork lift application...think about it....
Title: Re: A tech talk with a US battery guy
Post by: qrper on August 22, 2019, 05:00:13 PM
Quote from: Vic on August 17, 2019, 07:31:18 PM
Hi Mike,  not much time right now,   but,  here is a Thread on another Forum,   regarding REfurb Forklift batts:

http://www.outbackpower.com/forum/viewtopic.php?f=17&t=14158

Had thought about a new FL battery when one of the main banks here goes south  --  they are in their 14th year of service ...

73,  Later,  Vic

Vic....what are you using for batteries that you got 14 years (and running) The last batch of golf cart batteries lasted 7 years, and I was tickled pink with that amount of time. I hope to get 10 years out of the new US Battery L16HC that I just hooked up.

mike
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 22, 2019, 06:17:31 PM
Hi Mike,

Getting 7 years of service from GC batteries is very good!   You must have treated them very well.

The two main (off grid)  banks here are Surrette 4V 1350 advertised Ah (1280 Ah at the 1.265 SG electrolyte,  used),   in 48 V banks  --  one bank
for each of two separate locations.   Even the Surrette S-530 L-16s are also in their 14th year.   The 530s are lightly used,   and am sure that they would have died a number of years ago,  in daily cyclic applications.

73  GL with the USB L-16s.    Vic
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 26, 2019, 07:03:21 PM
Quote from: bee88man on August 22, 2019, 09:45:01 AM
As for FL battery having more heat in cente cells issuer, it is a factor of depth and durtion of discharge...for a solar application it may not be the same as in a real fork lift application...think about it....

Hi bee..,

BUT,   it is the recharging of FLA batteries that is the primary source of battery heating  --  the deeper the DOD,  the longer the recharge time.  Almost all of the heat is created once the Gassing voltage is reached (nearing Absorb voltage for most FLAs).

Discharge heating is,  primarily IR losses in the plates and plate interconnects.

Bulk is quite efficient,  until Gassing begins   ...Absorb not very efficient.

FWIW,   just my thoughts,   Vic
Title: Re: A tech talk with a US battery guy
Post by: bee88man on August 27, 2019, 11:07:04 AM
Thanks for clarification, Vic.

Generally a fork lift battery is *on easy street* in all respects used in a PV application compared to it's intended use as for charge and discharge goes.

FL batteries can be less effort for a LA battery as for cell upkeep...48 volt has 24 cell to keep water levels and connection clean and tight, all while approaching near to 1000Ahr...something to keep in mind.
Many FL batteries have cast lead inter-cell ties...so only 2 single wires for physcal connection for all.
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 27, 2019, 08:12:54 PM
Quote from: bee88man on August 27, 2019, 11:07:04 AM
Thanks for clarification, Vic.

Generally a fork lift battery is *on easy street* in all respects used in a PV application compared to it's intended use as for charge and discharge goes.

FL batteries can be less effort for a LA battery as for cell upkeep...48 volt has 24 cell to keep water levels and connection clean and tight, all while approaching near to 1000Ahr...something to keep in mind.
Many FL batteries have cast lead inter-cell ties...so only 2 single wires for physcal connection for all.

Hi again bee..,

Well, Fork Lift batteries often require more maintenance and tending,   because,   most of them have a small Electrolyte Reserve (space above plates for electrolyte),  AND their generally high SG electrolyte necessitates relatively high charge voltages,   creating more electrolyte vapor and spatter.

With the small reserve above plates,   high-ish charge voltages, and  extra heating due to reduced airflow around each cell in the tray,   electrolyte must be checked often,   and topped off fairly frequently.

The metal trays,   cram each cell in intimate contact with neighbor cells,   which makes cleaning of spatter,  and oozing of electrolyte a bit more difficult,   compared to batteries with space surrounding the battery cases.

A number of FLA batteries of similar Capacity to ForkLift batteries have four  posts per cell and interconnects,   and single flag terminals,   as do most Lift batteries.

Indeed,   Lift batteries  are designed for severe service,   that most Solar charged systems do not demand,   and would have trouble recharging Lift batteries sufficiently in one Solar day.

BUT,   Lift batteries may well be worth any extra effort,   for the considerable savings that they seem to offer,   compared to high quality Solar deep cycle FLAs.

All IMO,   not to pick the nit,   too  much.    Vic
Title: Re: A tech talk with a US battery guy
Post by: bee88man on August 28, 2019, 10:01:10 PM
My personal application of forklift battery is for "Back Up" power...so lots of time spent in 'float' cycle and so I do not experience most of the Cons, and more of the Pros.

At over 2000 pounds it takes a lot of heat to raise even 1 degree but float is not the heat causer.
Title: Re: A tech talk with a US battery guy
Post by: qrper on August 29, 2019, 11:00:52 AM
Quote from: bee88man on August 28, 2019, 10:01:10 PM
My personal application of forklift battery is for "Back Up" power...so lots of time spent in 'float' cycle and so I do not experience most of the Cons, and more of the Pros.

At over 2000 pounds it takes a lot of heat to raise even 1 degree but float is not the heat causer.

Wondering out loud. Did you purchase one of these forklift batteries new or a 'reconditioned' one? What's the voltage of the battery?

Inquiring minds and all..

mike
Title: Re: A tech talk with a US battery guy
Post by: ClassicCrazy on August 29, 2019, 11:49:58 AM
I know someone with large forklift battery for solar and he draws the battery down quite a bit at least once a month I think so that when it charges from that low a capacity it will stir up the electrolyte and mix it up good. Keeping it in float or shallow discharge  for long period of time could cause issues with the electrolyte stratifying and then having sulfation issues which are not good for the battery. That is what I have heard about all flooded lead acid batteries.

Larry
Title: Re: A tech talk with a US battery guy
Post by: Vic on August 30, 2019, 07:03:54 PM
YES,   Larry,   Deep Cycle batteries must be cycled,   for their best health.

One reason for deep-ish cycling is that doing so,  helps open pathways deeper into the plates,   preserving Capacity.

There are probably electrolyte diffusion current that might help mix electrolyte.

BUT,   getting the charge voltage above the Gassing voltage for that particular battery,   for a reasonably long time period (Absorb)  is what does substantial electrolyte mixing.

Personally,   would try to discharge FLA batteries to about 70% SOC,   or a bit less,   about once per month.

IMO,   Vic
Title: Re: A tech talk with a US battery guy
Post by: bee88man on August 31, 2019, 09:52:57 AM
Quote from: qrper on August 29, 2019, 11:00:52 AM
Quote from: bee88man on August 28, 2019, 10:01:10 PM
My personal application of forklift battery is for "Back Up" power...so lots of time spent in 'float' cycle and so I do not experience most of the Cons, and more of the Pros.

At over 2000 pounds it takes a lot of heat to raise even 1 degree but float is not the heat causer.

Wondering out loud. Did you purchase one of these forklift batteries new or a 'reconditioned' one? What's the voltage of the battery?

Inquiring minds and all..

mike

Reconditioned, and at 48 Volt.

I do equalize charge to 'stir' the electrolyte periodically.

I will adopt a 'discharge pattern' , followed by a heavy recharge.as suggested.