Author Topic: A tech talk with a US battery guy  (Read 809 times)

Vic

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Re: A tech talk with a US battery guy
« Reply #15 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
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

Vic

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Re: A tech talk with a US battery guy
« Reply #16 on: August 26, 2019, 07:03:21 PM »
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
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

bee88man

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Re: A tech talk with a US battery guy
« Reply #17 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.

Vic

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Re: A tech talk with a US battery guy
« Reply #18 on: August 27, 2019, 08:12:54 PM »
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
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

bee88man

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Re: A tech talk with a US battery guy
« Reply #19 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.

qrper

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Re: A tech talk with a US battery guy
« Reply #20 on: August 29, 2019, 11:00:52 AM »
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
System one: 7kWp with Trina 250 W panels wired for 90 Vdc. Via Classic 150 to 16-6 V U.S batteries. Trace 5048 sine wave inverter.
System two: 6kWp grid tie with solaredge inverter.

ClassicCrazy

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Re: A tech talk with a US battery guy
« Reply #21 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
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

Vic

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Re: A tech talk with a US battery guy
« Reply #22 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
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

bee88man

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Re: A tech talk with a US battery guy
« Reply #23 on: August 31, 2019, 09:52:57 AM »
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.