How to PUKE a $2k bat bank, and the outback trap

[Lloyd]

Boy Henry,

I wish Slim would get the new engine room pics on his web site. It's like going into a surgery center, all the bulkheads are sheathed in mirror polished SS, and the amount of 90/10 copper pluming for sea cooling is all polished, anything made of brass/bronze/copper/SS is all polished.

And talk about design order. Some real pre-thought went along with all the polishing...I love to see well executed machine spaces.

I think I'll email him and have him send me a pic, I can post of the ER.

I am going to bet the fittings are brazed instead of sweat fit, as electrolysis is a big issue in marine installations.

Lloyd

[Henry W]

I would love to see more of the work. I was a plumber and pipe fitter for 8 years and I know good work when I see it. I can't see the fittings up close but it looks like they were all wiped nicely before everything was polished. If you can get more pictures please post them.

Henry

[Lloyd]

Hi all there seems to be a lot of interest in bat banks.
So I thought I would give a little real life story, of the last week.


I then hit the bank with a 15.8 v equalize...now the spg after a 24hr rest on all cells is between  1.25 and 1.26....I recognize this as a surface charge. So I disconnect the string into individual 12 v bats, I set up a Peukert discharge  of 12 amps on bat 1, within in one hour the voltage drops to 12.3, Peukert says I have 20 hrs to hit a voltage of 10.5, that's not going to happen, so I recharge to full, and hit it with another eq this time 16 volts, after 24 hrs rest I have a bat voltage of 12.9, and an spg of near 1.3...maybe things are looking good, wrong. I set up a factory spec load of 12 amps, she pukes out at 141amps/10.5v drawn in about 8 hrs, well below any respectable bank/bat. So now, I have the bat on a 10 amp recharge, when she hits voltage...I'll hit her again with a 16 amp eq, and another load test. If one bat can't pass this, then the whole bank goes to recycle and a new group of bats will be installed.

I'll let you know

Lloyd

I ran another Peukert load "12 amp" test on a single 240 amphr bat from the string. Starting voltage is 12.9, spg is 1.3, this after a 24hr rest from the last eq. I energized the load with in seconds the bat voltage dropped to 12.23, after 15 minutes w/load the voltage recovered to 12.32. I dropped the load after 1 hour, the voltage was 12.1 after 15 min. rest, the bat recovered back to 12.57. This shows the bat has a huge internal resistance. I turned the charger back on after she came upto float I hit her with a 16v eq, for 1.5 hrs.


Ran the same load test as previous, this time I let it go until the outback dropped out(the load was only connected thru the OB). The OB dropped out after 141 amphr's in 13 hrs. The spg was 1.10 on all cells, and the resting voltage was 11.3, these measurements were taken after 1 hr. I chraged and eq again.

Final test started after 48 hrs. This time I am using close to a c/25 load, which according to Peukert, I should have 158.34 amphrs available, the OB should drop out after 3.3 hrs, the load is 48 amps. Starting from a float voltage of 13.6, After connecting the load, the bat voltage drops to 12.35, after 1 hr the voltage is 12.1, 49 minutes later the voltage is down to 11.46, then in 30 min the voltage is 11.01, After another 15 min the OB drops out at a voltage of 10.5. I leave the load going for another 15 mins, and the voltage drops to 9.5. It is time to disconnect, Test starting at 1:00pm and ending at 3:30 pm=2.5 hrs, total of 109 amphrs draw from the bank. After 15 mins the voltage recovered to 11.2.

This bank is effectively junk for its intended use as a deep-cycle bank for inverter loads. So it's going to the scrap heap for recycle.

A one time owner fopa on a brand new bank that should have lasted at least 5-7 years if maintained. Bat banks are unforgiving for any mismanagement.

Lloyd

[BruceM]

Perhaps the system design should have added a low voltage battery cutoff and warning piezo alarm, as humans are prone to these types of mistakes.  

There is little loss penalty now for a low voltage cutoff, as mosfet on resistance is becoming so fabulously low.

Cheap insurance for an expensive battery bank.

[Lloyd]

Hi Bruce,

I begged the owner for a low voltage cut-out for the main dc bus. His answer, it didn't have one to begin with so I don't think it needs it now. His reason every boat has it's start up shut down procedure. He's not laughing now. He thinks the batteries were bad to begin with...he is beside himself going on that there is just know way that a bank could be so unforgiving. Looking for some else to blame.

It's been a battle from the beginning just adding the ABYC required safety devices, ie fuses where they didn't exist. On more than one occasion I offered him to hire another electrician, and I would drop out. I just won't risk his and his families life, nor my insurance, to take a short cut.

Lloyd

[BruceM]

Pity he didn't take your advice on the low voltage cut out,  Lloyd.  Some people can't be helped. 

I have to try and idiot-proof everything that I use-  I'm way beyond absent minded now.  After smoking my house badly and risking a fire more than a dozen times, I finally installed a relay and mechanical timer on the electric stove.  It now turns itself off if I don't check on it or wander out into my shop or get busy in my office.  This most simple project improved my life greatly. I'm going to have to do the same for my off grid place with the propane stove. 

[Lloyd]

Yea  Bruce,

I am a big believer in idiot proof...it 's very few people that can do a full check list every time the start and stop...much as a pilot is required to do. Accidents happen closer to home bc we become complacent in the things we do every day. Which in no short order will, be one of those accidents close to home.

My first house I bought, I almost burned her to the ground...came home from work tired set a pan of oil on the stove...woke on the couch to a glowing orange flame in the kitchen. I went in and had flames from the top of the stove to the ceiling...9ft ceilings. As a scared fool I grabbed the pan and took it outside...thereby splashing flaming grease all the way to the door. It's a pure wonder I didn't splash it on me..do you think I had a fire extinguisher...no way...22 year old'ss don't think that far ahead.

As far the propane look into the marine shut-off valve, you can locate it next to the stove and it shuts off the tank at the tank.

Lloyd

[elnav]

I came to this thread late via reference to one of the pictures. Please pardon the tardy response.   
A client of mine  had a similar experience. His boat  arrived in the Phillipines with a delivery crew. Someone left several circuits energized  and the boat was hauled  for dry storage for 3 months before anyone came to look at it again. Needless to say the 1000 amp hour battery bank was  flat. These were 2V AGM cells made in China  so quality was definitely a question mark. Because I design my systems  to handle a dead ship restart  I could send instructions to the surveyor on how to get the vessel going  from a dead ship condition even when no shore power was available.  24 hours later  I got an email reporting that everything was back to normal. One year or so later  the vessel is back in the Phillipines  still with the original bank going fine. At least  the owner is not complaining  even when he runs the air conditioner over night  on the inverter system.  Something to be said for AGM technology.

I have had similar revival  experiences  with other brands of AGM batteries left for dead over extended periods of time. I am not saying they never suffer any damage but  in many cases the worst  problem is sulfation and Pulsetech technology  does a good job of recovering sulfated batteries. Nano pulser is another brand  and it is sold by Boat Electric in Seattle. 
I would highly recommend  installing pulse desulfators on any battery bank left sitting unused for periods of time. 
I have heard  less than sterling  product use reports about one brand called  Battry Mind(er)  but generally  the technology  seem to work as claimed. Why else are there  so many clone products available now that the original patent has expired. More than a few  people must  have had positive experiences  leading them to consider  copying the product.

regards
Elnav

[mobile_bob]

odd thing is, there is precious little scientific method testing to support the use of a pulse charger

in my experience, a careful recharge with a good charger, given enough time will recover the cells as well
as the pulse units do.

i recently killed a couple of agm's, don't ask how, but suffice it to say i was sick

it took about a week of charging, and discharge cycles to get the batteries back to better than 95% capacity
that using a standard charger set at 10amps, alternating to 2amps at a rate of 14.8 volts

agm's generally are much more forgiving to this sort of abuse, do this to a flooded cell and you will be crying alligator
tears for a very long time.

lots of folks swear by the pulse chargers, but i have yet to read a comprehensive report on testing in a controlled
3rd party lab such as sandia labs (and yes i am aware that they have tested the technology)

bob g

[elnav]

I must confess  that when I first heard of it my initial reaction was "snake oil!"   As luck would have it,  someone I knew said he had a sample in his desk drawer left by a sales rep but he didn't have any interest in testing it. He gave it to me to try and despite my intial scepticism  it really did work.  I was working for Xantrex at the time so had lots  of 'dead', abused  and sulfated batteries to test with.  The initial tests proved promising enough that Xantrex authorized me to buy more samples and set up a test program. The idea being we might licence the technology for inclusion in our own  chargers.
Unfortunately at about this time,  senior management  had a corporate policy revision  and decided instead to disband the marine division as a separate entity.   My work and much of the marine  directed activity got terminated. 
I carried on  by myself but  was unable to fund a rigorous  'scientific study'   and can thus only report anecdotal evidence.  I suspect this technology is regarded by the battery manufacturers and the industry as a whole  as  a potential  threat to sales of replacement of sulfated batteries so who else has an interest  in promoting the technology.?

In the past four years  I have  begun to see a few charger manufactures  include 'pulsing' in their advertising literature.  Considering the technology was originally made for the US Army it probably has some credibility.   It was granted some patent papers.
WWW.pulsetech.com  was the original  company but now there are about six  brand names on the market.

[loonogs]

Lloyd
a few questions
what type of charger do you use, you say that you hit it with 10 amps and then 20amps for 24 hours, is this selectable from your charger and is it at a contastant voltage ?

what make or model do you use.

"I then hit the bank with a 15.8 v equalize...now the spg after a 24hr rest on all cells is between  1.25 and 1.26....I recognize this as a surface charge. So I disconnect the string into individual 12 v bats, I set up a Peukert discharge  of 12 amps on bat 1, within in one hour the voltage drops to 12.3, Peukert says I have 20 hrs to hit a voltage of 10.5, that's not going to happen, so I recharge to full, and hit it with another eq this time 16 volts, after 24 hrs rest I have a bat voltage of 12.9, and an spg of near 1.3...maybe things are looking good, wrong. I set up a factory spec load of 12 amps, she pukes out at 141amps/10.5v drawn in about 8 hrs, well below any respectable bank/bat. So now, I have the bat on a 10 amp recharge, when she hits voltage...I'll hit her again with a 16 amp eq, and another load test. If one bat can't pass this, then the whole bank goes to recycle and a new group of bats will be installed."

so you can select the output/ charge voltage as well ?

Lloyd. you charge up the bank and then when it has reached full voltage you hit it with a 16 amp equalisation charge ?
the reason i am asking these questions is that i was given a battery bank, where it has not been charged for a few months but the batteries are reading from 11.8 to 12.3 volts,
what would you recommend to test them out, should i charge them at a low rate, 1 amp for a long time or at a higher current rate, 20 amps until the reach their voltage.
they are 12 volt 65ah deep cycle batteries

step by step what would you do ?

regards
Loon

[Lloyd]

Lloyd
a few questions
what type of charger do you use, you say that you hit it with 10 amps and then 20amps for 24 hours, is this selectable from your charger and is it at a contastant voltage ?

what make or model do you use.

I have a military shore charger, that I use when working with a bat bank. I can select the voltage from 1volt to 48 volts in 1 tenth increments, and amperage's in in increments of 1 amp up to a max of 40 amps. It has a time selection with a 24 hr clock, and a temp correction sensor.

A very low discharged bat will not take high amperage very fast in the beginning, it will heat up and shed, especially if its sulphated badly, the shedding can cause thermal runaway.

"I then hit the bank with a 15.8 v equalize...now the spg after a 24hr rest on all cells is between  1.25 and 1.26....I recognize this as a surface charge. So I disconnect the string into individual 12 v bats, I set up a Peukert discharge  of 12 amps on bat 1, within in one hour the voltage drops to 12.3, Peukert says I have 20 hrs to hit a voltage of 10.5, that's not going to happen, so I recharge to full, and hit it with another eq this time 16 volts, after 24 hrs rest I have a bat voltage of 12.9, and an spg of near 1.3...maybe things are looking good, wrong. I set up a factory spec load of 12 amps, she pukes out at 141amps/10.5v drawn in about 8 hrs, well below any respectable bank/bat. So now, I have the bat on a 10 amp recharge, when she hits voltage...I'll hit her again with a 16 amp eq, and another load test. If one bat can't pass this, then the whole bank goes to recycle and a new group of bats will be installed."

so you can select the output/ charge voltage as well ?

Yes, as stated above

Lloyd. you charge up the bank and then when it has reached full voltage you hit it with a 16 amp equalisation charge ?
the reason i am asking these questions is that i was given a battery bank, where it has not been charged for a few months but the batteries are reading from 11.8 to 12.3 volts,
what would you recommend to test them out, should i charge them at a low rate, 1 amp for a long time or at a higher current rate, 20 amps until the reach their voltage.
they are 12 volt 65ah deep cycle batteries

Yes, always equalize after the bat is up to voltage, never when its under charged...other wise heat and thermal runaway, at the very least it will badly corrode the positive plates

step by step what would you do ?
regards
Loon

First I would make a matrix and number each bat/cell ie; B1C1, B1C2, B1C3....B2C1, B2C2...where b=bat, c=cell, then I would take spg of each cell, and voltage of each bat, and mark the matrix.

Then  would choose the lowest bat in cell/voltage readings, hit it with about 4 amps until the the voltage quits rising. Take a spg/voltagereading, mark the matrix, then set up a 20 hr pukert discharge based on the manufacture ratings until voltage drops to  11.5, unloaded it, let it rest for at least 6 hrs, take a spg/voltage reading, mark the matrix, then charge at a 10 amp rate until the voltage quits rising, take a spg/voltage, mark the matrix.

Then I would run an EQ at the manufactures rated EQ voltage for a couple of hrs, let it rest for 24 hrs take a spg/voltage, mark the matrix, and repeat the above procedure. After the second cycle, I would then set up a 5 hr pukert discharge, and compare it to factory specs, if the bat last for 3 1/2 to 4 hrs I would recharge/eq....then run the same cycle on the rest of the bats in the group.

It's very important that each cell be with-in 15-20% of the other cells on spg at the start...if you have any cells that are wildly different, then watch like a hawk when charging, 1 or 2 very low cells on the spg as compared to the rest is an indication of possible short developing in that cell, which can cause a thermal runaway, and melt the bat in to a steaming pile of lead and gas clouds.

And if you can't get the worst of bats in the group to perform there is no reason to continue with the other bats...take em to the recycle and buy a fresh bank, and take care of it.

Lloyd

Lloyd

[loonogs]

Lloyd,
thanks for the clear prompt reply

Regards

Philip