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midpoint panic

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Just now, gabriel said:

i         will       wait           for         the          test         results      on         the            others...   

You can duck and dive ... My bets are on:
1) The balancer is shot. At least that is the hope.
2) BUT, purely on the inverter getting upset on a high SOC, my bigger bet is on the battery being the issue.

In all my UPS battery replacements a while ago, nothing we tried or did or tested, beat the Hawkins test.

<10sec and you smile or you have heart palpitations ... on top of the immense effort to lug that plastic box full or lead around with shirt / pants / car mats being damaged by acid residue, days later.

After the 5th shirt getting magical holes in it, the wife got really upset as shirts I wore at the time, trying to help, where not the DIY ones.

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  • Chris Hobson
    Chris Hobson

    Morning Gabriel I'll give a potted history of my battery balancing experience. My system I installed in July of 2015 and got a BMV towards the end of July and immediately noticed an imbalanc

  • When your earlier post came up on the weekend, I thought to myself... this isn't going to last, there is no reason to expect the deviation to go away. But I figured I'll let you enjoy the weekend.

  • But further to this: For the next few days, or at least today, I would use the grid for my loads and use everything to charge the batteries. Don't run them in normal cyclical use until you get to the

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  • Author
16 minutes ago, The Terrible Triplett said:

My bets are on

you've got yourself truly well covered by that sort of bet, very safe and 100% risk free - apart from the acid though :), gives a totally new meaning to 'i've got the t-shirt' :D

would it not be easier and quicker to load test the batteries with the inverter? 

1. fully charge the batteries

2. Load the inverter until it draws the maximum load from the batteries it is capable off.

3. After lets say 30 minutes (still under maximum load) measure the voltage of every battery

11 minutes ago, Fuenkli said:

would it not be easier and quicker to load test the batteries with the inverter? 

Cuts out at about 86%soc ... as per Gabriel. :D

EDIT: With one battery showing lower volts than the rest.

Edited by Guest

If @gabriel was not so far up the West Coast, I would have gotten in my car with my Hawkins tester and go and settle this matter for him. :D

  • Author
18 minutes ago, The Terrible Triplett said:

Cuts out at about 86%soc ... as per Gabriel. :D

yawell, it starts giving me a 4% midpoint deviation at about 83% soc. apart from that i don't know how sustain a full load.... maybe get a heater.... but wait, is it not what happened yesterday, when no 1 battery gave a <11 volt reading whilst the other three were >12 volt at 83% soc? that would obviously finger number one BUT number one battery has come back from 12.95v right after the lamp test to settle at 13.08v...

dadaaa, herewith preliminary [pre-hawkins] test results. the test results are before and after 60 minutes on a 21 watt 12 volt hella bulb test.

1. 13.44v [just after full charge, without having it rest to get rid of surface charge] 12.95v, after 3 hours it measures 13.08v
2. 13.15v 13.10v
3. 13.23v 13.04v
4. 13.36v 13.00v

  • Author
51 minutes ago, The Terrible Triplett said:

If @gabriel was not so far up the West Coast, I would have gotten in my car with my Hawkins tester and go and settle this matter for him. :D

thanks @The Terrible Triplett, on a day like this we could quickly sort out the batteries and then braai a couple of tjops - we all have braais inside our homes here :)

i see some hawkins testers only go to 200ah, as does the local battery shop's, is yours able to go higher?

45 minutes ago, gabriel said:

hawkins testers only go to 200ah

Mine goes up to max 600amps.

At 600amps, on Trojans and UPS batts (all 200ah and up) within <5 seconds you see the meter:
Diving to line between green/red, get ready to replace. Time is running out.
Dives into the red, game over, a dud, show me the money.
If it stays in the green for up to max 15 seconds, perfect. That is if you want to keep it there for "so long". Smells terrible. (No pun intended.)

So testing with teeny weeny 20w globies or small little balancers ... gmpf!

Scary as anything, I tell you, when you push these big batts to their limits and beyond. I don't like testing them at all. 

But in all my attempts to test UPS batteries, using a 350w halogen standing lamp (that was when I burnt my fingers), even once a 2000w heater, have not found a more accurate nor safer way to test them, and getting a definitive answer, with no risk of injury, bar putting out ones back moving the damn batteries. Even got a trolley for that. :-) 

 

45 minutes ago, gabriel said:

... sort out the batteries and then braai a couple of tjops ...

If it was not +-3-4 hour return trip, with fuel as it is, no drinking allowed as braai = beer and then driving back a bad idea, it would have made a lot of sense! :D

Switch off the system, take out the one batt and visit a auto shop with it before they close?

Or ask the auto shop very nicely to borrow their tester quick.
Or bring their staff member with the tester to your house for the test - probably the easiest option.

And If the batt is dead, they take it away for the lead price. Now that is just a cool idea, if they pay for lead.

Edited by Guest

  • Author
23 minutes ago, The Terrible Triplett said:

Smells terrible. (No pun intended.)

this is a sealed unit - where will the gas escape? wont it just explode ? :blink:

47 minutes ago, gabriel said:

this is a sealed unit - where will the gas escape? wont it just explode ? :blink:

Nope, nothing to do with gassing.

All to do with the connections getting red hot pulling 600amps out of the battery.

  • Author

edit

just called the guys at hawkins in durbs  - they say that i will not get the correct reading as my battery needs a 750amp draw [3xbattery ah] and they max out at 600...

just schlepped the prime suspect battery to the local solar shop, they did the hawkins test. verdict a for ok - if i could i'd do a couple of somersaults for joy, but i'm not in shape for that anymore.

we now have to wait and see how the ersatz ah02 will do.

thanks for all your help!

Edited by gabriel
xtra data

3 hours ago, gabriel said:

if i could i'd do a couple of somersaults for joy,

YES YES YES!!! 

I would have joined you!

Ps. Did you smell the burning?

 

3 hours ago, gabriel said:

... they say that i will not get the correct reading as my battery needs a 750amp draw ...

It was not about correct readings, it is about if the batt can hold the pull or not, as I understood from Dixon, who manufactures batteries.

Now we are back at square one, for how the dinges does you system conk out on SOC of 83%?

What are the chances that the alleged culprit was the good one, the others questionable?

  • Author
1 hour ago, The Terrible Triplett said:

it is about if the batt can hold the pull or not

ok, i did some editing which you might not see, the 'prime suspect' battery which gave a very low voltage reading under load and whilst all was attached and the bmv702 went bezerk has scored a1 on the hawkins - and yes, i saw the smoke :-) and the terminal screws have burn marks- as you can see the other batteries passed the hour lamp test flying colours, all voltages before and after above 13v.

obviously in order to completely rule out the batteries i will have to have the other three tested as well, this time they will have to bring the hawkins to me.

1 hour ago, The Terrible Triplett said:

Now we are back at square one,

so what i say is that i am not really back to square one - i see the things which happened as progress.

i don't know if my system can go lower than 83% soc at present as at that stage midpoint is 4% and i override it then to go to grid as i'd like to prevent possible damage. it can most probably go further down but what will the deviation be? and where will the voltage of the prime suspect battery [which has now been vindicated] be? but this is academic

1 hour ago, The Terrible Triplett said:

What are the chances that the alleged culprit was the good one, the others questionable?

i'll ask the guys to bring the hawkins tomorrow - then we will know for sure

stiffness and slight muscle pain has already manifested itself after schlepping the >70kg battery around today... :mellow:

Edited by gabriel
xtra data

2 hours ago, gabriel said:

..., this time they will have to bring the hawkins to me.

stiffness and slight muscle pain has already manifested itself after schlepping the >70kg battery around today... 

I am SOOO with you ...one time picking up a battery, 105ah (wot 25-28kg's), to put in the back of my Isuzu, I was in a bit of haste, left the "klap" and the spare wheel mounting closed.

Just lifted it over, slowly placing it down inside, on tiptoes and all.

So there I was, on tiptoes, twisting at a angle over the spare wheel, arms stretched out, carefully placing the battery down ... when the pain hit me. Nope, did not drop the batt. 

But I swore, let me tell you, I let rip. Obviously at myself till I just burst out laughing at the sheer stupidity of it.

Wife thought me a wee bit "high on acid", sitting there on the ground in pain, laughing with tears (from pain and laughter).

Never again.

Now I open everything, bend at the knees etc.

You with >70kg's batteries ... respect!

  • Author
10 hours ago, The Terrible Triplett said:

You with >70kg's batteries

well, archimedes would have been proud of me, i used all leverage tricks in the book in order to save me from said laugh attack; yet still that last part of getting it into the back of the car... although my knees did most of the bending, i still had to bend them elbows... now i sit with tender neck muscles etc - the wife emphasized that i should start of with smaller batteries, herhehe :D

3 hours ago, gabriel said:

... should start of with smaller batteries ...

Reminds me of that, urban legend?, government official who said that the reason we don't have water, is because the colonials built the dams too big.

If they where smaller, then they would be full. 

22 minutes ago, The Terrible Triplett said:

Reminds me of that, urban legend?, government official who said that the reason we don't have water, is because the colonials built the dams too big.

If they where smaller, then they would be full. 

That is not even legend. An ANC councillor  in Queenstown

  • Author
1 minute ago, Chris Hobson said:

That is not even legend. An ANC councillor  in Queenstown

unfortunately for some that 'rule' does not cover head-size :blink:

1 hour ago, gabriel said:

and here is some good news

ALL MY BATTERIES PASSED THE HAWKINS LOAD TEST :D

YES!!! What wonderful news!

Nothing so lekker than to be wrong, being a optimistic pessimist, and losing bet number 2.

That leaves bet number 1, the balancer, as the dud?

37 minutes ago, gabriel said:

jawohl

That German word has always fascinated me, for the simple reason that non-German people think that word is very German, and German people hardly use it at all. It translates literally to "yes well", probably in the same sense as you might say in the Cape "Ja well no fine". Another word that gives away your non-germanity is Wunderbar (wonderful). They don't use that as often as we might think they do.

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