Formula to calculate End Amp settings help?

[Seeker2]

Hi all,

First post here.  I have the Kid with WBJR and shunt, 1 Solar World 285 watt panel, 2 Diehard Platinum PM2 AGM batteries totaling 136Amp Hours.

What should I set End Amps to?  I have read anywhere from .5/100 Amp hours to between 1 and 3%. 

I just upgraded firmware to 1811 I think was the level.

Any help with calculating this number?

Thanks

[binkino]

I was told, AH of the batteries x2 and /100 = Amperes

So here in my case,  230Ah are 4.6A

With your calc it would be in my case 1.15A



... but please if this is not correct, would like to see corrected!

[Westbranch]

Andy, your formula is correct if the system is,(probably) a 12 volt setup with those 2 starter batteries in parallel. 

Systems like mine with 2V cells will, sometimes also have the amount (%) stated per cell and then if you have 24V you multiply the  % the by 12...

Starting out 5% can be a safe place and if the batteries do no show they are being fully charged, you can drop by 1% at at time till you get the desired result... The absorb time may be a more difficult  number to ascertain... start at 2 hrs and as above watcch your batteries performance, if poor, raise the time 1/2 hr at a time...

[Seeker2]

Thanks for the info.

Agree batteries could be better for storage.  They were new and close to free.  Being part time in van camper they sufficed so far.

I am going full time middle of September and may make changes.  I have had these batteries around 2 years.  Have been out for a month at a time powering a 50 quart ARB fridge and charging laptop, phone, electronic dog collar and rarely went below 85%.  Of course I have not done any test of those batteries so I could be way off.  Until I did firmware end amps was not an option.

I will either get a couple 6 Volt Trojans or jump up to  LiFePO4's.  Just sold my house so I got the cash with minimal bills so far.  So I may just use these batteries until they give up.  I will get a small generator to help out on occasion if there is not enough sun. 

I do like my SolarWorld panel as it still harvest something even in a total fog bank or sun filtered through trees.

Thanks again for the formula.

[Westbranch]

 I will get a small generator to help out on occasion if there is not enough sun.

  If you are dry camping in it, a Honda or like 1000W Inverter type gen will be a good match

[Seeker2]

Yeah 99% dry camp.  I rarely stay in an RV park as most I can not tolerate although the showers are nice.  I like to get out or back as far as I can in a big van.  It's just me and a large German Shepherd now after 3 divorces LOL.

Generator will be Honda or Yamaha although some others are looking better now.

[Westbranch]

try not to be swayed too much by price alone...  my 2 have served
me faithfully with just regular maintenance and SeaFoam gas treatment...

[Seeker2]

So 136 x 2 = 272  136 is my total amp hours of these batteries in parallel

272/100 = 2.72

I should set end amps at 2.72 is this correct?

[Vic]

Seeker,

You mentioned that the total Ah Capacity of your batteries is 136 AH from two batteries.   We are assuming that  you do have a 12 V system,  and that the two batteries are in parallel  --  68 Ah for each battery,  is this correct?

If the above assumptions are correct,  and you wanted the EA to be 2% of 20-hour Capacity,  then 2.72  might be a good starting place.

Normally,  we would suggest contacting the manufacturer of the battery for guidance on Absorb and Float voltage settings for Solar-charged systems,  although if may be difficult for you to find anyone at "Diehard"  who could answer these questions,  plus guidance on the proper End Amp,  or Finishing Current values.  Are your batteries made by Johnson Controls?

For Flooded batteries the customary EA values are in the range from about one to three percent of 20-hour Capacity,  with reasonable Absorb voltage settings.   Some batteries will have somewhat higher EA values,  yet.  Some AGM batteries like very,  very low EA values.   Some manufacturers spec a rate-of-change in battery current to end Absorb,  which generally cannot be accomplished by most Solar CCs.

What is the Absorb voltage that you are using on this system?   The Absorb voltage has s direct effect on the proper EA setting.

Be certain to use the MidNite Battery Temperature Sensor (BTS)  with the KID.   This is essential for proper charge of any battery,  especially Sealed batteries,  like AGMs.

Thanks for any additional information.     Vic

[Seeker2]

I emailed an engineer about these batteries a couple years ago.  Sorry don't remember which company he was with now.  May have been Diehard even though they did not manufacture.

He said set absorb to 14.7 and float to 13.6 and that is what I did.  He also said they like a minimum charge of 25 amps occasionally.

I do have the temp sensor also.

Thanks for all the info.  I may just use them until they die before getting  better batteries.  They actually have been working well but I did not work them all that hard.

My thinking is the end amp setting should work better then the kid was doing before without that information

[Westbranch]

so you did not have a WBjr previously?  If that is so you should see some  improvement in the amount of charge (Ah ) put in if the values were lower than those you just listed.

Let us know how you fare with the new values...

[Seeker2]

I have always had the WBjr and temp sensor.

I emailed a guy with the company that made these batteries and here is his response.

Essig, Bruce
Aug 16 (2 days ago)

to me
Bob â€"

Set the controller to switch to float at 400 milliamps.


Bruce R. Essig
ODYSSEY National Program Manager
EnerSys
Office: 660-429-7506
Fax: 660-429-1758
Cell: 816-668-6676
ODYSSEY Batteries are Awesome!

It actually does not matter now because I am going to pick up 2 Trojan T105's on Friday.  I need more Amp Hours.

So with the 105's I will set end amps to 4.5.  I will have to check specific gravity to make sure they are fully charged and adjust end amps to reach full.  Does this sound about right?

I guess as batteries age the end amp setting may changed.  I am just guessing.