Amps Rising not tapering During Abs Charging?

landyacht318 wrote:
My screwy31, which is about to jump off a cliff, when trying for an EQ'ing 16v, now has the amps increasing when voltage is dialed up above 15.5, but the amps still taper normally at 14.9v.

Exactly... that's what I would expect to see. But amps increasing at only 14.6v seems rather odd to me. I definitely need to include battery temps in any further investigation, if I'm gonna get a hold on why these batteries behave the way they do.

I can not tell from your posts if you are currently camping in your RV, or just getting ready for the new season.

If the RV is currently stored and nothing left on except a detector, or two, the solar-panels should easily keep the batteries charged and stay in "float mode".

Coming back on in either "bulk" or "absorption mode" would indicate a problem with one or more batteries being sulfated or a shorted cell causing the battery voltage to quickly drop and causing the solar-panel controller to come back on in charging mode.

If you are actually running some 12v equipment, doing that would be normal.

Smk,

The amps kept creeping up until float kicked in. From noon 'til 5pm they rose steadily from 8-9a @ 14.64v. The pm dropped into float sometime between 5 and 7pm? Once in float, @ 14.15v, they tapered as usual, from somewhere over 4a to 3.6a, by 9pm.

Yes, I usually shoot for about 2.5a @ 14.8v. In fact, I've done that several times without the pm going into float. Now it goes into float at a higher current and lower voltage, meaning it's not as deep into the charge. This is why I'm wondering if float is triggered by a timer, or Xa @ Yv, or whichever comes first?

I'm trying to avoid having to manually change voltages while charging, so I'm trying to determine if the pm getting 'hung-up' at that 8-9 amps is a good indication of the bank being very near full?

And yes, it may very well have something to do with starting the charge cycle on a near full bank to begin with? I will do a deeper cycle to see how it compares. thanxx!

Le ponte de resistance

My screwy31, which is about to jump off a cliff, when trying for an EQ'ing 16v, now has the amps increasing when voltage is dialed up above 15.5, but the amps still taper normally at 14.9v.

Time for a reality check.

You were doing your first solar charging in the evening (way past solar peak). The amp rate is far past peak charging so the amps should be dropping off.

The next morning (How late did you sleep? No times given) the sun is rising so available amps should be going up.

You have to expect funny numbers when over watching the meters. Especially if trying to read something into it when solar power is no where near peak times.

Also; having one bad battery with a bad cell can mess up controllers trying to charge the battery-bank. If you have a battery with a bad cell that does not recover after a charging try or two, it is time to replace it before it damages the others by not allowing them to receive proper charging.

jrnymn7 wrote:
Smk,

Have you seen current rise at the end of a Vabs charge? It seems strange, to me.

Except you started over so it is not really the end of an eight hour charge. This is not a clock spring you are winding. The electrochemical process is more varied and changing.

Did you let the 9 amps continue the rest of the day? Did it continue to increase? Fully charged should get you down close to 2 or 3 amps with 4x GC2.

No I have never waited around and watched an ammeter. Only on an over discharged battery have I see amps start slow and then increase. The process is a bit exaggerated at very low charge.

scrub,

That's as good as she gets. I can tighten them up a bit, but then voltage across individual 6's goes outta whack. And then, SG's just go back to the above within a couple of cycles, or less. And if you consider that the two prodigals used to be down in the 1.265 range, it can be seen as quite an improvement.

jrnymn7 wrote:
Yes, newer SG's are forth coming.

At last check, on April 26th, they were as such:

A1 1.285, 1.275, 1.275(prodigal cell)

A2 1.275, 1.275, 1.275(prodigal cell)

B1 1.285, 1.280, 1.280

B2 1.285, 1.280, 1.285

Those were taken 14 hours after a 10 hr charge at 15.0Vabs, the day prior, that started at 12.49v ocv, and, at some point after 8 hrs, dropped to the modded pm4b's float voltage, and finished at 4.1a @ 14.6v. At the time of the SG readings, ocv was 12.84v, with even voltages across the bank.

Another equalize in order? Cells should be closer.

Thanks Mex,

That's the only thing I can figure. I'm thinking it's both temp and soc related, as it appears to be more noticeable on warm days, but always in the same general soc range. I always thought that glitch at the ~20a/90+soc mark was unique to the Peak, but now I'm seriously reconsidering. And the Peak never did it on the split bank... only on the full bank... how weird is that? And yesterdays observations were also done while charging the full bank.

Most of my observations and logging were done on the split bank, using the 45a pm4b. I hope to get some more data with the 45a on the full bank, before going solar. And then, at some point, I'll have to introduce the pm3-75 into the mix, and start over. It sure is nice to know what IS normal for my bank. Just knowing what the bank will accept at various voltages and soc's should help me determine what to expect from solar, in the way of charging times.

I did buy an IR gun, but haven't put it into service, yet. That's something I need to do. I plan on paying much closer attention to temps, this year. And I need to see how effective power venting the battery cabinet is at keeping things cool.