6v 8GGC2 Battery - is this Gel Cell?

[john61ct]

Originally Posted by Neptune's Gear

AHT means how long the unit will stay at the absorption charge stage (constant voltage) before dropping to float voltage. Some regs will do this purely by time, some also monitor current and will switch earlier if tail current drops sufficiently. Thats what you want, as if the batts are already full when the alternator comes on, you dont want it to sit at absorption voltage.

Actually the concurrent loads means chargers **only** know the bank is Full if the shunt is at the bank measuring amps **accepted** there.

If at the charge source it has no idea.

[john61ct]

You do **not** want the VR dropping to Float before the bank is Full if you care about longevity.

https://www.google.com/search?q=mc-614+marinehowto

[john61ct]

In MaineSail's article
https://marinehowto.com/programming-...age-regulator/

best to parse / read the whole thing carefully

but for this specific topic,

search Ctrl-F for and carefully read the sections following:

4-*Avoid Premature Float

Just adjust

0.015c endAmps rather than 0.010

stay on lower side of voltage range rather than higher,

and a little on the side of conservatism in the eggtimer vs results benchmark / adjusting, as I said due to GEL

Setting an adequate absorption/CV duration, (time spent at constant voltage), is critically important to battery health. The factory settings of 18 minutes for bv and 18 min Av plus any “calculated” additional time are not going to help you get the most from these regulators. In a perfect world the “calculations that can extend or shorten the CV time calculations would work perfectly unfortunately they rarely do and this is why there is an advanced programming menu. B1C (bv duration) and A1C (Av duration) can be extended or shortened in the advanced programming, and should be in almost every installation

[BigAl.NZ]

Originally Posted by john61ct

too many manuals 8-)

I got the 3° from the first one linked here, did not see any temp curve spec in the last one

Any case, a few mV aren't critical, long as you're not right at the edge of the spec'd range, should be NP

just ask EPM next time it's convenient to call

I note on the link you sent me the temperature adjustment 5mV is per cell. So in my case (4 batts, each 6v, 3 cells per batt - thats 12 6v cells) adjusted for 10 degrees = 0.3v (if I use 6 cells since its in parallel series). That would make more sense in terms of the temperature adjustment i saw.

[BigAl.NZ]

Originally Posted by john61ct

In MaineSail's article
https://marinehowto.com/programming-...age-regulator/

best to parse / read the whole thing carefully

Read it a few times now - making more sense each time. Bloody good article. I would be extending Av time I suspect.

[john61ct]

Yes innit.

Once you have an objective measure for 100% Full nailed down, all the adjustment issues with the various sources, have a common standard goal to achieve.

The vast majority of banks go to Float prematurely, from owners leaving source adjustments at the defaults.

Not saying going too long on AHT can't happen, but it is rare.

[BigAl.NZ]

Originally Posted by john61ct

Yes innit.

Once you have an objective measure for 100% Full nailed down, all the adjustment issues with the various sources, have a common standard goal to achieve.

The vast majority of banks go to Float prematurely, from owners leaving source adjustments at the defaults.

Not saying going too long on AHT can't happen, but it is rare.

For GEL's I hear over charging is bad. So what is over charging? Is it charging at too higher voltage, or continuing to charge even at the correct voltage past a full float?

I am going to go and have to reread the manual on the BMV712 to understand how it works out what 100%SoC is.

I know the BMV712 can measure voltage, and I know it can monitor how much amps is going in, and I know I have programmed in the theoretical manufacturer max Ah (360Ah@12v) - but how does it use all that to get 100% SoC I haven't got my head around.

Thus I am not confident that the BMV has been fully setup correctly. For example the BMV manual says 100% SoC is reached when voltage exeeds 13.2v and charge current drops below 4% battery capacity for 3 minutes(360Ah so 14.4A). Well that was reached very quickly the other day when I ran my motor, yet I would have expected while the batteries were charged I would have been somewhere around the 90% mark.

See below - the battery was in Abs according to the BMV (constant voltage), the regulator said Bu (Bulk), and the BMV was saying 100% SoC....those readouts all seem to conflict.

[john61ct]

Originally Posted by BigAl.NZ

For GEL's I hear over charging is bad. So what is over charging?

Really?

Overcharging means, going significantly higher than the mfg spec for 100% Full.

Being conservative, for a sensitive chemistry, leave some margin of error and stay toward the low end of their range.

Again, 13.9 - 14.2V is my reco

Best 14.1V or lower for both setpoints.

Hold that until current falls below 0.015C

That's it!

Of course "significant" is the weasel word. 14.8V would be a lot worse than 14.6V.

Holding Absorb until current stops completely would be worse than stopping at 0.002C

Doing either, 80% of charge cycles, would be worse than 20%.

You might kill off 15% of lifetime cycles, better than 85%.

Undercharging, chronic PSOC is also harmful, the ideal is to get as close as you can, as often as you can.

[john61ct]

Originally Posted by BigAl.NZ

I am going to go and have to reread the manual on the BMV712 to understand how it works out what 100%SoC is.

Do not trust automatic calibration.

It is **your** job to manually reset the 100% mark, at the point you verify the definition above has been hit.

Ideally every cycle, accuracy will suffer if you only do it once a week.

Go here https://marinehowto.com And search / CTRL-F for

battery monitor

and read closely those three articles, starting with the HowTo about accuracy.

[BigAl.NZ]

Originally Posted by john61ct

Do not trust automatic calibration.

It is **your** job to manually reset the 100% mark, at the point you verify the definition above has been hit.

Ideally every cycle, accuracy will suffer if you only do it once a week.

Go here https://marinehowto.com And search / CTRL-F for

battery monitor

and read closely those three articles, starting with the HowTo about accuracy.

Another good article. Guess I will remove the batts (again) and get a capacity test done. Will also call East Penn and see if I can get a accurate Peukert.

Thanks

[BigAl.NZ]

Originally Posted by john61ct

Do not trust automatic calibration.

It is **your** job to manually reset the 100% mark, at the point you verify the definition above has been hit.

Ideally every cycle, accuracy will suffer if you only do it once a week.

Go here https://marinehowto.com And search / CTRL-F for

battery monitor

and read closely those three articles, starting with the HowTo about accuracy.

The BMV has a default Peukert of 1.25. Using the C/5,C/20 and C/100 for the GC2 to calculate Peukert ( https://planetcalc.com/2268/ ) you get a different answers depending on which two C values you use.

I got 1.06, 1.09 and 1.13. Average is 1.09 so I am going to use that. Big difference from 1.25!!

[john61ct]

Originally Posted by BigAl.NZ

Another good article

Yes, Maine Sail is Da Man.

Parsing every article on his site related to electrickery is a great time investment in knowledge.

Also help support his fantastic work for the community,

browse the store, he can supply lots of gear not listed,

and right down at the bottom of the home page is a Donate button to help him defray webhosting expenses https://www.paypal.com/cgi-bin/websc...=FLBF3379TLPGS

[BigAl.NZ]

Originally Posted by john61ct

Yes, Maine Sail is Da Man.

Parsing every article on his site related to electrickery is a great time investment in knowledge.

Also help support his fantastic work for the community,

browse the store, he can supply lots of gear not listed,

and right down at the bottom of the home page is a Donate button to help him defray webhosting expenses https://www.paypal.com/cgi-bin/websc...=FLBF3379TLPGS

To muddy the waters further - I spoke to East Penn this morning who said the Peukert for those batteries is 1.22 - not even close to what I calculated from the c/5,c/20 and c/100/.

[john61ct]

I thought seemed low.

Actually Peukert can vary depending on factors.

For those using a "pretty accurate" coulomb counting SoC meter, many try tweaking that and CEF keeping it headed in the direction of "more accurate"

Of course need an accurate updated SoH / Ah capacity number as a good basis before you start.

[BigAl.NZ]

Originally Posted by john61ct

I thought seemed low.

Actually Peukert can vary depending on factors.

For those using a "pretty accurate" coulomb counting SoC meter, many try tweaking that and CEF keeping it headed in the direction of "more accurate"

Of course need an accurate updated SoH / Ah capacity number as a good basis before you start.

What are you doing for your annual "sync/reset" for 100% SoC.

Capacity test?
Workshop mains charge to full then set SoC to 100%?
Or....?