6vdc Trojan T105 (225ah) Equalization

[john61ct]

PS Battery University is not always an accurate source.

OK for noob orientation and terminology

[GrowleyMonster]

I have a pretty simple setup for equalizing manually. I use the same gear to run the propulsion system from my Ryobi 2kw portable generator. I connect a big Variac to either shore power or the generator output. This feeds a rectifier from an old arc welder. Voltage and current are monitored by panel meters. The catch is there is no isolation transformer, and it requires careful monitoring. NOT idiot proof.



Another solution for 6v batteries is to use an old transformer type 12v charger. Feed it with a Variac. Monitor the output voltage and current as you adjust the variac control. At 55v or so the charger will output half of the normal voltage. Tweak it up until it puts out the proper equalizing voltage for a 6v battery. Watch temp, current, and voltage carefully and adjust as needed.

[john61ct]

"pretty simple". . .

[rgleason]

That's helful John. So when I set CV to 8.1 and the PS changes to CC, I should just wait (it was at about 28 amps and rapid decline down to 20a with frequent decline going down as the battery gets charged, but went into cc) ... so I just wait and then in about 10 min try setting on CV again.

I try not to exceed 26 amps continuous to save the PS.

Thanks.

[john61ct]

I don't know that PS, never seen a need to manually select CV vs CC.

If you have a max voltage limit set, the battery's low resistance at a given V/SoC level is what determines when it gets up to that limit.

Not up to the charge regulation, it just puts out current, then limits voltage once the setpoint is reached. The transition is determined by batt chemistry / physics, not the charge source.

Same with trailing amps.

[rgleason]

Yes, John. I might have forgotten that it did not stay on 8.1v when it awitched back to CC from CV. ,,still learning, will have to notice this next time.

[rgleason]

You are saying, the bat determines if it is in CV or CC.
However in bulk trojan manual asks for cc up to 14.82v or 7.41v for one 6v batt. For absorbtion they look for CV with other values.

[DotDun]

Originally Posted by rgleason

You are saying, the bat determines if it is in CV or CC.
However in bulk trojan manual asks for cc up to 14.82v or 7.41v for one 6v batt. For absorbtion they look for CV with other values.

CC isn't what some think. CC is the max the charger will produce (up to the battery's acceptance ability). IOW, if you have a 40A charger and the battery can accept 60A (for example), the charger will put out 40A until the voltage set point (14.82V in your case). Some think the charger is holding constant current, which it is, but not due to some magic, it's simply all the charger can put out. At 14.82V, the battery will determine how much current it will take, as the charger holds the voltage, the internal resistance of the battery determines current, simple ohm's law.

[john61ct]

Originally Posted by rgleason

You are saying, the bat determines if it is in CV or CC.
However in bulk trojan manual asks for cc up to 14.82v or 7.41v for one 6v batt. For absorbtion they look for CV with other values.

The industry standard definition of Absorb is CV, Bulk is CC before the transition.

[john61ct]

Originally Posted by DotDun

CC isn't what some think. CC is the max the charger will produce (up to the battery's acceptance ability). IOW, if you have a 40A charger and the battery can accept 60A (for example), the charger will put out 40A until the voltage set point (14.82V in your case). Some think the charger is holding constant current, which it is, but not due to some magic, it's simply all the charger can put out. At 14.82V, the battery will determine how much current it will take, as the charger holds the voltage, the internal resistance of the battery determines current, simple ohm's law.

Exactly.

And CC is only an accurate label in that cirvumstance.

When the batt acceptance is below the current available, the amps will vary even before reaching the setpoint.

[rgleason]

Right. I got it switched.

Dotdun, I understand what you're saying. Whether it stays in CC or CV depends on the state of charge of the battery, I think. If you are trying to push it too much the battery will refuse to cooperate.

[rgleason]

If your battery is not fully charged and you set the CC amperage low enough and below the batts acceptance, CC will work and the PS will hold it there.

[rgleason]

It is also dependent on the PS, for example, I could equalize at CV 8.1a a single T105, but when I paralleled them, and tried it with my 30a PS, it would not stay in CV. I guess had to wait for awhile until the amps dropped down lower, then switch it into CV, (However, I think John and Dotdun are telling me that when the amps drop low enough the PS will switch back to CV.

[john61ct]

If you have switches marked CC and CV, think of them as

"limit amps to a level below PS maximum"

and

"limit voltage only"

In both cases the charger is only setting a ceiling, what the actual V or A is is up to the batt SoC / resistance.

Most chargers only have the latter option.

[rgleason]

Thanks both are adjustible knobs.