6vdc Trojan T105 (225ah) Equalization

[john61ct]

So one limits V the other A, correct?

Where did you get the impression you were choosing CC/Bulk vs CV/Absorb stages?

If from the PS, can you link to their docs? Just curious. . .

[rgleason]

Yes, TekPower TP3030E DC Adjustable Switching Power Supply 30V 30A, Digital Display With Back Light

• Output Voltage: 0- 30V DC with low ripple
• Current Output:0-30A DC with low ripple
• Front AUX output 5A max
• Fuse Protection, Air fan for cooling
• 1 Year USA warranty

TP3030E , Tekpower supply, DC Variable power supply, Adjustable Power supply, DC Power supply
The user manual is pretty thin. I made two AWG 10 4' leads with connectors and clamps for charging.

John

Where did you get the impression you were choosing CC/Bulk vs CV/Absorb stages?

Please see this post re CC & CV process used.
In this post the title "Float" should be moved up one paragraph, like this:

Float
Then paralleled them and set it for Float Constant Current starting at 6.75a and adjusting down to 2.35a when the voltage got high. This took about 2hours.

Sorry about any confusion.

[john61ct]

OK so just misuse of terminology.

No such thing as "set CV to #.# volts", more like "adjusted Voltage setpoint to #.#"

And "set maximum Amps to #.#"

The actual V and A not being within the regulator's control, nor what stage (CC vs CV) the charging will be.

[rgleason]

Sorry, will try to use:

"adjusted Voltage setpoint to #.#"
"set maximum Amps to #.#"
as the battery does determine what happens.

[rgleason]

The new t105 sat for 2 weeks after full charge and equalizing 3 times. I could not discharge at c20 and do the entire commissioning regimen due to a condo owner's concern about hydrogen gas. We had a cruise and I installled the batts fully charged.

The cruise was 1 week with not much wind so there was motoring a good deal. The batteries got fully charged 3x's with tailing amps less than 2amps. During this time I increased Absorption duration setting to 20 x 6 minutes =120 minutes because I saw it dropped out too soon. We were drawing down and recharging about 35ah according to the Link10.

Today I tried using more ah but the voltage dropped to 12.15-12.2v according to Link10, with our laptop 6vdc on, having used a total of 53ah which is not 50% of 225ah! (While drawing the ref down to -7c.

Why? Do we have lousey new batteries? I guess I have to do a full charge and 20hour test to find out now. This stuff is all an impossibility on a mooring. It really ticks me off.

Now we are running our anemic alt with our engine at 1600a in reverse at the mooring to get the alt up to 40-33amps charge to put back the -57ah. It is noisey and hot and bad for the engine. Its been running for 2.5 hrs now and its in -A- absorption mode and charging back about 6.2 amps with the link10 showing we've put back the 53ah and have added + 3.5ah. We have at least another 2 hours of engine time to get fully charged, so trailing amps is less than 2amps.

I do not trust the Link10 anymore and I hate running this engine at 1500 because my balmar 90-65 was improperly repaired and has an undersized 1.75" pulley.

The alternator should be able to put out at least 60amps at 800 rpm IMHO!

Then I need good solar, and xxxx getting to 100%SOC on the engine all the time!

[rgleason]

Correction: The amperage output of the alternator is determined and limited by the battery condition and chemistry. For two flooded lead acid deep cycle T105 in series, 225ah x .25 acceptance rate for FLA (flooded lead acid)= 56 amps is the maximum acceptance, so the alternator if large enough will put that amperage out at the beginning, with that value dropping over the charging time to what is called "trailing amps" , or 1% of the full capacity of the battery

[john61ct]

Link10 is pretty old IMO outdated.

Victron BMV-712 is a good AH counter, but most accurate and easiest SoC meter is Merlin SmartGauge.

Voltage under varying loads will never give accurate SoC.

> getting to 100%SOC on the engine all the time

Is crazy even to try.

[john61ct]

Related thread http://www.cruisersforum.com/forums/...ad-205478.html

[GrowleyMonster]

I use a very simple setup for equalizing from shore power or for manual charging or equalizing from my portable generator. The only hitch is it requires monitoring, but even a "smart" charger should be carefully monitored when equalizing, anyway.


1. A big variac. I think mine is 5kw. A variac is a variable autotransformer. An autotransformer uses only one winding, as opposed to an ordinary transformer that has two or more. The primary is the entire winding. The secondary is tapped somewhere in there, and in a variac this is adjusted by usually a great big knob on the top. What it essentially does is reduce the AC line voltage either up very slightly or down down down, wherever you want it, all the way down to near zero.


2. A rectifier from an old arc welding machine. This converts AC to somewhat ripply DC current. In this case, it converts the adjusted output from the variac to whatever DC voltage you want.


3. Panel meters to monitor output voltage and current.


All together it makes a charger that will keep a float charge on any size bank up to 120v and down to a single cell. It will also equalize, and it will also do a regular three stage charge regimen except you have to manually adjust the output for bulk, absorption, and top off or float, and determine for yourself when each stage is completed.


My bank is 48v, 220ah or 10.56 kwhr. It consists of 8 GC2 golf cart batteries in series. For equalizing or capacity testing I isolate each battery. For normal charging I charge the entire bank as a unit.


If you are up to doing a bit of homework, and competent or fearless enough to connect a few wires together, this setup gives you complete control and flexibility. And yeah, I do recommend equalizing your Trojans separately, using the current/voltage recommended by the manufacturer.



Watch the battery temp and also the electrolyte level while equalizing. WEAR FULL FACE SHIELD when near the batteries! I also suggest a rubber apron or a pvc slicker coat, and chem resistant gloves. Stuff happens when you deliberately cook your FLA batteries.

[wsmurdoch]

For an estimate of the amount that a flooded lead acid battery terminal voltage drops with varying charge and discharge loads, you might take a look at http://www.arttec.net/Solar_Mower/4_...20Charging.pdf to get an idea of what the curves look like.

[rgleason]

"Getting to 100%SOC on the engine all the time Is crazy even to try."
Agreed. The cruise had long motoring, but the alternator needs improvement first, then wiring and solar.
Additionally we anchor or use our mooring, with rare shorepower.

My real question is a 53ah drawdown at 11amps approx, causes the batteries to drop to less than 12.2v. (Below 50%) after a nearly full charge (+3.6ah on link10)

This is not anywhere near 112.5ah (which would be 50%)!

Also considering applying a 20hr load test of 0.05C or 225ah × .05 = 11.25 amps for 20 hrs. and it appears these batteries couldn't even begin to provide the necessary power yet they are new and have been equalized. I suspect I got bad batteries.

[rgleason]

Wsmurdock thanks for the article, which shows during a C20 discharge that 50%SOC is 12.3 volts.

My Link10 properly wired with no wires on the battery side of the shunt recorded just 53 ah and the link10 showed 12.15v -12.2v

This would imply that I actually have a battery with 106 ah of capacity, yet they are new with factory ratjng of 225ah. However it is above 70degF here, about 86-88degF so there must be an adjustment for that.

[rgleason]

I think I found one problem, voltage drop. The Link10 seems to be measuring the voltage at the battery 0.18 lower than my new voltmeter measures at the t105 (in series) 12v terminal, so I had not drawn down the batts to 12.2 or 50%.
The other factor might be the heat. It's been at least 88 maybe 90.

[john61ct]

Yes voltage drops should me minimized as it is practical.

And monitors should ideally be periodically benchmarked against known-good, as in pro-quality and calibrated tools.

But do not put stock in voltage or specific gravity as indicators of SoC at any level of accuracy. Especially when the bank has not been isolated for at least 24 hours, can take 72.

Sorry I've lost track, have you actually got a functional problem going here?

[rgleason]

John, I can understand why you ask.



Old set of (2)T105 - Now with the larger DC Adjustable 1-30v 30A Tek Switching Power Supply, I have managed to get trailing amps at 7.3v Constant Voltage, down to 1.5amps with the batteries paralleled. That completes the Absorption Phase. These batteries would not get down to that trailing amps previously and were probably not charged right. It took about 5-6 hours to get to this point. I also discovered that my 10a Guest 3step charger is totally inadequate. I charged with that first, then spent another 4-5 hours really charging the batteries. Had occasional blurps and bubbles towards the end. Next will do float according to Manufacturer specs. Then rest for 5 days. Then Equalization. Then 20C load test - 20hr, 11.25amp load, down to 10.5 amps.


New Batteries (2)T105 - These are the ones that did not seem to have full capacity. I had charged and equalized several weeks ago, then used them in the boat for a week. The Link10 inaccuracy of 0.18v and hot weather must be the answers. Need to do a C20 Load Test on that too!


Sorry for the confusion. It looks like I might be able to fully charge batts at home and then switch them twice a summer!