Top Charge Question

[joelmyer]

Well it's been 33 days since I've seen hookups. The 245 watts of solar gets the Trimetric into the positive AH from full most days.

Specific gravity has dropped. A couple of cells to 1250, and a couple to 1260.

There are 4 x 6 volt batteries in two banks.

So at sunset tonight I'll switch to bank 2 and hit bank one with an hour of 15.3 volts from the Megawatt.

And then.... Bank 1 will have a higher voltage than bank 2. Is it ok to just switch back to 1+2? The voltages will equalize pretty quickly.

Or should I just stay on bank 2 for a week, switch to bank 2 and zap bank 1 with the megawatt? Then I can check weekly and zap the weaker bank as required.

The batteries are 232 AH so total nameplate rating is 464. Morning AH from full is averaging -30 so the batteries are living in their top 10%.

Joel

[time2roll]

joelmyer wrote:
Mostly I monitor amps which I have seen as high as 11 amps.

Max amps is more a measure of the solar collection not battery condition. You want to watch how far the amps taper off while holding at 14.8 volts.

With 4x GC2 you are looking for amps to taper to less than 2 amps at 14.8 volts to call full charge. (.5% of capacity)

[jrnymn7]

joel,

I think maybe niner is addressing the 'over 100% Ah's' result? The trimetric must be properly programmed. For example, if it's set for 14,8v and 5a, it will read above 100% if you go beyond those parameters when charging. The trimetric is more than just a bare bones Ah counter. There are several more settings to consider. I still need to learn how to use mine to its fullest.

[red31]

joelmyer wrote:

The morning I unplugged, I reset the AH from full to zero and have reset it several times when it got to more than +20 AH. The AH from full was the basics for my top 10% SOC statement. Obviously there is more going on. USB says charge inefficiency can be 5% to 50%. MEX posted a link to a paper that suggested it can be 100% in the top 10% of charge. TriMetric defaults to 5%.

So an amp/ah meter is not that useful.

[NinerBikes]

joelmyer wrote:

mena661 wrote:

NinerBikes wrote:
You should see 1.275 or better, for all cells.

X2

x3

That's what USB says. That's where I want to go.

Got involved with chili dogs, conversation and adult beverages last night. Today is advertised as partly cloudy with a high of 72. We haven't seen a totally clear day for about 10 days now. But it looks just a little hazy now at 8AM. So hopefully solar will get me up to near full and the MegaWatt tonight will get one bank on the road to specific gravity happiness.

To answer NinerBikes questions:

Trimetric is a meter, it measures the voltage at the battery as well as net amps into/out of the battery and amp hours from full.

The morning I unplugged, I reset the AH from full to zero and have reset it several times when it got to more than +20 AH. The AH from full was the basics for my top 10% SOC statement. Obviously there is more going on. USB says charge inefficiency can be 5% to 50%. MEX posted a link to a paper that suggested it can be 100% in the top 10% of charge. TriMetric defaults to 5%.

TriMetric

EcoWorthy is set to 14.8/14.4. I have rarely seen 14+ volts but I don't sit inside & watch volts. Mostly I monitor amps which I have seen as high as 11 amps (that's net as measured by the Trimetric).

US Battery recommends 14.4 bulk, 14.4 absorption, 15.3 top charge and 15.3 equalization.

Late breaking news: At 8:22 Mr Sun is putting more into the batteries than is being used.

Joel

Joel

Set your trimetric for 15.3 volts. Run it there for 2 or 3 full sunny days in a row. Measure your SG at 3 or 4 PM at the end of each of those days. If your SG is at or above 1.275, your work is done. If not, it's going to take heavy duty 16.0V to get a true equalize charge, not just a "top" charge, to get the plates desulfated.

Do a search here on "Equalize charging", with Mexicowander as the author. It's been discussed many, many times, how to do an equalize charge.

[RJsfishin]

I like my way, and it works !
Deep sixed my hydrometer long ago.
I used to see a degradation in battery voltage when I was on generator.
Now on solar, no change in voltage after 6 weeks, batts see a couple hrs of 14.6 every day before sundown. 2 12'ers, near 5 yrs old, doing fine.

I have funner things to do than to be unnecessarily babysitting batteries.
They take care of themselves,.....as long as that cheap china controller keeps chugging ! 🙂

[MEXICOWANDERER]

15.3 equalization, huh?

If I go to solar blvd, time to drop in to US Battery and harrass them a little
..

Looks like some of the younger fresh-meat engineers either are getting uppity or the fluorescent tie boys have tied up their keeper.

[joelmyer]

mena661 wrote:

NinerBikes wrote:
You should see 1.275 or better, for all cells.

X2

x3

That's what USB says. That's where I want to go.

Got involved with chili dogs, conversation and adult beverages last night. Today is advertised as partly cloudy with a high of 72. We haven't seen a totally clear day for about 10 days now. But it looks just a little hazy now at 8AM. So hopefully solar will get me up to near full and the MegaWatt tonight will get one bank on the road to specific gravity happiness.

To answer NinerBikes questions:

Trimetric is a meter, it measures the voltage at the battery as well as net amps into/out of the battery and amp hours from full.

The morning I unplugged, I reset the AH from full to zero and have reset it several times when it got to more than +20 AH. The AH from full was the basics for my top 10% SOC statement. Obviously there is more going on. USB says charge inefficiency can be 5% to 50%. MEX posted a link to a paper that suggested it can be 100% in the top 10% of charge. TriMetric defaults to 5%.

TriMetric

EcoWorthy is set to 14.8/14.4. I have rarely seen 14+ volts but I don't sit inside & watch volts. Mostly I monitor amps which I have seen as high as 11 amps (that's net as measured by the Trimetric).

US Battery recommends 14.4 bulk, 14.4 absorption, 15.3 top charge and 15.3 equalization.

Late breaking news: At 8:22 Mr Sun is putting more into the batteries than is being used.

Joel

Joel

[mena661]

NinerBikes wrote:
You should see 1.275 or better, for all cells.

X2

[NinerBikes]

What do you have the bulk charge voltage set at on the Trimetric, meaured at the Trimetric, and again, at the battery terminals?

What does your battery manufacturer recommend for bulk charging voltage?

1.250 and 1.260 SG is not in the top 10% SOC... You should see 1.275 or better, for all cells.

[time2roll]

Does it go 15.3 every day? How many hours of that?
Would seem like enough to me. How old are the batteries?

Otherwise I would pay for one night of power to just get it done.

[MEXICOWANDERER]

The 600 watt boost converter has an amperage limiting cermet pot with of course a metal adjustment screw. Dial it in. 16 volts limited to 11 amps. Make the booster + and -
Wires so they have a big alligator clip to connect to the incoming power. Another 2 wires and another clips so they connect to the disconnected + and - battery post. These boosters are pretty inexpensive and tiny.

Hope This Helps

[jrnymn7]

Joel, you can boost that 15.3v using a boost converter. Mex had a thread on that, not too long ago.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/28041640/srt/pa/pging/1/page/1.cfm


Or even better, use a bucker, and hit those 6's individually.

[joelmyer]

MEXICOWANDERER wrote:
Unfortunately a formula must be used. 5% of amp hour rating in amperes until voltage rises to 15.0

For 6 of your cells, 11-amps constant current would be appropriate. But top charging is designed to minimize sulfation not undo it. Equalization is needed. So continue on to 16.0 volts if need be. This means 11-amps at 15.8 volts should going that high be necessary. This is where most apparatus falls flat on it's face.

That'sa nice, but I have what I have which is a 30 amp MegaWatt. It goes to 15.3 period.

Experience says that it will push less than 5 amps into fully charged bank, gently bubble and raise the SG.

Joel

[MEXICOWANDERER]

Yeah...

Batteries can be so...

so...