Equalization with Victron 75/15 MPPT controller

pnolans · January 2018

Hi, I have purchased a Victron 75/15 MPPT controller recently, and got the bluetooth dongle to allow me to change settings. I'm trying to start equalization on my 2 Duracell 6 volt batteries wired in series. I set the equalization to be "every 1 day"... last night. I can NOT tell if it's actually doing anything. The monitoring sw shows that the charge state is "BULK"... I was expecting to see something like equalization.

It seems that Victron has no real support service, so I thought I'd start asking .

The batteries are 2 duracell SLIGC115 wired in series. The panel is a Canadian Solar CS6P-220P...

Thanks in advance for any help.

Pat

Here's what I see:

BB. · January 2018

Equalization is a "higher than normal" (for flooded cell lead acid batteries only) charging voltage held for an hour to a few hours, and in some cases many hours over a couple days.

13.4 volts is not high--You are in bulk charging (all the current the solar array can produce should be sent to battery bank--early morning or "bad weather" for this screen shot?).

For equitation, at "room temperature" I would expect somewhere around 14.8 to 15.2 volts or so (for some Surrette or Rolls batteries, they seen to need near 16.0 volts or so at times). And the equalization current around 2.5% to 5% of battery AH capacity (230 AH * 0.05 = ~11.5 amps typical equalization).

Some systems are set to equalize for a couple hours once a month. Other folks prefer manual equalization (around 0.015 to 0.039 SG units difference between high and low cell--do an equalization. "Full charge" then equalize until all cells stop rising after an hour between readings--That is your new 100% full SG).

If you are equalizing for more than an hour or two--Watch the battery bank voltage... Many hours of equalization in one day at even 2.5% rate of charge can overheat the cells (~110F to 120F maximum battery temperature--Check battery specs.).

-Bill

pnolans · January 2018

Yeah, the screen shot was taken at 9am. (up in the upper right hand corner)...

Without further information, do you have any recommendations? The ONLY thing I have not replaced yet is the PV panel. This was an item on my "to get" list. This Victron replaced a Renogy MPPT 40 amp controller (the slightly older "tracer" model).

Again, thanks in advance for any help,

Pat

BB. · January 2018

Need to see charging voltage and current closer to solar noon.

Bulk = all available power from solar panel
Absorb = hold charging voltage ~14.75 volts for 2-4 hours (estimated) then drip to float voltage around 13.4 to 13.8 volts.
Float = around 15.0 volts for 1-2 hours typical

On a sunny cool day neat noon with panel pointed at sun, a battery below ~80% state of charge (oor good size dc load), i would expect a typical best case Bill charging of

220 watt panel × 0.77 panel+controller derating = 169 watts into the battery

Bill

pnolans · January 2018

Wow! Ok... then , based on my experience, this panel is NOT cutting the mustard. OR the Mayo! Sheez. Well, a new panel has been on my "to buy list"... guess I'll be driving down to Phoenix on my next payday, in a week. To go to Sun Electronics. I hear they have the best prices around Northern and Central AZ.

Thanks again, You have been a great help.

Pat

BB. · January 2018

I really cannot tell.

There is how much current the battery will take (state of charge, temperature, battery age, etc.), the state of the mppt charge controller (what it thinks the battery state of charge is, programmed voltage set points, time spent charging, etc.), any dc loads present on the battery bus.... amount of sun, how clear the air is, clouds, how close the solar panel is pointing to the sun...

If you are getting 100+ watts from the panel/system into the battery, it actually may be working properly (or at least close to normal). In bulk mode.

Absorb and float mode are restricted charging voltages, so in full sun, the charge controller is less than available power from the solar panel.

If toy have a dc current meter that can measure over 10 amps, you can short the panel to the Meyer and see how much current the pane outputs in full sun. Ideally it should be close to Imp or Isc (max power or short circuit) current. If less than 50%, you may have a bad panel.

See if the shop can test your panel or system.

Also, long and or skinny wire from panel or to battery bank can reduce charging current too.

Bill

Dcmike · January 2018

https://professional.victronenergy.com/account/login?next=/ this is there page for help out with there stuff

mcgivor · January 2018

Some controllers will only display they are in EQ once the battery is fully charged, it has to go through bulk/absorb before it can proceed to EQ, if there are any loads present, and or the PV is limited it may never get to that point. Other controllers may display they are in EQ mode, but still need to reach a fully charged state before entering a over charge, or equalization. What is the maximum voltage achieved during a sunny day and do you have any loads during this period?

pnolans · January 2018

Thanks for the pointer dcmike.

mcgivor, no loads while I'm trying to test (in fact, I have the output disconnected) and the max voltage was 14.11 .... that must have been instantaneous, because the highest I saw it go was 13.4 ... checking it pretty constantly. 50w was also the highest I saw, but the history says it hit 91W ...

mcgivor · January 2018

Did a search on the batteries, they are 225Ah and require at least 12A minimun for occasional use or 25A daily use, the single panel is not sufficient , it would take days to achieve a full charge without any overnight loads. You are on the way to destroying those batteries, going to need at least 2 of those panels minimum to be close, but a system needs to be designed and calculated including all factors, loads, location equipment and so forth. My suggestion is start from the beginning again in a new thread asking assistance in designing a system, assistance will help you in getting it right.

Estragon · January 2018

91w peak is about 1/2 what I'd expect for the panel in full sun charging in bulk. Is it roughly perpendicular to full sun with no shading when you see 50w and battery ~14v?

At 9am, I assume the panel was fairly cool, 26v seems a bit low to me. How is it wired (size of wire and distance) to the controller?

pnolans · January 2018

Estragon, yes it is roughly perpendicular with no shading. I use the cable that came with the panel... I believe it is 10 ga.

Thanks,

Pat

pnolans · January 2018

Thanks to everyone for their assistance. My original question has been answered. It's clear to me that I need to pursue another panel and see what that does for me. It has been part of my plan, and once my SSA check gets here next week, I'll get another panel. I'm really interested in seeing what THAT displays.

Regards,

Pat

pnolans · January 2018

mcgivor said:

You are on the way to destroying those batteries,

So, just to be clear, even though I mention in the post you are replying to that I have removed them from service, you still maintain that I'm on my way to destroying these batteries?

For the time being, I'm using my backup generator for things I need.

I'm just unclear as to how I'm destroying them with no load on them, and only charging them, albeit with insufficient amperes.

I plan to go buy another 220 watt panel today. That is the only thing I have NOT replaced. I believe i mentioned that as well.

Please, make no mistake, I appreciate all input from the experts here. Every comment gives me something to think about, even if I reject it later.

Thanks again,
Pat

BB. · January 2018

Use a digital volt meter and check the voltage at the charge controller terminals and the battery bus. You are looking for the two sets of measurements to be within 0.05 to 0.10 volt from controller to battery bank (12 volt bus) under maximum charging current.

For example, if you have 10 AWG cable with 0.05 volt drop, using a simple voltage drop calculator, the maximum length would be:

https://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=3.277&voltage=12&phase=dc&noofconductor=1&distance=1.2&distanceunit=feet&amperes=20&x=0&y=0

1.2 feet (one way run), 10 AWG, 20 amps
Voltage drop: 0.048
Voltage drop percentage: 0.40%
Voltage at the end: 11.952

If you have too long, of cable and/or too small of diameter, the high voltage drop from controller to battery can dramatically limit charging voltage+current at the battery bus.

I am not convinced that you have any bad hardware. Need to know more about your setup before I would be telling you to start replacing stuff. Could also be configuration of your charge controller causing issues too.

-Bill

pnolans · January 2018

BB. said:

{snip}

I am not convinced that you have any bad hardware. Need to know more about your setup before I would be telling you to start replacing stuff. Could also be configuration of your charge controller causing issues too.

-Bill

I will definitely check those things. Good point. I also am not CONVINCED that I have bad HW, however, the history of this panel is somewhat in question; as well as there's a chance I hit it on a tree limb around Labor Day. I started noticing problems at that time.
And, as I've said, I was planning on getting another 220W panel this month. I found a guy with a pallet of them for $125. If I do the "swap HW' thing and it performs better, then I will be reasonably confident that that was at least ONE problem. The wiring could certainly be another . I did have some help from some friends who have been using solar on their rigs for a long time.

I've been living full-time on the road for a year now. I made a lot of mistakes the first few months. After 10 years, I'll look back and see what I'm doing now and shake my head!

Thanks again,

Pat

pnolans · January 2018

I got back from town, and now it's in Float. No load for 2 days, and it caught up.

Image: https://us.v-cdn.net/6024911/uploads/editor/r8/bn93met4qi07.png

Estragon · January 2018

I think your batteries are flooded, so you should be able to check the specific gravity of the electrolyte in each cell with a fairly inexpensive meter. All voltage and/or current based indicators of battery health are, IMHO, only approximations of the health of lead acid batteries. Regular checks of SG are your best way of catching a problem, and dealing with it before it's too late.

westbranch · January 2018

If the vendor has more of those panels and you were planning to add to the array of 1, You might think about getting 2, since the one you have is suspect.... That is a good price! for those panels and they probably won't last long..... Trying to match a panel several years later can be a lot of hard work!

pnolans · January 2018

Estragon: I often do. I will do that in the morning, and post the results. I DO have a hydrometer.

Thanks again,

Pat

pnolans · January 2018

westbranch said:

If the vendor has more of those panels and you were planning to add to the array of 1, You might think about getting 2, since the one you have is suspect.... That is a good price! for those panels and they probably won't last long..... Trying to match a panel several years later can be a lot of hard work!

Sounds like a great idea. Problem is my limited income on Social Security. I can't always afford what sounds like a great idea!

mcgivor · January 2018

pnolans said:

mcgivor said:

You are on the way to destroying those batteries,

So, just to be clear, even though I mention in the post you are replying to that I have removed them from service, you still maintain that I'm on my way to destroying these batteries?

For the time being, I'm using my backup generator for things I need.

I'm just unclear as to how I'm destroying them with no load on them, and only charging them, albeit with insufficient amperes.

I plan to go buy another 220 watt panel today. That is the only thing I have NOT replaced. I believe i mentioned that as well.

Please, make no mistake, I appreciate all input from the experts here. Every comment gives me something to think about, even if I reject it later.

Thanks again,
Pat

Please forgive the misunderstanding, my question regarding loads was in reference to whilst charging, with the assumption it was being used overnight, in which case the single panel would be inadequate, resulting in the battery becoming discharged at a greater rate than it can be replenished, over time.The comment was an indirect observation based on the percentage ratio of PV vs battery capacity which in your case is ~ 5%, with the panel at maximum output, which may be adequate for occasional or backup use, but not daily cycles.

westbranch · January 2018

You should be aware that you may not get the 2 panels to work with your Charge Controller because the 2 outputs are too different...
You may find that you will get some very strange results.

pnolans · January 2018

> @mcgivor said:
> pnolans said:
>

>
>
>
>
> Please forgive the misunderstanding,

Yes, of course. I just wondered if I was missing something.

pnolans · January 2018

> @westbranch said:
> You should be aware that you may not get the 2 panels to work with your Charge Controller because the 2 outputs are too different...
> You may find that you will get some very strange results.

Absolutely true, though they are both 220 watt. My system has evolved over the last year, and I have an extra charge controller and pair of batteries.

it's complicated.

pnolans · January 2018

I got paid today, and purchased a panel from someone on Craigslist. My controller started doing equalization!!!! YAY!

That's the one thing I have not replaced.

Thanks again for all your help,

Pat

westbranch · January 2018

Congrats, tell us the all numbers you were finally able to see on the charger... and the specs on those 3 panels.. This might be interesting...

pnolans · January 2018

Will do!

pnolans · February 2018

I forgot about providing the specs for the panels. There was only one "new to me" panel left. I have already given the other panel to a friend from here on the road. I gave my friend the caveat that it was substandard, but DID work. And.. it was free. He's very happy.
At this time, I only have the one panel ... it gets to float by 9:30am every morning.

Thanks again,

Pat

Equalization with Victron 75/15 MPPT controller

Here's what I see:

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