Solar not Working Correctly?

[monte]

Thanks a lot Noelex. I checked the battery specs and they recommend 13.5-13.8 float so I have set the solar controller to 13.8 for float.
They recommend " Charge with 14.8V - 15.0V limit for 12 to 24 hrs or when current drops below 1% of the C20 rating " so I have set the controller at 14.8V instead of 14.4. I also changed the Absorption time from 8 hrs to 3 hrs. I don't see an option in the controller to change the % of the C20 rating.
Manual equalize is on and set at 16.2V for one hour. I will check battery fluid levels over the next few days and equalize as I haven't done that yet.
Thanks again, clear as mud!

[simonpickard]

So trying to work out all the bits of this puzzle came to this setting on my controller.

I have 2 x 165Amp hr gel batteries at 12v. What setting would you use as I think it's just on default.





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[simonpickard]

Found out the cable specs as well..
K2X4 - 4mm Solar cable.

I have about a 6-7m run from the panels to the solar controller box which is right next to the batteries.

There is a 'plug' from the solar panels next to where I plug my shore power in so I can disconnect if needed. Wiring here looks a bit suspect to me but I didn't install so hope it's ok. That wouldn't be causing a drop in amps would it?









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[simonpickard]

Also just read this in the manual which I'm a bit lost with..

"
For example:
12V battery and mono- or polycristalline panels
● Minimum number of cells in series: 36 (12V panel).
● Recommended number of cells for highest controller efficiency: 72
(2x 12V panel in series or 1x 24V panel).
● Maximum: 108 cells (3x 12V panel in series).
4
24V battery and mono- or polycristalline panels
● Minimum number of cells in series: 72
(2x 12V panel in series or 1x 24V panel).
● Maximum: 108 cells (3x 12V panel in series).
Remark: at low temperature the open circuit voltage of a 108 cell solar array may exceed 75 V, depending on local conditions and cell specifications. In that case the number of cells in series must be reduced."

It says max 3 x 12v panel's. I have 2 x 50watt and 2 x 100watt panels. Does that mean I've gone over?

Regards,
Simon

[socaldmax]

Originally Posted by simonpickard

Thanks for all the info here everyone. Lots to read through which I will.

My controller is a victron mppt 75 | 50
Not sure what it's set to as I didn't install it but will check. Will also check out the wire gauge.

Need to run a load more tests but here in Spain on a hot day today with no shading on the panels at 11am I'm seeing 7amps in. However the battery monitor is saying I'm at 13.1v so I'm not sure if that's due to me not running the batteries down enough. The battery monitor is saying soc is 100% but the solar controller is in bulk.

Need to read up more of course but wanted to post these..

Great advice about the ARC also. This is the main reason I'm trying to get this sorted now.



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You can go to your battery mfr's website to see what they recommend for charging V and times.

I'm using golf cart batteries and the recommended V is 15V, so I have mine set for 15.1v. My controller doesn't hold a voltage for a period that I can select, once it achieves that voltage for a few minutes, it goes into float mode. So I set the V a little higher, which means it had to spend some time at 15v before it rose to 15.1v, close enough.

I see a lot of people who think their batteries are fully charged at 13.8v, 14v, etc. and they're really surprised to find out they're missing 20 or 25% of their capacity. I also use Water Miser caps. to minimize water loss and terminal corrosion, it really makes a huge difference on my batteries.

[noelex 77]

Originally Posted by simonpickard

It says max 3 x 12v panel's. I have 2 x 50watt and 2 x 100watt panels. Does that mean I've gone over?

Solar controllers are damaged by a voltage even momentarily above their maximum specifications.

The warning only relates to series connection. If you panels are wired in parallel you don't need to worry about this maximum voltage.

How are your panels wired?

[ErikFinn]

Originally Posted by socaldmax

I also use Water Miser caps. to minimize water loss and terminal corrosion, it really makes a huge difference on my batteries.

What are these exactly? Googled and found their homepage and a youtube vid but its still unclear to me, looks just like a taller cap??

[barnakiel]

Originally Posted by simonpickard

It says max 3 x 12v panel's. I have 2 x 50watt and 2 x 100watt panels. Does that mean I've gone over?

Regards,
Simon

Did you say 330 Ah battery? And you say 300 W panels.

(300W / 15V =) Roughly 20 A charge current at max. Into a 330 Ah battery. = 6%. Correct?

Your shore charger will easily put in more.

You are unlikely to have gone over. We have 150 Watts panels over 110 Ah battery. And there is still a margin to go if we had to. More so with gels.

Make sure your charger does not overvoltage your batts. Gels do not like overvoltage.

Do not worry about to many Amps. You are not there yet. Probably at least 50% margin as you are.

b.

[socaldmax]

Originally Posted by ErikFinn

What are these exactly? Googled and found their homepage and a youtube vid but its still unclear to me, looks just like a taller cap??

They're caps with a few beads or grains of something inside of them that condenses the vapor that would normally escape from a vented battery cap and keeps it inside of the battery. They're advertised to reduce water loss by some percentage, in my application (in the desert, higher voltage, infrequent checks) they drastically reduce water loss. The added benefit is virtually no corrosion on my terminals, since the corrosive gasses are kept in the battery.

In the past, I didn't see my trailer for a few months, by the time I checked the batteries they were pretty dry. Refilled them, they were toast. Even though I had 4 yrs on them, I was angry with myself. Next set of batteries, I installed those from the beginning and water loss is 1/4 of what it used to be, giving me a lot more grace period, lot less chance of drying out, which saves me a lot of money.

[ErikFinn]

Originally Posted by socaldmax

They're caps with a few beads or grains of something inside of them that condenses the vapor that would normally escape from a vented battery cap and keeps it inside of the battery. They're advertised to reduce water loss by some percentage, in my application (in the desert, higher voltage, infrequent checks) they drastically reduce water loss. The added benefit is virtually no corrosion on my terminals, since the corrosive gasses are kept in the battery.

In the past, I didn't see my trailer for a few months, by the time I checked the batteries they were pretty dry. Refilled them, they were toast. Even though I had 4 yrs on them, I was angry with myself. Next set of batteries, I installed those from the beginning and water loss is 1/4 of what it used to be, giving me a lot more grace period, lot less chance of drying out, which saves me a lot of money.

Thanks for that
I'll be getting new batteries soon and maybe these caps would be worth getting as well.

[roetter]

Originally Posted by ErikFinn

Thanks for that
I'll be getting new batteries soon and maybe these caps would be worth getting as well.

Just keep distilled or demineralized water on the boat and check the batteries for water loss.

It is good practice to check the batteries once a month and check for cable problems. Hot cables on bad connections are the main source of boat fires. I have come across 4 or 5 hot connections on three (friends and my) boats in the last 12 months alone. One of my friends boats had dead batteries even though he has solar when he returned after 3 months. The in-line fuse from the solar panel to the charge controller (located in the battery compartment) had a corroding connection which started to get hot. When he arrived at the boat the in-line automtive fuse holder was just black crumbly stuff and the fuse had failed due to the smoldering head from the plastic. He was extremely lucky that his boat did not go up in flames. It was a very close call.

You want to check:
Is there any melting or discoloring of any of the cables?
Any corrosion building up on the terminals?
Is there any acid spillage?

I think it is better to be "forced" to check the batteries once a month for water loss and refill if required, and at the same time check for other potential problems, than have a set-and-forget system.

I check my battery compartment at least one every two weeks, and I have LiFePo, so no worry about water loss. I usualy check during high load or high solar charging and use a infrared thermometer to check that all cables and connections are close to ambient temperature. One day I found a cable for a solar charger to my battery at 90ºC (~200ºF). Cut the connector open, see nothing wrong. Had to crimp a new one on. I had checked because my solar was not delivering as many amps as two days before under similar sun conditions.

[roetter]

You asked "Did I go over the maximum voltage of my Victron 75 - 50 solar charger?"

I don't think so. You say you have 2x50W and 2x 100W.

Most likely your panels are connected in parallel. Very easy to check. Disconnect the plug as shown in your picture and measure the open connection voltage. If you panels are in parallel then you would read somewhere around 21V.

The only other sensible option I can see would be that the two 50W panel are in parallel, creating 100W and then in series with the other two 100W panels. Now you would read on open circuit voltage at your plug of about 63V. Your controller can handle 75V maximum. (i.e. 3x12V panels )

Now, if someone had no idea what he is doing then maybe the solar panels are all connected in series, which also would be bad for the controller, but then you would have no output at all.

[noelex 77]

Originally Posted by simonpickard

Found out the cable specs as well..
K2X4 - 4mm Solar cable.

I have about a 6-7m run from the panels to the solar controller box which is right next to the batteries.

I am not sure from the cable designation what sized wire you have. Is that 2x4=8, 4mm2 wires? Can you measure the conductor size to confirm?

That cable sounds way too small. Can you determine how your panels are wired (series, parallel or a combination) and someone will do the maths on the voltage drop if you can confirm what sized wire you have.

[Ex-Calif]

This story has come out in bits and pieces over 57 posts and frankly has been hard to follow and make recommendations. So maybe a reset is in order...

330 amp hour of GEL batteries - What brand?
300 watts of solar - Wiring set up ambiguous
Victron MPPT 50/75 controller - Charge Setting not decided
Newly installed BMV700 series monitor - Calibration suspect
Daily power usage - Unknown

Max amps to be expected from the solar is probably 20 amps @80% percent of capacity for say max 6 hours a day or 120 amps. This may be optimistic.

There are 165 amps usable capacity in the bank and the ability to put in 120 without engine.

If it were my bank I would be planning consumption at 80% of predicted solar - 96 amps a day. Assuming at least half the amps are used overnight (lights etc.) that's a 48 amp drain or about 30% of the banks usable capacity (48/165) but maybe a bit higher.

So during usable daylight the panels need to make up a 48 amp deficit and supply the running loads throughout the day. For me this is borderline and I expect these banks will deep cycle frequently due to overcast in the northern latitudes.

I would be cautious and judicious in the use of generator or engine to try and avoid >30% battery discharge on a regular basis.

[sailinglegend]

Originally Posted by Ex-Calif

This story has come out in bits and pieces over 57 posts and frankly has been hard to follow and make recommendations. So maybe a reset is in order......

There are over 1700 watching it as well and they are probably confused as well. Thanks for the "reset", but I fear many people posters on here really need to get a good marine electrician on board to physically go through and explain all the points covered here. The trouble is GOOD marine electrical engineers are hard to find, better to find another cruiser who can help who really knows his stuff. This thread has highlighted a lot of the questions to ask.

Ex-Calif - one request as an Moderator you should be able to go back and edit your last post to correct your major blunders in confusing Amps and Amphours. Sorry for the criticism but this only adds to the confusion here!