Solar install

Forgot to post up pics of my simple, El-cheapo solar install Healhustler and I did a few weeks ago.

I don’t have much room on my boat for panels so I had to shoehorn two of these big panels up there. They are 300W panels I got from a home installer that were “left over”, for $125 each.


Used these rail mounts, which were pretty easy to set up and use. The mounts were almost as much as the panels at $200 for 4 rails and all the goodies, but it seemed to be a good solid system. [emoji15]
https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/173716531296



Used these controllers, one for each panel so boom and sail shading would be minimized.


Wired it up with this wire and 60a fuse at the battery.



The panels hang off the back of the roof a little bit, which looks a little odd, but it gives me more shade!


All in it was about $1000, not including the rum Larry and I drank.

Nice looking setup, and a great deal on the panels.

Finally got back to the boat to get ready for our Bahamas trip. Checked the solar history and this is what showed up. Each panel has its own VictronConnect controller.

Port panel



Starboard panel (gets more sun at the dock).



When I left the boat I didn’t turn on the AC battery charger so I could see what the panels did while I was gone. There was no DC load left on in the boat either, so I’m not sure what to make of all this.

Is it surprising the battery voltage swung between 12.8v and 14 plus volts during the day? I switched the fridge and freezer on today so I guess that’s why it briefly showed 12.5v today.

I don’t know what to make of the WH (guess that’s watt hour?) panel output history either.

When I got to the boat first thing I checked was the Balmar “Smart-gauge” battery monitor and it showed 100%, but after just 30 minutes running the fridge and freezer it showed 90%, which doesn’t seem right at all. It’s never dropped that fast. Maybe it needs to recalibrate or something?

Any ideas appreciated. Batteries are 4 year old Lifeline AGM.

One thing that scared me initially was that when my batts are "topped off" the voltage/incoming drops to near nothing. The first time I realized this I was worried that I was only getting incoming of 1 or none, when I should be seeing 15-25!!!

Now my set-up is not nearly as fancy as yours, however the 90% is okay. What's happening is a big draw is showing a false picture of your battery status.

In my cabin, when I turn on my fan the voltage reading goes down .2 (from 12.4 to 12.2 for instance) however as soon as I shut off the power draw it goes back to normal. (12.4, in this scenario)

Your set-up looks spiffy. Very nicely done. And congratulations. Your Bijou is better than ever!

Something does not seem quite right. You have two 300W panels but the most output you have seen is 80W on one side and 40W on the other. Also, only getting 80 Watt hours or 40 Watt hours of energy per day seems very low unless you live in the PNW in the winter.

With no clouds and the sun directly overhead and no shading, you should be seeing 250+Watts per panel.

Hey Janice! Thanks! Larry helped me install all that stuff.

We are finally getting ready to go on a trip to the Bahamas in a few days. My wife is supposed to show up in a few days and then we are off.

I was looking at some recommendations on the Lifeline site and they recommended these absorption charge rates and times. My battery box is in a pretty hot area so assume I need to use the 90 degree charge rates of 14.15v absorption and 13.13v float charge. Is a 3 hour absorption charge time enough I wonder ?

gsholz said:

Something does not seem quite right. You have two 300W panels but the most output you have seen is 80W on one side and 40W on the other. Also, only getting 80 Watt hours or 40 Watt hours of energy per day seems very low unless you live in the PNW in the winter.

With no clouds and the sun directly overhead and no shading, you should be seeing 250+Watts per panel.

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Exactly. It looked funny to me as well. This is sunny Florida. No shading on the starboard side at all.

Maybe because the batteries are full the controller is limiting the output? I’m a newbie at this stuff so don’t know! Will test it more tomorrow in full sun and put a load on the batteries.

Yes, it is probably the controller limiting output because it sees high battery voltage. Turn on some heavy power users (inverter+microwave) at noon and you should see how much the panels can produce.

[emoji106][emoji106]

Your output looks completely normal to me. If the batteries are fully or almost fully charged you won't get much output from the controllers otherwise they would be overcharging the batteries.

Ken

When your batteries are fully charged the Victron controllers will push the panel voltage up to near its maximum to reduce charging current to only what is needed to float the batteries. So basically what you are seeing is just the amount of power from the panels needed to push the batteries into float mode and keep it there every day. Leave something on overnight and you will see a much higher output from the panels the next day. Alternatively, look at the panel output when nothing is connected during full sun, then turn the refrigeration on. You will see a big jump in panel output coupled with a drop in panel voltage down to the maximum power point. In other words, what Ken (Kchace) said.


Your batteries drop to 12.8 at night when there is nothing coming in from the panels and then go up to 14+ during the brief period of bulk charging each day. Those vertical bars on the display have three shades. The bottom is bulk mode, middle is absorption and top is float. You can see that your batteries are in float mode most of the time. The watt hours is the amount of charge put out by the panel.

As others have mentioned, if your batteries had no load on them your output looks good. Each morning your controller is going to wake up, and start bulk charging your batteries and quickly go to absorb.

Ideally, according to the page from Lifeline that you posted, the absorb charging phase should continue until the current being accepted by the battery bank is .5 % of its capacity. I don’t know what your battery bank capacity is but if it is 600 Ah, then you would want to change in the absorb phase (ie constant voltage) until the current was down to 3 amps. Then it would convert to float and hold the float voltage until the panel loses the sun. Then the process would start again the next morning.

I believe that your controllers will switch from Absorb to Float when the absorb current drops to 2 amps. Depending on your battery bank size, this could be too high or too low to be ideal. Each day will be different but when you are on the boat during your Bahamas trip, try to check in with the controller and see how long your controller is in absorb charge each day. Also check to see what how many amps is being provided near the end of the absorb period. If you only need a tail amperage of 3 amps for your bank, but the controller is often switching to float before the absorb time limit you set (ie you hit a 2 amp tail current), then you might want to shorten the absorb time limit.

FWIW here is what my controller has done over the 7 day period before this weekend. I have only 1 365W panel. The charger was off and I had two refrigerators running. We has lousy weather this past week with lots of heavy overcast days and rain. My battery bank is nominally 780 Ah.

Continued because I can’t edit.

You will notice that 4 days, my batteries never made it out of bulk charging. 4 days it made it to float.

Ahh thanks all. I get it now. Here is the history so far this AM with the two fridge/freezers running and some lights on.

Sorry another question:

What battery voltage should I shoot for by the time the sun goes down. Reason I ask is it seems like the controllers go into float by noon or so, and then when in float the charger doesn’t seem to keep up with the load and get the batteries to 100% (according to my Balmar battery monitor). It doesn’t seem like the float charge level really keeps up with the boat load.

Should I up the float voltage? I have it at 13.25V for float and 14.21v absorption.

Also, it doesn’t stay in absorption very long before switching to float. Was only in absorption for 30 minutes today.

cardude01 said:

Sorry another question:

What battery voltage should I shoot for by the time the sun goes down. Reason I ask is it seems like the controllers go into float by noon or so, and then when in float the charger doesn’t seem to keep up with the load and get the batteries to 100% (according to my Balmar battery monitor). It doesn’t seem like the float charge level really keeps up with the boat load.

Should I up the float voltage? I have it at 13.25V for float and 14.21v absorption.

Also, it doesn’t stay in absorption very long before switching to float. Was only in absorption for 30 minutes today.
View attachment 89353

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The numbers you used seem low. According to Trojan batteries, Bulk charge should be 14.8 for flooded cells and 14.4 for AGM style. Float charge voltage should be 13.5 for flooded and AGM style batteries. The recommendations can vary slightly by manufacturer so if you can find data on the actual batteries you have that would be best.


Ken

Highly recommend you add these to your setup -

https://www.victronenergy.com/accessories/smart-battery-sense

Takes all the guess work out of coming up with temperature adjustments. The Victron MPPT controllers will figure it all out with these little wireless sensors.

I think I was using the wrong setting for my batteries. The more I read others with Lifeline AGMs are using absorption of 14.4v and float of 13.6v.

AdmiralS said:

Highly recommend you add these to your setup -

https://www.victronenergy.com/accessories/smart-battery-sense

Takes all the guess work out of coming up with temperature adjustments. The Victron MPPT controllers will figure it all out with these little wireless sensors.

Click to expand...

Ahh thanks. Will get those.

Do I need one per controller?

cardude01 said:

Sorry another question:

What battery voltage should I shoot for by the time the sun goes down. Reason I ask is it seems like the controllers go into float by noon or so, and then when in float the charger doesn’t seem to keep up with the load and get the batteries to 100% (according to my Balmar battery monitor). It doesn’t seem like the float charge level really keeps up with the boat load.

Should I up the float voltage? I have it at 13.25V for float and 14.21v absorption.

Also, it doesn’t stay in absorption very long before switching to float. Was only in absorption for 30 minutes today.
View attachment 89353

Click to expand...

My notes show that Lifeline recommend an absorb voltage of 14.2-14.4 and a float voltage of 13.2-13.4. So if it was me, I'd aim for 14.3 absorb and 13.3 float. Your settings are fine, but are on the low end of the range and unless you have a battery sensor telling your controllers what the actual voltage is, there may be some drop from the controller to the batteries.


Check your controllers manual, but the controller will go back into bulk mode if there is a large enough load to lower the battery voltage below a set level. Once the absorb voltage is reached again, then it will stay in absorb mode until the amperage hits 2amp or the timer runs out then it goes back to float.


If you have low loads on the battery, the loads may draw a higher current than your controller is supplying in float. If that continues long enough, then it will go back to bulk, then absorb mode. I've found that on mine, it can enter float a couple times during the day depending on the battery loads.

cardude01 said:

Ahh thanks. Will get those.

Do I need one per controller?

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Thats a good question. I am assuming that you don't have these all connected to a Victron Venus gateway or other management system and connect to each individually via Bluetooth so they are standalone.

I would think you need 2, 1 paired with each controller. They are hooked up to the same battery bank, but will report the corresponding temp and voltage to their controller.

I would call Victron and ask them their thought. But I am guessing 2 in your setup.

Given Victron makes controllers that allows multiple panel inputs, I am surprised you installed a second charge controller. You would have gotten the same result with a single MPPT controller with the MC4 Inputs.

Seems like some with multiple controllers are having a problem with them going into float too early. That’s what mine seem to be doing.

I don’t see a setting for how long to charge in bulk or absorption mode, just a max absorption time.

Maybe increasing the absorption and float voltages will give me longer bulk and absorption charge times.

https://community.victronenergy.com...-the-documentation-warn-that-multiple-mp.html

AdmiralS said:

Given Victron makes controllers that allows multiple panel inputs, I am surprised you installed a second charge controller. You would have gotten the same result with a single MPPT controller with the MC4 Inputs.

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I actually can’t remember why I installed one controller per panel. Something about the wiring, and better for shading I think? I’m obviously not a guru.

Shot a drone video. This is the DJI montage thing in the editor software. So easy!

https://youtu.be/UmtqwJTUwPY