Solar Charge Controller for Lithium Battery

kipwill

We recently bought a lithium 100 Ah battery, based on input from this forum, and I am now ready to hook it up to our 2018 320 CS-S.  However, I've run into an obstacle with solar charger controller and need some advice.

We inherited the solar controller, and I don't even know who manufactured it, but I tracked down a manual on the internet.  The instructions explain how to change the settings from a lead-acid battery to a lithium battery by clicking on the right symbol.  I've been able to move the cursor to the lithium symbol by "long clicking" the up/down button, but I can't figure out how to get it to remain there - and I'm reluctant to hook up the battery and have the solar panels "wake it up" and charge it until I know it is on the lithium battery setting.

I'm including pictures of the controller and the relevant instructions from the manual in hopes that someone has the same controller, or one that is similar enough that you can advise how to be sure it is set to lithium before I connect the battery.

Any suggestions are much appreciated,

Will (and Kristine)

pthomas745

These types of settings are always a bit of a pain to maneuver.  The way I read this manual: when you reach the "battery type" setting, the one that is "flashing" is the one that the controller is set for.  You may have to "circle back" to the battery setting page again and see if the "LI" battery setting is flashing.  If it is, then the battery setting is correct for lithium.

Even if the controller is set for a different type of battery, the controller will still charge your battery.  The major difference between those battery types will be the charging current: the lead acid types will charge at around 13.6V, the lithium is around 14.4.  A "13.6V" setting will simply charge the battery to around 85-90 percent.  We have seen tons of the Victron solar controllers set to the wrong lead acid parameters, and except for not "fully charging" the lithium, there was no "damage" to the batteries.

kipwill

Hello pthomas,

I really appreciate your response, as it make me confident that I wouldn't harm the new battery if I just went ahead with my best understanding of what the manual directed.  So I installed the battery today, it did "wake up" and is being charged by our solar panels, and I think it will be fully charged soon.

Thanks for the informed encouragement,
Will

pthomas745

Great!  Take a look at the screen and see if you can sort out the battery type down in the lower right hand corner of the LCD screen.

You can also watch the voltage going into the battery as it charges.  A lead acid battery will be showing around "13.6V".  A lithium as it approaches full charge will go all the way to 14.4 or so.

kipwill

I now have the controller set to lithium, based on the "Li" battery icon showing in the lower right corner of the controller LCD screen.

I'm going to report what I see on the controller screen, because I don't understand all of them and you may be able to tell me what we should focus on:

As I cycle through the screens, it starts with a 13.2V reading on the initial screen with symbols indicating power from solar panel to battery to power  usage (a light bulb image).

The following screens show 13.9 with a solar panel image, 0.0 with image from solar panel to battery, 100% for battery charge, 13.2V for battery, 13.9V for solar panel, 0.00 for usage (we have the fridge turned on, but it has already cooled down), 18V (with no symbol indicating what this measures), 3.352 with image connecting panel to battery, 16 with light bulb image, and finally, "EO" with no explanation.

On the other hand, since the battery is equipped with a Bluetooth app, the app has been reading "54% SOC" since shortly after I hooked up the battery.  Initially it also said "7.19 hours to full charge," but that message no longer appears.

My main conundrum is that I don't know whether to trust the solar controller reporting that the battery is 100% charged, or the battery app that reports it is only 54% SOC.  That's a big difference!

Thanks for any insights you may have!

kipwill

P. S.  I just realized there was one other icon I needed to touch on the app for BT to engage.  Having done that, SOC is now up to 74%, and still charging.  

So I'm feeling better about getting closer to 90% in the next day or so.

I'd still appreciate any comments you may have about the other battery & solar readings . . . 

-Will

pthomas745

@kipwill, I believe the photo below is the screen you are mentioning.  These sorts of screens/readouts are pretty common in solar controllers.  I have a newer controller from a year or so ago, and my screens look very much the same.  (This is hard to tell, though.  Let us know if this matches your manual, since I may not have the correct one.)

First: ignore the mentions of "Load" and the little lightbulb setting.  Unless you wired up the "load terminals" on the controller to a 12V device (the two completely separate terminals from the solar and battery terminals) they will not pertain to your battery charging or power usage.

What your numbers sound like: with the battery capacity showing 100 percent, your battery is fully charged.  The solar panels are simply waiting for the charge of the battery to drop before they begin to send a charge to the battery. 

Your various state of charge numbers could be influenced by whether or not things are actually running in the trailer.  See if you can get a look at the controller numbers when you see the fridge cycle on and off, if you can. 

For your App....check to make sure the settings are correct for the capacity of your lithium battery, etc.  It may be necessary to go through a charging cycle or two before it settles down.

The thing to do here is let the fridge run overnight, with no power coming in, and watch how the solar reacts in the morning with sun on the panels.  There isn't much "action" showing in most battery monitors if the battery is fully charged.