Only difference is voltage set point. Absorb, Float and Equalize are Constant Voltage modes. Absorb is not a timed event. Thus why solar charge controllers fail to completely charge batteries. Absorb is a Current Event. Full charge is achieved when charge current tapers to 3% of C. That can take 6 to 10 hours. Equalization can take up to 24 hours.
Three stage charging does not work with Solar because the sun does not shine 24 hours. You have to use you hydrometer to set voltages. You want to force your controller to be a simple CC/CV charger and the way you do that is set Bulk = Absorb = Float. Start at 14.4 volts. As the sun sets check specific gravity. If it is low, raise the voltage. This time of year you will likely find there is no voltage high enough. There is simply not enough sun. This is why you must have a generator.
Take Mike's advice and read the stickies. Starting with this one.
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Thanks Mike - I understand that if you can't get enough power from the sun, you need to use the generator. However, I'm trying to configure my voltage points in the best way. (I appreciate that for my current out of warranty batteries all hope is lost, but we take this as a good time to learn as much as we canRead some stickies (link below) - you have some incorrect info you typed out
EQ'a should be done in limited amounts every other month is good.
if your SG is low. you must run your generator, preferably in AM, so the solar can finish the absorb & bulk parts of the cycle. When the SG is low for more than 24 hours, the sulfate crystals start to harden and become difficult to return to solution. This is called Sufated Battery and generally, cannot be easily reversed, the longer it sits low (below 80% of full) the deeper the damage
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I read the sticky threads and based on that I've set Absorb = float which triggered the questions I asked.
I more or less understand the different phases if we'd have 20 hours of sun every day, but want to make sure I get as much charge to my batteries now in winter time as I understand it's silly to have my batteries float at 13.7 if there are only 4, 5 hours of proper sun to be used.
ps: This is from the sticky thread
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Absorb & BULK are generally the same voltage, Float is a slightly lower voltage to gently finish charging and not stress the battery too much. Float will seldom happen wintertime, off grid
If you can't extend your Absorb time longer, increase the Bulk/absorb voltage slightly ( just 0.2 v at a time) till you see some current (amps) reduction part way through absorb. A week of long absorbs may be needed to get the battery charged enough to be able to EQ it. Only a fully charged battery can be EQ'd
If your batteries are 6 years old, they may have reached their End of Life. What was the warranty on them ?Leave a comment:
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Read some stickies (link below) - you have some incorrect info you typed out
EQ'a should be done in limited amounts every other month is good.
if your SG is low. you must run your generator, preferably in AM, so the solar can finish the absorb & bulk parts of the cycle. When the SG is low for more than 24 hours, the sulfate crystals start to harden and become difficult to return to solution. This is called Sufated Battery and generally, cannot be easily reversed, the longer it sits low (below 80% of full) the deeper the damageLeave a comment:
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Battery life lessons
We bought a fully off-grid property with lead acid batteries about a year and a half ago, which were already not in the best state ever. At that point, we hadn't even heard about charge controllers, lead acid batteries, ...
https://www.solarpaneltalk.com/forum...your-batteries... already makes a lot more sense to me, compared to a year ago when I had absolutely no knowledge whatsoever. I now feel confident-ish to start asking some questions...
In winter time, here in Portugal where I live, we only get 4 hours of proper sunlight due to hills in the east/ west (days are about 8 hours). We use about 1.5 kW every day (on non- hoovering days) and with float set to 14.8 we generate about 1.5 kW/ day. When we set EQ (15.4) on in the morning, we'd generate about 2.5 kW/ day
I'd like to get to a better understanding of some (basic concepts) to adjust the settings to make sure we get most out of our new batteries in the future and to see how far we can stretch the life of our current battery.
The specific gravity has not been at its peak compared to measurements in September/ October (where we'd get more than the double of direct sun)
1. If Absorb and Float are both set to 14.8, what's the difference between the two stages? I want to find out what I should do with the time for the absorb phase.
2. If Float and EQ are both set to 15.4 and currently the battery is on 15.0V, would float and EQ at that point behave the same?
3. Currently absorb/ float is set to 15; if I let's say up this to 15.2 then this basically becomes the same as my EQ V was in summer time. In the sticky thread, I read that you shouldn't EQ too often so I don't know what to make/ do with this info. I understand this is to avoid corrosion, but should I worry about this having 6-year-old batteries which went unmanaged through many of these winters.
Can I go too high with float voltage (as long as I don't go over my batteries max Voltage)?
WLast edited by Woutah; 12-27-2017, 11:33 AM.
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