float voltage

This is a solar float when it is night more than it is daytime and when daytime isn't sunny so much (Nov-Mar) So the set voltage will be reached sometime some days but Vbatt usually will be lower than that on average.

Thanks mex.

The blue Sky is currently set to 13.2 float. Batteries want a little more than this and I can reliably set it higher by increments of 0.2 volts.

If your solar controller is reliable enough to guarantee no more than 13.6 volts then daytime floating would be just fine.

If floating was not necessary then Telecomm chargers would wait until an outage depleted the batteries then recharge them then go offline once the charge cycle was complete. The low self-discharge rate of calcium/calcium flooded and AGM is a positive attribute not an excuse to ignore them. Teleomm companies are like golf courses - they maintain meticulous records of value, performance, and maintenance. Then theychoose the cheapest course. Pay attention. They are the masters.

I believe no float would be worse than leaving just the Blue Sky doing its 'thing'. After all, I coaxed 6 and 10 years out of walmart jars in this manner.

chuckbear wrote:

BFL13 wrote:
Since they are AGM's why do you have to float them at all if disconnected?

Even a new AGM can self discharge at about 3% per month. Older batteries, even more. The discharge rate is also temperature dependent. The higher the storage temp, the higher the discharge rate. Chuck

Storage in Saskabush from November to mid-March would be low discharge rate then.

Choice is float at maybe wrong voltage and undercharge or overcharge the whole time or some of the time doing one or the other with whatever bad consequences, or

Let each battery sit with no wires on it and take the hit from sitting undercharged by however much for how long, and then do an AGM type "recondition" in March.

I like the predictable outcome of disconnecting. Hate to be away and wonder if the solar is still working and how it is going. Plus the OP, who is not a battery newbie, would have confidence in being able to do the AGM recondition properly on his return

BFL13 wrote:
Since they are AGM's why do you have to float them at all if disconnected?

Even a new AGM can self discharge at about 3% per month. Older batteries, even more. The discharge rate is also temperature dependent. The higher the storage temp, the higher the discharge rate. Chuck

Since they are AGM's why do you have to float them at all if disconnected?

Snow has only been an issue once in the last 16 years. Dec 21 will net 17 amp-hours of charging. I have rv'ed at -37 C

21 day equalize?

What may happen if you charge them to 14.4v daily, hold that for 2 hrs then hold 13.2v till no more sun, them no voltage till there is sun to start over?

What about snow?

pianotuna wrote:
Phil, at -40 I will need temperature compensation.

-40 .... are you kiddin' me?! With the upper atmosphere CO2 levels where they're headed .... is anywhere on the planet going to get down to that level anymore?

Methinks that high temperature compensation for battery charging is going to be the name of the game going forward. In the not too distant future lead acid battery charging boost voltages need only be 13.8 volts and floats need only be at 12.6 volts ... of course by then RV'ers (my grandkids?) may/will be off lead acid altogether and onto aluminum-ion graphite batteries or quantum batteries. ;)