Temperature Compensation--Battery or Ambient?
OK I have had my fill of why you need a temp comp probe to the battery casing or battery post (whichever one this week it is supposed to go on, the neg or the pos :) )
I understand temp comp and agree with it. My VEC1093DBD has it, and you can see the higher voltages it does in cold temps compared with summer values. Also, most $15 eBay solar controllers have temp comp in the unit itself.
So all you have to do is mount the $15 controller in the same ambient temperature as the batteries are in and you are good to go. Right?
Wrong say the fanatics. The temp comp is supposed to be for the battery temperature itself, not the ambient temp. Well what is the "battery temp?"
Some have the temp comp sensor stuck onto the side of the battery, others are with ring terminals that go on a battery post. Other people say you need to peer down a battery cell with an IR temp gun and find out what the "real battery temp" is.
But the electrolyte heats up when being charged. Maybe it gets hotter than ambient. So now who's right? And at what SOC are they right assuming it keeps getting hotter as SOC rises?
And outside a chemistry lab, or in deepest, darkest Saskabush, what real difference does it make if ambient and "battery" temp is not quite the same (if we even know what "battery" temp means ? ) as long as you are in the ballpark for charging voltages?
I strongly suspect that the $15 solar controller with its internal temp comp sensor, if mounted where the ambient temp is the same as the ambient temp in the battery compartment, will do just as well as the fabled "required" remote sensor to the battery itself, available only in the $900 solar controllers the fanatics insist are the only ones you can have that will keep your batts alive more than a year, even in such desolate regimes as found in the hinterlands.
( We sure don't need it in on the Northwest Coast of North America, but of course I am posting for the less fortunate who don't live here, and for those who do, but might be misled into getting a too-fancy charger)
However, it may prove that there are indeed valid reasons--in which case we will all benefit if we get any sensible replies here. :)
I understand temp comp and agree with it. My VEC1093DBD has it, and you can see the higher voltages it does in cold temps compared with summer values. Also, most $15 eBay solar controllers have temp comp in the unit itself.
So all you have to do is mount the $15 controller in the same ambient temperature as the batteries are in and you are good to go. Right?
Wrong say the fanatics. The temp comp is supposed to be for the battery temperature itself, not the ambient temp. Well what is the "battery temp?"
Some have the temp comp sensor stuck onto the side of the battery, others are with ring terminals that go on a battery post. Other people say you need to peer down a battery cell with an IR temp gun and find out what the "real battery temp" is.
But the electrolyte heats up when being charged. Maybe it gets hotter than ambient. So now who's right? And at what SOC are they right assuming it keeps getting hotter as SOC rises?
And outside a chemistry lab, or in deepest, darkest Saskabush, what real difference does it make if ambient and "battery" temp is not quite the same (if we even know what "battery" temp means ? ) as long as you are in the ballpark for charging voltages?
I strongly suspect that the $15 solar controller with its internal temp comp sensor, if mounted where the ambient temp is the same as the ambient temp in the battery compartment, will do just as well as the fabled "required" remote sensor to the battery itself, available only in the $900 solar controllers the fanatics insist are the only ones you can have that will keep your batts alive more than a year, even in such desolate regimes as found in the hinterlands.
( We sure don't need it in on the Northwest Coast of North America, but of course I am posting for the less fortunate who don't live here, and for those who do, but might be misled into getting a too-fancy charger)
However, it may prove that there are indeed valid reasons--in which case we will all benefit if we get any sensible replies here. :)
