-
-
Probably the most detailed Exide charging specs I've ever seen from them:
But as Sunking mentioned, the hydrometer tells all, not just voltage. For us agm guys, that is all we have to go by.
Related to the max-smoke thread, take a look at the absorb column! Quite enlightening, BUT this is valid only for *single* 12v batteries, not in a series / parallel arrangement.Comment
-
OK so what does your current hydrometer tell you? Is it low? Once you get the second one and it agrees or close, then you will know what is going on. If you are running low, your only counter action is to raise the voltages in an attempt to see if you can get them charged up. If you have sufficient power, by the end of the day should have 100% or pretty close. On the other hand you may also find there is no voltage high enough which simply means not enough panel wattage. Your controller stays in MPPT mode all day but still cannot keep up.
On an Outback FM80 and FM60 is real easy to set up. You set Absorb to 2.467 per cell example 14.8 volts on a 12 volt battery. This will force your controller to stay in MPPT mode (full available power) or Constant Current until the battery voltage reaches 14.8 volts.
Once 14.8 is reached the Absorb stage starts and is a Constant Voltage mode. Your controller now operates in PWM mode, less than full power. Current will begin to taper off as panel voltage and battery voltage begin to equalize. After several hours the batteries become saturated at 14.8 volts and charge current will drop down to .01C to .02C indicating full charge. So the second setting is Absorb Time = Maximum or 6 hours. Third setting is Absorb Current Cut-Off = .02C. Last setting is Float = 13.2
Set up that way on eof two things will happen.
1. A daily cycle will be normal go through Absord stage until charge current tapers to .02C indicating full charge, then switch into Float before the sun sets.
2. You do not get a full cycle and never make it to Float before dark.
If you are fortunate and get a full cycle, use the hydrometer to fine tune the Absorb Voltage. It means you have enough panel power. We all know what #2 means, not enough panel power.MSEE, PEComment
-
Probably the most detailed Exide charging specs I've ever seen from them:
But as Sunking mentioned, the hydrometer tells all, not just voltage. For us agm guys, that is all we have to go by.
Related to the max-smoke thread, take a look at the absorb column! Quite enlightening, BUT this is valid only for *single* 12v batteries, not in a series / parallel arrangement.
Woa, thanks PNJ! That's exactly what i was after, i just wanted to make sure i know of any quirks that these things might have.Comment
-
I wonder where 14.8 come from. Did someone just make it up? Bad question, the real question was Exide first (leader) to go up significantly on Absorb. or did they follow another company lead?
Thanks PN, you got my back. So if anyone takes issue with the Stickie is just not up to date, so take note.
Battery voltage is not an exact science, just way too many variables. It is more of an Art than Science. Thee old recs were based on assuming commercial AC power using 3-Stage charging algorithm. Works pretty damn good that way, but not worth a damn for solar. Thus now you see significantly higher charge voltages. Reason is real simple, the older 14.1 to 14.4 Absorb range operated the batteries just short of going to the edge of 100% SOC or more. In other terms on the slightly undercharged side of the knife edge. Couple that with Solar limitations leaving you even further from the edge of significantly undercharged. Chronic under charging shortens battery faster than fully charged or slightly over charged batteries. Living on the edge or just over the over-charge side will last the warranty period and make customers happy. Chronic under charging will not likely make it through the warranty period leaving both customer and manufacture unhappy.MSEE, PEComment
-
-
I think some of the reason for the conservative specifications is due to trying to dumb-down, or out-think the abusive user from "going to 11". (for you Spinal Tap fans..)
I've been tearing my hair out for years about the conservative values (well at least for agm) and why they didn't add up under my testing usage ...
An example:
In a cyclic scenario, Enersys (at least in the 1998 EV guide) and even Optima recommend basically an IUI protocol, but that last "I" is hard to do with a consumer charger! But it points out that one REALLY needs to stop undercharging - the question is how to do it properly. This implies finishing, or nearly finishing absorb before an attempt at the last CC (at whatever voltage that takes to do it!) occurs.
But, the average consumer who doesn't have any chargers available to do it right, may end up using a high voltage at the START of the absorb phase with some old wheeled charger in the shop, which just gasses and spins wheels, instead of at the *end* of absorb. Even so-called auto-parts "speed-chargers" that I have tested can go into this mode prematurely with bad results!
Optima's own charging guidelines under the "cyclic" 14.7v heading, promote IUI without actually spelling it out. But that last "I", when most people read it, think of float! Not so.
But they don't have the gear to do an IUI properly, so the second best thing is to extend absorb up near the high end of the normal spec-rating and forget about float. Temp comp preferred too of course.
This is just one example hidden amongst many manufacturer's older documents. They may hint at it, but might suggest that commercial customers should contact our tech support. Us peons who are likely to do it wrong - just replace your batteries sooner than later.
Comment
-
Conservative values from a manufacturer's standpoint - put yourself in their shoes ..
A single battery with an unknown charger may be bad enough, but what about the guy that slaps together a big series / parallel arrangement that is totally unbalanced to begin with?
With conservative values, the purchaser will get some life out of them, not really knowing about the walk-down in capacity until much later, but with the *right* values may end up smoking a good battery with poor balance, high resistance interconnects, etc, and demand a speedy warranty replacement - despite the fact his own environment was really at fault.
I like conservatism when it comes to solar - it is one of our major tenets - but in this case of truly getting the most out of a battery, it hurts, rather than helps as long as one doesn't swing to the other extreme.
Egads man - I might even be interested enough to actually pick up an FLA, and not baby it and see if I actually need a monthly EQ. The goal here would be to not have to do it at all, or perhaps have only a very minor EQ here and there.. HmmmmComment
-
It took a while to kill my first 2 DC12V200s, over 3 years. That was a combination of very deep discharge cycles, a PWM controller, and pretty well NEVER getting to full charge. and STILL 3 years before a cell died. I was really bad on those things, but i DID actually have a hydrometer even though it wasnt temp compensated, and did actually top up with deonised water.Comment
Tweet
Comment