battery, your thoughts-help

Re: battery, your thoughts-help

Watt wrote: »

For absorb, I stick with just a volt or so lower than bulk

How do you do that? It sounds like the charging profile used by some of the grid powered forklift battery chargers that use a constant current finish charge. Those chargers get all confused by loads.

Most RE chargers (such as your classic or your magnum) do not have a way to set Absorb to a different voltage than Bulk.

--vtMaps

Re: battery, your thoughts-help

vtMaps, good catch.

In that mess above, I should have written EQ. Thanks, I will fix that now.

By the way, this is the set points I use.

http://i261.photobucket.com/albums/ii74/Chevy_l88/20131201_104035_zps7a849f97.jpg

Re: battery, your thoughts-help

I wouldn't know what is right or wrong for your battery. You talked with the manufacture and by that, you can't go wrong. I don't have a new battery like you do, I have some old beat up ones.

My thoughts, though, are:

Why beat the batteries up with extra voltage.
' My ' experience has been to find the lowest possible absorb voltage setting that increases SG and minimizes gassing yet bring SG up to near max every charge.
Complete an EQ at the end of an absorb stage: This lets me;
Get a handle on when the battery requires an EQ.
To see if the absorb scheme is working correctly.
Check the SG to see if I even need an EQ charge.

Re: battery, your thoughts-help

Vic wrote: »

Hi Wattr,

I do not want to be too argumentative, however. If those of us with battery-based power systems are beating our batteries to death with discharges at the 6 hour rate (or similar heavy discharges) for extended times, then believe that there is a serious battery sizing issue.

The systems here have battery discharges well under the 100 hr rate, for extended times.

You and BC04 HAVE made good points about the Peukert effects regarding Forklift batteries. These are good points. But it is my bet that these very high relative current demands of RE battery systems are quite rare.

Some UPS and similar systems may well beat the batteries to near-death, but seems that this is not very common.

Realize that gww IS grid connected, and the exact nature of that system is not clear to me -- seems that that system has large Opportunity loads that are not extracted from the battery ... still trying to figure out just what/when all of the demands are placed on the system, and so on.

Just an observation. Vic

Hello Vic

My observation on the Peukert law seems to point out just how " not so good " these forklift batteries are for RE. I also believe that Peukert's law points out that in a RE environment, these type batteries require far more AH to replenish what was stored and the grid is not a viable solution to replenish these charges.

No argument, you guys rock on.


As an edit:

I think I eluded to the Peukert law and my comments regarding such. Knowing Peukert's law allows the correlation to current draws and AH ratings. He has indicated that he has a 800Ah battery and knowing Peukerts law would indicate that to be a current rate of 40A for 20hrs. Now, reading his posts also indicate that at other times his AH draw is higher than this rate, which based on Peukerst law, indicates that storage AH capacity is no longer the case and has now dropped to a lower level which may be 4 or 5 hour capacity. My comment on that was regarding when the battery would be " dead ". I understand that he is grid connected and that grid and those chargers will help insure his battery does not stay at a very low SOC if he keeps an eye on it and he will also not have to worry about the lights going out. And, by knowing the 6hr rate and the 20hr rate, he can have a clearer view as to why his battery is dead or low depending on the loads he draws and the charge he replenishes. Also, just want to point out that voltage readings of the battery under load do not correlate the state of charge directly. The load has to be considered before a " disconnect " voltage can be accurate to represent the SOC.