jrnymn7 wrote:
Hey everyone... hope your summer has been as enjoyable as mine. (...loving the cooler than normal weather!!!)
I recently installed a new pm4b 75amp charger and Trimetric meter. My batteries are 4 Transcanada tc-2gc-220, wired in series/parallel for 430ah.
I have been unsuccessful in finding any specs on these batteries, although they are considered among the best out there. I have also read that a really good battery can be charged, in ABSORPTION mode, to as much as 99% of its capacity, i.e; until the charge current reaches 1% of the ah capacity, before it will kick some chargers into float mode. so, in my case, that would be when the charge current drops to 4.3 amps.
But according to the meter, I have reached a charge current as low as 2.4 amps before I've just shut things down and gone to bed... that's almost 99.5% charged!
So, I either have an amazing set of batteries, or something is stopping the pm4b (and all but one other charger I have tried) from dropping into float mode. I cannot obtain any info on the pm4b as to it's parameters, and I'm concerned about whether there's something amiss with either the charger or one or more of the batteries?
The batteries seem to charge well, and hold their charge well at rest. For example, last winter they sat for 5 or 6 weeks in freezing to sub freezing temperatures, and held steady at 12.78 volts. But they seem to discharge rather quickly while under load... thus the reason I installed the meter and shunt. The meter does not detect any unaccountable loads, and everything seems to be drawing power as expected. So now it's just a matter of keeping better track of my actual usage.
So I find myself in a position where, 1) I don't feel comfortable leaving the charger unattended (even though it's at a reasonable 13.67 volts in absorption mode, and 2) not sure as to what readings I should consider the batteries to be "fully" charged?
any help and experience you can share is much appreciated!
Without using a hydrometer to verify where you are at, all the numbers on all the gauges in the world are useless. When should a charger drop to float?
When lag and over run chemical idiosyncrasies are factored out, the batteries approach 100% state of charge, then the charging mechanism should default to stasis float. Temperature compensation of the battery is vital in establishing this.
I wouldn't try to do this without hydrometer verification for all the tea in China.
Does this help you?
