RESULTS of a 50-90+% charge with modified pm4b-75:
well, i finally got around to doing a charge on one of the 215Ah banks, from 50% soc, with the modified 75. now keep in mind, this un-modified pm4b had yet to go into boost mode on discharged batts… neither the 430 bank nor the 215 banks… and it would only go into boost on near full batts (for its preset 15 minutes). and after the mod, and with no batts attached, it would do its 15 minute boost at my setting of 15.2v boost and then drop to 14.15vabs, and do the same on near full batts (it appears to no longer go into float when charging).
charge cycle results:
with no loads attached, batts at 12.21v and -106Ah, and the mod pm set at 15.2v boost and 14.15 vabs:
- the pm started at 13.1v and 46.1 amps… volts quickly rose to 13.83* and stayed there for about 5 minutes… then rose to 13.93v over the next 10 minutes. (amps held steady at 46.1)
* at this point i figured it was not going to do a boost charge, seeing as it hadn’t risen quickly to 15.2v… but lo and behold, it shut off for a few seconds (at the 15 minute mark) then turned back on and carried on from where it had left off. then voltage rose to 13.99 over the next 5 minutes, and 5 minutes after that voltage was 14.01 and amps had begun to taper (45a). i then checked voltage drop, and it was .09.
- i took readings every 10 minutes from this point, and over the next 6 hrs 15 min., it was at 14.15** volts and 2.6 amps… 104 Ah replaced, according to tri-metric.
** not sure if the gradual rise to 14.15v is a coincidence or not???
i let the pm rest about 5 minutes, then did a bench test with no load… it quickly rose to 15.2v., and dropped to 14.15 at the 15 minute mark. so i connected it to the other 215 bank, which were at 12.76v, and it quickly rose to 15.13v, and then 15.18 over a couple more minutes.
... it was late, i was tired and hungry, and perhaps a little tipsy by this point, so i shut ‘er down for the night.
i checked batt voltage about 18 hrs later, and it was at 12.82v… that’s possibly the highest it’s been after resting that long… perhaps because of the smaller bank being charged?
so,
1) it quickly goes into full voltage boost on the bench;
2) it goes into some modified (not by me) version of boost on 50% batts; where it then appears to enter abs mode, and rise to my vabs setting once the batts are near full??? ;
3) and for the first time, it went into what appears to be a slower rising voltage boost on near full batts???
