Steve, Inside your NG3 are two calibration pots. One is marked U for Voltage and the other I for current. If you are comfortable with working with live parts and know how to do it safely you could take the cover off and adjust the voltage down within the limits of the pot. Just remember you will need some way to cool the components, I used a large box fan, and that the internals of the charger are live.
As for T3, if it is like my Zivan NG1 and NG3 then T3 is dependent on how long the charger was running before reaching that point. On mine the time ranged from around 45 min to two hours. The Um of 132V is just the voltage that the charger will not go above. If the batteries never get to that voltage then the charger will keep the equalizing current at its max setting. Again, be careful if you operate on your charger while it is plugged in to anything, including the batteries. Use an insulated screwdriver to make the adjustments. On Tue, Oct 22, 2013 at 3:35 PM, zeke Yewdall <[email protected]> wrote: > Yikes, 190 for a 144 nominal is a pretty high equalizing charge every time.... > > Sent from my iPhone > > On Oct 22, 2013, at 1:27 PM, RightHand Engineering <[email protected]> > wrote: > >> Hi Steve,My comment is that the US distributor for Zivan seems to >> consistently program the Zivan chargers to be too aggressive when charging >> wet PbA batteries. I got an NG5 from them which charged my 144V pack to over >> 190V each cycle, and that was in effect doing an EQ charge each cycle. I >> checked with the manufacturer of my T-145 batteries (Trojan) and they agreed >> that it wasn't good for the batteries. So I went back to the distributor and >> asked to have it reprogrammed (for free), but they refused and defended >> their charging profile as "good" for the batteries. My batteries were dead >> within 3 years, rather than the normal 5 years. I've since replaced my NG5 >> with a PFC-30 by Manzanita.-Randywww.evalbum.com/1253 >> >>> Date: Tue, 22 Oct 2013 11:54:24 -0400 >>> From: [email protected] >>> To: [email protected] >>> Subject: [EVDL] Charge profile on Zivan NG3 for 108V US Battery 125's >>> >>> Below is the charge profile in my charger for a 108V pack if US-125's >>> >>> Im = 13 Amps constant current until voltage hits U1 which is 128.7V >>> >>> Hold voltage at U1 which is 128.7V until current fades to I2 which is >>> 6.7Amps. >>> >>> Current is held constant at I2 which is 6.7 Amps for T3 which I am a little >>> unclear on, but I believe T3 ends when the voltage hits Um which is 132V >>> (seems very high for a 108V pack, but that is what the data sheet says). >>> >>> Then it floats forever at 119V >>> >>> I believe this profile is overaggressive and damaging the batteries, >>> espicially the part where it goes up to 132V. So, I am looking for some >>> expert opinions as to if this is too aggressive. >>> >>> Also, I plan to monitor the voltage and pull the plug at a certain point. >>> I believe I should terminate the charge somewhere around 130V, so I know >>> it is at least 80% charged. Then literally plug it back in, which I >>> believe will go straight to the float charge. This would essentially skip >>> step 3 of the charge cycle. >>> >>> Does anyone know if I can actually do this and the charger will behave as I >>> am thinking it will? If the pack is >80% charged when I unplug, wait a few >>> minutes, and plug back in, will it go straight to float charge mode? I >>> would think it should as a safety precaution so as not to overcharge the >>> pack in case of a power outage (which is what I am simulating). I know >>> other smart chargers go straight to float if they are near 80%, but the NG3 >>> manual doesn't say anything about this. >>> >>> Also, is there a way to fake out the temp sensor to trick it into charging >>> to a lower threshold? That was my other idea. Or, send it back and tell >>> them I need it programmed for small AGM batteries instead of these big >>> flooded batteries. >>> >>> Thanks, >>> >>> Steve >>> -------------- next part -------------- >>> An HTML attachment was scrubbed... >>> URL: >>> <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20131022/f0b47acd/attachment.htm> >>> _______________________________________________ >>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>> For EV drag racing discussion, please use NEDRA >>> (http://groups.yahoo.com/group/NEDRA) >>> >> >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: >> <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20131022/79cfc6fa/attachment.htm> >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> For EV drag racing discussion, please use NEDRA >> (http://groups.yahoo.com/group/NEDRA) >> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA > (http://groups.yahoo.com/group/NEDRA) > -- David D. Nelson http://evalbum.com/1328 http://www.levforum.com _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
