RS2000 Charging Question

afrank1971 · 12-30-2007, 08:24 AM

I just finished installing 6 Lifeline GPL-31T batteries and had previously installed a Xantrex RS2000. Upon completing the project, I plugged the coach in to bring the 630aH battery bank up to full charge. RS2000 is set for AGM batteries, 630aH size, yet, much to my surprise, it started charging them at 15 volts in Bulk mode. Then went down to about 14.8 in absorb. Isn't this too much voltage? Isn't the RS2000 supposed to know to keep under 14.4v for AGM's. Or does temperature affect the charging voltage? It's 50? right now, could that be why? Main question, do I have a problem, is my RS2000 frying my brand new batteries?
Thanks,
Alan

afrank1971 · 12-30-2007, 08:24 AM

I just finished installing 6 Lifeline GPL-31T batteries and had previously installed a Xantrex RS2000. Upon completing the project, I plugged the coach in to bring the 630aH battery bank up to full charge. RS2000 is set for AGM batteries, 630aH size, yet, much to my surprise, it started charging them at 15 volts in Bulk mode. Then went down to about 14.8 in absorb. Isn't this too much voltage? Isn't the RS2000 supposed to know to keep under 14.4v for AGM's. Or does temperature affect the charging voltage? It's 50? right now, could that be why? Main question, do I have a problem, is my RS2000 frying my brand new batteries?
Thanks,
Alan

Route 66 · 12-30-2007, 09:20 AM

Alan, I've linked your post to the RV systems forum for a wider audience.

I'm curious about this also.

The Xantrex owners manual does state the charging voltage is higher in colder conditions, and gives a formula to determine the charging rates, but it's over my head.

If it were me, I would contact both Xantrex and Lifeline for their thoughts.

John_Canfield · 12-30-2007, 12:18 PM

Hmmm.. My RS2000 manual is out in the coach but off the top of my head it does sound just a tad high. I really haven't paid too much attention to my charge voltage when in bulk mode.

I think Dirk has the best idea - give Xantrex a call tomorrow - let us know what they say.

afrank1971 · 12-30-2007, 02:08 PM

Okay, I found this temperature compensation table (below) online, which, based on this, at 50?, the RS2000 should be adding 0.504 volts to the normal voltage, which would be 14.9-15.0 volts. So perhaps my Xantrex is doing exactly what it is supposed to, and I should just trust it. I sure hope so. Does this make sense to everyone? And would certainly be interested in what other RS2000 owners have noticed in regard to Voltage/Temperatures.
Thanks,
Alan

CHARGING VOLTAGE
TEMPERATURE COMPENSATION
@ 2.8mv/degree F/cell

Temp F / Add to Charger's Voltage

160? / -1.344
150? / -1.176
140? / -1.008
130? / -.840
120? / -.672
110? / -.504
100? / -.336
90? / -.168
80? / 0
70? / +.168
60? / +.336
50? / +.504
40? / +.672
30? / +.840
20? / +1.008
10? / +1.176
0? / +1.344

Route 66 · 12-30-2007, 02:22 PM

Now, I don't understand all I know about this, but I would think the bulk charge would heat the batteries up, and the absorption charge would be lower than you saw.

Is the battery temp sensor hooked up to the inverter?

afrank1971 · 12-30-2007, 02:32 PM

Yes, the battery temperature sensor is installed. I'm hoping that's why the voltage was reading so high this morning.

Another question for RS2000 owners with AGM batteries, do you use the charger in the 3 stage or 2 stage (no float) mode?

NoMoreAZ · 12-30-2007, 04:41 PM

Voltage seems about right. Just finished my RS2000 install. Also replaced the 1/0 cable battery bank to inverter/charger with 4/0 as recommended by Xantrex and others. Battery to battery cables where already changed before.DW is now trained on pulling cables!

System here is 4 Lifeline GPL4s. On the roof is 450 watts of solar feeding a MPPT controller charging both coach and engine batteries.

My charge voltage in all three stages was lower today than yesterday; had warmer weather. My solar charger charges the batteries at about the same voltages as the RS2000; not so with the Demented inverter/charger.

Yes, use three stage for sure.

John_Canfield · 12-30-2007, 05:50 PM

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Alan Frank:
Yes, the battery temperature sensor is installed. I'm hoping that's why the voltage was reading so high this morning.

Another question for RS2000 owners with AGM batteries, do you use the charger in the 3 stage or 2 stage (no float) mode? </div></BLOCKQUOTE>I have group 31 Lifeline AGMs and use three stage charging.