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Erikpope
June 20th, 2012, 21:36 PDT
I have a xw6048 and a wx-mppt60-150. I also have 24 liberty hd-1100 batteries. They are setup in a 48v 1210ah config. Is there anyone that knows about these batteries? Do I need to have a custom setup for my Charge Controller? Also do I need to change any settings on my inverter? The reason I ask is I get a fault ( F48 ) Low DC voltage and my inverter stops inverting. The thing is for that fault the DCv would have to drop below 44v and my batts read 47v+. Im not sure what is wrong. Any help would be great.... Oh and my daily usage is about 10kwh and my daily production has been 13-14kwh. But I still get faults....???

westbranch
June 20th, 2012, 21:47 PDT
I have some C&D batts, see sig line.

I would look at ALL your connections for a bit of corrosion build up IF the per cell voltage is as listed, possibly even at the CC or inverter (probably this or connected to it, since it is giving you a fault), buss bar etc. or a bad cable crimp...

Charge regime, yes you will need a custom charge setup as they are not 'meant' to be heavily discharged without a quick recharge to float specs. I am looking at a TBS (Holland) charger http://www.tbs-electronics.nl/products_omnicharge_features.htm as it will allow for a 'custom' setup.
HTH

Erikpope
June 20th, 2012, 22:02 PDT
Do you know where I can get the values for the custom settings. My Charge controller allows for a custom batt type but I am not sure what to enter. Such as recharge volts. or bulk or absorb or float.... I did find this per cell... Float v @ 2.25-2.27 (*24=~54) so Im good with the float v. then there is Cycling v @ 2.27-2.30 (*24=~55.2) and Equalize v @2.33-2.37(*24=55.92)

What is Cycling voltage?

westbranch
June 20th, 2012, 22:39 PDT
that is part of the (their) secret. for mine they just list FLOAT and Refresh/Float numbers. I have spoken to the local C&D reps and they don't even use (know) Bulk or Absorb terminology.
These batteries are meant to be constant voltage charged, yet the Absorb cycle is an anomaly to them(??), as normally Absorb is a constant V and declining Amps.

Cycling??? make sense that the Absorb would be higher than Float. Can't seem to find the Cycling Voltage reference in the manual for Liberty 1000 http://www.cdtechno.com/pdf/ref/rs_990_03.pdf

Endur II AT model specs Float 2.25 - 2.3V, Fresh/EQ 2.35V for 12 - 16 Hrs
see sec 7 http://www.cdtechno.com/pdf/ref/rs_02044_0508.pdf

HTH

Erikpope
June 21st, 2012, 9:17 PDT
That PDF looks like it is for a slightly different batt... mine is in this pdf http://www.battery-usa.com/Catalog/12_371.pdf but It doesn't have the info like the link you gave me.... My rack looks kinda like the pic on the PDF but mine is 4 by 6 batts.

Vic
June 21st, 2012, 10:18 PDT
Hi Erik,

I know nothing from personal experience with these batteries,

But, from westbranch's second link, these are AGM batteries designed for Standby Service -- constant Float service. They are NOT designed for cycling. This is why the charging specs appear so different from batteries that ARE designed for cycling.

In that second westbraanch link, look at page 26 in the about mid page, it says that Cycling should be kept to a minimum. You CAN cycle them, but their life will be shortened by every cycle. Sounds like your Inverter is shutting off from Low Batt Voltage, and you need to rechrge immediately.

I'd try the instructions for initial charging. I have NO experience with AGMs, so there are those here who know what you should try to do in this situation, but, it seems that the batts are in a low state of charge. You should temperature compensate any charge voltage if the battery temps are very far from the standard temp of 77 degrees F. The link provides temp comp into.

Good Luck, Vic

Photowhit
June 21st, 2012, 10:37 PDT
A few things here;

You obviously have some heavy loads, loads will draw the voltage down, so when the inverter kicks out it's only seeing 44 volts or less, when you measure it w/o loads it looks like 47V which is still pretty low, off the top of my head under 50% for floaded batteries, not sure about AGM's.

Also not sure where your reading your production, if this is at your Charge Controller, you may NOT be keeping up with your use. The batteries don't store as much as they are presented, so your loosing some there. Also if your using 10Kwh after inverting, you have to figure in your inverter losses, most inverters are at best 90% effiecent at best, so a 10Kwh draw uses 11.1Kwh's at best, and likely more.