low battery hydrometer readings

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low battery hydrometer readings

Postby beenak47 on Sun Jan 30, 2011 4:22 am

Hi,
Our house system comprises 2000w of 24v BP solar panels, 6 x 4volt 1000a/hr Raylite batteries, Outback MX60 MPPT and 24v Powerstar inverter charger.
Over the last month we have experienced low hydrometer readings on our battery bank with each 2v cell reading about 1200. We have had to disconnect our fridge and go back to using our LPG unit until we can get the readings up again. Normally during the Australian summer we have no problems with power issues, in fact more than we can use, however this problem needs to be fixed before we head into winter.
The batteries are about 8 years old, I maintain the electrolyte levels but I don't normally do a hydrometer reading unless a problem occurs. The Outback MPPT was installed before last winter and I believe it reduced our generator use considerably, the Powerstar unit was installed in January this year replacing an older Xantrex unit. I have tried altering the Outback 's program to increase equalisation of all the batteries however I have been unable to get the bank up over 28v and any battery bubbling is minimal. Any thoughts that may help us would be appreciated.
beenak47
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My RE system: BP 24v Solar Panels
6 4v Raylite 1000a/hr batteries
Outback MX60 MPPT
PowerStar Sinewave Inverter Charger

Re: low battery hydrometer readings

Postby tallgirl on Sun Jan 30, 2011 10:38 am

Do you have any way of measuring the DC currents going to and from the batteries?

It's not at all unusual for batteries to become more inefficient as they age and the only way to determine that is to look at the amp-hours in versus the amp-hours out. At 8 years of age, I wonder if they aren't just old.
Julie in Texas

greenMonitor(tm) for OutBack Power Technologies systems from greenHouse Gas and Electric. Learn more now!
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Re: low battery hydrometer readings

Postby beenak47 on Sun Jan 30, 2011 2:33 pm

The Outback MX60 tells me the amp hrs into the battery each day and records the detail for the last 60 days however I have nothing on the amps out side. Since I have removed the fridge from the system our usage has been low in comparison to what goes in each day, so I would have hoped for some improvement in the hydrometer readings. Prior to these batteries we had used 620 a/h telecom batteries that were over 10 years old when we got them and still used them for another 6 years before we upgraded to the present setup so 8 years is not that old if they are looked after, I never let them get down in the winter without recharging from the generator and always keep the water levels up in summer. Thx
beenak47
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Posts: 6
Joined: Sun Jan 30, 2011 3:39 am
My RE system: BP 24v Solar Panels
6 4v Raylite 1000a/hr batteries
Outback MX60 MPPT
PowerStar Sinewave Inverter Charger

Re: low battery hydrometer readings

Postby tallgirl on Sun Jan 30, 2011 4:23 pm

I'm wondering if either your loads have slowly increased over time or the new inverter is less efficient than the old one.

One of the best reasons to have a good quality battery monitor, such as the FLEXnet DC, is that it includes historical logging so you can look at how much you've used over longer periods of time.
Julie in Texas

greenMonitor(tm) for OutBack Power Technologies systems from greenHouse Gas and Electric. Learn more now!
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My RE system: 16 Kyocera KC175GT (2,800 watts DC), MX-60, 2 OutBack GVFX3648, 24 GC2 batteries (6v @ 215AH), 14 Pantheon-based ACPV modules (3,200 watts DC), La Crosse Technologies WS2310 Weather Station, greenLogger Sensors environmental monitor, WattNode watt-hour meter, greenLogger Lite data logger.

Re: low battery hydrometer readings

Postby blackswan555 on Sun Jan 30, 2011 5:39 pm

each 2v cell reading about 1200
What would you call "normal" readings ?

The Outback MPPT was installed

Any idea what settings were changed from default ? Do you have temperature sensors on all charge sources ?

when did you last service batteries ? please describe "how you did it" briefly

Have a good one
Tim
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.
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Re: low battery hydrometer readings

Postby beenak47 on Fri Feb 04, 2011 11:43 pm

Hi Tim,
I suppose I am at fault for not taking regular hydrometer readings however the last hydrometer readings I did take over a year ago were showing 1.225 in each cell.
When I took the reading last month before the fridge was removed from the system they were showing 1.175 and the inverter had cutout because of low voltage, now with it removed I have them up to 1.200.
The Outback is showing battery voltage as 24.5 first thing of a morning without any load.
I did have the MX60 only set on factory default however I have sinced lowered the absorb rate to 28.2C, the float to 27.2C and the Rebulk to 25v, I am not sure if I should alter anything else.
I am taking Tallgirl's advice and will have a battery monitor in place within the next week or so and I hope to have some better detail from it.
Thanks for your assistance
Gerry
beenak47
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Posts: 6
Joined: Sun Jan 30, 2011 3:39 am
My RE system: BP 24v Solar Panels
6 4v Raylite 1000a/hr batteries
Outback MX60 MPPT
PowerStar Sinewave Inverter Charger

Re: low battery hydrometer readings

Postby blackswan555 on Sat Feb 05, 2011 4:17 am

I did take over a year ago were showing 1.225 in each cell.
Refer to you bat manufactures, But in a "Normal" battery, That would be considered low if fully charged, !.260 > 1.280 would be more normal, BUT
The Outback is showing battery voltage as 24.5 first thing of a morning without any load.
Sounds like they are are not to bad, ???hmmm :?:

MX, refer to bat`s manufacturer recommendations on voltage, What have you programmed for time`s ?

Tim

To add, on first impression you are undercharging your bats, A "good" sg range for 50% DOD would be 1.270 > 1.200, Check your MX absorb time, If it`s default, it needs increasing, Give us as much info on usage, climate, System & loads as you can,
You also do not mention servicing so please have a look through this post viewtopic.php?f=17&t=4913 it may be helpful
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.
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My RE system: Other peoples, VFX "E" versions, FLA`s, Generators.

Re: low battery hydrometer readings

Postby petertearai on Mon Jul 11, 2011 3:52 am

Is That absorb voltage a little low?
1220 pv. fm80. 4times rolls 450 ah 12 volts. victron battery monitor. xantrex 1800ps inverter
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