48 volt reading 52 volt after chg month ago

[Mooncarter]

Put charger on and let it run until it shuts off.

[ThreeCW]

Originally Posted by Olddog72

Reading 48volts after 2hrs sitting

48 volts is not a good sign ... did you let the charger shut off on its own or did you manually disconnect it? If you manually disconnected, then "Put charger on and let it run until it shuts off", as Mooncarter suggested. Then disconnect the charger and wait 12 to 24 hrs to get a stabilized voltage. Then check the voltage of the battery pack and of each battery ... to determine if you have one (or more) weak batteries.

For your reference, below are typical charge voltages for Trojan batteries ... other brands will be the same or similar. You can see from this chart that the "finish charge" will take the charging voltage up to approx. 64.8 volts for a 48 volt pack. A lot of people get concerned when the charging voltage increases into the 60 volt region but this is normal ... if the voltage did not get this high, then the batteries would not charge sufficiently. Also attached are some typical charge profiles for Trojan and US Batteries for your reference.

Trojan Charger Voltage Settings - 2015.JPG Trojan - Typical Charge Profile.JPG US Battery - 3 Stage Charge Profile.JPG

[Olddog72]

Results after 12hrs

Pack voltage 48v
Each battery ..All at 7v(individually)

Batteries US 8Volt GC
Amp hrs 170
Min@75 amp 90
Min @56 amp

[cgtech]

Definitely still needs charged

[Olddog72]

The charger shuts off on it,s own,I here the batteries charging (gurgle) .If I turn it back on when it shuts off ,it will charge for couple minutes ans stop when it gets to 4 amp on charger meter.Should I keep turning it on and see if it goes to zero on meter.Could charger be problem?If so how do I test it?

[Olddog72]

Pack voltage 52v. All 6 batteries 8v charger removed check in morning

[ThreeCW]

Originally Posted by Olddog72

Results after 12hrs
Pack voltage 48v
Each battery ..All at 7v(individually)

Batteries US 8Volt GC
Amp hrs 170
Min@75 amp 90
Min @56 amp

Olddog72,

If your battery pack is only 48 volts at 12 hours "after the charger shut down" one or more things could be happening:
(1) The batteries are heavily sulfated and not capable of accepting a full charge
(2) The charger is not working correctly so is not charging the batteries fully
(3) Your voltage meter is not reading the correct battery voltage

Trouble shooting these problems is often a process of elimination ... so let's start with #3 above - your voltage meter which is the easiest item to check.

I suspect the their could be a problem with your meter still, based on you stating the battery pack voltage is 48 volts after 12 hrs but you also indicate that each battery is at 7 volts. Your 6 batteries at 7 volts each would result in only 42 volts (i.e. 6 batteries x 7 volts each = 42 volts total). So something is not adding up ... and it could be a metering problem.

When measuring battery voltage with a meter you want to measure it to two decimal places - example 8.49 volts for a single 8 volt battery or 50.93 volts for a 48 volt battery pack would be 100% State of Charge (fully charged).

To confirm the accuracy of your meter, make sure that you are on the DC scale and test it by measure a few know batteries ... for example, a new 9 volt cell that is commonly used in a smoke alarm (I checked a few new ones and they measure 9.30 to 9.47 volts), my 5 year old car battery (12.55 volts which is only 85% state of charge), fresh AA battery (1.61 volts), etc. If you are measuring something considerably different, then it could be your meter ... or the battery in your meter might need to be changed. If possible, try to borrow a meter that is known to be accurate and compare your meter reading to it.

Once your are confident in your meter, then measure the voltages of each battery (to two decimal places) and also the voltage of the entire battery pack (again to two decimal places).

With that information, I suggest you then do a charging test on your batteries. Start by measuring the battery pack voltage before charging. Start a new charge cycle and record the battery pack voltage and charging amperage (if your meter displays it) ... take a reading every 5 minutes for the first 15 minutes and then every 15 minutes until the charger shuts down.
The idea of this test is to determine what the charging voltage (and amperage) is to see if your battery charger is working properly.

What make and model of battery charger are you using?

Once you are fully charged and the battery charger shuts down, then disconnect the battery charger and allow the battery voltage to stabilize over 12 to 24 hours ... and then again report the individual and battery pack voltages (to two decimal places).

How old are your batteries ? Check the US Battery date stamp information that I have attached below.

With the above information, the members on the BGW forum should be able to help you troubleshoot your problem.

Regards, 3CW

US Battery - Date Codes.JPG

[ThreeCW]

Originally Posted by Olddog72

The charger shuts off on it,s own,I here the batteries charging (gurgle) .If I turn it back on when it shuts off ,it will charge for couple minutes ans stop when it gets to 4 amp on charger meter.Should I keep turning it on and see if it goes to zero on meter.Could charger be problem?If so how do I test it?

(1) The batteries gurgling are a good thing ... that likely (?) indicates that the charger is working properly ... but could indicate a battery problem if they are not getting fully charged.

(2) The charger turning off at 4 amps is normal - that is a typical charge rate for the "finish stage" (see charts in my previous post). Most modern chargers will do this.

(3) Charging will not likely go to zero on the meter ... finishing at 4 amps is normal

[ThreeCW]

Originally Posted by Olddog72

Pack voltage 52v. All 6 batteries 8v charger removed check in morning

6 pieces x 8 volt = 48 volts vs. your measured 52 v pack ... metering problem?

[Olddog72]

Batteries are June 2013 evans (thanks for code) Charged last night till charger shut off,readings after 12hrs plus
8.31(80%) 8.41 8.40 8.34 8.39 8.34 (50.19)pack 4@80% 2@90% from charge chart you so kindly posted.