RBC123 vs. RBC124

[chknight_apc]

This was originally posted on APC forums on 3/10/2016

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I have a Back-UPS XS 1000.  I need a new battery.  A local store has the RBC124 in stock but not the RBC123.  Can i use the RBC124 in my unit? The seem to be the same physical size.  Wondering if the RBC124 would give me more time on battery power?  Or would it overheat unit and not work properly?

[BillP]

This reply was originally posted by Bill on APC forums on 3/11/2016

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Hi,

The UPS has been designed and test to use the RBC123 so you should not replace an RBC123 with an RBC124. 

[PenisNinja_apc · Accepted solution]

This was originally posted on APC forums on 11/4/2017

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Why it doesn't works? The battery has the same size... only the capacity will be growing up. What can be happens wrong?

[BillP]

This reply was originally posted by BDC Services on APC forums on 11/6/2017

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Hi Dirk, a higher capacity battery will take longer to charge and will also provide a longer runtime. APC would recommend not increasing the capacity of the batteries from 7.2ah to 9.0ah as it falls outside the manufacturer specs and would not be supported in the event of a fault. 

[bu11etpr00f_apc]

This was originally posted on APC forums on 8/29/2018

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@BDC Services

You have an error in your response; using an RBC124 over an RBC123 does not increase Voltage (not to mention, you can't go from Volts to Amp Hours anyway...). The Voltage for both batteries is the same; 12V. The Amp Hours (capacity) is the only thing that changes; from 7Ah to 9Ah. The RBC124 is a higher Capacity Battery than the RBC123, and will take longer to recharge; however both batteries have the same output at 12V. Unless someone can produce a specific technical answer from and engineering standpoint, I don't see any problems with using the higher capacity battery (especially if it is already out of warranty). 🙂

On 2017-11-05 21:44, BDC Services said:

Hi Dirk, a higher capacity battery will take longer to charge and will also provide a longer runtime. APC would recommend not increasing the capacity of the batteries from 7.2V to 9.0ah as it falls outside the manufacturer specs and would not be supported in the event of a fault. 

[BillP]

This reply was originally posted by BDC Services on APC forums on 8/29/2018

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Just a typo... V changed to ah

[zmargalit_apc]

This was originally posted on APC forums on 7/24/2019

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RBC123 is a 12V 7Ah battery while the RBC124 is a 12V 9Ah battery.  The rule for charging lead acid batteries is that the charging current be 25% of the battery capacity thus the ideal charging current for the RBC123 is 7Ah x 0.25= 1.75Ah and for the RBC124 it would be 9Ah x 0.25 = 2.25Ah.  That said, if you plug a RBC124 in place of RBC123, it will take longer to charge.  If you plug a RBC123 in place of RBC124 the charging current may be too high and this can result in a premature battery failure.