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Kevin
Kevin, Licensed Electrician
Category: Electrical
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Experience:  30 years Licensed Electrical Contractor in Illinois, Adjunct College Electrical Instructor, Former Electrical Inspector, Diploma: Digital Electronics, FCC Technician License
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Im looking to equalize a 48 volt DC battery bank consisting

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I’m looking to equalize a 48 volt DC battery bank consisting of 32 batteries: (4) eight-battery arrays connected in parallel including the following:

(8) 350 aH 6 volt Rolls S460 deep cycle batteries
(8) 400 aH 6 volt Surrette S530 deep cycle batteries
(8) 400 aH 6 volt Surrette S530 deep cycle batteries
(8) 400 aH 6 volt Surrette S530 deep cycle batteries
Total: 1550 aH x 48 VDC

I was planning on equalizing at 61.0 volts DC for (4) hours. My question is, does it matter that one of the arrays is comprised of 350 aH batteries instead of 400 aH batteries.
I also found one of the batteries had built-up a light cream colored powdery substance around one of the terminals. Additionally, its rectangular body was a little bulged out compared to the others.

Hello.....my name is XXXXX XXXXX I will be happy to assist you with your electrical question. My goal is to exceed your expectations on Just Answer!

 

1) I have done much research over the years on deep cycle batteries since I have a small 120 watt solar panel system installed at my home. Based on the research that I have performed, many experts state that having batteries which are not 100% compatible, may have the potential to cause battery problems down the road, ie, not proper charging.

 

They state that only "like batteries" with the identical amount of amp-hours (AH) should be used when installed as either a series or a parallel bank. The reasoning behind this is that "un-like batteries" will have contention with each other since they are not equal or balanced in terms of the AH. I have also read where using multiple battery manufacturers within a string or an array can contribute to similar problems.

 

2) Since you have one battery that has corrosion around one terminal and it is partially bulging, this presents a safety hazard. A bulging battery is typically caused by over-charging and this presents a very serious safety hazard, since a bulging battery can explode and shoot acid everywhere. For your safety, you need to immediately remove the bulging battery from the array before it causes major problems and replace this battery. You do not want to be anywhere near an exploding battery.

 

I would recommend to contact your local fire department and ask them where you can safely take the bulging battery. Some fire departments will accept batteries for proper disposal or recycling. DO NOT throw the bulging battery into the garbage as this can also create a potential safety hazard for the local waste hauler driver.

 

3) You did not state the application of your battery arrays, but I'm assuming you are using these for a solar PV application since you mention that you have an Inverter. If using these batteries in a PV application, I would recommend to check the Charge Controller (CC) unit to make sure the amperage of the PV panels are sized accordingly to the CC. You can use a clamp-on amp meter to determine the maximum PV panel amperage output on a full sunshine day if your application is PV panels. Compare the actual PV amp output to the Charge Controller. Perhaps, the reason why one of the batteries is bulging is that the Charge Controller is over-charging the battery array?

 

 

 

 

Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.

 

Otherwise, don't forget to rate me before you log Off.

The next time you have an electrical question, you can also request for me at:http://www.justanswer.com/home-improvement/expert-your-electrician
..........Thanks..............Kevin!



 

Customer: replied 3 years ago.


I am recommending to the customer, as you suggested, to have the bulging battery removed and replaced. (It's only a slight bulge; and its specific gravity & voltage readings are not that bad...) But, it's better to take care of it now and avoid future trouble.


 


And yes, the batteries are used in conjunction with a PV solar array. The batteries serve as back-up power when the utility grid is down. The charge controller is built into the inverter unit and I've verified the charge amperage is correct.


 


The 350 amp-hour batteries are made by the same company as the 400 amp-hour batter(Rolls/Surrette). The manufacture was not too concerned about the battery amp-hour mis-match in this situation -as long as the batteries in each array were identical. But, they agreed it would be best to migrate 400 amp-hour batteries into the system whenever replacing them -to keep all strings alike.


 


The main reason I wanted to get your advice was because I wanted a neutral view point. -which you have given me. Thank you for your comments and advice. I am satisfied with your answer. Have a good day! I am closing this file...


George

Thanks for your replies George..........Yes, all battery manufacturers will recommend that the batteries be the same.

 

 

 

Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.

 

Otherwise, don't forget to rate me before you log Off.

The next time you have an electrical question, you can also request for me at: http://www.justanswer.com/home-improvement/expert-your-electrician
..........Thanks..............Kevin!



Kevin and other Electrical Specialists are ready to help you

George..... thank you for the positive rating....... much appreciated!

 

If you have any other questions, just let me know.

 

Take care and have a great evening...............Thanks..............Kevin!

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