Rotating batteries in a battery bank!

I would like to get everyone's opinion on rotating batteries. I have tried to google this and can't find anything.
I have a 12 volt battery bank @ 1248 Amphr. Built with 12 6 volt batteries in parallel and series.
I have a DC amp clamp and i can monitor and see that the bulk of the amps get pulled from the front of the battery bank.(60 amps) Where the load is connected too. The batteries on the back end of the bank pull a much smaller (8 amps) .
This got me to wonder if the batteries should be rotated in different spots of the battery bank every so often. Any thoughts on this???
I have a 12 volt battery bank @ 1248 Amphr. Built with 12 6 volt batteries in parallel and series.
I have a DC amp clamp and i can monitor and see that the bulk of the amps get pulled from the front of the battery bank.(60 amps) Where the load is connected too. The batteries on the back end of the bank pull a much smaller (8 amps) .
This got me to wonder if the batteries should be rotated in different spots of the battery bank every so often. Any thoughts on this???
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The basic problem is that you have too many parallel batteries... it's doomed to failure. I just explained this to someone with 4 strings in parallel: http://forum.solar-electric.com/discussion/comment/356663/#Comment_356663
If you want to make the best of a bad (parallel) situation, it helps to wire them with bus bars.
Another factor that can cause batteries (series or parallel) to diverge is temperature variation. All the batteries must be at the same temperature.
If you decide to do an equalization, disconnect 5 of your battery strings and equalize just one string at a time.
--vtMaps
Thank you for the information. Did not know that there should be limits to parallel connections. Could you elaborate on wiring them with bus bars? I would love to do what i can to keep this battery bank alive. It has no more then 150 cycles on it. Also i will ask again is there any logic to battery rotation? What about wiring the main line into the middle of the battery bank?
It sounds like to me that the answer is not to rotate batteries but to get them balanced.
http://www.smartgauge.co.uk/batt_con.html
There has been discussion here by a few people that even with one string of batteries (no current balancing issues) that find they have better battery life/performance if they rotate the batteries once a year. For some folks, the battery near the + bus may not charge to the same level as the battery at the other end of the string.
I cannot give you a reason why this is true for some folks (other than if battery ventilation is uneven--temperature variations)--But it has been seen.
-Bill
http://members.sti.net/offgridsolar/
E-mail [email protected]
I certainly do not recommend it as a matter of standard operating procedure.
-Bill
http://members.sti.net/offgridsolar/
E-mail [email protected]
The way you got it wired the way I understand is like in this link http://www.smartgauge.co.uk/batt_con.html
figure #1.
You have the incoming wire to the battery and then you measure the amps right in front of the battery bank at the incoming wire to the batteries.......this will give you the total amps that all your batteries will take since the battery-supply-wire in front of the bank will supply power to all of the batteries and strings.
Then if you take a measurement between string # 1 and string # 2 you will measure only the last 5 strings while you leave the 1st string out of your measurement and this will lower the amp reading since you only measure the amps of 5 strings and not 6 strings now.
If you go between the 5th and 6th string (last string of the batteries) then you read only the amps of the last or 6th string ....right at that location of your measurement, you are reading the amps of one string only and that is why you get the lowest reading there.
I hope that I understood it right the way you got it wired and the way you measure it..
First off i want to thank everyone for there inputs. I have decided to show my battery bank. I have also noted where and what the readings were. There is a correction to my original post. It is 30 amps at the load of the bank and 8 amps at the end. It appears that i need to rewire this to accommodate method #3 of the http://www.smartgauge.co.uk/batt_con.html .
By the way, it appears that you are doubling up cables on your battery interconnects. That will increase the potential points of failure and the instability of the system.
--vtMaps
30 Amps is what your total battery bank is taking, while your 8 amp point is only part of one battery string out of 6 battery strings.
To measure the 8 amp point more precise, you need to put both of your red wire (parallel wire) into your amp meter. If you clamp only 1 wire at the 8 amp point you are going to read only part of the amp reading for the last string. You may have used both wire to measure already....
If you want to measure the amps for each battery string (2 batteries in series), clamp your amp meter on the red and black wire together between the 2 batteries. Do this for each string, Now compare your readings.
Like this image below where the blue circle represents your amp clamp. Then go to the next battery string and so on. This way, you will read each battery string.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
The ability to rotate the batteries makes it easier to water them... the cells in the back of the box can be rotated to the front.
There is no reason you can't rig a motor, powered directly by solar panels, to the turntable. The batteries would rotate continuously while charging. Don't let them turn fast enough to develop lateral stratification.
Good luck with the project!
--vtMaps
http://members.sti.net/offgridsolar/
E-mail [email protected]
I've been considering adding an automatic waterer, saw one on ebay.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
Bunch of jokers on here today

Here is the total amp draw on each connection when the charger is on bulk charging mode.
http://members.sti.net/offgridsolar/
E-mail [email protected]
The good thing is with the double wire on everything is you should have lower resistance, but the bad part of that is more connection points that could fail.
As Dave noted, that has got to be difficult to check water they way it is now.
I have a 6 stud bus-bar and 6 parallel batteries to tie in. But, then i still need to wire in the inverter/charger and 12 volt load.
To combine 6 batteries properly you should have a battery combiner box with circuit breakers or fuses for each of the combined batteries. Of course, combining 6 batteries in a cycling application is foolish, but with a combiner box you could be properly foolish.
--vtMaps
I quickly rewired to method # 2 because that was easy. http://www.smartgauge.co.uk/batt_con.html
I don't think it balanced it out any better.
Next step to work on rewiring a bus bar.
Where is the best place to find a bus bar? The one i have is https://www.bluesea.com/products/2126/MaxiBus_250A_BusBar_-_Six_5_16in-18_Studs I need more terminals then 6 and i can't find one.
http://www.electrical-insulators-and-copper-ground-bars.com/ground-bar.html
-vtMaps
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Why--I have no clue if all is otherwise OK (good ventilation, one battery not hotter than the rest, etc.).
-Bill
19 SW285 panels
SE5000 inverter
grid tied