When charging and drawing a load from a parallel string do you need to have the load Pos & negative connected same terminal as the charging? Charging ends of the string of course ,and drawing load from ends as well,not the middle, or 1 battery.
Load connected to the same terminal as charge
Collapse
X
-
-
Depending on how you have wired your battery bank it is usually a good idea to charge and discharge from the same + and - terminals.
Hopefully your bank is not all wired in parallel then you might have a problem and should at least use the + terminal on the first battery and the - terminal on the last in the ladder. -
The details for up to four are shown, along with a good discussion at http://smartgauge.co.uk/batt_con.html
along with a good discussion.
There is no reason that I can think of to use the opposite diagonals for CC and load connections. And since there need to be fuses at each external terminal of the battery bank, you will be better off using the same two points for all purposes.
If you have a situation where the batteries are getting unequal currents for some reason (like a non-diagonal connection) then drawing from one set of terminals and charging on the other will just double the unbalance seen by the batteries.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
-
Comment
-
Comment
-
Comment
-
If you use a load setup which tends to draw more from one battery than the other and a charging setup which tends to send more current to the second battery than the first you will be perpetuating a serious imbalance between the batteries.
Other than your relatively unimportant concern about connecting and disconnecting, which can be addressed just fine in other ways, there is zero advantage to connecting charge and load to different batteries.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
-
Here is an image of what I'm describing, I am not connecting to Just One batteryAttached FilesComment
-
But your connection will require four fuses (one for each battery post) while my connection allows the charge and load to share one pair of fuses.
There is also a marginal advantage in terms of wiring resistance to my (common points) connection when you are charging and loading at the same time.
You need to keep firmly in mind that the required fuses are there to prevent the batteries from discharging into a short, not to protect either the CC or the load.
Also, your mention of "the middle" led me to consider the case of three or more batteries, not just two.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
-
I have fuses on the positive from the charge controller & the positive from the panels to the charge controller .and on the load .I thought just one side of it needed a fuse. What is the name or style of the fuse that works for both load and charge at same time? And if you do have three batteries in parallel still not correct to have load and charge opposite sides of batteries?Comment
-
I have fuses on the positive from the charge controller & the positive from the panels to the charge controller .and on the load .I thought just one side of it needed a fuse. What is the name or style of the fuse that works for both load and charge at same time? And if you do have three batteries in parallel still not correct to have load and charge opposite sides of batteries?
And an array of PV panels cannot generate enough current to ever blow a fuse, so that fuse is not necessary except to handle the case of a shorted array and a shorted CC at the same time.
If you do not ground one side of the battery bank (your choice of + or -, but - is more common) then the NEC and general safety require that you put fuses on both + and - leads from the battery bank.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
Comment