Load connected to the same terminal as charge

[Brian53713]

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.

[SunEagle]

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.

[inetdog]

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.

With a parallel "string" of batteries, you really should not have more than two if possible, up to four in some cases. The wiring to the battery bank should then be wired on the diagonal to the + of one battery and the - of the other.
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.

[Brian53713]

Reason for doing so is to get at one or the other for connecting disconnecting .

[inetdog]

Reason for doing so is to get at one or the other for connecting disconnecting .

Not a good enough reason. If that is a serious concern for you use a bus bar instead of connecting directly to the battery terminals.

[Brian53713]

Sorry to beat this issue up, but what would be a reason or Advantage for doing so if any?

[inetdog]

Sorry to beat this issue up, but what would be a reason or Advantage for doing so if any?

When you have more than one battery in parallel it is difficult to get them to carry equal current during both charge and discharge (which will give the longest battery life.)
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.

[Brian53713]

Here is an image of what I'm describing, I am not connecting to Just One battery

[inetdog]

Here is an image of what I'm describing, I am not connecting to Just One battery

Your setup is what I would describe as double diagonal. As long as you have just two batteries, each diagonal connection will provide balanced current for both batteries.
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.

[Brian53713]

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?

[inetdog]

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?

Any fuse will carry the net current and so protect against a short in either direction. I told you that the fuses are not there to protect either inverter or CC, so there is no need for separate fuses.
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.