Solar battery bank switching

[CarlLuz]

Hi I'm a lower 48 guy living in Puerto Rico and I've been off grid for about  fifthteen years. Recently I purchased a new set of batteries but my old batteries still have some storage capacity. I'm wondering if any of you have had the same issue and how you resolved it?
I'm using solar PV panels coupled with two separate 48 VDC battery banks to power a 220VAC inverter which powers my home. I need the ability to switch between the two sets of batteries instantaneously in order to fully charge and discharge the two sets of batteries...this switch requires + cable, - cable and charge controller cable which may be coupled with the + cable on each set of batteries. The reason for this arrangement is one set of batteries is near retirement and the other set is new and they can't be combined without possible damage to the new set of batteries. Thanks!

[DamonHD]

There are specialised dual battery controllers, eg https://www.sunshinesolar.co.uk/Item/EDR30A whas the first thing that came up in a famous search engine with the query:

    dual solar controller

Some may also be able to switch loads.

Rgds

Damon

[CarlLuz]

Thanks Damon but that doesn't help me because I need the ability to switch between the two battery banks tethered to the 48VDC power inverter. I think I need some sort of a switch directly installed on the positive/negative leads going to the inverter which would allow me to run/use/charge one set of batteries at a time. I already have two charge controllers for the 48VDC system, one for the PV array and one for a wind turbine I only use for charging the batteries on continuous days (I have the wind turbine alternator connected to a small gas engine in a soundproof building).

I'm thinking a pair of Digital LCD Programmable Timer switches CN101A AC/DC 12V AC 250V 16A Timer Relay  switches might be the least expensive way to manage the two sets of batteries? I'm thinking of controlling the negative cables of each set with the timer? The problem would be there would need to be a one or two minute separation between the timing so both circuits wouldn't be on at the same time?

[OperaHouse]

Diodes from each battery bank to the load would insure continuous power.  The bank with highest voltage would provide the power minus a voltage drop of a couple diodes. Then a relay could switch between the actual bank that powers. 

[Scruff]

Clicky

Bi-Stable (magnetic latching) would be a better shout.

[OperaHouse]

I should mention I wanted to switch two panel arrays from parallel to serial.  A low tech solution would be a three phase drum motor reversing switch, ON/OFF/ON.  The array would not be switches under load and center off providing a margin of safety.  I found this cheap QS-60 60A 380V switch from China with easy to remove jumpers. It had an arc fest when switched.  The stupid thing momentarily shorts out when switching to off.  Only thing I can figure out is they saved a little bit of plastic.  Can't imagine what this does on three phase. Don't be tempted to buy this.

[CarlLuz]

Thanks! I've been using a 4 wire 10 gauge jumper between the positives of the two battery banks with red & black for day and white & green for night with 2 10A diodes rated 1000V 10A 1KV Axial Rectifier Diodes inline on each set in opposite polarity and manually switching them after sunset. We often have afternoon storms that would reverse the higher battery storage so I manually  switch them daily when the sun goes down and with my morning coffee and it works pretty good but is a pain in the butt. The blocking diodes get pretty hot with the panels under a blue sky. The other setback is the transfer is much slower over night so starting an electric coffee pot pulls down the primary set of batteries.
I'll try to look for the switch...Thanks to all!