Dual battery bank charging

[jroblesdemedina]

Hi,

We have a solar installation at a very remote village.
We have 8x115Amps battery bank. 4x 142Watt Solar panels.

During the day it is charged by solar charger Morning Star 60A.
During the night there is an option to also charge the batteries by AC generated by the village generator.

So we bought a 60Amps Xantrex Truecharge2 battery charger to charge the battery bank at night.

The question is: how do we connect the Xantrex to the battery bank?

First - and last + in battery bank is for Solar Charge Controller (Morning Star)
First + and last - in battery bank is for Inverter

Where does the Xantrex Battery charger fit in?

Kind regards,
Jerry

[Naptown]

How are the batteries configured

[jroblesdemedina]

Hi,
They are parallel connected. So it is 12v/920A.

Kind regards,
Jerry

[Naptown]

Connect at the same location as the solar
You will need the generator as you don't have enough panels to support that battery.
For that matter neither is the generator charger

[Sunking]

Jerry as stated you just connect the charger directly to the battery term post like the charge controller. However as also mentioned your panel wattage and charge controller and your AC battery charger are not large enough for a 12 volt 920 AH battery bank.

Assuming you use a MPPT controller minimum panel wattage required is 1000 watts to generate at least 80 amps charge current. Preferred panel wattage would be 1200 watts generating 100 amps. You did no tmention if your charge controller is PWM or MPPT, but with with only 560 watt panel power a PWM Controller can only generate at best is 32 amps, and for MPPT 47 amps. Either way it is not enough.

[jroblesdemedina]

Thanks Rich!

I have a little problem understanding with what you mean by "for that matter neither is the generator charger".
The village generator(115v) only works at night from 18:00 - 24:00.
The Xantrex Battery charger is 115v input, output 12v@60A

Pls explain?

Many thanks for your patience and help!

Kind regards,
Jerry

[jroblesdemedina]

Thanks Sunking for your reply as well.

I have taken note of your and naptown's comment regarding the capacity of the panels/charge controller.
Think I will need to take care of that first.

But I understand now, that I can connect the Xantrex battery charger, plus and min connectors, to the same poles as the Solar Charger is connected rigth now.

Kind regards,
Jerry

[Naptown]

Neither the solar or the charger are large enough to generate enough amps to properly charge the batteries and create a bit of bubbling to help prevent stratification
Batteries should be charges at a C/12 to C/ 8 rate where C= amp hour capacity of the battery bank.

[Naptown]

Thanks Sunking for your reply as well.

I have taken note of your and naptown's comment regarding the capacity of the panels/charge controller.
Think I will need to take care of that first.

But I understand now, that I can connect the Xantrex battery charger, plus and min connectors, to the same poles as the Solar Charger is connected rigth now.

Kind regards,
Jerry

Yes
And when those batteries fail which will happen fairly rapidly look at replacing them with one single string of 2 or 4 volt batteries.
Batteries in parallel never last as long as ones in series as it is near impossible to balance exactly an equal charge/ discharge on the bank so one battery starts to get discharged and takes the rest down with it

[jroblesdemedina]

Thanks Rich!

I understand now.
I think as an immediate measure, I will take 2 batteries off.
This will leave me with 6*115A, which I think will work much better for the 60A chargers and the complete system? (Morningstar and Xantrex)

Kind regards,
Jerry

[Naptown]

Going down to 5 would be better.
What is the daily load on the batteries in watt hours?

[jroblesdemedina]

Rich,

The daily load is about 5000 WattHours daily...

Kind regards,
Jerry

[Naptown]

Sorry to say this but you have serious issues with this system
Assuming 4 sun hours a day (not daylight hours) you would need about 1500 watts of solar.
You are discharging the batteries almost 50% daily and not near enough of anything to recharge them.
A charger on the generator will help tremendously but it needs to be more like a 100A charger.
Don't take any batteries out now. You will only further damage the ones left.
Does the generator have enough capacity to add another 1600 or so watts load? For its entire run time?
What is the location of the system ( nearest city)

[jroblesdemedina]

Rich,

Yes, the generator has that capacity for another 1600Watts

Location : Suriname, Paramaribo. (South America)

Thanks for the help!

Kind regards,
Jerry

[Naptown]

Great insolation there at 5.4 hours in the worst month

So for 5000WH daily and assuming you use MPPT conhtrollers (check yours as Morningstar make a 60 A PWM and a 60A MPPT)
It will take 1400 watts of solar and another 60A charge controller.

What does this system run? any way to change battery voltage to say 48V?