The following information provided is guides and tips of our own opinion.
Connecting multiple battery banks in series and then in parallel in the following manner will create 2 floating battery packs and our systems will only be able to monitor the top connected battery pack.
In order to monitor multiple series connected battery banks in parallel the following diagram can be studied. In this configuration the batteries is first connected in parallel and then in series, the batteries can now share current with each other like any other 2 Batteries in parallel would do. The batteries in parallel become one large battery of double the capacity and our system can monitor the complete battery bank in this configuration.
Important information for 12V parallel connected batteries !
In order to double up on Amp hour capacity 2 or more batteries will be connected in parallel.
To create a “Balanced” parallel connection the wires connecting to the battery pack should be connected to the first and last battery in the parallel pack.
As per top drawing battery A will work the hardest in charging and in discharging mode due to small resistances from the connecting cables between battery A,B and C and will most likely fail(deteriorate) first.Battery B will also work harder than battery C.
In the bottom drawing Battery A,B and C will equally charge and discharge as all 3 batteries now share the same resistance path caused by the connecting cables between battery A.B and C.
Battery Backup power for wireless communications sites tips
Usually small communication sites with not too much equipment installed with a current consumption below approximately 5 Amps can be run from a 12V battery system
A single 12V battery or multiple 12V batteries in parallel will last longer than series connected batteries due to the voltage imbalance occurring in 24V battery systems
The 12Vdc from the batteries can be step-up to 24Vdc with our DC-DC 12-24 unit and to 48V with our DC-DC 12-48V Converters.
Should 24V and 48V be needed at the site the installer can use our single DC-DC Converter units or the DC SMART 12V with both converters integrated into one 19″ rack mount unit.
Usually larger communication sites with lots of equipment installed or multiple high power microwave links will have to be powered with a 24V battery system
Batteries might not last longer than 2-3 years in series due to voltage imbalance but it is necessary to power the site from 24V to reduce the current consumption from the battery system and to reduce the overall power cable size.
24V Equipment can be powered directly by the 24V batteries but remember the batteries will charge to 28VDC which in turn can sometimes be a little high for some equipment
Our 20V constant voltage regulator can keep the 24V to 28V battery voltage constant at 20VDC for sensitive equipment.
Our DC-DC 24-48 V DC converters can be used to power the 48V equipment.
The installer can use our single DC-DC Converter units or the DC SMART 24V with both the 20V constant regulator and the 48V converter integrated into one 19″ rack mount unit.
POE MODE B and PHANTOM explained
Gigabit MODE B POE -usually for low power POE devices up to 25W. Data over all 4 pairs of the cable and power over 2 pairs. Normally pin 4 and 5 will carry + power and data and pin 7 and 8 will be negative power and data.
Gigabit PHANTOM POE -for high power POE devices > 25W. Data over all 4 pairs of the cable and power over all 4 pairs. Normally pin 1 and 2 and 4 and 5 will carry + power and data and pin 3 and 6 and 7 and 8 will be negative power and data.
Phantom POE devices complying to the IEEE standards have diode bridges inside the device for auto input power polarity correction -meaning even a Phantom POE with output polarities on pins of the cable that does not match with the radios polarity will still power the radio correctly.
The Mi-Passive Phantom POE injector outputs the following on the RJ45 / + on 1,2 and 4,5 and – on 3,6 and 7,8 – this is the correct polarity for eg. Ubiquiti Air fibre radios but completely reversed for a CIA 17Ghz radio however both radios will work on the Phantom POE due to Phantom powered radios having auto polarity correction diode bridges.