# Two inverters sharing one battery

Registered Users, Users Awaiting Email Confirmation Posts: 2
Will the Outback Radian 8048A operate alone with its own Mate 3 and Hub and share power from the batteries used on my older Outback Radian 8048 system? Of course that means the 8048A will not have its own FlexMax chargers. My old 8048 system will maintain the four 12v (48vdc) Hawker LA batteries rated each at 6 hours capacity at 650 amp hrs; finish rate 45 amps. NOTE: There is an input on the Hub communications manager for the FlexMax charger. Will this create a problem with the Mate 3 and the rest of the operation of the 8048A system?
Please notify me by email: 2jackmans@gmail.com

• Super Moderators, Administrators Posts: 33,569 admin
With batteries, there are "optimum" (rule of thumb) guidelines will start with (especially if lacking Battery Mfg. specifications)....

For loading, suggest the minimum AC inverter load would be 10% of a FLA bank's 20 hour AH capacity (we use 20 hour discharge rate for our rules of thumbs here--Generally closer to how off grid solar system's current draw):
• 650 AH (6 hour rate) * 1.22 (6 hr to 20 hr rate conversion--pure guess on my part) = 793 AH @ 20 hour rate
• 793 AH battery capacity (48 volt bank) * 1,000  Watt inverter / 100 AH @ 48 volt bus) = 7,930 Watt max suggested AC inverter loading
And charging... 5% rate of charge (minimum). 10%-13% typical FLA suggested rate of charge. And ~20-25% max suggested rate of charge
• 793 AH * 58 volts charging * 0.05 rate of charge = 2,300 Watts minimum charging (power)
• 793 AH * 0.05 rate of charge = 40 Amps suggested minimum FLA charging rate
• 793 AH * 58 volts charging * 0.10 rate of charge = 4,600 Watts nominal charging (power)
• 793 AH * 0.10 rate of charge = 79.3 Amps suggested nominal FLA charging rate
Note sure your specifications of "finish rate of charge"... If 45 Amps "bulk/absorb" rate of charge, it is a bit over the 40 amp suggested minimum rate of charge (2.5% to 5% is suggested FLA rate of charge for Equalization Charging" of an FLA battery bank).

If your batteries are AGM, the above numbers are still useful for a typical off grid battery bank that is used daily (or perhaps on weekends for a 5% rate of charge)... But AGM batteries are not EQ'ed charged at elevated voltage (overcharging/over voltage charging of AGM batteries can cause batteries to vent, overheat, and shorter life).

When charging over ~10% rate of charge, highly suggest that a remote battery temperature sensor be used to prevent batteries from overheating during high current charging.

I will email this post to you too... But it is really better to have discussions on the forum... Both for others to learn from your questions, and have other chime in with their suggestions (nice to have feedback from multiple posters).

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 6,863 ✭✭✭✭✭✭
Kind of weird that this guy can't come back to the forum heh?

Also nice when someone gets help, that they come back and try and be of help to someone else.

Maybe he is really off the grid.....
"we go where power lines don't" Sierra Nevada mountain area
htps://offgridsolar1.com/
E-mail offgridsolar@sti.net

• Super Moderators, Administrators Posts: 33,569 admin
I did receive a "thank you" from JackManns... We will see if he has any more questions.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset