Bossrox
Solar tinkerer
Will they work together well? Yes!
I just acquired my 1st 280 a/hr 8s lith pack & have a good 300 a/hr agm bank I didn't want to abandon, so I decided to tie them together to see how well or not they'd work together.
1st surprise was the lith pack took on the total inverter load til the voltage got down to about 25.6v, then the agm's started easing in, & because the agm's began contributing before the lith's bms cut off, it slowed down the the discharge rate of the lith's towards their end of cycle.
Now on the charging side it's a bit trickier, the lith bank robs most of the charger current & knocks down the volts to about 28v thru the entire charge cycle so the agm's charge slower.
Since I only draw no more than 35% off the agm's, they're charged before the lith's anyways, so my concern was, if the charger is in bulk mode when the agm's were fully charged, would they get overcharged? No & or maybe, 'cuz the lith's hold down the chargers voltage to a near steady 28v until the lith's reach saturation so if the agm's are charged, they're getting 4 tenths of a volt more in float than normal. Not sure if that's much of a concerning issue.
But when both banks are charged & the charger goes to float, to get 3.5v to the lith cells, I had to set the float volts to 28v rather than the normal 27.6v. I can't say if having a float 4 tenths of a volts higher than normal is damaging to the agm's & I may be taking a risk of their longevity doing that.
What I really like about this set up is with them tied together you won't get a sudden shutdown of your inverter like if you were on lith only.
I just acquired my 1st 280 a/hr 8s lith pack & have a good 300 a/hr agm bank I didn't want to abandon, so I decided to tie them together to see how well or not they'd work together.
1st surprise was the lith pack took on the total inverter load til the voltage got down to about 25.6v, then the agm's started easing in, & because the agm's began contributing before the lith's bms cut off, it slowed down the the discharge rate of the lith's towards their end of cycle.
Now on the charging side it's a bit trickier, the lith bank robs most of the charger current & knocks down the volts to about 28v thru the entire charge cycle so the agm's charge slower.
Since I only draw no more than 35% off the agm's, they're charged before the lith's anyways, so my concern was, if the charger is in bulk mode when the agm's were fully charged, would they get overcharged? No & or maybe, 'cuz the lith's hold down the chargers voltage to a near steady 28v until the lith's reach saturation so if the agm's are charged, they're getting 4 tenths of a volt more in float than normal. Not sure if that's much of a concerning issue.
But when both banks are charged & the charger goes to float, to get 3.5v to the lith cells, I had to set the float volts to 28v rather than the normal 27.6v. I can't say if having a float 4 tenths of a volts higher than normal is damaging to the agm's & I may be taking a risk of their longevity doing that.
What I really like about this set up is with them tied together you won't get a sudden shutdown of your inverter like if you were on lith only.