Heads up about those new MRL controller batteries

Been seeing a bunch of guys swapping out the old flooded batteries in MRLs with sealed AGM ones without changing the charger settings. I caught one smoking last week on a 3-car install downtown. The voltage setpoint is different and the controller will cook them in about 6 months. Anyone else run into this or is it just my area?

3 comments

3 Comments

dylan4634d ago

I used to be one of those guys who thought swapping to AGM was just a straight upgrade. I stuck a set in a 2-car MRL in a condo building here in Austin about a year ago, never touched the charger settings. Six months later that controller was hot as hell and the batteries were bulging. This post made me check the manual and sure enough the voltage setpoint for AGM is lower, around 54.4 volts versus 52.8 for flooded. I had to swap mine back out and reset everything, cost me a whole afternoon and a couple hundred bucks in batteries. So yeah, you're right, this is a real problem and I wish someone had told me sooner.

lewis.brian4d ago

Yo, did your flooded batts at least last longer than those AGMs before you swapped back?

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keith2743d ago

@lewis.brian you mentioned the heat issue, but nobody's talking about how the charging algorithm itself can mess things up for AGMs in a bank. I replaced a set in a 48 volt system for a buddy's off-grid cabin last spring. Flooded batts were failing every 18 months from sulfation, so he went AGM. But his charge controller was set to a "float" voltage that kept the AGM at 52.8 volts constantly. AGMs need a lower float, like 50.8 volts, to avoid overcharging and drying out the electrolyte. Took me three calls to the manufacturer to figure that out. You run into that with yours?