Opinion about Crown batteries for solar system

Re: Opinion about Crown batteries for solar system

No sun = no charging from the FM80. If the panels are hooked up it will produce something, but not full current.

I think westbranch was referring to using charger built-in to inverter if there is one or else a stand-alone battery charger to make sure the batteries are at least above 75% SOC if the sun is not co-operating.

You have the right Absorb Voltage of 57.6 for those. It is a starting point as is the 2 hour Absorb time. The batteries need to be cycled to see if both are sufficient to achieve full charge on a sunny day after use. If not, increase Absorb time first; watch the current through that stage and see where it plateaus in respect to how long it has been in Absorb. The FM80 allows you to set an End Amps value that should be at or near this level, with maximum Absorb time being longer than it takes to reach that current plateau.

Your Float Voltage level should be adjusted down a bit. 55.2 would be maximum, and you may find it works better at 54.

The Equalization Voltage is too high. It should not need to be more than 60 Volts.

Again all Voltage/currents/time figures are guidelines; you have to check system performance over a few days and see how they work, then adjust the settings to get the best performance for your particular application.

Re: Opinion about Crown batteries for solar system

Never believe the info from a company. They are trying to sell you their product and therefor will slant any 'tests' in their favour. Or even outright lie.

All they have to do is pick 'similar' (i.e. different capacity or application type) batteries to test and they get the results they want. T875 is 170 Amp hours @ 20 hour rate. The US Battery listed does not give a model that would indicate Amp hour capacity, only that it is 8 Volt and XC (extra capacity) design. We can hope it is the 8VGCXC2 which is also 170 Amp hours at the 20 hour rate. The Crown is 165 Amp hours @ 20 hour rate.

Note also that these are 8 Volt batteries, rarely used in RE but there's no reason they couldn't be with 24 or 48 Volt systems. The Trojans operate at a higher Voltage than the other two. And if you charge them all the same, they will not perform the same. Note also that these tests are run from utility source charging with controlled discharge as well; neither of which is found in an RE application.

Out here in the real world Trojans are more expensive per Watt hour capacity, need higher charging Voltage (as per their spec) which is not always attainable, and do not last noticeably longer than the other brands. I've got nearly 500 cycles on my US Batteries and they have not lost significant capacity yet; still completely usable. According to that chart even the Trojans would be dead by now.

The truth is lab information for battery life doesn't mean anything in real world application. More batteries are killed by misuse than anything else, and the brand doesn't matter when that happens; you can kill an expensive battery just as easily as a cheap one, it just costs more. There are people who have gotten satisfactory life from warehouse GC2's that cost <$100 each. And there are people who have murdered Surrette's in one year.

In short, don't get hung up on battery brand names as an assurance of quality or longevity.