We typically consume about 150Ah per day and can recharge about 300Ah on a sunny day. I bought four 206Ah SOK's so that we'd be able to last through longer stretches of dark skies and so we can use the air conditioner if necessary. For both of these instances, the ability to quickly recharge is important.
At maximum current, these batteries take four hours minimum to fully charge. Other batteries can be charged in as little as one hour and even SOK's smaller battery, which is at the slow end of the range, takes two hours.
Clearly, I don't have enough solar to completely recharge all 824 amp-hours in one day. On a typical day, I get about 300 amp-hours so we count on being able to recharge that additional 500 amp-hours of battery capacity as quickly as possible, using generator and alternator charging. With slower charging the extra capacity isn't nearly as useful.
With faster charging batteries, we could top them off in about 5 hours. With the SOK's we'd have to run the generator for 10 hours. That's a big difference!
But the other problem is that these batteries actually turn off if that 50A per battery limit is exceeded. When we use all three sources, we have potential combined charging of about 225 amps. (Before discovering the 50A limitation I was planning on increasing our charging ability by another 150 amps.) That means we have to continually manage the current going to the batteries so that we don't find ourselves in a position where we think we're charging and we aren't.
I realize that we could get by with these batteries, but if they can't be quickly charged we may as well just stick with the 300Ah LifeBlue battery that they are replacing. The extra 500Ah isn't going to be of very much benefit to us.
And, to be clear, it's my fault. I would have appreciated if some of the reviewers had emphasized this point and the ramifications, but I believed what was convenient and thought that the 50 amp limit was just a recommendation, not an on/off trigger.