Sonnyboy I think a lot of the back and forth here is mostly trying to establish that it 'really is' more complicated than hooking them to a 10a charger meant for lead acid and saying it's good enough. Maybe it could have been established in a better way earlier and things would not have drug on so much, but.. we march on! lol
Basic amp-hour (Ah) math:
- Amps X Hours = Amp-Hours (Ah)
- Ah / Hours = Amps. Ah divided by the hours you got to spend equals the amps you need to do it.
- Ah / Amps = Hours. Ah divided by the amps you got to give equals the hours you need to spend.
100ah battery / 10 amps = 10 hours. So a 10amp supply would need 10 hours
under perfect conditions to put 100ah into the battery. BUT... that's if:
- The supply could put out 10amps throughout the entire charge (i.e. against a 'moving target', a battery whose voltage rises).
- The chemical process of charging the battery was 100% efficient (with lifepo4 it's close but not 100%).
Any charge source that puts out a fixed voltage cannot even get close to that 'ideal' charge time unless that fixed voltage is a fair bit higher than a fully charged battery's voltage. So maybe if the charger put out 15v or more, it could sustain 10a throughout the entire charge to a '12v' lifepo4 battery. But the way 'good' chargers typically operate is 'multi-stage' charging where they put out different voltages and monitor different things and apply different limits during different 'stages' of the charge. Unfortunately lots of 'consumer grade' charging equipment gives you little adjustability or detail about how the charger operates.
Your SCC seems to be somewhere in the, say top 20th percentile of what's out there because it does do multistage charging and lets you adjust a lot of it. Which is all well and good except it's operating from an unreliable power source (sun) into a vague bag of problems (batteries, possibly wiring) while your grid-powered 'reliable' charge source is far from optimal and doesn't let you adjust it any closer to optimal, either.
So i agree with everyone else who said you need to do a more complete charge of the batteries, the only practical way to do it is from the grid, and it will require you to use a different grid-charging source than what you've got now. You can use a 'dumb' power source such as a bench power supply to do this, but it will not protect you from your own mistakes in any way and require careful monitoring in return for dollars saved. It is probably best to bite the bullet on a nice, adjustable, multistage charger on the thinking that it is still cheaper than killing 3 lithium batts and having to buy 3 more.