Solar discussion continued..
That thread appears to have been closed and I can't add additional information. Addressing this to time2roll...Thanks for your post. I have a better sense of things now. Agreed...just need to figure ...
Forum Discussion
cannesdo wrote:
I was thinking that with 200 Ah 6v batteries you'd have 400v so the total Ah of 4 6v golf batteries won't be much higher than 4 12v deep cell batteries. So what's the advantage? They last longer? This gives me only 200v to play with. How do you know when you're at 50%? I do have green, orange and red lights on the control panel. Nothing below orange?
No idea what you mean by "400v" and "200v" :h but regardless a single GC-2 flooded 6 volt battery such as the Trojan T-105 is 20-HR rated @ 225 AH so obviously four connected in series parallel would offer 450 AH, half of which is usable @ 50% DOD (Depth of Discharge) which is about as far as you'd want to draw them down on any regular basis. Compare that to the Trojan SCS200 12 volt flooded 12 volt deep cycle battery which is 20-HR rated @ 115 AH - obviously four of those connected in parallel would offer 460 AH, half of which is usable @ 50% DOD.
While GC-2s like the T-105 are perennial favourites with the dry camping crowd some do prefer 12 volt versions because they may fit available space better and because if one goes bad the others can still remain in service. 12 volt jugs also generally have less internal resistance so for those of us running an inverter that can mean less voltage drop under heavy inverter load, which in turn means the inverter is less likely to low voltage alarm compared to powering it with a 6 volt battery with higher internal resistance.
Next is the issue of whether you want flooded or might benefit from the advantages more expensive AGMs can offer, not the least of which includes easier installation as they don't have to be mounted sitting up, generally can be safely drawn down to a lower DOD than flooded, and will usually accept a recharge more quickly. These of course are generalizations so the key is to make sure you compare apples to apples when designing your battery system which consists not just of batteries but also an appropriate charger for properly maintaining those batteries.
Idiot meters with coloured bands to indicate state of charge are just about useless - at the very least get yourself a reasonably accurate DVM but those seriously interested in solar and wanting to accurately track how much power they're using and how much their system can restore are much better served by investing in a Bogart Engineering Trimetric.
