Neddy wrote:Exactly. That's precisely why so many people use 2x 6v batteries in series rather than a single 12v battery.
Actually, I think you will find that more systems have 2 x 12 volts in parallel than one huge 12 volt battery.
Neddy wrote:Maybe, maybe not - but either way that is not what is under discussion here.
Actually, it is what is under discussion here - you choose to use the less common single 12 volt battery as your comparison, because the answer will differ if you use the common 2 x 12 volt parallel system.
Neddy wrote:What he read was of course absolute twaddle.
What you forgot to add is, "In my opinion".
Lets just look at a bit of theory here. The battery when charged has one plate with much higher electrical potential than the other. When the external circuit is complete, it discharges its "surplus" electrons through the electrolye to the other panel until both are at the same potential. At that point, the battery is dead flat. To recharge it, you then add an external source of power (the charger) to one of the plates to reverse the process and increase the difference in plate potential. So, at that point, you could quite easily reverse the positive and negative plates if you want.
A starter battery has thin plates with lots of surface area in contact with the electrolyte. This allows it to give relatively large current flow. A deep cycle has thicker plates for longer cycle life. However, that external charger has to get those electrons into that much thicker plate. As an analogy, the difference between wading in 50mm mud and 500mm - which is harder. So if an average golf cart battery is designed for extreme cycling, it will have very thick plates. So why would it not need more energy to charge?
The actual question is whether the effect is really noticeable in practical terms. I don't think so, but I have never charged a golf cart battery with solar. Unless you have and compared it directly with the alternatives, you won't know.
So in Neddy's focused example, one 12 volt battery will have similar characteristics to 2 x 6 volt of equivalent voltage and capacity. But if the common 2 x 12 volt parallel configuration is used, then the 6 volt in series solution for equivalent capacity has half the number of plates. This is one reason why in theory it is less likely to fail than 2 x 12 volt in parallel. But to get the same capacity, the plates must be.... I'll leave that to others to figure out. Of course it will make a difference to how they charge.
Just to add, I also think a bit of hyperbole is going on with the Bushtracker response. Professional wisdom dealing with many years of investigations has taught me you don't go in and rubbish something without absolute proof. Heck Neddy, I even listen to you some of the time