Hi,..All..........when you hook bat's in series,..voltage increases,...when you hook,..parallel...current increases??......How do you determine the value of the strenght of the current,.........or measure the available power,.......when you hook Par,..seems I lose ~2/3 the amps,...........they don't add like series voltage...........artv
When you hook batteries in series, the voltage does indeed increase to the numerical sum of the individual batteries.
Ie, 4 x 12V in series makes 48V.
When you put them in parallel, the current doesn't automatically increase over say a single 12V battery, but the POTENTIAL to deliver current increases. That is, the "internal resistance" of the source drops so it can deliver a larger current. A 120 watt load will draw 10 amps from a 12V battery. Putting 2 or more batteries in parallel won't increase the current because the load only *needs* 10A at 12V.
The only time the current automatically does increase, is if you're comparing a given load (that can run from a variety of voltage sources and take the same POWER - so not just a light or heating element - it needs to be a switch-mode power supply) - at different voltages.
Lets take that 120W load. 120W @ 24V will take 5 amps.
Reconnect the batteries so they're all in parallel, but now at 12V, you will need 10 amps for the load.
Reconnect the batteries so they're all in series, but now at 48V and you will only need 2.5A for the same load.
All bets are off with a plain old load like a dump-load resistor. A 4.8 ohm resistor will draw 5A from a 24V supply, and use 120 watts.
The same 4.8 ohm resistor on 12V will take 2.5A but only dissipate 30 watts, while at 48V it'll take 10A and dissipate 480 watts.
Hope that helps rather than just confuses!