MightyMax 18Ah AGM battery

[sternwake]

Ok why not decide to measure the battery resistance?

Apparently One can measure the voltage of the battery before the load is app;lied, apply the load, see how far the voltage drops.

Voltage drop divided by load should give the resistance

So test number 4 I start with 13.07v and apply a 2.83 amp load (02mm computer fan) and voltage drops to 12.69v

13.07v - 12.69 = 0.38 voltage drop

0.38 divided by 2.83 amps = 0.134275 mΩ, well less than the claimed 18 mΩ resistance on the UB12180 data sheet

Now my particular fan takes a few seconds to ramp upto being a 2.83 amp load........... Room for error.

Must find other steady 2+ amp DC loads.........
2+ amps as my easy to use wattmeter is way more accurate reading above 2 amps.