DC Load for Battery Testing

[testian]

Hi,

for testing lead acid batteries I am currently designing a DC load with charging function and data logging. The data will be logged to an USB-Stick through an external PCB. Voltage and Current will be logged while discharging (constant current) and charging.
It would be nice if you could look at the schematic and give me feedback about it.

Basic principle:

The Supply for the Load is from an external 12V Supply

Spec:
1.5-20V
0-5A

[testian]

New Version.
Everything cleaned up and the decoupling capacitors have been added.
The AD8671 might not be the best choice for the differential current measurement but I had it laying around.

[Mechatrommer]

i think BC327 pnp should be replaced with npn transistor and D1 reversed.

[testian]

Thanks, you are right.

[testian]

Update: Added a charge current limiter, changed the 1wire Temp sensor to an PTC

After I etched the PCB from the previous design I noticed that I goofed up on the Arduino footprint. It had the wrong numbers assigned to the pin. Therefore I changed a few things and try it again. Attached you find the current schematic and PCB design. The relays will be on a cheap 2-Channel 5V module.

[qrper]

Here's my version.

Shown loading battery at 24 A. It's not smart, but works great.

Mike

[testian]

Looks very professional.

Here is my first prototype: