Create cacading batt charger for batt capacity test & auto shutoff @ volt drop of test batt

Thread Starter

RogueRose

Joined Oct 10, 2014
375
I have a battery capacity tester (pics below) that draws up to 200W and is dissipated as heat. I can set the amp draw from 0-~30+ but it will drain the battery to zero. I want to create an auto-cutoff that is dependent on the battery type and the voltage of the battery, so it won’t drop below a set point (maybe 60-80% of full charge). I was thinking this might be possible using a switch or relay on the cable connecting the battery being tested (or power supply) and possibly controlled by an Arduino. So if a 12v SLA batt drops below 9.5v it will cut the connection to the battery (while keeping the data on the tester unit. Obviously the cut-off V needs to change for a 3.6/7v Li-Ion vs a 20v Li-Ion.


Since the unit turns the power to heat, I’d like to change that and use the power to charge other batteries (probably the same battery V and maybe Ah as well), maybe this could be done with a buck/boost converter and Arduino?


I have the option of getting 1000’s of battery packs or SLA’s a week that need testing, so being able to do 10-20 tests at a tine would be SUPER helpful!. I’m wondering if multiplexing could be used in this type of setup where the V is measured for the cut-off



I’m also considering looking at some li-ion chargers – 1A TP4056 and 5A XL4015 E1 all because they seem to be well supported and widely used. The li-ion’s I get are 18650’s, 26650’s, 32900’s and 42120’s so some are fairly large Li-ion’s (45-60AH)..


The 12v SLA’s are usually 9, 12, 17, 26, 35, 40, 54, 74 and 95 Ah


The li-ion’s are usually 3.6/7v, 7.2v, 12v, 14.8v, 20v & 60v



I’d also love to be able to output the data test results to some kind of file, CSV, DB, XLS, etc, I don’t think that is possible in the device I have, but maybe if the Arduino were involved it could record this. Recording to microSD is OK, though network connection is better IMHO.

Battery Tester top.jpg

Battery Tester LED readout and controls.jpg

Battery Tester bottom.jpg
 
Top