adding adjust potetniometer/switch to charger?

[szczur333]

hello

I have 30A charger - GTK (20s - max 84V) solid alu IP68 charger, I simply dont need 30A charging all the time so switch or potentiometer to adjust current will be great, it can be done?

I saw chargers with adjust current but usually they are just server psus moded for charging, loud and definanetly not weather proof

 

[john61ct]

The controls to allow current adjustment rather than just simple limiting, need to be designed and built into the regulation circuitry, not just a matter of adding a pot.

That makes a source a fair bit more expensive, so they would definitely advertise that feature to justify the higher pricing.

Some people use long/thin gauge wires or resistors with certain ratings to burn off a certain percentage of current before it gets to the battery, but of course that messes with voltage setpoints too, and could be dangerous.

I reco Grin Satiator for that sort of flexibility

 

[amberwolf]

YOu should check with GTK to find out how to adjust the current on it. It may already have adjustments available. Or it may be programmable (probably only at the factory). Or it may be completely unadjustable.


If it is not adjustable, then you would have to reverse engineer it to determine where it's current-monitoring shunt is, then figure out the circuit that leads from there back to the main electronics. That circuit will be what you want to figure out where you can put an adjustment pot in to create a voltage divider, to "fake out" the main circuitry into thinking the current is actually higher than it is, so it turns the current down on it's own.

 

[szczur333]

ALSO I have small version 0-12A of this one

https://www.aliexpress.com/item/4000121088149.html?spm=a2g0o.cart.0.0.47753c000Uh6x2&mp=1

its has adjustable current but its more really like 9,5-10A charger

so this bigger one will be max 20A, if this red one will be capable of real 25-30A will be perfect but it doesnt so thats why I spend only littel more to get gtk 30A