I created a modular armor with 3 roboports, 2 batteries and the personal transformer, but the battery doesn't charge when I get close to a power pole. Even using the keys to change the power output/input doesn't work.
I think it might just be slow. Roboports have a decently sized power buffer and they'll get charged before the batteries do. You may consider swapping out a roboport or two for a personal transformer. Or adding in solar panels to help.
