I am using Roboport Mk2 with a charging pad Mk4 next to it. I have a swarm of robots doing stuff around but none of them are using the charging pads, they all just keep queuing up for the roboport.
Factorio 1.0.0
Bobs Logistics 1.0.0
Bob's Library 0.18.0
I don't use the whole Bob's suite, but I do have more than just the above mentioned active in the game.

there is a library 1.0.0 available, but that's not going to change anything in this case.

related to your issue... that's just how the game engine works. When a robot is running low on energy and wants to recharge, the game literally just sends the drone to charge at the nearest charging facility. If that is a full vanilla style Roboport, then that's where it goes, if it's one of my cut down role specific entities like a charging pad, then that's where it goes.
Charging pads work best when you're using Logistic Zone Expanders instead of Roboports, so there are no other charging points for it to use. But armed with the knowledge of how things work, look to see where your robots go, then place charge pads on this route.
As an example, if you're dealing with the north-most Roboport in your network, and everything flies towards and from the south, placing a charge pad north of this Roboport will be useless. Placing it just south of the Roboport instead will result in the charge pad being used frequently.

Something else to consider:
When traffic is light, robots are always available, and instead of going from job to job, a robot will do one job then try to dock, It's a bit complicated but jobs only appear the instant they are given, or if the job was unable to be filled 1 at a time per tick. This means that if you have free robots available, a new job will always be assigned to a new robot and never to busy one, so robots will always want to dock between jobs.

Now, this becomes a problem for charging pads when you consider that ROBOTS ALWAYS CHARGE AT THE ROBOPORT THEY'RE DOCKING WITH!
There is a condition that they only charge if their energy level is below a certain threshold, so a drone that barely did anything may dock immediately without charging, but if a tired drone wants to dock, and there's a chargepad available next to the busy roboport, it will ALWAYS join the queue to charge at the roboport rather than using the charge pad first. It's just the way the game engine is written.
This is why Robochests have a single charging port, they NEED to have one because of robots always wanting to charge at the roboport they're going to dock with. If you remove the charge port from a Robochest, robots will fly towards the chest then Queue to use a charging port, even though there aren't any.

So in summery... Charging pads do work as intended, but there are certain situations where robots ignore them in favour of charging at a busy roboport.

Ah, so in my case they are doing the landfill and going to dock, so they will never use the charging ports I put out. That's annoying. I guess I will have to update to the highest tier roboport so at least they can all charge at the fastest rate.

Yeah, even if they were going to use the MK4 charging pad vs the MK2 roboport, they charge at least double the speed in the charge pad, so even if they are using it, it may seem like they're not, because even with 2x the speed, a queue will quickly form at the slower one. Couple this with everything wanting to dock joining the queue, and you end up with quite the bias.
Making everything MK4 will help, but ironically, the queue will likely have very little effect on your robots productivity (unless a large number of robots not in the queue decide they want to charge at the same time), as when there's none left in the roboport, the job will be assigned to a drone already in flight (not in the queue, but not currently doing a job), which will either run directly to the new job, or decide it wants a quick charge at the nearest charge point (which if correctly positioned will be your charging pad, rather than the busy roboport)

The best scenario would be to use the MK5 robots, also known as fusion powered robots. (or I may have renamed them when I added RTG power) These don't need charging, as they have a generator onboard.

So in summery... Charging pads do work as intended, but there are certain situations where robots ignore them in favour of charging at a busy roboport.

I disabled vanila roboports in favour of modular only. Robochest becames the biggest bottlneck. No matter how many charging station and how they are positioned after any "burst" delieverers when a lot of robots are released from chest and then going back to dock an infinite queue of charging robots are created.
If you will add more chest to break queue to smaller ones few other issues appearing. First - having more chest leads to smaller queue that making charging pads less desirable. Second - chests < roboports in charging speed so building actual roboports is preferable then chest.

I will appreceate a setting that allows to increase charging spots on chest from 1 to atleast vanila 4, as for now there are no way to build efficient logistic network only with modular parts.

The big issue with the robochests is that they MUST have a charging pad on them.
When Robots want to dock up, they always try and charge at the port they're trying to dock into, and if the robochest doesn't have a charging port, they fly up to it, then wait for the non-existent charging pad to become available for them to charge before trying to dock.

The problem is, the same rules apply, to roboports as it does to the chest, so, yeah, maybe they should have a faster charging port to fix such issues.

Personally, I don't use many robochests, I stick to using LZEs, Charging pads and full size Roboports. I do use some robochests, but they're usually clustered in the same area, with Roboports offering storage elsewhere, due to this charging issue.