TP4056 Charging board instead of a recharge port?

[harmless_toast]

I was wondering if anyone has any experience using a Micro USB TP4056 (http://www.buildcircuit.com/how-to-use-micro-usb-5v-1a-lithium-battery-charging-board-charger-module/) Charging board in a lightsaber as a recharge port. Would I need to wire a separate kill switch, or could I just wire up the charging board exactly the same as a standard 2.1mm recharge port?

I'm working on a fairly simple NBv4 install that has a ton of extra space in the pommel, and I'm thinking it would be really nice to not have to worry about keeping extra chargers around when these boards are <$4 on eBay and I already have so many micro USB cables lying around.

[Tom Tilmon]

If its a NBIV install, you don't need a kill key. If you can wire the port to the battery, I think you'd be good. The only problem I'd see is while charging, you are delivering juice to the board as well. Does that Micro USB TP4056 have some kind of cutoff leg in it? I'm unfamiliar with it. Some of the logic behind using a traditional recharge port was the cutoff leg. You aren't sending charge voltage across the board.

Tom

[jbkuma]

This is a fairly well trodden topic. The chips are very common and reliable. Some boards come with a cut off, but they are only rated for 1A. Ideally you should still use a method to cut power to the saber when charging with the board. The draw from the board can confuse the charger and cause the badness with your battery.

[Strydur]

We have tested a few and they seem to work good. We plan to look into making some boxes and other things to go with it if we ever find the time. I would think that since these are just a 3.7v charger there should not be a issue with not having a cut-off but I will ask the powers to be and report back.

[harmless_toast]

Thanks for the replies everyone!


I would think that since these are just a 3.7v charger there should not be a issue with not having a cut-off.

This is what I was hoping for. It seems like the NB should be fine getting the 3.7v from the charger, and that the only potential downside might be slower charging times with the split current. but I'd definitely appreciate hearing from someone who has tried it before I start just wiring things up.

It would be pretty easy to wire in a little latching switch so I can cut off the soundboard when charging, but I'd rather not have to bother.

[PCModulus]

You dont need a board like that, just a USB port, the charging circuit is in the charger, i just use something like this (with a kill switch) and it works fine https://www.ebay.com/itm/10pcs-USB-Micro-B-Female-Port-Connector-Breakout-Board-Socket-Power-Arduino/391667888584?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

[Strydur]

USB port on the saber should have this board or something similar to know when to shut off, etc.. There are many things people can plug the other end of the cord into and I would prefer to know there will not be a issue rather than just hope there is not one.

[harmless_toast]

Yeah I have a PCB on the battery pack, and probably one on whatever charger I'd be using too, but with so much extra space in this hilt, and for only an extra $2 a board, I'd definitely feel more comfortable having that extra overcharge protection on the port as well. I only want this saber to emit light, not smoke!

[Don Se Wion]

When using these USB charger boards, always include a switch to cut power to the board when charging.
If you leave the NB (or other boards) connected while charging, it will absorbe current and produce a voltage drop.
This additional load will trick the USB charger, making difficult for it to precisely understand where it is in the charging process, potentially creating problems with the battery.

I was planning the same setup for a saber and asked Erv over at the FX-Saber forum.

To avoid the switch, it would be possible to use one of these charging boards:

https://www.amazon.com/TP4056-Micro-USB-Battery-Charger/dp/B01LHD9D7E/ref=sr_1_5?ie=UTF8&qid=1520501118&sr=8-5&keywords=TP4056

They have separate pads for battery and board and can be used with unprotected cells because they incorporate the over-discharge protection circuitry.
However, the cut-off current is 3A, which might be a bit too low in case of RGB setups.

[Strydur]

Not seeing the logic there or not wrapping my head around it.. I am not seeing how that board (which is the same basically as the ones I have here) can be used to isolate the board from the battery since the battery is the source except for when charging. Unless that negative out is cutoff during charging. I have not looked at the schematic so not sure.

[Don Se Wion]

Initially, when looking for information about these modules, I found descriptions that were suggesting the load was separate from the battery, making possible to skip the switch.
Deepening the research, I found another page where, for the same kind of board, it is suggested to disconnect the load when charging.

So, looks like the information I got initially might not be precise enough.
To play safe I believe we always need to include the switch to cut power to the board when charging.

Sorry for the confusion I may have created.

[Strydur]

As to the other issue.. I have asked Erv and he said it was not a issue using these.. but maybe that is in regards to damaging the board and I did not consider it fooling the charger. But I am pretty sure if the sound module is in deep sleep then this would not be a issue but I could be wrong.. will ask what he thinks.


EDIT.. Okay so Erv does not think it would be a issue as long as the board is turned off but still thinks some sort of cut-off such as a latching switch, etc would be a good safety measure.

[PCModulus]

As to the other issue.. I have asked Erv and he said it was not a issue using these.. but maybe that is in regards to damaging the board and I did not consider it fooling the charger. But I am pretty sure if the sound module is in deep sleep then this would not be a issue but I could be wrong.. will ask what he thinks.


EDIT.. Okay so Erv does not think it would be a issue as long as the board is turned off but still thinks some sort of cut-off such as a latching switch, etc would be a good safety measure.

Yea, thats why i used a kill switch. The batt and USB neg go to one side of the switch and board neg goes to the other. All pos's are wired normally. As far as indicating when its charged, its the same as with a cell phone, the charger knows when to stop supplying power.