I did state that there was a design completed by DEL that used the BQ25895. However, I do not have the equipment to solder this part to a PCB for testing purposes. I really like the part and the circuit DEL designed, but am unable to build a prototype. That was part of the reason I wrote this post to see if there were any forum members willing to assist in this part of the project.
If we receive offers for the ability to build prototypes using the BQ25895, then it is certainly still a possibility.
Thanks Tom Tom, I will take a look into those parts. Ok, I took a quick look and they quote reverse discharge protection. I think those are strange words to say the leakage back into the chip is “low” whatever that means. I did not look at those specifications. What I did look at was that if the voltage between the BATT output and the return are reversed, then you exceed the rating of the part, and it likely fails. It only takes once to kill the part.
You can protect against reverse polarity very simply with just a small inexpensive FET. No significant voltage drop (unlike a diode).
Edit: a PFet protection is pretty much universal for automotove electronics, together with a big Transzorb to protect against alternator load dump events (not a torch problem).
As for using the BQ25895 that’s a mad idea. to benefit from any of the features it has to have a microcontroller to set it up, and I think the firmware required would make the stuff to run the LEDs on the lantern seem trivial.
And it is an expensive part. Very expensive.
Study the datasheet.
This is just a torch/lantern, a simple USB micro to charge it up is all that it needs.
If you want it to be a powerbank, well, it’s possible, but take a look at how they are usually done, a USB micro to charge, and a big clunky (but so reliable) USB A for power output.
USBC is not necessarily the next big thing. And is expensive to implement. I have two devices that use it (a smartphone and a Samsung Galaxy TabPro S. Both of them now have dodgy connectors, only used with the OEM cables, a couple of insertions per day. If the connectors fail completely then I will have no way to get my data out, or even charge them. Not happy.
I also thought we had decided on Usb-C. I am 70 and my eyesight is failing. Up until recently I struggled with multiple different Usb cables trying to find the right one and especially the right orientation. Last year I got a Note8 which has ‘C’ and it has been SO MUCH easier …… I know we usually learn from our mistakes, and I think this would be one, but I am confident BLF L2 will have ‘C’…. if I am still around for it.
@ Tom Tom- Are you saying that the C is more prone to damage than the others? I would think it would be the other way around since usually if there is a problem with a damaged connection it is because users either try to force a wrong plug or try to connect with the plug upside down…… Are the C plugs inferior in quality? If it is a cost issue…… how much more would it be per lantern?
Thanks for the link Tom Tom. BlueSwordM described an identical circuit to me recently and for some reason I just did not get it. Seeing it in a different presentation made it click I guess. :student: I will be adding this to the driver for sure.
well said TomTom, that’s the reasons why i tested the 1 amp TP4056 to be perfectly suited for the lantern, as even with four 3600mah high capacity cells, the 1A TP4056 would charge them in less than a day (of which time the lantern is not used) and the lantern will run for a few nights on a charge at 5 to 6 hours per night on high. There is no need for “Fast charging” at 2+ amps what so ever for this application, which causes problems i tested when trying to charge from lower powered Solar panels, wall adapters, RV USB ports, etc. it will be likely limited to 1 amp charging for the production model for those reasons. Unlike phones & tablets where fast0charging ratea are a great idea, for the lantern purpose it really does not need it at all.
USB-C is the planned charging port interface for the production lantern (if it do not add to much more to the retail price of the lantern) if USB-C is to cost-prohibitive, then we will have to go with USB-Micro. we will know once Barry can determine the cost difference for us.
EDIT: - I been searching for USB-C type charger/USB power bank modules and have had no luck with finding anything at all that seems to use the USB-C port for both charging cells and use as a power bank output all in one port (as some people said it was capable of, but i have not found that option existing at this time)
it seems to have both the charging capability & USB power bank option there will be have to be two ports, and a separate female-USB-A socket for connecting devices like smart phones to charge them. (USB-C for the charging-in port, (or revert to USB-Micro if the manufacturer determines that USB-C is too cost prohibitive for the production lantern)
To all those who doesn’t have USB type C yet, I suggest you get some of these. Great quality at an affordable price. I have one in my car, a couple in my house as well as in my camping box.
The USB C connectors are supposed to be more significantly more durable than the predecessors. As rated by number of insertion/extractions before wear (the plug is designed to wear preferentially to the socket, as is the USB micro).
However my real world experience with my two devices is that the connectors soon become loose and wobbly, to the extent that I now often have to wiggle the connector a bit before a good connection is made. This particularly affects the data connection.
My Samsung Tab is utterly reliant on this connection, I have an external dongle that is used as a docking station to connect three standard USB devices (printer, external HDD, SD card reader, TV tuner, etc.) as well as a gigabit ethernet port to my home network. When the connection is playing up it is extremely frustrating, and data loss is a very real risk, particularly with the HDD and SD card.
I regret buying the Samsung Tab, I trusted that USB C was to be as reliable as advertised, but my experience has been quite the opposite. Even finding a dongle to use as a dock, that also passed back the power connection so the Tab could charge whilst in use, was an expensive and frustrating challenge.
My ’phone is less problematic, as it is primarily used just to charge it, but again, when I use it for a data connection it can be temperamental too.
DBSAR, I’ve had a quick look for powerbank ICs that are simple to use and not reliant on configuration by an MCU, the Active-Semi ACT28xx range looks promising.
In particular it appears to modulate the input current when charging “Accommodation for 10mA-3000mA input current” to suit the source capability. If so, that would be ideal for solar panel use, as well as adapting to low powered USB sockets etc, whilst making good use of high current chargers.
I have a 10 AH battery bank with integral solar panel for charging. It uses an ACT IC and works very well. Keeps my smartphone charged on backpacking trips (left in flight mode except for two 1 hour windows per day for friends and family to call me, or to collect texts and e-mail). Main use of the phone is for GPS navigation and mapping, which is still a significant power draw even in flight mode.
As well as having a puny LED torch built in, which is sufficient for campsite chores, once eyes are dark-adapted. The ’phone torch is much better, and of course I carry a proper one too (Olight S15 powered by AA alkaline if on a long walk)
It can also recharge my DSLR battery, though that flattens it and it then takes a couple of days to re-charge on solar.
My Type-C phone has got quite a bit of abuse with me fumbling and pulling the wire often at odd angles. After a year it’s still perfect. Micro-USB port would have serious issues after surviving that.