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  • New Charging Board from Sure

    Looks like the Sure 3S 18650 battery bank/charger is has evolved. From the description, it looks like it can be used as an independent board apart form the JAB & KAB series.

    http://store3.sure-electronics.com/3...on-board-bcpb2
    "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

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  • #2
    Nice catch Gordy. I can imagine using two with DPDT switch to operate with 24V on batteries or charging and AC PS voltage when plugged in You know, for those of us that are power hungry ...

    That would go nicely with PE's new 2.1 amp module (the 5 knob version).

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    • #3
      Sure does some really cool stuff. Not a fan of the charging LED situation. A board like this is internal. Give me a 2-pin JST PH header for the charge indicator led. When charging led is on. When fully charged the led is off. I just ordered 3 to see how they work. I think this would also implement well into the small 2.1 amp board as well.
      "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

      The Madeleine
      The Roxster
      Swopes 5.0
      Acoustic Panels
      Living Room Make Over

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      • #4
        Cost ... the SMT LEDs cost way less than a connector and pigtail. Maybe one of those light filament / optic cable could extend the LED status to the outside world.

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        • #5
          I have the original version (KAB-BE) powering a boombox using that PE-branded TA2024 amp and a separate Bluetooth module. There are some solder tabs on one end and I just wired everything to that.

          The only thing I don't do is play while charging -- but that's because the BT board max rating is 15V and I'm charging at 19V. So the audio board circuit disconnects when charging, but plays for a long while before it needs to be recharged.

          Do you suppose they could be wired in series to produce 24V? I always hear horror stories about lithium batteries exploding, but I'm not sure that series wiring would negate the protection circuits.

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          • #6
            Originally posted by jdhill View Post
            I have the original version (KAB-BE) powering a boombox using that PE-branded TA2024 amp and a separate Bluetooth module. There are some solder tabs on one end and I just wired everything to that.

            The only thing I don't do is play while charging -- but that's because the BT board max rating is 15V and I'm charging at 19V. So the audio board circuit disconnects when charging, but plays for a long while before it needs to be recharged.

            Do you suppose they could be wired in series to produce 24V? I always hear horror stories about lithium batteries exploding, but I'm not sure that series wiring would negate the protection circuits.
            The original KAB (Sure) battery boards have cell protection built in: cell over voltage, under voltage, max discharge.. What they don't have is any sort of MPPT controller. That function, on the KAB amp module, manages charge voltage to limit charge current. And that's where you could run into trouble charging the batteries directly with a high amperage capable PS.

            Either the new or original battery modules will protect the cells from exceeding the discharge current limit. So once properly charged, they can be wired in series for a 24 V PS as long as the current draw doesn't exceed the modules protection limit. If it does, the protection circuitry will shut down the battery module output. The question is; What is the max discharge current limit set by the battery board's protection circuitry?

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            • #7
              Hm, that's not good... I'm using a 19V 75W brick (so ~4A). The cells are not protected cells but are rated for about 10A, so I guess I'm safe from over-current? Or is there some sort of current-versus-charge curve that is recommended for charging that the MPPT would regulate? Not trying to start any fires.

              My question is, how do you wire in series? The original boards have multi-pin connectors that wire the boards in parallel. Do you use the solder lugs to wire the boards in series and then splice it back to the 4-pin connector to connect it to the amplifier board? Asking because I made a pair of Classix II with built-in amplifier and battery but at only 12V I can't really get the max volume out of the 50W bluetooth amp (KAB-250 or whatever the Sure equivalent is).

              Comment


              • #8
                Originally posted by jdhill View Post
                Hm, that's not good... I'm using a 19V 75W brick (so ~4A). The cells are not protected cells but are rated for about 10A, so I guess I'm safe from over-current? Or is there some sort of current-versus-charge curve that is recommended for charging that the MPPT would regulate? Not trying to start any fires.

                My question is, how do you wire in series? The original boards have multi-pin connectors that wire the boards in parallel. Do you use the solder lugs to wire the boards in series and then splice it back to the 4-pin connector to connect it to the amplifier board? Asking because I made a pair of Classix II with built-in amplifier and battery but at only 12V I can't really get the max volume out of the 50W bluetooth amp (KAB-250 or whatever the Sure equivalent is).
                Max charge current for almost all 18650 batteries is significantly less than max discharge current. Post the battery mfg and model number.

                The KAB-250 board had an issue with overall gain when driven with headphone output from most phones. So even if you get the higher voltage to the amp board, you may not see that at the output to the speakers.

                I think a DPDT switch (or relay) can be used to charge and playi using the AC PS versus running off the batteries at 24 V. I need to put pencil to paper to figure out the circuit ... maybe in a day or two.

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                • #9
                  Here is the spec sheet... page 4 says max charge current is 2.5A. So I guess I need to dig up another brick with a lower rating, just to be safe.
                  https://cdn.shopify.com/s/files/1/06...les/lg_M26.pdf

                  I think I understand the concept with the DPDT switch... I started to lay it out and I couldn't quite figure out how to get there, but basically the boards charge in parallel and then flip the switch and they discharge in series. So you have to use the solder lugs.

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                  • #10
                    Originally posted by jdhill View Post
                    Here is the spec sheet... page 4 says max charge current is 2.5A. So I guess I need to dig up another brick with a lower rating, just to be safe.
                    https://cdn.shopify.com/s/files/1/06...les/lg_M26.pdf

                    I think I understand the concept with the DPDT switch... I started to lay it out and I couldn't quite figure out how to get there, but basically the boards charge in parallel and then flip the switch and they discharge in series. So you have to use the solder lugs.
                    Since you charge only, then play running on batteries, I would use a MPPT module. It is made for this application. The one shown has voltage and max current adjustments. You just have to wait for the "slow boat from China" to get it.

                    You can select one with a display for the current and voltage setting - a nominal increase in price - or use a DVM. If you don't have a DVM and want to play in this arena, get a $5 unit from HF or the bay.

                    Also, I'd set the max charge current at 0.5 C (1.25 A) for longer battery life.

                    Click image for larger version

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                    • #11
                      EDIT: I have received new information from Sure. The design below needs a slight modification. Do not use as-is. I will post an update shortly.


                      Safe Harbor Statement

                      The following is a theoretical design. It is untested. Use at your own risk.

                      Overview

                      The picture shows a 24 V Li-Ion battery system for powering portable boomboxes using Sure's new battery management module (BMM). Each Sure BMM supports 3S Li-ion 18650 unprotected cells for a nominal 12 V output.

                      The design shows: (1) Battery operation using two BMMs in series to run an amplifier at 24 V; and (2) AC operation using a 24 V AC PS to charge the batteries and simultaneously power the amplifier.

                      Battery Operation

                      When the switch is in the BAT position, the BMMs are wired in series and provide a nominal 24 V to the amplifier. If the AC PS is plugged in, it will not supply any energy to the amp as the fully charged batteries are at 25.2 V. The diode prevents any battery voltage from entering the AC PS. As the batteries drain, their voltage will drop below 23.5 volts. At that point, the AC supply (minus 0.5 Voltage drop in the diode) will power the amplifier and the batteries will not provide any energy to the system.

                      AC Operation

                      When the switch is in the AC position, the BMMs are wired in parallel. Each BMM sees 23.4V (24 - 0.5 V diode drop), and will charge the batteries. The AC supply will also power the amplifier at 23.5 V. In this position, if the AC PS is removed, the amplifier will be powered by the BMMs in parallel at 12 V

                      Optional Relay - Automatic Operation

                      A DPDT relay can be used in place of the switch. Without an AC PS, the relay's default position is battery operation with the BMMs in series. The batteries will power the amplifier at 24 V. With an AC PS present, the PS DC output will trip the relay to the AC position. The batteries will charge and the AC PS will power the amplifier. The diode prevents the batteries from tripping the coil when the AC supply is not present.

                      Notes:

                      (1) We assume the amplifier has a on-off switch to turn it off, else it will always be on - powered by either the AC supply or the batteries.
                      (2) No specification is given for the BMM max discharge current limit. Will it support 5+ amps peak demand?
                      (3) EDIT: BMM battery charge current is 1.5 A. Two BMMs in parallel will draw 3.0 A. No specification is given for the BMM charge current. The AC PS may not have enough amps to charge multiple battery sets and simultaneously power the amplifier at high volumes.
                      (3) Additional BMMs can wired in parallel with BMM1 and BMM2 for longer run times. Additional amps will be required from the AC PS during charging. EDIT: You'll need at least a 6 A PS just to charge 4 BMMs (see note 3). That's hard to come by in the convenient "Brick" format; easy for a "cage" type supply such as a Meanwell.


                      Attached Files
                      Last edited by Millstonemike; 07-10-2018, 07:34 PM.

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                      • #12
                        Spectacular, thank you! I have a setup with two boards wired in parallel so this should be a straightforward modification.

                        Can you recommend a diode? It seems like the typical IN400x series is a little under-rated for this application.

                        Comment


                        • #13
                          Originally posted by jdhill View Post
                          Spectacular, thank you! I have a setup with two boards wired in parallel so this should be a straightforward modification.

                          Can you recommend a diode? It seems like the typical IN400x series is a little under-rated for this application.
                          For a diode I would use one with minimum rating of 100 V and 10 A. PE's Part # 6A-1KV, is 1000 V at 6 amp. I'd put two in parallel.

                          Did you notice that this design is for the new Sure BMMs that Gordy identified. You still have the charge current management issue with the old Sure KAB BMMs.

                          EDIT: BMM max discharge current is 10 A: Very Good. As I stated in the write up, we do not know the max discharge current the Sure BMMs will support. Exceeding that will trip the BMM battery protection. It shouldn't be a problem with an 8 ohm L-R setup. With an additional 2.1 4 ohm sub - can't tell. I will ask Sure about missing spec.'s to see if they will divulge the info.

                          What amp are you planning to use? Some lack the gain to fully utilize the 24 V power when fed with a phone headphone output (e.x., the KAB 2 x 50 W amp at 20 dB gain). That's also a design consideration with a BT module feed as well.

                          And as a side note: two BMMs with the highest rated 18650 batteries (Panasonic 3,400 maH rating) will not last very long with a 2.1 setup using a 4 ohm sub at the highest volumes (estimating < 2 hours). Hence, the ability to parallel BMMS for longer run times. Efficient drivers help mitigate that issue as well. It really depends on your application / intended use. And: any 18650 battery rating above 4000 maH is total BS (physics of the Li-Ion chemistry).

                          My 2.1 boombox required high volumes to over come background noise at the edge of the Atlantic, where I'm on the sand for up to 12 hours a day, including afternoon dance parties. I have a custom built 24 V 18 aH Li-Ion battery for that application.

                          Good Luck ...

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                          • #14
                            I have 2 arriving Friday but am out of town and won't be able to get a look at them until we get back. I plan on using the small 2.1 board that I have used in other projects along with the the Sure 4.0 BT board. I order two 4.0 boards, one i think has the amplified line level and I think the other one does not. Not sure how runs times will be impacted but it will be a good test bed to see what the board can do. I am not looking for large power hungry applications. Mainly indoor single room use stuff.

                            I really want to find a way to mitigate the charging LED issue. My board will be inside the enclosure with no way see the charge status.
                            "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

                            The Madeleine
                            The Roxster
                            Swopes 5.0
                            Acoustic Panels
                            Living Room Make Over

                            Comment


                            • #15
                              Originally posted by Gordy View Post
                              I really want to find a way to mitigate the charging LED issue. My board will be inside the enclosure with no way see the charge status.
                              I suggested one of those light, optical fibers. Perhaps carefully epoxied to the LED and then the correct size hole in the enclosure. Not sure how it would work. But I bet you could get some for a buck or two from the auction sites to test.

                              Me, I'd remove the on-board LED and solder wires to the PCB pads with a connector on the end to mate with a connector on the LED mounted to the enclosure.

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