MAX745 Multi Cell Lithium Battery Charger (MEHS) Episode 62
ฝัง
- เผยแพร่เมื่อ 16 มิ.ย. 2017
- A quick look at the MAXIM MAX745 multi cell lithium battery charging board. This board can charge 1 to 4 cells in series correctly. Use included DIP switches to set the number of cells and use the included potentiometers to fine tune the charging current and voltage.
Ebay item number 111825916930. - วิทยาศาสตร์และเทคโนโลยี
Nice, I was waiting for a decent battery charger board!
Nice little review, keep up the good work!
- Thanks.
The comments just show how much this video has been useful! Thanks for this. Will look forward for more! Cheers!!
- Thank you.
I cant wait until you demonstrate the multi cell hookup. I have a project I would very much like to use this for but I cant imagine not doing some sort of balancing. Nice work. Cheers.
- Thanks. Yes it is coming. Cheers.
Looking forward to seeing it in more detail.
Great little charger.
Can you please describe or make a video on how to fine tune and set the two pots CC & CV as mentioned in the datasheet?, I couldn't understand it, and also how to use the thermistor function, THM/SHDN terminals.
Thanks for the informative video and for your help.
Hi, the -+ on the bottom middle of the board? What is that for? I'm looking for a led indicator to know when there is a full charge and was wondering if that was it's objective
thank you! couldn't find a board like this, everywhere there are either crappy bms boards claiming to charge the baterries or full sized balance chargers which im not going to embed in my project.
Maybe think about cooling - even some sort of small heatsink. I had one fail on me a few months ago after it exceed 85c. Pushing it too hard. Cheers.
Thanks for the nice job you do to help the community. I agree with you. I did not find any BMS board doing its job properly. But I am a bit troubled with the MAX745 (that is not a BMS and needs to be associated with a BMS). To me, it seems to simply be a Buck converter with adjustable Constant current feature and ajustable output voltage. The only difference with a standard CC/CV buck converter is the 'dip switch' feature offering some 'preset' ranges for the CV depending on 2S, 3S or 4S choices. But the MAX745 board is quite expensive compare to more common CC/CV buck converters. And unless I misunderstood some added values of the MAX745, don't you think we could use a cheaper solution? I.e: XW026FR4 or other boards based on LM2596S. Thanks.
- Hi. Yes the MAX745 is a bit pricey but its more than a buck converter. If you take a look at the MAX745 datasheet it shows the charging characteristics and ability to transition from CC to CV smoothly. This is what differentiates it from a dumb converter or reg and what provides a better lithium charge. Have a look at - www.maximintegrated.com/en/products/power/battery-management/MAX745.html . Cheers, and thanks for the quality post!
1 the limiti when you try to build a pcb board is 990mΩ of total resistors.after that you wasted curent. 2 the max curent for safe charge is 300-400 mAh for AA battery after that you need to programing charge with a lot of curent changes and voltage .
If you're using this with more than 1 cell, you would need to use a BMS too similar to your powerbank video right?
- Hi. Yes , correct. This charging board can charge a pack of 1-4 cells but treats the pack as 1 battery so all the cells needs to be connected together correctly which means a BMS. Cheers.
Great stuff. Is there a version of same board that can charge up to 6 cells? Thanks & regards.
Fantastic little chip! Does it charges balancing the batteries? Or does it still need a BMS?
- Hi. You still need a BMS to do the protection and individual cell distribution but it is the missing component for a complete charging solution. Cheers.
My Electronics & Hacking Show Nice!
Could you show an example of it all wired up?
- Hi. I will be doing another video using this in a build, so yes, coming soon. Cheers.
My Electronics & Hacking Show
Hi, I've been using this charger for a year or two, but now I need a 5S, and I was wondering if you recommend a 5S charger?
Did you ever do a video using this board and how you wired it.
Hello sir, why are the holes next to the switches? One with "+" mark . I'm wonder where should I connect the load to this BMS, to BMS battery pins or to these near to the switches? I don't find any kind of information on internet about that
Have you come across anything similar for more than 4 cells since then? Such as for a 6S?
I too am waiting to see how you wire it into your LED light as part of the backup system. I'm also still wondering if this works for a 3s2p pack to double the power available? Been looking but not yet finding how to deal with 2p or 3p systems.
- Hi. Short answer is yes as the cells in parallel will simply be treated as once cell. Cheers.
thanks, I'm sold!
Pls post a URL link for the device
cool! if only it supported 5S, that's what I need for my project
- Haven't seen a 5S lately but I'll keep my eye open. Cheers.
Thanks for the video! I am looking for a DIY solution for powering a raspberry compute module4 I/O board with 3x18650 batteries (and recharge them when connected to the line). Could you suggest a "limited space" solution to that? Thanks!!
so if I want to charge a project, I would need this charger and a BMS together? Can I keep the load connected and when powering the device, it will charge and power the load?
thanks!
- Hi. Yes you need the BMS and the MAX745 together. You can leave the load connected but only if you know that the load is less than the 1A that the MAX745 can supply. If not you will stress the cells and they will eventually go flat anyway. Cheers.
Can you provide a link to this on Ebay as I have searched it and cant find it anywhere. Cheers Tim
- Hi. search for item number 111825916930 . Cheers.
Is it suitable for 3,7volt battery's??
Does anyone know the make and model of this or similar module or if it's is available anywhere? Thanks
If I were to add a battery meter module, where in the circuit should I connect it?
Hi. It depends on the type of meter but just before or after the BMS connecting your cells. In other words as close to the battery itself as possible. The output from the cells to the project would be good. Cheers.
@@michaelsstuff4402 thanks! One more question, since the MAX745 seems somewhat difficult to find, does this accomplish the same thing? It would also forgo the need for the step up www.ebay.com/itm/3S-2A-11-1V-12V-Lithium-Li-ion-Lipo-18650-Battery-Charger-Module-Charging-Board-/323206350966?_trksid=p2385738.m4383.l4275.c10
Does MAX745 has any notification pin/LED to let know the charging is done?
Igor Spitz - Hi. If I remember correctly it has an indication led that goes out when charge is complete. Cheers.
Thanks for the answer! I've read somewhere that led is on for CC part of charging and off for CV part. It does not make a lot of sense, but you never know. Thanks again, great channel btw. May I have another question? What happens after charging completion. At what voltage will the charge start charging again?
Igor Spitz - Hi. No, the led does not turn off for the cc or cv portion of the charge, only when the whole charge cycle is compete. Once a charge is compete the board monitors the voltage and starts charging again if the voltage drops below 4v, if I remember correctly. You can google max745 and get the details you seek from the manufacturers website along with other good info and schematics etc. Cheers.
I've missed that information when reading the datasheet. Great!
ehhh, sorry to disagree. Looking at a switched off LED at this moment, @12.50Volts (3s config, obviously), still flowing 400mA. Awaiting 12.60 volts, and 0.0mA
Is there chip like this but for 8 battery cells. I couldn’t find anywhere this kind of charging regulator for 8 battery cells. Or if there is an alternative version for this i would be so happy. Does any knows if there is one?
- No sorry I haven't seen one. You could always use 2 of these boards and have a relay to separate the 2 x 4 cell packs when charging. Cheers.
at 14 dollars it a little to much still for small project that only cost that
The problem is I don't think it has charge termination.
Hi, i am looking for a simulare charging board to MAX475 that i can find easily in europe.Would you be so kind and name some?( sorry cause of my poor english)
- Hi. The MAX745 is available anywhere so just keep looking at your available providers, or Ebay or Alibaba. You will find one. As far as alternatives, there are some made by other IC manufacturers but I haven't used any as comprehensive as the MAX745, and nothing already prefabbed and ready to go. Cheers.
Thank you :)
You actually didn’t show us how to use this board. 1, you said you have it set for 3cells but all 4 dip switches were off.
2, how do you set the current and what current should you set for 3cells.
And 4, what voltage should be set for 3 cells?
- Hi. If you take a look about 40 seconds in to this video, you can see the dip switches 2 and 4 are in the ON position. A couple of seconds later I show the back of the board with the DIP switch settings needed for 1-4 cell charging. Mine was set to 3S in this example. The board (the MAX745 IC really) needs 3V more than the expected maximum charging voltage, so a 3S pack needs 12.6V max to charge correctly. In this instance you would need to supply the MAX745 board with 15.6V for it to correctly charge the 3S pack. As you would expect, this means a power supply going through the MAX745 and charging a 4S pack would need 19.8V (16.8v for a 4S pack plus 3v overhead for the MAX745). Hope that helps. Cheers.
You can supply the board with voltage 15.6+V. Up to 20V i guess. Am I right?
How about a board for cells in parallel?
- Hi. You can run cells in parallel without anything, just butt them up against each other if nipple type cells. They may benefit from a full individual charge every now and then but they will work without individual cell monitoring and charging. The MAX745 or any other charger will just see 2 or more cells in parallel as 1 cell and it will take longer for the charge to be applied as you are doubling (or more) the capacity. Cheers.
please show us how to wire it up
would you make a video showing how to wire this to 3 batteries?
- Hi. Done. Take a look at th-cam.com/video/SyiUzZJHVx8/w-d-xo.html
Thanks a lot buddy! I tried to find one on your chanel but couldn't, so i didn't think you had one!
so is it better than a BMS?
No. Its what you use to charge a lithium pack, either 2s, 3s or 4s. The BMS is still required. Cells plus BMS makes a lithium battery of say 12.6v. The MAX745 contains a proper charging IC so can charge the battery pack properly. Cheers.
cant find max745, it seems discontinued
Hi. I just did an ebay search and got dozens of hits. Start there. I am at present looking for other options and will be doing another video on making a complete rechargeable lithium battery pack soon. Multiple applications. Cheers.
unfortunately i dont have access to ebay but we do have shopee which manufacturers are usually based on china. i guess ill stick to my buck converter for a while to charge every 3s packs
@@michaelsstuff4402 Looking forward to that video.
@@michaelsstuff4402 hello! Did you finish this project (which uses other options)? If so, would you be able to post the video, please? Thank you
Hello! I been seeing your videos about this subject, I'm on a project that I'm scraping 18650 batteries, and making 12.6 batteries with a bms (S3/20a) but not for use more than 10a. they are 6 batteries per S. I bouth this BMS www.winddeal.net/image2/0251/add251/1A40529.jpg that it claims that will charge the batteries. This are the specs:
Specifications:
Over Charge voltage:4.25-4.35v±0.05v
Over Discharge voltage: 2.3-3.0v±0.05v
Max Working current: 20-25A
Max Instantaneous current: 35-40A
and they add:
Features:
1) high-accuracy voltage detection circuit;
2) terminal of the charger using high voltage device;
3) Built-in three-stage over-current detection circuit (over-current 1, over-current 2, or load short circuit);
4) MOS transistor can control the battery charge and discharge;
5) low standby current consumption
Not sure if I can use this but with a power suply at 12.6v with a CC, or any higher voltage power suply without CC, or I need to use this board (max745) at every pack.
One more question! (sorry) if I soldering this board to the cells (to leave permanent on each battery that I'm making), you think that this board will draw power from the batteries when is not receiving input? (charging)
THANKS