May 28, 20241 yr Hi I would like to use something like this to control the charge capacity: https://www.aliexpress.us/item/1005005278656856.html?spm=a2g0o.productlist.main.13.667bN88qN88qYo&algo_pvid=d426c673-b8c7-48e5-b134-85a644a4a288&algo_exp_id=d426c673-b8c7-48e5-b134-85a644a4a288-6&pdp_npi=4%40dis%21USD%212.87%212.87%21%21%2120.71%2120.71%21%402101e9ec17143727560768493e75bd%2112000032464153029%21sea%21US%21850824197%21&curPageLogUid=ZFZ5kvXgte9c&utparam-url=scene%3Asearch%7Cquery_from%3A&gatewayAdapt=4itemAdapt The device however takes power from the "detection end" (battery), which the swytch battery pack does not seem to provide even when I press the indicator button. Do you think it would be a good idea to short the inner flat pins and charge via the outer ones (normally the power output)?
May 28, 20241 yr Author With nothing plugged into the battery pack the output of the battery pack isn’t presented to the outside world - for safety when carrying the battery in your backpack, etc. Shorting the two inner flat pins on the yellow plug turns on the output of the battery pack and presents the power to the outside two flat pins. I’ve got no knowledge of what circuitry is inside the battery pack to turn the output on and off, so I believe that back-feeding the battery output pins (through whatever circuitry is there) would be a bad idea. Doesn’t get my vote!
May 28, 20241 yr Author Using the “reverse O-D” IC5 type connector in the centre of the battery yellow connector (that you normally charge through) might be possible way forward for you, but again it probably will have protection circuitry. At £300+ a go, I wouldn’t be risking blowing your pack up just for a “nice to have” modification!
May 28, 20241 yr Author Final thoughts (I promise!). The Swytch charger is very good quality and is trustworthy. Maybe do what I have done and put a connector in the charging cable that allows you to have a voltmeter inline that’ll give you a good indication as to the charging progress. secondly, I use a 240v count-down timer (eBay) in the charger wall socket. I can tell it to charge for fixed periods of time, and when I forget to check how it’s going, it has turned it off automatically at a reasonable time interval.
May 28, 20241 yr Thank you for your insights. I want a zero cognitive load solution, setting a timer is not an option for me. Well I happen to have 3 air packs atm. I was mentally ready to lose one when I was reworking it to 21700 batteries. All went well so I mentally still have one to break ;-). I feel like the worst case is i blow the BMS, which should not be a big deal to replace with a different one. I am still waiting for a datasheet about the BMS from the producer. I will let u know once I have any news.
June 2, 20241 yr I have not heard from the producer so I decided to risk the charging on a "turned on" Air unit - tl;dr: it works. I started a little more carefully with a power source at 0.1A. All went well so I ended up with this test setup :-D Interesting note: despite the charging pins reporting identical voltage with the outer flat ones when "on" they could not turn on the XH-M604. Swytch must have protected the charging pins somehow inside the yellow connector, since there are only 4 cables from the BMS.
June 2, 20241 yr Author I’m pleased it worked for you - it all adds to our knowledge. The puzzle for me though is why then have separate connectors for putting power into the battery (the OD connections), to taking power out on the outer flat pins, if everything can be accomplished via the flat pins.
June 2, 20241 yr OK, sounds like you found a way of 'forcing' an external charge ? Whilst that might work, what are the exact implications ? Given the issues there can be with charging eBike batteries, if you have a setup that does not behave in an expected manner with regaurds to charging, you would want to be really really sure that what you are doing is appropriate and safe. This yellow connector is the key to the understanding, what is inside it, if there was nothing in there then why would there be any issues with connecting a standard charger ?
June 2, 20241 yr I’m pleased it worked for you - it all adds to our knowledge. The puzzle for me though is why then have separate connectors for putting power into the battery (the OD connections), to taking power out on the outer flat pins, if everything can be accomplished via the flat pins. It's a safety measure to stop the pins shorting when you carry the battery in your pocket or bag, otherwise a loose 10p coin would start a fire there.
July 9, 20241 yr Hi all thinking about doing this on my wifes swytch max, with battery on the front, due to terrible range. Based on what has been said, I need to have the standard battery fitted as well, or the outer ports dont do anything to the other controls, in effect fitting a second 36v battery and having both power the bike
July 9, 20241 yr Hi all thinking about doing this on my wifes swytch max, with battery on the front, due to terrible range. Based on what has been said, I need to have the standard battery fitted as well, or the outer ports dont do anything to the other controls, in effect fitting a second 36v battery and having both power the bike Not correct. if you open the compartment, you can splice a battery connector into the wires going from the battery to the controller.
July 10, 20241 yr Author Simplest way is with this adapter sold on ebay https://www.ebay.co.uk/itm/135087147642?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=xK9mEcvUQZu&sssrc=4429486&ssuid=IB4nVD07Rea&var=&widget_ver=artemis&media=COPY It just plugs onto the outer spade connectors of the swytch battery plug. great for the non-technical, but there are better ways if you can solder.
July 10, 20241 yr Author Here’s what for me, was the final solution. A twin Schottky diode on the back of the swytch housing (nice and cool, and hidden pretty much). You can have any extra 36v battery attached, the normal swytch pack, or both together, with no fear of battery cross-feeding..
November 17, 20241 yr Hi could you send me instructions on how to do this please ? is it necessary or could you just cable straight to battery ? (I've found the cable online) I'm not great at soldering etc, also no equipment for it, thank you, Ahh *edit I just realised this would be for multiple batteries ? in that case I'll just use cable , thanks
November 18, 20241 yr Simplest way is with this adapter sold on ebay https://www.ebay.co.uk/itm/135087147642?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=xK9mEcvUQZu&sssrc=4429486&ssuid=IB4nVD07Rea&var=&widget_ver=artemis&media=COPY It just plugs onto the outer spade connectors of the swytch battery plug. great for the non-technical, but there are better ways if you can solder. I think I've found that cable on 3 bay , seems a bit overpriced if it's the one for £28 + (£6) postage, I could just make my own , I would have bought if wasn't so expensive, thanks though , *edit , found all parts, could do for about about £14 in total , just need soldering iron, so yeah suppose not too bad a price and is made well and good idea and after ebay fees, but I think more like £25 with free postage be more reasonable and would prob sell more Edited November 18, 20241 yr by qwertyman900
November 21, 20241 yr more like £25 with free postage be more reasonable "dual battery adapter" finds them from £27 including postage. [mention=40675]Cisco-man[/mention] At 7A it would shed 3.5W so could need a heatsink depending on your setup. If the bolt touches the diode case the nut carries battery +ve which shouldn't be a problem but I'd cover it. Very neat!
November 21, 20241 yr "dual battery adapter" finds them from £27 including postage. [mention=40675]Cisco-man[/mention] At 7A it would shed 3.5W so could need a heatsink depending on your setup. If the bolt touches the diode case the nut carries battery +ve which shouldn't be a problem but I'd cover it. Very neat! *edit , I found the same cable half length for £25 with post, so yeah reasonable , didn't realise first one was 2 meters, think is made by same person
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