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  1. geoff57

    DIY bms

    Thanks I’ll pick some up and set up a 4 cell test circuit will take a few days to get the parts and program the Arduino. Looked up on eBay and other sites and the avalibility of 1 or 2 ohm resistors at 2 watt will mean getting from china, I’ll build the circuit with a gap for the resistors to...
  2. geoff57

    DIY bms

    I want to build my own Bms not rely on a Bms bought off the internet where I am not sure what is going on. I will brake the designing of thiss down into several sections LVC, HVC, balancing, forced balance and amp limit on both charge and discharge. I want to be able up to 20 cells in series...
  3. geoff57

    Does it matter what brand of battery i use?

    Hi If you still have the case and can open it up, you could change the cells for new ones depending what was used in the first place. Geoff
  4. geoff57

    quick battery drain in 1500W engine motor

    Hi An alternative watt meter https://www.aliexpress.com/item/1005003713078282.html?spm=a2g0o.order_list.0.0.b49118028fRtdS Not as high a wattage but you would never get close anyway. Geoff
  5. geoff57

    ISDN batterygo BG-8S

    Hi Since posting the initial post I have been testing the BG-8s With various sizes of battery I’ve used both 18650 and turnigy lipo, From 1000 mA hours to 26 ah. The small batteries balanced in 1/2 an hour the 25 took a day. I can live with those times my reasoning for wanting to change the...
  6. geoff57

    ISDN batterygo BG-8S

    I found this a while back on hobbyking it is unavailable at the moment but banggood and aliexpress both have them in stock. It has a battery balancing function available similar to the battery medic that has been out for years but it is a lot more accurate. It does not have a discharge and...
  7. geoff57

    Size of heat shrink tube to use

    It’s been a while since I last had to build a battery pack and have forgotten some of the things that make a pack look neat. I’m building the pack out of turnigy 5ah 5cell battery “bricks” to wire them up I need to remove the heat shrink to get at the cell tabs. To keep the whole pack looking...
  8. geoff57

    15s lipo/li ion with 48v controller

    I have a 48v controller that has 63v capacitors in it. Will a 15s lipo (max 63v) work with the controller? At the moment it has a 14s battery it came originally with a 13s battery. Changing the controller would not be impossible but would not be easy. Geoff
  9. geoff57

    BMS confussion 16S or 17S -- CF-20S90A-A

    I have the same bms configured as a 14s 45a. I have no problem with the number of cells it works with and an wire up the balance wires with no problem, from using previous similar bms boards I know how to wire up the positive power wires. The problem I have is with the negative power wires. I...
  10. geoff57

    Laptop PSU with 60v+battery packs

    Had a look at the meanwell converters and for what I want it is too expensive since I use build my own battery packs with my own BMS I’ll put a 12v and maybe 5v output into the battery. Geoff
  11. geoff57

    Laptop PSU with 60v+battery packs

    Hi I’ll want it to be a 12v output for the 5v I’ll use a dc converter on the 12v. As for amps it’s to replace the 12v dc converter on a e-bike that looks like a Vespa so I’ll dad about 5A so I have plenty to spare. Do tell me more about these meanwell dc to dc converters that go up to 177v. Geoff
  12. geoff57

    Laptop PSU with 60v+battery packs

    Hi With a battery pack less than 60v there is no problem finding a dc converter to get a low voltage (12 or 5 v) output, once you go over 60v we run into problems. I mostly work with 20s lipo “72v” batteries, are laptop PSU’s still the best method to get a low voltage output from the battery...
  13. geoff57

    single cell or prebuilt pack

    They look ok, bus bars will not work all you will need is the silicone wires from the balance cables. Personally I would build the pack as several 1p packs the bus bar each end once that is done link across each cell that is in the same place with balance cable wire then attach to a BMS I...
  14. geoff57

    single cell or prebuilt pack

    looks like the way the original "duck tape" lipo4 batteries were constructed multiple cells in parallel then add them together in series. the old duck tape batteries never used copper bus bars but that was the circuit. geoff
  15. geoff57

    single cell or prebuilt pack

    Not sure that copper bus bars would work except for joining in parallel for the serial connection the tabs of the cells can be directly connected by soldering. When I build the pack I will document it but that is a few months off, the pack is going to be made with a custom BMS I am designing...
  16. geoff57

    single cell or prebuilt pack

    hi I need to build yet another battery pack and want to check which is the best way to go. the pack will be a 72v 20ah LiPo pack it will be in the 20S 4P configuration using turnigy 20c 5ah cells. The BMS and charger are sorted. The problem I have is what cells do I use multi cell battery packs...
  17. geoff57

    BMS Vs LVC/HVC

    Thanks for the link fechter, it’s not the whole thing I want to duplicate by any means. The zephyr used hard wired logic with chips that did an action when certain criteria were met e.g. cell goes down to 3v. I want to take a BMS through several stages of production the last being balancing, I...
  18. geoff57

    BMS Vs LVC/HVC

    Thanks for the examples. From what I can see most of those can manage the voltage of the cells but are weak on balancing ,not to be expected good balancing is hard to do fechter do you have a link to goodrums BMS v4 thread. These BMS’s that you’ve given me info on look like they are all...
  19. geoff57

    BMS Vs LVC/HVC

    Just had a look in my BMS from the size of the resistors I found the BMS has the same or less ability to balance cells that the old battery medic had Which is kind of ok if it is left alone for a few days attached to a trickle charger but on a ride there is no way it could keep up. Best idea...
  20. geoff57

    BMS Vs LVC/HVC

    Hi I thought it was voltage dividers on all channels. Any idea how the amplifying method worked if the circuit is too complicated I’ll juststick to 6 cells with that the 6th cell will have a resolousion of 0.026 the other way is to use high resolousion ADC’s 16 bit in theory 15 in practice an...
  21. geoff57

    BMS Vs LVC/HVC

    Hi Fechter both the bm6 and the cellog8 used the Arduino chip so I’m going in the right direction. The Nano has 8 ADC’s which the cellog8 used I’ve found a small screen and so be able to make something similar to the cellog8 but with a better buzzer and better switches I can’t duplicate the usb...
  22. geoff57

    BMS Vs LVC/HVC

    Hi After a runaway battery without a BMS causing a fire that wrote of the bike and shed I now always use a BMS so far off the shelf from China with a non balanced charger. I have not had any problems since. The cells I use are turnigy 20c 5ah, these were recommended to me by Jozzer who I...
  23. geoff57

    BMS Vs LVC/HVC

    Hi I want to make up a battery pack that has some form of battery management on it but am not sure Which route to take, an off the shelf BMS or build a LVC/HVC setup with no balance capability’s. The circuit I could make would have a plug in display for visual reference of the cell voltage and...
  24. geoff57

    Arduino powered Speedometer

    Thanks for all the help you have given with the problem of getting the hall information from the controller to the Arduino . I now have another problem or should I say question. I used the program I wrote to find the number of poles in one revolution, I started by just doing one revolution then...
  25. geoff57

    First E-bike Conversion advice

    Sorry for the late response I understand what you mean when you say voltage sag I’ve worked with Pb battery’s and most of them had huge voltage sag, I have bought bikes with supposed ok Li ion batteries they had the same problem and a steady voltage drop over a short distance with a rise once I...
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