Very useful video! I will try your methode by charging each cell-item with RC charger before deciding witch single cells to change. One of my batterypacks is charging in the mower with service test battery display on, and all cell-items shows from 2,9 to 3,2V. Has been charging for days now, but it is still difference of 0,3V, and the mower will not start. I will start working on two other batteries. Thanks again!
Thank you! Very useful video. Would be nice if you show also cells models/capacity. I have RS622 which has 5Ah battery from stock, meaning it has 2.5Ah LFP 2P8S cells, but as I see it is almost impossible to find 2.5Ah cells for replacement. Available only cells with less than 2Ah or more than 3Ah. But it is not good to mix different capacity cell as they will "run away". So most probably I will replace all cells. Found good feedback using 32700 7Ah cell instead of those paralleled 26650. Most probably it will not fit into battery protection metal case, but it is not a big issue. However in my case RS622 allows to discharge battery on 4Ah only, and making battery more than 5Ah not efficient as this capacity not being used at all, the only benefit longer cells live because DoD will be not more than 60%.
Thanks for feedback. Yea you are right about mixing difrent cells but my opinion is If you choose too big capasity for replacement you only pay for biger capasity but you never cant use it because old cells will drain empty before those biger ones and bms shutdown the battery. And visewersa if you use too small capasity for replacement then the bms will shutdown battery when old cells stil have juice left. So If The right ma/h cells are not awailable i recommend to choose biger ones. But after all it all depends condition off all cells. Example If you have 2500mA cells in paraller then you shud have that 5000mAh but when testing cell pairs and if The old cells only performs example 4000mA because they are old then you have that 2000mA / cell. In that case i think it is okey to to use 2000mAh cells insted 2500mAh because if you use in that case those exact 2500mAh cells you really cant use that 500mAh benefit because old cells will drain empty before that. I always first charge and disharge cell pairs individually to get mAh ratings what are real and not just what is written on cells. Then i can see witch cells are too broken and witch are still usable. Offcource old cells will perform like bit less than what is written on cells but that is normal wearout off cells. In my case i bought on ebay 26650 3000mAh 3.2v cells so in theory i should get 6000mAh rating when two cell are sidebyside =)
I see this post is 2 years old, but I also have the RS622 and bad battery. It is clearly a 8S2P configuration. I see that the battery has a 2-conductor plug with Red & black heavy wires. And a 10-conductor plug with 10 smaller wires going to it. I assume one of these is for charging? The 2-conductor? Is the BMS outside of the battery itself, perhaps connected by the 10 conductor wire plug to a bms inside the mower?
2 pin plug is for charge and discharge and bms on built inside off battery.. 10 pin connector is just for diagnostic use that mover can show on service menu independend cell voltages. . On My mover i had rough start after Winters storage and fjew cells on The pack was discharged way too low and battery did not take enough charge.. mover just tells charge battery... I opened pack and charged one cell pair at a Time fully charge and now battery performs again as normal.... If battery pack go unbalanced after Winters storage it is hard to get balanced again because of working principal off bms unit. Bms unit inside battery can not charge cells what are to low voltage. Bms can only discharge all another cells what are higher voltage level and it Will do it with resistors what bleeds The Juice from cells. But they Will do it kind a slow so when you start charging your pack The charging proces stops because one sell bank is getting over charged. Typically aprox 4v and then bms disconnects battery from charging terminals. But at that point your pack have thoose fully charged cells on 4 v and then there might be one cells depleeted and low charge. Lets say aprox 3.2 v or something like that. So charger Will stop charging and overall battery pack voltage is still too low.. bms Will do balansing work 24/7 and My advice is take The charged head from base station inside and charge mover fully.. after that check independend cell voltages from mover service menu and take picture from The readings... Then shut down mower and mabye disconnect battery and wait one Day. The. Plug battery Back and again out mover to charge and after that again check in service menu cell voltages and If The voltages are getting closer each other then i would repeat Steps until all cells are readings aprox same value. If i remember right mover shows celll voltages just 3 number row.. example. 348. That. Means that cell voltage are 3,48volts in that cell pair. There is also higher number what is like 23000 what means pack total voltage. Example 23,000 volts.
Thank you for a great video. Mine have the low battery issue after winter storage. How to I enter the service menu? It ask for a PIN code. Also do you need to disassemble the battery to recharge each cell that is low voltage? I have a lipo charger for RC with option to charge other batteries as well. Will that be sufficient?
@@ShoaibEjaz pin code is easy. Mover gives you 3 digit code same Time when it asks pin code.. Google robomow service code and you Will find Image where are list off used servicecodes. Then just search that 3digit code and next to it is given The matched service code . And openin The pack is pretty simple but attaching RC bat charger to difrent cell pairs and getting The polarity right is litlebit More tricky to Do.. battery Will balance itself without opening but it needs Time. Myself i just opened batt and fully charged cell pairs one by one with RC multi charger thing where is difrent charging programs for difrent chemistry batteries.. good start would Be just monitor cell voltages on service menu and keep charging The battery to see are cell voltages starting to balance or not
