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Old 02-10-2022, 06:15 PM   #4
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Default Re: Rebuilding an Li-Ion Tool Battery with Li-Po Pouch Cells (Ryobi P189)

I would highly recommend that you do not use pouch batteries for this as a replacement for tool battery packs

I would recommend that you look Battery hookup for some tool rated 18650 li-ion batteries

Unfortunately right now they do not have any in small quantity available right now but just keep checking because from time to time they have some for sale I just checked


You can get 18650 with the tabbing already on the battery but you would also need the tabbing material to join them together do not go with using regular wire because it might not fit in the enclosure you can get these batteries from AliExpress but be careful to not get non brand batteries recommend brand ( Panasonic Samsung LG [ Sanyo only certain series type ] but make sure that they are ( tool rated batteries drain current of at least 10 amps continuously ) you will have to look at the data sheet for this specifications of the battery )

AliExpress <—

I would caution you that if and when you re-cell this battery pack make sure that you have full battery voltage when using the battery charger made for the battery pack when the battery fuel gauge shows that they are fully charged and that you can fully load the battery pack and it can deliver full current to the tool because one of the failure is that they can no longer can deliver full current or if can it can only for a short period of time and not for long or the other failure is that it will not fully charge up or not at all

One note if you can not get any voltage from the battery pack after putting it on the battery charger and you have put power to the positive and negative battery terminals and put it back on the battery charger and still does not have voltage on the battery terminals then the BMS protection board is in failure mode and would probably be unrepairable if you have full battery voltage but it can not deliver full current the mosfet failure and sometimes it can be repaired but not always

I hope this helps you if decide to re-cell this battery pack I have done this in the past with this brand and this battery pack in question and it can be done I will probably go back to re-cell-ing my battery packs again because the battery packs have gone up in price again

Here are some more failure with these battery packs are the following

All fuel gauge led lights flashing when battery pack is depleted not sure exactly what this failure is and how to fix it

One fuel gauge led light flashing and not wanting to charge not sure exactly what type of failure this is either

Or while you are using the battery pack all of sudden all of the fuel gauge led flashing but turning off the tool and restarting the tool seems to correctly the issue but sometimes happens not sure exactly what this type of failure is either

Here are some signs of battery cell or battery cells failure

Very short running time
Not wanting to charge battery pack ( could be batteries unbalanced battery voltage between battery cells ) recharge individual battery cell to 4.2 volts then discharge battery pack ) and recharge battery pack on charger and retest individual battery cells and see if they are still unbalanced between battery cells if so battery are at there end of life sin drum and need to be replaced
9 PC LCD Monitor
6 LCD Flat Screen TV
30 Desk Top Switching Power Supply
10 Battery Charger Switching Power Supply for Power Tool
6 18v Lithium Battery Power Boards for Tool Battery Packs
1 XBox 360 Switching Power Supply and M Board
25 Servo Drives 220/460 3 Phase
6 De-soldering Station Switching Power Supply 1 Power Supply
1 Dell Mother Board
15 Computer Power Supply
1 HP Printer Supply & Control Board * lighting finished it *

These two repairs where found with a ESR meter...> Temp at 50*F then at 90*F the ESR reading more than 10%

1 Over Head Crane Current Sensing Board ( VFD Failure Five Years Later )
2 Hem Saw Computer Stack Board

All of these had CAPs POOF
All of the mosfet that are taken out by bad caps

Last edited by sam_sam_sam; 02-10-2022 at 07:16 PM..
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