Roomba Vacuum Battery Removal and Cell Replacement

We had an iRobot Roomba 890 vacuum with a bad battery. We elected to replace the four 18650 cells inside rather than pay $80+ for a genuine replacement or try our luck with a cheap aftermarket battery with a heavily-inflated claimed capacity. This is a model 1800 which fits various 600, 800, and 900 series Roombas.
Check out our eBay store for DIY lithium ion equipment and cells!
www.ebay.com/str/higherwirebatterysupply
WARNING: Lithium ion batteries are potentially dangerous! Do not attempt to repair any battery unless you are experienced and comfortable with electronics, and understand the risk. Even if properly handled and assembled, a lithium ion battery can still result in FIERY DEATH. This video is for educational purposes only and we are not responsible for any damage should you attempt to disassemble and repair your own battery.
#irobot #roomba #18650 #lithiumbattery #lithiumionbattery #batteryreplacement

[@redheat0]

"We are going to show you how to solder them" "So here they are soldered" 😂😂😂 Still, great video. Thank you for making it

[@trevor2561]

Busted! Forgot to get video of that.

[@tetchelex11]

Which is the best brand of cells for using ?

[@ozkan3488]

Hello! Can i replace li-ion battery with ni-mh? Can it work? Or can i upgrade li-ion 1800 mah to 2500-300-4000-5000 not BMS? Do i need another BMS for this?

[@EShirako]

I'm about to swap my 1800mah pack cells for 4x 2600mah Moli cells. I expect it to work, though it may charge more slowly than the new cells might optimally be able to handle. If my work fails or if it dies in no time flat, I'll add a comment in the future. Just make sure you use the right kind of cells...these are 3.6V nominal, 4x3.6 = 14.4. I think the 3.7v cells have a higher 'minimum safe discharge level', like 3.0 or 2.8v where 3.6 nominal cells might be 2.6v. Over-discharging a cell can mess it up in a hurry, so just try to make sure that you use similar battery chemistry (IMR and ICR, not LiFePO4). LiFe cells are 3.2v nominal, 3.6v max, and WOULD definitely require a new BMS to let them charge safely.

[@ne0tekk1]

@@EShirako Which model roomba do you have? Looking at some of the other comments, the 900 series might have a bms board that self destructs if the bms reads 0v for any of the cells, which would happen once your disconnect the battery cells. I think the only way around it is by connecting 18650s onto the bms board. Just seems like alot of trouble to save less than $40 for a replacement off Amazon.

[@EShirako]

@@ne0tekk1 Mine is a much older 650. The Li-Ion pack that came with it had UTTERLY flat-dead 0V cells in it, so if it does the "self-destruct for a 0v situation" thing then my BMS is already wasted. Luckily for me, I went back to where I got mine from a thrift store and found the NiMh pack for one of them as well, and that seems to still be working fine. I got lazy and used that for the moment. I'll try to use upgraded lithium cells if the NiMH pack ever seems to get weaker, or whenever I get bored and think of rebuilding the lithium pack for it. :)

[@357Maxim]

Thanks for the video. 5:57 If the batteries are connected in the middle, doesn't that make them in parallel, and not in series ?

[@frankenfoamy]

It appears there is a middle connection to the board that would allow balance charging. Still a series pack

[@kvnhmmd]

Great video. I'm going to attempt to refurbish my Roomba 980 battery. I'll try replacing the cells with LG MJ1 cells (3500mah, 10a drain). In theory, it should greatly outperform the OEM replacement battery that sells for around $110. Only thing I'm worried about is the Roomba throwing a code, since it will take much longer to charge the higher capacity cells.

[@Iinustechtips]

it'll be fine

[@Space_Aids]

How did it went? I'm thinking about doing the same

[@kvnhmmd]

@@Space_Aids I actually never got around to it. My roomba no longer has to run for as long, so the OEM pack is still hanging in there

[@ne0tekk1]

@@kvnhmmd Looking at some of the other comments, the 900 series might have a bms board that self destructs if the bms reads 0v for any of the cells, which would happen once your disconnect the battery cells. I think the only way around it is by connecting 18650s onto the bms board. Just seems like alot of trouble to save less than $40 for a replacement off Amazon.

[@kurtwm2010]

I like this video. That takes me to my question. I have an old Roomba Discovery. The battery won't charge. Even replaced it with a new one and still no charge. It takes a 14.4V, 4000mAh battery. The charger that plugs into the docking station is rated at 22V, 1.25A. When I measured the voltage at the two docking probes I get only 4.37V. I didn't think this was correct and maybe a failing docking station. So, I replaced that too. Sure enough, the "new" docking station puts out the same voltage. Would you know if that is correct and sufficient to charge the battery or do I have 2 failing docking stations?

[@SuitedMoose]

It is supposed to be that. It will only jump to 22V once it recognizes the roomba is connected

[@kurtwm2010]

@@SuitedMoose thanks for your response. I measured the voltage and it is what you said. I suppose something internally is not working correctly because batteries do not fully charge. Even with a new one.

[@stevehodges6792]

Hi Hello from the UK good video My 980 has 3300mah stated on the battery. Is that just an 8 cell version of what you rebuilt on your video. Any tricks/tips on resoldering the centre / balance connectors back to the BMS board. Also how's the vacuum performing with your new cells, better run time ? or about the same. Thank you

[@higherwireinc]

Get an iron with a fine point, not a lot of heat. This was for a customer but we’ve had no complaints, we offer this service on many electronics packs.

[@gigimorphe6194]

could you please let me know the polarity on that smal pcb those 4 contacts what is what? plus minus ntc or ?

[@BoggyBogdan]

My roomba runs but on load(when fan is connected) , the fan output is 7v instead of 15-16 and the fan runs slower. I believe it's the battery since individual cells measure 3.3v. Though measured in series i get 13.7v What do you think?

[@bradsuen4901]

Hello, I have an iRobot Battery for Roomba 960 that is faulty. I replaced it with a new battery (sony vtc5d 2800mAh) according to the method in your video. After assembling and measuring the branch point voltage, it is also normal. But when the sweeper is installed, it just can't sense the battery. My new battery is fully charged to 4.2v and then assembled. Is it limited by the rated voltage? Does it only work when charged to 3.7V?

[@ne0tekk1]

I was reading how some roomba batteries have a self destruct feature where the fuse keeps blowing itself up if the bms board is reading 0v on any of the cells. Your post confirms my suspicion, I think some of the really old packs might not have had this destructive feature in it. I think you'd need to have another set of 18650 cells to connect to in parallel with the bms so that the bms board doesn't permanently disable itself. It just seems like alot of work to save around $30-$40 if bought off Amazon.

[@danielhenriquedasilva7532]

Very good video. I disassembled the battery same as you. All 4-cel were showing 4.0V+. Seems the problem is the BMS itself. Do you have any tips for raising the BMS back? I'd appreciate your replay.

[@higherwireinc]

Typically when the BMS board goes it can't be replaced in these. You should be able to reuse the cells, though, and we have new Roomba batteries for sale at lower than retail. Send us an email [e-mail].

[@ne0tekk1]

Looking at some of the other comments, the 900 series might have a bms board that self destructs if the bms reads 0v for any of the cells, which would happen once your disconnect the battery cells. I think the only way around it is by connecting 18650s onto the bms board. Just seems like alot of trouble to save less than $40 for a replacement off Amazon.

[@danielhenriquedasilva7532]

Indeed, thank for your concern.

[@colindgrant]

Really nice video. Thanks!

[@MathijsGroothuis]

What if you manually slow charge on the whole battery block? Would that work, or do you really need to charge/replace the batteries individually?

[@higherwireinc]

That’s not a bad idea if you have a charger capable of single-cell li-ion (3.6/3.7v nominal) and none of the cells have flat-lined. That effectively rebalances the pack, though degradation typically means runtime will be down regardless. As others have mentioned, it seems that the BMS on some of these packs needs to be reset when swapping cells, so it’s worth charging cells individually before tearing into it.

[@MathijsGroothuis]

@@higherwireinc I meant just charging the battery without modifying anything. But I think the BMS would be in the way then.

[@higherwireinc]

@@MathijsGroothuis Right, BMS is likely going to block it. You can bypass the BMS by identifying the battery positive and ground, but that will require at least partial disassembly and at that point you'd want to check individual cell voltages.

[@mirek3542]

I replaced the old Ni-HM battery with a Li-Ion battery with BMS, and now the iRobot 780 vacuum cleaner doesn't recognize it when charging. Error 1, what to do with it?

[@higherwireinc]

The vacuum likely has a check for battery voltage, and the difference between NiMH (1.2v/cell) and li-ion (3.6/3.7v) is enough to trigger the error. These seem a bit smarter than many electronics.

[@fermogo]

Interesting video Charge Error 1 is Battery not connected (Bad contact) or defective battery. The problem with the old Roombas is that the firmware is not prepared for the lithium charging parameters and they normally end up with Error or some worse: charges but damaging the Lithium batteries. The charging parameters for Ni-MH that are totally different from those required for Lithium. In fact once the charge is complete, a 50 mA stand-by charge (know as 'trickle charge') is applied in a continuos cycle between 40 (start) and 42 ºC (stop) intended for typical Ni-MH self-discharge, wich for Lithium should not be applied. Although the vendors say Lithium batterys are suitable for old Ni-MH Roombas (in some cases the say some things as these batteries simulate Ni-MH parameters to trick Roomba into believing that they handle Ni-MH) the fact these batteries have not worked for me neither in the 560, nor 531 nor 650, in some cases due to Error 1 or 5, and in others it apparently worked, but the battery died after only 6 months, which implies an enormous 'mistreatment' in charging (probably after a a lot of hours of damaging tricke charge) because this iRobot 1800 mAh lithium battery has been working for my 671 more than 4'5 years and only lost 15-20 minutes... I asked about to iRobot about and was confirmed, Ni-MH for Ni-MH Roombas, and Lithium for Lithium Roombas

[@mirek3542]

@@fermogo my lithium batteries had their own BMS

[@fermogo]

@@mirek3542 This is the charging algorithm extracted from iRobot Service Manual for 500/600 Ni-MH Roomba's (must be similar to a 700 serie Ni-MH Roomba): 1. Check charging FETs - If FETS fail then charging is aborted 2. Pre-charge cooling { 0mA } - Runs until battery temperature is less than 50°C, or an end of charge condition is true. Sets the charging state to NORMAL or RECOVERY based on the battery voltage. 3. Charging - Runs until an end of charge condition is true, in one of the following modes: a. Normal { 1250mA } - for initial battery voltage greater than 10.8V . b. Recovery { 300mA } - for initial battery voltage less than 10.8V . 4. Post-charge cooling { 0mA }- Runs until battery temperature is less than 35°C, or 2hrs passes. Sets charging state to WAITING/TRICKLE. 5. Trickle { 50mA }- Runs indefinitely. If the temperature goes above 42°C, trickle turns off until the temperature drops below 40°C, then re-enables. End of charge conditions: Charging is terminated as soon as one of these conditions is true. These conditions are tested in variable times during charging: o Voltage Dip : Voltage dips more than a 30 mV from the maximum voltage. o Temperature Slope : Temperature increases by more than 0.5°C per minute. o Coulombs Max : If battery level is more than 2 times the nominal capacity. o Normal Charge Timeout : 9 hours maximum in normal charge mode. o Recovery Charge Timeout : 16 hours maximum in recovery charge mode. o Temperature Max : Battery temperature exceeds 60° C for at least 1 minute. o Voltage Max : Pack voltage exceeds 21.6V for at least 1 minute. o Previous end-of-charge : If a battery has been discharged by less than 150mAH since the last complete charge. Are you sure that the BMS is not protecting the battery from any point of this charge process? I'm not, cause iRobot charging algorythm for Lithium batteries is not available If your Roomba reports Charging Error 1 the Service Manual says: 1. Is battery pull tab removed? 2. Remove bottom cover, remove battery and make sure there is nothing obstructing contacts. 3. Re-install battery and securely tighten all 4 bottom cover screws. (Tighten the two screwsup front near the battery first.) 4. If problem persists, replaceBattery. So if as I understand you've checked your battery makes good contact, may be that charging sequence for Ni-MH battery is not suitable for Lithium.

[@jozsefmihaly9381]

Megcsináltam de nem tölt 1 órája de nem változik!! Akkor az akku electronikája is hibás?

[@86Koksu]

I kill my battery changing cells. After cell replacement pcb won't let to power roomba or charge. Probably it saw 0v accros cell and prottection on pcb kicks in...

[@higherwireinc]

Interesting. Many BMS boards require the battery negative to be disconnected if they trip (i.e., over-/under-current or voltage). It's possible that iRobot added such protection in this BMS, though it seems like a big strike against right-to-repair to be unable to reset the board.

[@jeffm2787]

The BMS has a self destruct thermal fuse. Looks like a fork kind of with a blue square in the middle. If the BMS detects any type of fault it heats up the resistor in the fuse and blows it. Replacing the fuse later just causes it to blow again from my limited experience.

[@romansand918]

@@jeffm2787 Did you find any way to recover original pcb, my cels had a deep discharged and now fuse is dead.

[@jeffm2787]

@@romansand918 Sadly no, Even after having fully charged cells the BMS was still wanting to blow the fuse. I didn't want to spend too much time on the project so I just purchased one of the Chinese knock off batteries. So far so good. If that fails hopefully it has a easier to deal with BMS.

[@romansand918]

@@jeffm2787 Tomorrow I'll have some time to play with it, If I'll find something will let you know.

[@FranciscoJavier32423]

Nice video, now I understood why that battery is heavier but supposed to be lighter than the Ni-Mh, why add extra weight?, is no sense.

[@lenturnbow8038]

I think they are heat sinks rather than weights.

[@XRinger]

Should be added for over all weight, so the wheels don't spin. Like when we used to add weight in the back of a RWD car during snow season. The center of gravity of the design, might have been for an old tech heavy battery. Maybe even a really old lead acid pack.

[@jeffm2787]

I took mine apart to get the 3 Philips head screwdrivers and was disappointed. Edit: It's a thermistor, not a thermocouple.

[@tralala3696]

nice

[@nebojsa1976]

My 890 has 1800 mah, just like the one shown but it is cleaning maybe 50 minutes. I need more then that. I have another roomba 860 that uses 3300 mah lithium battery. Can I put 3300mah into the 890 series roomba (that uses 1800mah)? Will it damage the unit? I need it to run at least 1.5 hours.

[@higherwireinc]

Yes you can. Be aware, though, that others have found that the BMS needs to be reset in order to work. This one didn't have any issues like that but it is the case sometimes with electronics that the BMS effectively shuts off if the cells are removed or die completely.