tag:blogger.com,1999:blog-825227734527676377.post6123085300460000821..comments2023-04-30T05:47:22.339-07:00Comments on dreaMING of Fusion: Repairing Roomba charging circuitYewMinghttp://www.blogger.com/profile/00485107543380065465noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-825227734527676377.post-44717967062084132922021-01-01T10:01:47.793-08:002021-01-01T10:01:47.793-08:00Thanks for this, even so many years later! The U2/...Thanks for this, even so many years later! The U2/U4 burnout problem continues to plague owners of the early Roomba models (mine is a Discovery 4210 from 2004). I made a similar constant-current charging circuit from my extensive junkbox of parts, but with a TO-220 PNP transistor TIP32. I'm currently using it as an external charger powered from the Roomba charger supply, and found that ordinary crimp lugs will slot right into the battery terminals. My circuit is self-regulating, reverting to low current trickle charging after the battery reaches 17.25V. I can't upload the circuit here, but here are some details: TIP32 emitter connected to 4.7 ohm 2 watt resistor to +22.5V, base connected through green LED (2.0V) to +22.5V, and collector goes to battery +. Also from TIP32 base is 270 ohm resistor to collector of a 2N2222 NPN transistor. Base of 2N222 goes to voltage divider 10k/39k ohms between +22.5 and - terminal (connected to battery -) to make 18V, emitter goes to battery + terminal to sense charging state. When battery is not charged, current is 0.33A, when charged LED goes out and current is much lower. Hope this is of interest all these years later.Dhttps://www.blogger.com/profile/06972178821780368958noreply@blogger.comtag:blogger.com,1999:blog-825227734527676377.post-18864277798142752692013-01-24T07:06:51.318-08:002013-01-24T07:06:51.318-08:00hi ryan
yes, you can splice the +V from home base...hi ryan<br /><br />yes, you can splice the +V from home base J25 and it should be the same.<br />Alternatively if you can locate diode D30 or D32, you might be able to use both home base and direct input if you solder the regulator input to the cathode side of either one of the diodes. However, as I don't have a roomba with me anymore, I'm not sure if the point is easily accessible.<br /><br />YewMinghttps://www.blogger.com/profile/00485107543380065465noreply@blogger.comtag:blogger.com,1999:blog-825227734527676377.post-82833901506810100272013-01-24T02:43:13.051-08:002013-01-24T02:43:13.051-08:00hi again val,
sorry to bug you again!
I just got ...hi again val,<br />sorry to bug you again!<br /><br />I just got the parts so now I've managed to disassemble the robot...<br /><br />From your pictures of the circuit you designed, you've connected the yellow wire (regulator output) to the red wire on pin J7 (which in turn connects right to the battery.<br /><br />Only problem is, it looks like you've connected your red wire to J15 which is from the wall charger jack. If I wanted to use the home base rather than the direct wall connection, should I instead splice into the wire on plug J25? (The red one of course) Since it looks like the home base +V and the wall plug +V are separated by diodes... so I have to pick one or the other? Thanks again!Anonymoushttps://www.blogger.com/profile/14446367595960542643noreply@blogger.comtag:blogger.com,1999:blog-825227734527676377.post-53550397060042290992013-01-19T16:08:05.845-08:002013-01-19T16:08:05.845-08:00hi ryan,
i've almost forgotten most of the de...hi ryan,<br /><br />i've almost forgotten most of the details until i read the article again!<br /><br />anyway, for the manual direct changing, yes... i've connected the 5ohm resistor in series with the positive as a current-limiter.<br /><br />for the 2nd question, the new circuit basically bypasses all the motherboard's circuit, it takes 22V Vin directly and output directly to the battery positive terminal. it depends on the diode to prevent reverse current.<br /><br />thanks!YewMinghttps://www.blogger.com/profile/00485107543380065465noreply@blogger.comtag:blogger.com,1999:blog-825227734527676377.post-77099331972926873992013-01-19T12:33:01.671-08:002013-01-19T12:33:01.671-08:00Hi fusion! I'm super glad this article is sti...Hi fusion! I'm super glad this article is still up... and thank you for describing your process! It's hard to find information on older models.<br />I have a question though. My roomba is in the <i>exact</i> same situation as the one you described...<br />When you used the default charger to manually charge the battery, how did oyu connect the 5ohm resistor (in series with the positive?)<br /><br />And lastly, the new circuit you designed to replace the U2 and U4 mosfets, how does it integrate properly with the motherboard (hard to tell from the envelope diagram).<br /><br />Thanks!Anonymoushttps://www.blogger.com/profile/14446367595960542643noreply@blogger.comtag:blogger.com,1999:blog-825227734527676377.post-47153460815391046932012-10-01T08:25:05.849-07:002012-10-01T08:25:05.849-07:00Hi val, I won't be able to make this for you u...Hi val, I won't be able to make this for you unless you are in Malaysia, but it will cost a dollar or 2 of component and someone with basic soldering skills to make one.YewMinghttps://www.blogger.com/profile/00485107543380065465noreply@blogger.comtag:blogger.com,1999:blog-825227734527676377.post-24922761241874593852011-11-16T14:09:02.908-08:002011-11-16T14:09:02.908-08:00How much would you charge to make a charging circu...How much would you charge to make a charging circuit for my broken roomba that I could install. My problem is identical to this!!valhttps://www.blogger.com/profile/04221618124085661720noreply@blogger.com