roomba discovery 4210 wont turn on

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roomba discovery 4210 wont turn on

Postby juls095 » August 31st, 2008, 3:06 pm

My husband just bought me a what looks to be a brand new roomba discovery off of craigslist. There is no indication that this unit was ever used. However, we plugged it in set it on the charging dock and it just started blinking a red plusing light on the power button, which from what i have read means it is charging. We let it sit there over night about 12 hours, woke up in the morning to use it and it was still doing the same thing and it will not start. we read online to charge it for 16 hours the first time. so we left it again, charging well over 16 hours. still same red pulsing light. Roomba will not turn green (power light) and it will not start? DEAD BATTERY? any suggestions?
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Postby numan » August 31st, 2008, 5:43 pm

It sure does sound like a dead battery, here are a few things you might try. With, a volt meter checked the power supply that connects to the Roomba. Using your volt meter put the positive lead from the volt meter inside the barrow of the power supply and the negative lead to the outer barrow you should measure a constant 22 volts D.C. If you have the docking station use the volt meter to test the output of the docking station by putting the leads from the voltage meter across the two metal contacts on the base station it should measure about 4 volts D.C. If both reading are correct, you might try just charging the Roomba directly using the power supply and not using the base station. I?ve once had a docking station that would measure the correct voltage however it still would not charge the battery correct even though the voltage was correct it would discharge the battery.

But if the battery has sat a long time and the voltage has dropped too far down in the battery, the battery might not take a charge. So to answer your question your battery might be too discharged to take a charge at all.

Sorry about you problem give those idea a try and see if they make any difference.
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Postby Robotic » September 2nd, 2008, 11:54 am

These batteries do not take kindly to two situations:
1. sitting connected to the roomba in a box for weeks (or months) on end
2. sitting connected to the roomba on charge for weeks (or months) on end

They need exercise at least once a week, preferably more!

A 'new' roomba from CraigsList may indeed have zero hours of running on it, but if it has sat for a year the battery will have suffered.

The good news is that you have a few options for battery replacement!
You might even want to upgrade to Lithium-Ion cells, which have at least three advantages:
the battery will
1. be lighter
2. give twice the cleaning time per charge (apprx)
3. be much more robust wrt charging and sitting
11 Roombas in various states of functionality and loan.
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Postby Gordon » September 2nd, 2008, 4:14 pm

{I have a couple additions, and some notes for your list}

the (Li-ion) battery will {cont.):

4. exhibit a longer lifetime than one using NiMH cells

5. charge to designated capacity within a shorter period than a NiMH battery of similar capacity.

Note-A: The "sitting" statement in item (3) means that Li-ion will hold its charge much better than NiMH during battery-disconnected standby periods.

Note-B: Notice, it remains unwise to store any Roomba/Scooba with its battery connected to the robot. The robot will slowly run down the battery unless trickle-charging is invoked.

Note-C: When you invoke trickle-charging of a NiMH battery, you have no way of knowing that such charging may be exceeding the battery's self-discharge rate (which is also combined with any standby-load the robot may be placing on the battery). (Eventually, an unusable battery gives you a clue.)

Note-D: Excess charge can ruin energy-storage cells. Excess charging of the Li-ion cells is prevented by the charge/discharge controller built into each cell. NiMH-cell batteries have no equivalent controller.
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