The battery in my Botvac 75 failed last week after 2 years with the message “My battery is low. Please charge me”. It currently measures 12.9 V.
A replacement from Neato arrived today and the vacuum doesn’t show any indication of life, ie no lights or messages. It measures only 9.77 V. After 2 hours at the charging station the Botvac is still dead. It’s not surprising since the open circuit voltage at the charging station is 18.2 V and it doesn’t change when the Botvac is connected.
My question is this. I’m tempted to charge it for a few hours it with a 15 V bench supply and try to get the voltage up to a point where the Botvac can take over. Will that work? Any downsides?
No, the cycle button did not pulse at all while at the power station for about 2 hours yesterday. There didn’t seem to be any point in continuing as there was no sign of life. I’ll try a 24 hour charge right away and report how it goes.
Over the past 24 hr the voltage has dropped another 200 mV all the while it was in the Botvac and connected to the charging station. It dropped from 9.77 to 9.56 V.
As a point of interest, while waiting for the replacement to arrive I recharged the old battery hoping to get a few more uses out of it. But as you must be aware the ’ battery is low’ message persisted.
I’ll rephrase my original question. If I top it up to say 12 V using a bench supply will Botvac finally recognize it and start to perform in a normal fashion? Will there any problems?
If you charge the battery externally, you can certainly install it into the robot and verify if it turn on.
However, the battery will appear as depleted on the control panel, the robot needs to charge it for a small amount to detect the battery voltage.
If, the robot does turn on but doesn’t charge both batteries, then it’s strongly possible the problem you are experiencing is due to the charging circuit / motherboard.
You are correct.[/size] The problem appears to lie with the charging circuit / motherboard.
Here’s what I did over the weekend.
I gave the battery a small charge. Fifteen min at 3 A took it from 9.6 V to 13.8 V so I tried it. Botvac woke up and I told it that it had a new battery. The home button showed green but then the lcd said “My battery is low. . .” I then placed it on the charging station for 24 hr. The home button pulsed orange for short periods and occasionally showed solid green. The lcd battery icon showed normal charging at times. But for long periods all was dark. After the 24 hr was up Botvac still wouldn’t run and still showed “My battery is low. . .” The battery had dropped to 11.1 V.
As a further experiment I’m now monitoring the voltage across the charging terminals while Botvac is connected to the charging station. It shows an curious pattern:
~ 30 sec at 18.3 V
~ 10 sec at 14.9 V
then over the next 3 or 4 sec it drops quickly to ~9 V before climbing back up to 18.3 V. It might be my imagination but on the way up it might linger for a second at 11 V.
Repeat ad infinitum
So with the replacement battery Botvac is displaying the same symptoms as it did before with the original battery.
So if both batteries seem to be OK and the charger puts out 18 V I’ll guess is the fault lies with the motherboard. Agree?
1, The periodic voltage pattern I described previously, ie 18.3 -> 14.9 -> 9.0 -> 18.3 V -> … continues unchanged even when botvac is switched off. That doesn’t make much sense but I can move the switch from on to off to on and the voltage pattern doesn’t skip a beat. When it’s turned off there are no lights or lcd or startup sounds.
The open circuit voltage of the charger is a steady 19.5 V. No variation at all
With a small load on the charger, 310 mA, the voltage is a steady 18.3 V. My load is a 100 W incandescent bulb and it glows a dull red. Unfortunately I don’t have any other incandescents that could provide a more substantial load. But it probably doesn’t matter. The charger is working properly.
So that’s more confirmation that the [/size]charging module / motherboard is kaput.
[size=2]
Which in turn begs the question, what happens next?
Will RobotShop send me a new board or do I have to ship Botvac back?
