charge error 5 after new (universal) charger

[iwan]

Hi guys,

my roomba charger died....after about a month i bought me a new one. a universal one that delivers 24V and 750mAh. I have read on this forum that this would be a good charger. After i plugged it in my docking station the light (power light) turned green. But when i put the roomba (500 series) on it, the 2 lights on the base station lashes on and off. Also the light on the roomba flashes orange...i thought it was the batterie that was drained empty and need to charge a bit...but after about 45 min. the roomba gives a error 5 code and stops. I pulled out the battery and charged it outside the Roomba for about an hour. Put it back in the Roomba but it still flashes and gives a charging error 5....

Why....i thought tht you could connect a normal charger to it...

hope someone can clearify this.

Iwan
The Netherands

[vic7767]

I suspect that your battery is marginal at best. What voltage is your battery showing after an external charge ? Have you performed a load test on that battery ?

[iwan]

I suspect that your battery is marginal at best. What voltage is your battery showing after an external charge ? Have you performed a load test on that battery ?

when i measurd it after an hour on the charger it was around 15V ( while the battery is 14.4V)
i did not do a load test on this battery.

should i put it on the external charger for a whole night first? and then test it again?

extra info: The battery was new and worked for about 2 months before the charger died. But i left the battery in the Roomba and the Roomba was on the base station for around 1-2 months..(draining the battery i think)

Iwan

[vic7767]

Your battery should indicate 17 to 17.5 vdc after a proper charge. That battery may be suffering from a reversed or defective cell.

[TechGuy]

my roomba charger died....after about a month i bought me a new one. a universal one that delivers 24V and 750mAh. I have read on this forum that this would be a good charger.

The Roomba charger output has 22.5V and 1.25A.
The 750mA is not the problem as long as it can supply more than 400mA.
The 24V output may put load on the internal charging circuit.

when i measurd it after an hour on the charger it was around 15V ( while the battery is 14.4V)
i did not do a load test on this battery.

The no load terminal voltage should be around 17V after charging.
Your battery is not being charged. It may due to your universal charger.
If your universal charger is not the switching power supply type, when Roomba is drawing 1.2 - 1.3A, the output voltage of your 0.75A universal charger will drop to the level below the Roomba charging requirement. This may be the reason why you are seeing only 15V no load battery voltage.

[Gordon]

To: iwan
The Roomba-500 charger output is 22.5V, NOM. for load current between zero amperes and 1.25A. When current draw exceeds 1.25A (as it does in the initial Hi-Rate phase) Roomba's charging PSU will lower its voltage to prevent excessive current being drawn. Not only is this a safe tactic for the PSU and on-board charging control components, but it is part of Roomba's charging control scheme!

If your PSU's stated "750mA" falls below 400mA for 30-minutes Roomba will announce "err5" and halt the charging process.

It could be educational for you to measure (via use of a DVM) two parameters resulting while applying your "24V, 0.75A" PSU to Roomba. The values to measure are: "charging voltage across battery terminals" and "actual charging current".

Doing those measurements would require you to access Roomba's main_PCA (upper surface) so voltmeter probes can contact four specific PCB pads on the PCA.

An alternate path, easier to do but less demonstrative, would be to resistively overload your Universal PSU so it delivers current in excess of its rated 0.75A (say, to load it enough to make its output voltage fall so low that resultant load current drops below 0.4A). This test assumes the PSU's voltage / current regulator uses a "current fold-back" circuit -- a different protective function than iRobot uses (voltage roll-off protection).

[iwan]

thanks for all your input......i wil try and test some things and let you know.

[iwan]

i bought a new battery, tried again with the universal charger and it does the same....

what now....

[mfortuna]

Read Gordon's post again. If you don't want to try measurements then you may want to search ebay for an Irobot charger.

[iwan]

I have measured some things...

i measured the voltage of the charger, this is 23.3V
I try to measure the same thing when charging, but this is impossible, because as i said in my first post. The docking station flickers on and of, so the voltage is jumping around.
I try to measure Amps, but this is also jumping up and down when the docking station flickers...

So what do i do now?

hope someone can shine a light, because i really don't know.

Iwan

[iwan]

at the end i bought me a new charger of of ebay for 20 dollar incl shipping...cannot fool around for that money. Hooked it up and works fine...

topic can be closed.