Battery charging

Hi bought HPS140I, Started to load the battery of HPS, red led goes on… will the red led go out when the battery is charged… or… how do I know the battery is full.

thanks Cees

Recharging the HPS140 can take up to 10 hours. The led will fade as the battery is charged.

I would like to say that I also did not understand when the HPS140 was charged. The red LED was supposed to be off when fully charged.
I am actually on my second unit after getting it exchanged because the first one stopped working and I thought it had failed or was faulty. The replacement one did work for a while and as I do not use it very often, but now also has the same symptoms as the first one - the screen will try to flash the start logo, but never starts properly and the screen just flashes.
I have discovered that there is actually an issue with the USB charging cable. I decided to check the battery voltage and it was only 3.6V. I then checked the output of the USB cable which was plugged into a USB power pack capable of 2000mA. The output voltage at the plug that plugs into the device was only 5.4V.
I have now used a seperate 9V power supply (9.5V output) and immediately the red LED came on and the device actually started properly. I also measured the volatage at the battery it is now approximately 5.6V which is what I expect to be able to chrge the 4.8V battery. I will now leave it for a while to charge the battery.
As both units have behaved in he same way that there is a fault in the USB charger cable. The model of the USB adapter I have is a UP1-1 SEC 9V 200mA. I assume that this is using a low input boost module to boost the voltage from 5V to 9V and it is not working as expected.
I can not remember when I got this replacement unit, but I would suspect that it would now be out of warranty. I am wondering if Velleman would be able to exchange my cable with one that works.
I would also suggest that you are having the same issue.

We are not aware of any USB cable issues, except for the one-off that is simply DOA.
Compared to the 20K units sold, it is really not an issue.
Anyway, please supply an address and we’d be happy to mail a spare USB charger cable.

PS: The led does not turn off at full charge, it will glow less bright.
(The led is used as a voltage reference for the current source battery charge circuit. Since the charge current is less than 1/10 of the battery capacity, it is not a problem to leave the charger connected for a prolonged time).

I do appreciate that you would have sold quite a few of these so I guess that I have just been unlucky 2 times in a row!

I am more that happy to send you my address, but I can not find a way to PM you on this forum. I also noticed that others have also asked ho to PM on this forum. Maybe a “how to” could be added or it could be the subject of an FAQ.

If you send me an email address that I can send a private message to I am happy to provide my address.

If you do not feel like posting your address here, then you can mail your address and requirements to supportatvellemandotbe

Groots thanks for your post.I too had this same problem.I’ve been using my maplin purchased scope with a 9Vdc/1amp power supplyfor awhile now.I second what you said about the usb packaged supply.Hope Velleman soughts this out ASAP! Too late for me though…Ouch!


Appreciate your comments. Velleman did offer to replace the charging cable - Thank you. I have received the cable and immediately tested the output voltage. It is approximately 9V - which is good!

While I was waiting for the cable I used a 9V DC 1A power supply and this worked well. It charged the battery properly. I would suggest that as USB 2 0 is only good for 5V 100mA which is boosted to 9V with much lower current output is only able to provide the device with a “top up” rather than keeping it charged while using it. However it will probably charge the battery to a reasonable level when the device is turned off if you leave it charging for a long period - if the charging cable is working properly.


i have just recieved my first …and had exactly the same problem… is opened the charger an the base of T2 was broken from the pcb

so also my topic… it gives 5 volt and after repairing 9

if i look at the charger it wil be hard to imagin that we are the only lucky guys…i want to buy a lotery ticket with this much of luck

DEAR mr or mrs Velleman …the HPS140 is a very nice and good product ,but the charger needs some love care and attention

As I have mentioned in an earlier comment, and thanks again to Velleman, I have received a replacement charger and it seems to be working fine now.
The real problem is that you do not know that you have a problem untill the scope starts to play up, particularly if you are only using it infrequently.
None the less, it is easy to check - just use a voltmeter, and if it is not showing the correct voltage, the faulty one shows about 5.1V and the replacement shows about 9.7V.
If it is not correct, just drop Velleman an email and take them up on their offer to send you a replacement.