Search found 15 matches

by upsss
Sat Jan 26, 2019 4:44 pm
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

I wouldn't use their JYE118, it doesn't solve any of their problems. If anything, I would use a USB 18650 power bank which has a built in charger and a step up converter to 5V. You can find these power banks with a battery cheaper than their JYE118. This way you have a constant 5V output, a built in...
by upsss
Tue Jan 22, 2019 5:21 am
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

@MorganFlint, eliminating the ±5V regulators and powering everything from 5V is probably OK. However, powering it directly from a single lithium cell it is a bad idea. That kit doesn't have a battery charger circuit and no low battery voltage indicator. The battery voltage could be all over the plac...
by upsss
Thu Dec 27, 2018 7:02 pm
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

@aiyiadam, Good idea if you can live with an external power bank (everyone has one) and can install a small step up module inside the scope. Instead of using a 9V Step-Up USB cable, taking it apart and soldering a mini USB connector, all you need is this $0.75 module https://www.ebay.com/itm/DC-DC-5...
by upsss
Wed Dec 26, 2018 6:19 pm
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

It is unpredictable and it will vary from unit to unit. Basically at around 7.5V, which could actually be 7.5V ±0.5V the +5V and the -5V regulators will stop regulating and then anything is possible. The problem is that at that point the scope will NOT just die but will stop functioning properly and...
by upsss
Tue Dec 25, 2018 5:17 pm
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

Whoever came up with this idea of using two Lithium batteries in series without a step up converter did NOT do his homework and take into account worst case condition of the batteries voltage. THIS SCOPE WILL NOT FUNCTION AT BATTERY VOLTAGE OF 6V! Anything less than 7.5V is very unpredictable! Most ...
by upsss
Sat Jul 21, 2018 5:50 pm
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

You can use any battery where you can positively identify the + and - terminals. Most cell phone batteries have a 3rd terminal which is a thermistor to monitor the battery temperature, the 4th terminal if it has it, usually it is not used. Whatever you do, make sure you don't overcharge it and ALWAY...
by upsss
Sun Mar 04, 2018 9:01 pm
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

Please forgive me if I was somewhat rude. You are partly right. Of cource, the regulator MAY be unstable when difference between the input and output voltages becomes small. But it does not stop regulating ! Simply, the characteristic becomes nonlinear, which facilitates self-oscillations. Whether ...
by upsss
Sat Mar 03, 2018 7:45 am
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

Regulating the 3.3V supply directly from the Li-Ion battery as you are suggesting, your new LDO 3.3V regulator will stop regulation under worst condition with battery voltage of 3.6-3.7V, Absolutely NOT! See the regulator's datasheet. Moreover, I tested XC6203 in practice. It works normal down to 3...
by upsss
Fri Mar 02, 2018 5:24 am
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

@UnKaiF, first let me say a few good thinks about your ideas. I like your clear drawing especially the 2nd one where you point out the potential excessive power losses. Eliminating the original series diode at the power input is a no-brainer. This original diode was there for reverse polarity protec...
by upsss
Wed Jan 31, 2018 6:30 pm
Forum: DSO Shell
Topic: Li-ion power mod
Replies: 144
Views: 184297

Re: Li-ion power mod

I have a different module. https://www.ebay.nl/itm/USB-Lithium-Li-ion-Lipo-Battery-Charger-Module-3-7v-4-2v-Boost-Step-Up-9V-6F22-/191978851987? Unless you you perform some delicate surgery on this module and wire your On-OFF switch between the charging circuit and the step-up converter (as describ...