* THE FORUM FOR ALL THOSE INTERESTED IN BUILDING AND OPERATING MODEL SUBMARINES *



Join the AMS - Registered Forum users can become members of the AMS and it's free ...... To join send an email with your name , address and phone number to amstreasure@googlemail.com


For further details of any events shown here also see the "Shows and Events" section on the forum

*STOP PRESS* Coronavirus. A lot of Clubs have already cancelled all activities. Check carefully before you plan any travel

.

CANCELLED because of coronavirus. Papplewick Pumping Station, Nottingham, Sunday 12th & Monday 13th April
CANCELLED because of coronavirus. Bournville Sub Day, Sunday 10th May 2020

. ,

Submarine, Boating & Sailing Weekend, Norwich MBC, Weekend of 25,26th July

,./
.
Model Boat Convention, Haydock Park (Cancelled this year)

.

Bournville Sub Day, Sunday 13th September

,,,,

Club Submarine Regatta, Furness MBC, Barrow in Furness, Sunday 20th Sept 2020

Who is online?

In total there are 3 users online :: 0 Registered, 0 Hidden and 3 Guests :: 1 Bot

None


Most users ever online was 180 on Tue Nov 05, 2019 6:03 am

Latest topics

» today's work
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyToday at 3:45 am by merriman

» RC for Submarines
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyYesterday at 10:26 pm by Hermann

» Telemetry on openLRS
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyTue Apr 07, 2020 10:55 am by david f

» 3D printed sub kits
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyThu Apr 02, 2020 10:40 am by david f

» British Submarines in Two World Wars by Norman Friedman publ by Seaforth.
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyTue Mar 24, 2020 11:27 am by david f

» stretching sprue
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyThu Mar 12, 2020 1:13 pm by merriman

» Arduino proportional control of a piston tank
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyThu Mar 05, 2020 2:30 pm by david f

» Looking for Paint Colour Advice
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyWed Feb 26, 2020 10:30 am by david f

» Voltage or data measurement by WiFi - Node Mcu (Arduino) - A failed experiment
Simple, elegant voltage shut off - Lipo protection perhaps? EmptyMon Feb 17, 2020 11:10 pm by C-3PO

Statistics

Our users have posted a total of 11109 messages in 1818 subjects

We have 845 registered users

The newest registered user is exceed

    Simple, elegant voltage shut off - Lipo protection perhaps?

    david f
    david f
    AMS Treasurer

    Posts : 2086
    Join date : 2010-11-10
    Age : 69
    Location : Cumbria

    Simple, elegant voltage shut off - Lipo protection perhaps? Empty Simple, elegant voltage shut off - Lipo protection perhaps?

    Post  david f on Wed Feb 15, 2012 8:53 am

    A rather interesting link from John Main of C for Microcontrollers.

    http://www.best-microcontroller-projects.com/rechrgbatprotect

    Let us know if you use the circuit principle. I already use a MOSFET in a slightly similar way as an on/off switch (Triggered by magnet and reed switch.)

    David
    johnrobinson
    johnrobinson
    Guest

    Posts : 97
    Join date : 2011-06-10

    Simple, elegant voltage shut off - Lipo protection perhaps? Empty LIPO PROTECTION PERHAPS LOL

    Post  johnrobinson on Wed Feb 15, 2012 7:39 pm

    HI David
    Problem with lipos is you need to monitor each cell in the pack because one cell will always go down in voltage first, you should not really take a cell down below 2.95V or you risk damageing the cell. The circuit that you showed will just monitor the hole pack and that is not the way to do it.

    If you had a 3 cell pack of lipos just say 1 cell was at 3.5v and the next was at 3.5v but the last cell was at 3v the 3v cell should be switching the power off to speed controller or what ever but if you put 3.5 and 3.5v together would make 7v plus 3v for the cell that should be turning the power off add voltage up it comes to 10v but if you carried on discharging pack down to 9volts the cell that was at 3volts when the pack voltage was at 10volts by the time it got to 9volts would now be damaged and that is how you would slowly cream cracker a lipo pack. This is just the basic idea that's why it is the best thing to monitor all cells in the pack, say you went to 10 cells now gets worse and becomes more important to monitor the cells
    SUB JOHN
    david f
    david f
    AMS Treasurer

    Posts : 2086
    Join date : 2010-11-10
    Age : 69
    Location : Cumbria

    Simple, elegant voltage shut off - Lipo protection perhaps? Empty Re: Simple, elegant voltage shut off - Lipo protection perhaps?

    Post  david f on Thu Feb 16, 2012 9:06 am

    Hi John,

    In a perfect world it would be best to monitor each cell but it can make it much more complicated.

    I think you are speaking more of aircraft applications - many cells and drawing very high amps.

    The lipos I have used in subs for several years are only 3 cells and I only draw about an amp. In these circumstances I suspect you don't get big voltage differences between cells and I always balance charge them. I also don't push my luck and sail for too long (I have never had a low voltage alarm.)

    So I think in the absence of anything else this type of circuit would give your Lipo a good level of protection.

    David

      Current date/time is Thu Apr 09, 2020 11:50 pm