{req} Cable Length for a amp meter shunt Resistor Please

[PaulC]

Hi zab
i think that the bq24450 uses stat1 & stat2 for different modes
STAT1      STAT2     CONDITION
  HI             HI         Float Mode
 LOW          HI         Bulk Charge
 LOW        LOW       Boost Mode

this is why i was using the AND (2x2n222 for switching on in Float Mode).
Boost mode is for very low battery to bring it up to a level for Bulk mode.

what do you think is best

[zab]

Hi PaulC,
Yes you are right, I consulted the data sheet. in that case you can you two transistor option or the circuit attached.
in both case connect a diode across relay in reverse direction.and add a resistor in series of 555 supply so that High volt does not damage the IC. the 3 diode connected with base of transistor can be skipped if desired.
Hope it will work. All views all given with best intention.

[PaulC]

Hi zab i thank you for your responses
i updated 1st post picture , are the 10k res (pull-ups) ?
do you think the protection diodes will work o.k. this way (to stop any transient volts reversing to BQ24450).
I very much appreciate all views, this i think is how i learn..

[zab]

Hi PaulC,
You have intermingled two differnt method of doing one thing.In present circuit disconnect R34 and R35. and add them in series of D9 D10. this is option 1.


Or
Reverse D9 D10 to do the same thing.This is option 2.

Or
Use the way I suggested in previous post.In that 1 transistor is used with 2 diodes.


Please add a resistor in series of the IC 555.otherwise zener Diode D2 will get short with Hi volt Pulse. This resistor is very important.See my previous post for ref....
Please never give in

[PaulC]

Hi zab
Added new drawing.. to 1st Post.
modified drawing
thankyou zab
Any comments Ideas most welcome

[zab]

Hi PaulC,
Try right side circuit.
the circuit on left need the same modification or little adjustment.if you want to try that.
Best of luck. share the results as well.

[Ichan]

Looks like the charger still connected to the battery when the desulfator working, won't it interfere with (or even break) the BQ circuits?

-ichan

[PaulC]

Hi Ichan
The Desulfator is only enabled when in float mode (i.e. topping up or trickle charging).
current is at minumal & is going through Q11 2N2222..
if you can add to the circuits then please feel free.
any & all ideas are great...

[zab]

Looks like the charger still connected to the battery when the desulfator working, won't it interfere with (or even break) the BQ circuits?

-ichan

I think desulfator will not damage the BQ IC but there is a chance of disturbance, interference  ,For the feed back lines are connected with Main supply. To eliminate this chance a diode may be add before R 13 for insuring protection,separating BQ circuitry from Hi Volt Pulses.
The second option is the diode dext may be sifted to right with Ampre resistor and feedback circuitry will be attached before the diode dext  on anode side of the diode.

[PaulC]

Please check 1st post Diagram and see if o.k.
Protection Diode on Supply to Desulfator

[zab]

Hi PaulC,
The diode is not for Desulfator protection rather charger circuit protection from Desulfator high volt. ref to my previous post for necessary action.

[zab]

Hi PaulC,
No need to use such words.I will readily help you,what ever it is possible for me. Please attach the soft copy of the diagram so that change can be made easily.Modifying a picture is little bit  difficult.
Any how, what I recommended is add a diode only in series of supply going from BQ charger circuit to battery. Please remember in this case battery volt be .5 to .7 volt less than set volt.
(set volt - diode drop volt).


Where did you get charger circuit? It appear to be faulty.
the transistor q4 bc556 need attention as well it can not work in present configuration.The emitter and collector need to be swapped for practical use.

Please use the bases for ICs.check the entire circuitry before placing ics in ic base.
Please check both circuit individually.
to separate desulfator from the charger remove Fuse F3.and check charger. after making charger fully operational remove diode D2 this will disconnect charger from battery.reconnect the fuse f3.to make desulfator operational. After successful test of both circuit, test the unit as one.
Hope it will be helpful.

[PaulC]

Excellent
I really cannot remember where circuit came from as did a lot of research from net..
and bundled ideas together the drawing program i am using is SPLAN 7 from
http://www.sonsivri.to/forum/index.php?topic=9657.25
i will attach diagram to 1st post it may be easier for others to follow.

[zab]

Hi
Reverse the LED attached across fuse F3 and remove R 19.
 Ref to the previous post attached file.

[zab]

I am not referring to R 18 I was talking of R 19 attached  in ground line.

The polarity of led connected across fuse F3 is wrong. it will not work in this position.
for correction just reverse the LED only.

[PaulC]

yep nicely spotted thank you.
changed 1st post to suit