Adjustable voltage box mod

[Scubabatdan]

You owe me a monitor - I just spit coffee all over mine..

I am just going to sit back and wait for Dan and Willy to finish off this project, I want the USB charging circuit / passthough in there too... And maybe a cappuccino maker..

LOL would have love to see that hehehe

Seems the cap requirements for the regs aren't as critical as they are for the booster. Many folks in the past have gone capless. I'm not even going to use one at Vout.
For vaping I don't think we have to worry about 'good transient response'.

You might read this post for some low ESR surface mount caps.

http://www.e-cigarette-forum.com/fo...2-these-caps-good-ti-booster.html#post1705811

You realize a charger for stacked, series batts will require some sort of 'balancing' circuit. A Li-Ion pack needs independent voltage monitoring, and each cell in series must be monitored for voltage

Cool I just ordered some SMD caps and will test with and without the cap on the vout.
Yes I kinda figured I would open a can of worms asking about a usb charge port with stacked batteries, but hear me out for a sec....
If I used a single cell 400ma charger on two stacked "Protected" batteries, they will both charge at 200ma's once the first reached the optimum charge state, the pcb board (since it is protected) will stop the charge and the lower voltage battery will continue to charge at 400ma until its onboard pcb circuit stops the charge. This would only be viable IF they were both protected, otherwise the charge circuit would have to allow for balancing and individual charge state.
This sound do able?
I have charged two protected batteries in parallel with a 400ma single cell charger before, but not in series.

Dan,
Is your volt meter an internal one? If it is can you tell me what one you are using?

These are the two I am going to test:
NEW RC Lipo battery Voltage Indicator voltmeter (1S-6S) - eBay (item 270576533827 end time Sep-06-10 09:02:47 PDT)http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120606175425&ssPageName=STRK:MEWNX:IT
And
http://cgi.ebay.com/LiPo-Battery-Vo...0462177440?pt=Radio_Control_Parts_Accessories

Still waiting on them to show up, the first ones display is approx 1" x 1/2" which might be too big for a small fist pack (14500's), but for a dual 18650's it should be an ok size for the box mod.
Danhttp://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=160454354069&ssPageName=STRK:MEWNX:IT

 

[Shad0w]

Dan,

Is your volt meter an internal one? If it is can you tell me what one you are using?

It is the EXACT one that a vendor is now carrying...

Independently found for 1/4 of the price.

It measures roughly 1"x1" from what Dan showed me.
Too large for a tube, but doable for a boxmod at 14mm thickness iirc.

ETA

Dan ya beat me to it! LOL

 

[bigblue30]

LOL would have love to see that hehehe



Cool I just ordered some SMD caps and will test with and without the cap on the vout.
Yes I kinda figured I would open a can of worms asking about a usb charge port with stacked batteries, but hear me out for a sec....
If I used a single cell 400ma charger on two stacked "Protected" batteries, they will both charge at 200ma's once the first reached the optimum charge state, the pcb board (since it is protected) will stop the charge and the lower voltage battery will continue to charge at 400ma until its onboard pcb circuit stops the charge. This would only be viable IF they were both protected, otherwise the charge circuit would have to allow for balancing and individual charge state.
This sound do able?
I have charged two protected batteries in parallel with a 400ma single cell charger before, but not in series.



These are the two I am going to test:
NEW RC Lipo battery Voltage Indicator voltmeter (1S-6S) - eBay (item 270576533827 end time Sep-06-10 09:02:47 PDT)
And
LiPo Battery Voltage Indicator Checker Tester 2S 6S New - eBay (item 290462177440 end time Aug-09-10 10:36:37 PDT)

Still waiting on them to show up, the first ones display is approx 1" x 1/2" which might be too big for a small fist pack (14500's), but for a dual 18650's it should be an ok size for the box mod.
Dan

LOL... I am waiting on the same 2...

I just received 2 of these...They are meant for unprotected batteries, but they might keep the batteries from over charging. They are only 5 mm by about 25mm.I will see if this will work.

PCB for 7.2V Li-ion battery packs

 

[Scubabatdan]

LOL... I am waiting on the same 2...

I just received 2 of these...They are meant for unprotected batteries, but they might keep the batteries from over charging. They are only 5 mm by about 25mm.I will see if this will work.

PCB for 7.2V Li-ion battery packs

That should work since it handles both batteries:

So three wires to the batteries and it should all be set. Then we can wire a USB port plug for power.

OH SNAP, the pdf for this shows all the chips and circuit layout, I could incorporate this into the board I am working on! Awesome!
http://www.all-battery.com/productimages/pcb/PCB-F7.4V 7-13A.pdf

Nice find!
Dan

 

[WillyB]

That should work since it handles both batteries:

So three wires to the batteries and it should all be set. Then we can wire a USB port plug for power.

OH SNAP, the pdf for this shows all the chips and circuit layout, I could incorporate this into the board I am working on! Awesome!
http://www.all-battery.com/productimages/pcb/PCB-F7.4V 7-13A.pdf

Nice find!
Dan

Well it depends what you are trying to accomplish. A protection circuit is used for unprotected batts. I think a protection circuit on top of protected batteries may cause some complications.

If your plan is to use the protection circuit's cut-off for charging/balancing a series Li-Ion pack note:

Over charge detection voltage: 4.35±0.025V

Note, from BatteryU that voltage will cut a batts longevity (charge cycles) in half.

Also would not the batts' own protection circuit have to be in exact sync (same cut-off or slightly higher)? And would not a protected batt on it's own do the same thing?

Maybe if you could adjust the cut-off (resistor substitution?) to a more reasonable 4.18 - 4.2V it may work.

 

[Scubabatdan]

Well it depends what you are trying to accomplish. A protection circuit is used for unprotected batts. I think a protection circuit on top of protected batteries may cause some complications.

If your plan is to use the protection circuit's cut-off for charging/balancing a series Li-Ion pack note:
Note, from BatteryU that voltage will cut a batts longevity (charge cycles) in half.

Also would not the batts' own protection circuit have to be in exact sync (same cut-off or slightly higher)? And would not a protected batt on it's own do the same thing?

Maybe if you could adjust the cut-off (resistor substitution?) to a more reasonable 4.18 - 4.2V it may work.

Well Poo, always a kiljoy, LOL
Thanks for watching and advising on our potential mistakes. I answered my own question earlyer of a single cell charger on two protected bats in series, the first to charge fully will cut off, cutting the charge circuit to the other bat.

I see what you mean about killing the batteries by over voltage charging. If we are using two protected batteries, then this senario would work fine provided the over current charge does not exceed 4.18 - 4.2 volts.
And to do that would be to change the resistors to provide for 4.18 - 4.2v of charging power.

Looking at this charger/balancer it seems as though the BM lead would switch to either pos or neg depending on which battery was fully charged first.

So we would have to increase resistance on the R1 and R2 resistor to lower the charging voltage. Correct?
Dan

 

[bigblue30]

That should work since it handles both batteries:

So three wires to the batteries and it should all be set. Then we can wire a USB port plug for power.

OH SNAP, the pdf for this shows all the chips and circuit layout, I could incorporate this into the board I am working on! Awesome!
http://www.all-battery.com/productimages/pcb/PCB-F7.4V 7-13A.pdf

Nice find!
Dan

Dan,

I believe WillyB is correct. A USB will only supply voltage and not constant current... and that is not good. I am going to try this chip with a 2 cell li-po charger from my helicopter. If I do not blow myself up I will let you know how it goes.....I do have a fireproof charging bag...

 

[Scubabatdan]

Dan,

I believe WillyB is correct. A USB will only supply voltage and not constant current... and that is not good. I am going to try this chip with a 2 cell li-po charger from my helicopter. If I do not blow myself up I will let you know how it goes.....I do have a fireproof charging bag...

I do not see where he talked about USB power supply above, but I disagree, I could care less about the amperage (Too a point) the amperage will determaine how long the battery will take to charge at the proper voltage. Voltage can be limited based on I*R but most USB port's push a max of 500ma. We could always come up with a dedicated power supply for our needs also. It is just a matter of determining the resistance needed to obtain 4.18 - 4.2 volts. I did notice this PCB does not have a max power input denoted.
Would be curious to know the voltage before the resistors on usb power at 500ma and on a 5v 500ma ac power supply, that way we could determine the proper resistance.

BTW did you notice that most all of the batteries from that site are protected, and the 14500 that is not has a picture of a protected 14500 LOL
My point is how may people are using protected batteries with a charger that has a protective circuit?
Dan

 

[bigblue30]

I do not see where he talked about USB power supply above

So three wires to the batteries and it should all be set. Then we can wire a USB port plug for power.

I thought Willyb was warning us about just hooking up a USB port to the “charge” pads of the chip.

We could always come up with a dedicated power supply for our needs also.

I will test my charger today. It is a dedicated charged that is used to charge a 7.4 volt flight pack. Its output is 8.4 volts at 500 ma.

My point is how may people are using protected batteries with a charger that has a protective circuit?

Right… Even if the “board” has a higher voltage cut off, shouldn't the battery built in protection cut off at a lower voltage?

 

[bigblue30]

I just went to wire up the protection board.......They send me the wrong ones...I have the 3.7 chips...

 

[Shad0w]

3.7 as opposed to the 7.4? So yours is for a single cell then?

 

[roadrash]

I just went to wire up the protection board.......They send me the wrong ones...I have the 3.7 chips...

Just some more parts to add to the parts in the parts drawer.

 

[bigblue30]

3.7 as opposed to the 7.4? So yours is for a single cell then?

Yes, They are for a single cell. I can use them I have 10 unprotected calls from a new laptop battery.

 

[Scubabatdan]

Ok, I just orderd 2 of these 7.4 charge boards to conduct my tests with, I will provide futher updates whe I get this assembled. If this works I can add this schematcs to a double sided board and have everything in one board, that would be convinient.
Dan

 

[hova]

that switch is pretty hot. hadnt thought of side mounting like that , im going to have to go to radio shack now for that 3AA box...


i should just pick up a bunch of boxes while im there...


a+ mod , let me know when you decide to sell the guts commercially....


-hov

 

[Bubo]

I swear there is a modder in Lakeland Florida.. I just went to the Radio Shack and everything on my shopping list was out of stock....

 

[hova]

yeah i had to go to 3 different radio shacks to get lead free silver solder. seems dan has been having to call farther and farther around...


you leave my supply of flux alone damnit!


-hov

 

[bigblue30]

that switch is pretty hot. hadnt thought of side mounting like that , im going to have to go to radio shack now for that 3AA box...

I think you are talking about the blue switch...yes it is a very nice switch. The supplier down the street where I get it from tells me that there is another local mod'er is using the same switch. I have no idea who the mod'er is.

I have made this mod with the switch on the front and on the side. I think I like the side better.

The best price I have found on boxes is here..$0.79 a piece:

SBH-331-AS-R: JAMECO RELIAPRO: Batteries

 

[hova]

yeah all eclectronics had some nice clear ones a long time ago ,but i couldnt find them for the life of me.

madvapes i think had some nice ones too. way to classy for me . black abs all the way.

 

[WillyB]

I do not see where he talked about USB power supply above, but I disagree, I could care less about the amperage (Too a point) the amperage will determaine how long the battery will take to charge at the proper voltage. Voltage can be limited based on I*R but most USB port's push a max of 500ma. We could always come up with a dedicated power supply for our needs also. It is just a matter of determining the resistance needed to obtain 4.18 - 4.2 volts. I did notice this PCB does not have a max power input denoted.
Would be curious to know the voltage before the resistors on usb power at 500ma and on a 5v 500ma ac power supply, that way we could determine the proper resistance.

BTW did you notice that most all of the batteries from that site are protected, and the 14500 that is not has a picture of a protected 14500 LOL
My point is how may people are using protected batteries with a charger that has a protective circuit?
Dan

The Maxim folks's charging chips differentiate between USB vs. power supply inputs, because the current that a USB computer port outputs is up for grabs. Simply providing 5V to a standalone protection is not how Li-Ions are charged. That's where the terms CC/CV come into play.

The Li+ battery-charging process requires medium-accuracy constant-current (CC) charging in a first phase, transitioning to high-accuracy constant-voltage (CV) charging in a second phase.

My point is how may people are using protected batteries with a charger that has a protective circuit?

The chargers cut-offs are not really a protection circuit like you find in batteries. The chargers circuit senses the batts condition, starts charging in CC mode then at a certain point switches to CV till the cell reaches 4.2V. My comment on double protection was how it may impact the batts output under high current demands.

There's alot of good info at Maxim's site. Maybe the easiest solution would be to build two charging circuits. The Max1811 is pretty much self contained and has some great features.

MAX1811 USB-Powered Li+ Charger - Overview

USB Single Cell LiPoly Charger Rustic Engineering

Not trying to rain on your parade, just going for some healthy discussion that we can all benefit from.