Hi !
i have taken the decision to try rechargeable batteries as power supply.
I decided this on the basis of a post of a great audio designer using a 9V battery to power a very low noise amp dealing with uV signals.
I need about 9-10V and possibly 4-5000 mAh
I have found Turnigy brand but i have no clue about which would be the best battery solution.
Do you have any suggestion ? anyone using batteries for low V and low A devices with success ?
Thanks a lot indeed. gino
i have taken the decision to try rechargeable batteries as power supply.
I decided this on the basis of a post of a great audio designer using a 9V battery to power a very low noise amp dealing with uV signals.
I need about 9-10V and possibly 4-5000 mAh
I have found Turnigy brand but i have no clue about which would be the best battery solution.
Do you have any suggestion ? anyone using batteries for low V and low A devices with success ?
Thanks a lot indeed. gino
The most you can get from Ansman 9V is 300mA, those are Low self discharge, good performers but not cheap.
Announcement: Ansmann PowerLine 4 PRO NiMH Charger scheduled review by ITTSB.
Announcement: Ansmann PowerLine 4 PRO NiMH Charger scheduled review by ITTSB.
Hi and thanks a lot for your kind and valuable advice.
The needed voltage is in the range 9-11 VDC.
Unfortunately i do not know the current draw of the circuit.
The PS has to supply a usb receiver chip by Xmos and a clock circuit.
I have no clue about the consumption.
I have decided to try batteries because i saw a famous audio designer using them for a uV signals amp for noise measurements.
Maybe i will discover that batteries are the noisiest thing around.
At least they will provide isolation from mains ... i hope
Thanks a lot again, gino
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I found these Lithium Polymer 9V but they are only 520mAh and are $22 each. One iPOWER 9 Volt 520mAh Lithium Polymer Rechargeable Battery
You will need to know the current draw in order to determine your Ah capacity need. If you need more capacity and have room, perhaps you could use six or seven NiMh C-cells in series.
Maha Imedion 2 Pack C Cell 5000mAh NIMH Rechargeable Batteries (Low-Discharge, Pre-Charged).
You will need to know the current draw in order to determine your Ah capacity need. If you need more capacity and have room, perhaps you could use six or seven NiMh C-cells in series.
Maha Imedion 2 Pack C Cell 5000mAh NIMH Rechargeable Batteries (Low-Discharge, Pre-Charged).
You will not notice any difference between batterys so just buy a 9V battery from your local shop. The difference will come from the isolation of common mode disturbances. You will be able to get the same level of isolation from an old fashioned transformer based 9V "wall wart" that has no earth pin.
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Hi and thanks a lot for the useful link.
I think i have made a mistake ... i have bough this one a little on the high side of V
ZOP Power 11 1v 5500mAh 35C 3S T Plug LiPo Battery for RC Helicopter Plane Car | eBay
now i am concerned that the regulator could get a little hot.
But i could not wait.
And now i need a charger ... i asked the seller and waiting for an answer.
I have to try a battery maybe only to then go back to a normal ps
Thanks a lot again.
gino
Hi and thanks a lot for the valuable advice.
I have some experience but with SLABs 12V ( around 13.5V when full charged). They were 7Ah heavy but they worked very well.
Problem is that 8-9V is the best value for the circuit i have
I remember the story of a guy powering the clock and i think the dac of a Sony SCD1 with a car battery
He reported a spectacular sound.
Unfortunately i have discovered the noise measurements are much more challenging than what i thought, especially when noise is low of course.
A good testing rig could be very expensive and much above my budget.
But i like noise vs. Hz spectra a lot indeed.
And i think they are very telling of a ps quality.
I would like to see a spectrum of a battery also to see the battery noise of which many talk about
Maybe spectrum noise is more important than the level ?
some noise at critical Hz could be particularly detrimental for sound ?
I talked with a guy designing simple RF devices. In some very challenging application he was able to eliminate noise only using batteries.
I am very curious to listen for myself.
Thanks a lot again. Kind regards, gino
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Hi and i understand now that i have made an horrible mistake
i bought a LIPO battery that if pierced catches fire.
I understand also that putting it after complete discharge in a bucket of salt water makes it inert.
Is it true ? what a stupid mistake indeed.
Are the Lithiun Ion type safe instead ?
Thanks a lot for any advice.
Regards, gino
i bought a LIPO battery that if pierced catches fire.
I understand also that putting it after complete discharge in a bucket of salt water makes it inert.
Is it true ? what a stupid mistake indeed.
Are the Lithiun Ion type safe instead ?
Thanks a lot for any advice.
Regards, gino
Hi and thanks for the kind advice.
Actually i am planning to dispose them on arrival.
Look here ... obviously i cannot run this rik for sure ...
https://www.youtube.com/watch?v=QjkW3KUz5uo
if this is the only option i would use a normal power supply for sure.
Regards, gino
Hi and i do not think so.
The battery in my cell is Lithium Ion .. and i do not think it cactches fire if pierced.
I know that they even sell a carrying bag for LIPO batteries ... a particular one.
They are potentially firecrackers ...
I wouldn't consider LiPos any more critical than regular LiIon cells (which are critical enough by themselves). They just need to be charged properly and monitored in order to avoid deep discharging - so best used in a "smart" device that's got a microcontroller at the very least.
For a "dumb" device I'd probably just stick with a bunch of LSD NiMH cells and battery holders. (That would be about 7 cells in series.) If you can get 9V blocks like that these days, maybe there's C or D cells, too? Or just parallel two AA Eneloops each? They usually stray so little that it should actually work. A low-voltage power-down circuit (for about 0.9 V per cell) is still advised though.
For a "dumb" device I'd probably just stick with a bunch of LSD NiMH cells and battery holders. (That would be about 7 cells in series.) If you can get 9V blocks like that these days, maybe there's C or D cells, too? Or just parallel two AA Eneloops each? They usually stray so little that it should actually work. A low-voltage power-down circuit (for about 0.9 V per cell) is still advised though.
if it where me I'd look into 2 or 3 x 18650 protected cells, most easy to find good cheap chargers and safer than hobby LiPo packs. there has been more work done to advance this chemistry than all others. also flexible and better Wh bang for buck too.
so many to choose from, use a test data base to compare http://lygte-info.dk/review/batteries2012/Common18650comparator.php
protected cells will cut off at under voltage and overcurrent
I can recommend this Chi vendor > only buy "authentic" labeled listings and you should be GTG https://www.fasttech.com/category/1420/batteries
so many to choose from, use a test data base to compare http://lygte-info.dk/review/batteries2012/Common18650comparator.php
protected cells will cut off at under voltage and overcurrent
I can recommend this Chi vendor > only buy "authentic" labeled listings and you should be GTG https://www.fasttech.com/category/1420/batteries
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Hi Guys thanks a lot for the very helpful advice.
I am actually waiting for some 18650 format Li Ion batteries with charger and holders.
I am still not sure if just two in series will be enough ... i have bought series holders up to 5 slots. However 3 would surely be enought.
I need around 9-10 VDC.
I am extremely curious to listen the sound ... very very curious
I do not know how long a charge will last ... i will see
I will leave a Voltage meter attached and see.
I wonder at what point they will need a recharge. They are 3.7VDC nominal.
3.7 x 2 = 7.4 no much headroom ... the regulator puts out 5VDC
I think i will end with 3 batteries in series ... 11.1 VDC
and start a recharge when the voltage reaches 9 VDC ?
What do you think ?
Regards, gino
I am actually waiting for some 18650 format Li Ion batteries with charger and holders.
I am still not sure if just two in series will be enough ... i have bought series holders up to 5 slots. However 3 would surely be enought.
I need around 9-10 VDC.
I am extremely curious to listen the sound ... very very curious
I do not know how long a charge will last ... i will see
I will leave a Voltage meter attached and see.
I wonder at what point they will need a recharge. They are 3.7VDC nominal.
3.7 x 2 = 7.4 no much headroom ... the regulator puts out 5VDC
I think i will end with 3 batteries in series ... 11.1 VDC
and start a recharge when the voltage reaches 9 VDC ?
What do you think ?
Regards, gino
run a test with 2x18650 fully charged should be headroom enough for a decent 5V Vreg ~3.2V. recharge when the regulator drops out of regulation. What regulator is used and the calculated load currents? otherwise you'll have one extra battery just for heating the thing.
some folks recharge at 3.4 others go down lower to 2.8, the lower DoD (depth of discharge) means less cycles of life. > 3.0V per cell is per OEM spec ~ 500 cycles.http://na.industrial.panasonic.com/sites/default/pidsa/files/ur18650zy.pdf
store at 3.7-3.8V / cell
some folks recharge at 3.4 others go down lower to 2.8, the lower DoD (depth of discharge) means less cycles of life. > 3.0V per cell is per OEM spec ~ 500 cycles.http://na.industrial.panasonic.com/sites/default/pidsa/files/ur18650zy.pdf
store at 3.7-3.8V / cell
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Hi and thanks a lot for the very helpful reply.
how can i know this ?
lt1963 .... i do not know the current draw of the circuit ... it has a usb receiver chip and clock generator circuit.
I do not have a clue ... and i do not know how to measure it.
yes ! and this is exactly what i would like to avoid
Do you know which would be an optimal voltage drop across a lt1963 ?
Because i could do also another thing
To put 4 batteries in series and an additional regulator stage ... i have bought some low noise ... but this of course complicates things even further.
thanks a lot again for the very valuable advice.
I have only experience with SLABs ... when fully charged they were around 13.5 VDC open circuit ...
The more i think about them the more i see the idea complex ... very complex.
Thanks again, gino
if you want to learn to mod and build stuff. I suggest some basic test gear!
a simple DMM measures ohm volts and amps, the cheapest can be had for the price of one 18650 battery! then either buy or build a bench top adjustable DC lab supply as a 1st project perhaps.
V regulation can be estimated from any VR data sheet and then can be verified in the lab by watching the output voltage stability with respect to changing input voltage. When you see the output dropping reflected by the lowered input level, then it has left or "dropped out" of regulation. The input voltage should then be increased to supply the needed "overhead" for that device for the performance to be fully operational..
so recharge batteries when Vin ~ 6.0V or 3.0V / cell
a simple DMM measures ohm volts and amps, the cheapest can be had for the price of one 18650 battery! then either buy or build a bench top adjustable DC lab supply as a 1st project perhaps.
V regulation can be estimated from any VR data sheet and then can be verified in the lab by watching the output voltage stability with respect to changing input voltage. When you see the output dropping reflected by the lowered input level, then it has left or "dropped out" of regulation. The input voltage should then be increased to supply the needed "overhead" for that device for the performance to be fully operational..
that's a very nice LDO part! most specs are with Vin =Vo+1V
so recharge batteries when Vin ~ 6.0V or 3.0V / cell
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SLA batteries have impedance @1kHz in the hundreds of milliOhms, best paralleled with poplypropylene film cap.
In the audio listening, (not RF) you'll find that noise is pretty far down the list in terms of importance, high PSRR is #1 and low impedance is #2.
The small size of the 9V is a plus.
In the audio listening, (not RF) you'll find that noise is pretty far down the list in terms of importance, high PSRR is #1 and low impedance is #2.
The small size of the 9V is a plus.
Hi and thanks a lot indeed for the both very kind and valuable advice.
I will think about seriously but this needs time and dedication.
For now i have really only this issue ... to provide 9-10 V and 1A very clean.
Stop.
From what i understand to provide the exact voltage another regulator is needed.
From the lt1963 i see that 1A gives a drop out voltage of 0.4V across the regulator.
Stock transformer has 7.5 VAC secondary ....
But i am open to completely different option ...
Another one i am evaluating is a quality SMPS for pc and a further regulation stage inside the unit. A DC-DC step down converter.
I bought many little device on ebay ... of unknown quality actually.
So i am very confused ...
Thanks again, gino