Batteries Revisited

jkeny · 2nd May 2009, 12:21 PM

My growing awareness of the importance of PS in any piece of analog or digital audio equipment has led me to reconsider batteries again as a PS.

Good PS are not cheap and usually not simple. If we are looking for a regulated supply then these can be as complicated as the equipment they are supplying power to. Also if a PS is found to be good in one piece of equipment it is not guaranteed that it will be good sounding in another.

SLA Batteries were dismissed some time ago as being noisy when current was being drawn. I believe these tests (TNT audio) were done with a single battery? Very low internal impedance of the battery was considered the important factor & only achievable through expensive SLA batteries or paralleling ordinary SLA batteries.

I know this seems just as expensive but there are a lot of batteries thrown out in recycling centers whose only problem is sulphation & these more than likely can be reformed.

Has anybody tested this parallel use of batteries against good quality mains powered PS?
What are the thoughts on this?

scott wurcer · 2nd May 2009, 12:37 PM

Just curious has anyone compared deep cycle LA to normal automotive LA? The deep cycle batteries have a much larger amount of lead so survive repeated deep discharge. The action is probably a lot of surface chemistry so it might not matter. Also a new way to spend $$ phone closet and locomotive versions are available at 10000's of A/H and several tons. I have not verified the noise myself.

Ziggy · 2nd May 2009, 12:52 PM

Maybe car batteries........believe it or not?

http://www.mother-of-tone.com/byob.htm

paulb · 2nd May 2009, 12:58 PM

Quote:

Originally posted by Ziggy
http://www.mother-of-tone.com/byob.htm

950 Euros for a 10W amplifier without a case...do you think anybody has actually bought one of these?

Back on topic,
Do you have a link for the TNT Audio battery tests?

okapi · 2nd May 2009, 01:12 PM

my impression was that TNT tests were done without a capacitor on the output (correct me if i am wrong). I think an output capacitor would make a battery as close as we can get to an ideal power source.

EWorkshop1708 · 2nd May 2009, 02:57 PM

I've used batteries before in parallel with power supply, and it works great! I highly recommend good output filtering in addition to the battery for best results.

I did one power supply with a paralleled 14.4V NiCD battery, and 10,000uf filter capacitor for running a car radio. The peak unloaded voltage of the 2A transformer (~19V) is not enough to overcharge the battery, so it stays cool. When the load got heavy, (more than the rating of the transfomer) most of the time, it would only drop to ~15V where the battery took over, and held the voltage pretty steady, then as soon as the load lightened, the transformer takes back over for the majority of the power.

Another PS I made is for driving 3.7V LED headlights for bicycle. Takes 12V down to 4.2V max, and has a 3.7V Li-Ion directly in parallel, so either the charger and/or battery feeds the load, and the great thing about Li-Ion, is they hold a VERY constant voltage, and don't vary as much as other battery chemistries.

The Lead-Acid battery in your project should be great, but IMO I recommend large filtering capacitors to filter any noise generated either by the power supply or battery.

EWorkshop1708 · 2nd May 2009, 03:05 PM

Quote:

Originally posted by paulb

950 Euros for a 10W amplifier without a case...do you think anybody has actually bought one of these?

Back on topic,
Do you have a link for the TNT Audio battery tests?

$950 for a PCB on a piece of Wood? WTF? That's crazy!

I bet one could be built for less than $20.

MJL21193 · 2nd May 2009, 04:06 PM

I use cordless tools till they get broken, worn out or stolen and go through battery packs like crazy. The latest is lithium-ion and I have 3 packs that are dead. I opened one up and found that only 2 of the cells were toast - the rest were fine.
I've been looking for a holder for these size cells but there doesn't seem to be any (I guess since these cells are used in packs where the terminals are joined with strips that are spot welded on). I could DIY a holder I guess.

Nice to use some of these in a preamp, phono amp or even a low power amp. Should be ultra quiet, no?

jackinnj · 2nd May 2009, 04:23 PM

Can't you just use "AA" battery holder from Keystone Products?

MJL21193 · 2nd May 2009, 04:28 PM

Hi Jack,
These are 65mm long and 18mm diameter so quite a bit bigger than AA which are 50mm x 13mm.

2nd May 2009, 12:21 PM	#1
jkeny Banned Join Date: Feb 2007 Location: Dublin	Batteries Revisited My growing awareness of the importance of PS in any piece of analog or digital audio equipment has led me to reconsider batteries again as a PS. Good PS are not cheap and usually not simple. If we are looking for a regulated supply then these can be as complicated as the equipment they are supplying power to. Also if a PS is found to be good in one piece of equipment it is not guaranteed that it will be good sounding in another. SLA Batteries were dismissed some time ago as being noisy when current was being drawn. I believe these tests (TNT audio) were done with a single battery? Very low internal impedance of the battery was considered the important factor & only achievable through expensive SLA batteries or paralleling ordinary SLA batteries. I know this seems just as expensive but there are a lot of batteries thrown out in recycling centers whose only problem is sulphation & these more than likely can be reformed. Has anybody tested this parallel use of batteries against good quality mains powered PS? What are the thoughts on this?

2nd May 2009, 12:37 PM	#2
scott wurcer diyAudio Member Join Date: Jan 2004 Location: cambridge ma	Just curious has anyone compared deep cycle LA to normal automotive LA? The deep cycle batteries have a much larger amount of lead so survive repeated deep discharge. The action is probably a lot of surface chemistry so it might not matter. Also a new way to spend $$ phone closet and locomotive versions are available at 10000's of A/H and several tons. I have not verified the noise myself. __________________ 2012, our time is running out.

2nd May 2009, 02:57 PM	#6
EWorkshop1708 diyAudio Member Join Date: Nov 2004 Location: Florida	I've used batteries before in parallel with power supply, and it works great! I highly recommend good output filtering in addition to the battery for best results. I did one power supply with a paralleled 14.4V NiCD battery, and 10,000uf filter capacitor for running a car radio. The peak unloaded voltage of the 2A transformer (~19V) is not enough to overcharge the battery, so it stays cool. When the load got heavy, (more than the rating of the transfomer) most of the time, it would only drop to ~15V where the battery took over, and held the voltage pretty steady, then as soon as the load lightened, the transformer takes back over for the majority of the power. Another PS I made is for driving 3.7V LED headlights for bicycle. Takes 12V down to 4.2V max, and has a 3.7V Li-Ion directly in parallel, so either the charger and/or battery feeds the load, and the great thing about Li-Ion, is they hold a VERY constant voltage, and don't vary as much as other battery chemistries. The Lead-Acid battery in your project should be great, but IMO I recommend large filtering capacitors to filter any noise generated either by the power supply or battery. __________________ You can call me Mad Professor, building crazy experiments in my Electronics Workshop

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2nd May 2009, 12:52 PM	#3
Ziggy Account Disabled Join Date: Jul 2004 Location: West Australia	Maybe car batteries........believe it or not? http://www.mother-of-tone.com/byob.htm

2nd May 2009, 01:12 PM	#5
okapi diyAudio Member Join Date: Aug 2004 Location: Buffalo	my impression was that TNT tests were done without a capacitor on the output (correct me if i am wrong). I think an output capacitor would make a battery as close as we can get to an ideal power source.

2nd May 2009, 04:23 PM	#9
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	Can't you just use "AA" battery holder from Keystone Products?

2nd May 2009, 04:28 PM	#10
MJL21193 Account disabled at member's request Join Date: Mar 2007	Hi Jack, These are 65mm long and 18mm diameter so quite a bit bigger than AA which are 50mm x 13mm.

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