Battery management system - how complicate is it ?

[Rush]

Have you experienced the sonic difference between SLA and Lithium cells? Or is this more theory?
The idea is to charge the battery while you sleep/during the day, use battery power only for the few hours of critical listening each night. Background music could be run off any supply or while the battery is charging.

[star882]

Originally Posted by qusp

optical isolation?? and add jitter at the same time.

Fiber has proven itself in lots of very demanding applications. It is very easy for it to perform better than copper.

[J.R.Freeman]

Originally Posted by star882

The lead acid battery in a car is essentially charged and discharged at the same time, acting as a filter capacitor and peak power reserve.

Bear with me, I've had some drinks tonight! :P I see what you are saying, but it is never really charging and discharging at the same time, but rather, it is going through cycles of charging and discharging rapidly. What you are speaking of is a virtual charge/discharge, when really if you zoom in close enough in the time domain it is charging and discharging, correct?

Jim

[qusp]

Originally Posted by star882

Fiber has proven itself in lots of very demanding applications. It is very easy for it to perform better than copper.

indeed it has, i'm not arguing that, but very few of them are audio related. there are far too many conversions with optical for my liking. perhaps if its then buffered again and reclocked, but that kinda defeats the point does it not? the only excuse I can think of to use it is if you have issues with your grounding or need to cross between a very high voltage Vground and a different voltage ground.

well I have heard several dacs using SLA, such as the RWA isabellina, which I did enjoy. but there just seems too many issues with it, they are massive, charge slowly, have pretty meager current capabilities and not the best output Z. even RWA is now looking at or possibly even already moved to LiFePo4. just look at the datasheet and tell me its not a good idea. much more compact, just as low maintenance (unlike lipo they take a bit of mistreatment before they explode in slow motion), MUCH higher current capability, output Z better than all but the best low Z PSU caps. fast charging (like literally a few minutes fast charging if needed), very low noise.

I have been looking for ways to use them anywhere its convenient to use batteries, I have found they are that good. I have fair experience of low noise regs in my system of all types and a fair bit of experience of other batteries for audio (i'm right into high end portable headphone audio, so lion, NIMH and Lipo) but I cant lay claim to heaps of time with SLA, I have always thought of them as a PITA for practical reasons, but as I said, I did enjoy the RWA dac/headamp

and no, a battery is either charging, or it isnt, when it reaches the point where the flow of energy is higher than the battery can absorb (whether because the current is higher than it can take on, or because its full, this overflow will just go somewhere that it can. this is at (or closer than) an atomic level, dont know you can go any closer than that

of course the idea for SLA is to charge overnight and use for listening off grid, but it seems many people do not do this and yet claim improvements even when they are just listening to the switching power supply of the charger (not pointing specific fingers here, just an observation)

[star882]

Just ask Tiffany Yep why fiber can go a longer distance than copper... Really, as long as the data is sent fast enough without errors, it does not matter what you use to send it. Fiber has the added advantage of providing unmatched isolation against noise. Its main disadvantage is cost, but it's still cheap enough for use at home.

And if you're really looking for low noise, put your circuit in liquid nitrogen.

[qusp]

of course it is, and the distance when talking about home audio is relevant how? that wasnt even in my radar. its not the transmission speed thats the problem, its the current use of optical spdif is the highest jitter spdif there is. now of course if we are talking optical (and perhaps asynch) USB, or some sort of fiber channel network based system; thats another story and would be excellent.

nitrogen...now why didnt I think of that I mainly use them for a mix of convenience and performance. lifepo4 also happen to be a very useful output voltage, most of their useable life they sit at nominal 3v3. full charge starts at 3.6-3.65 drops quickly to 3.4 and then drops to 3.2 slowly over the rest of the time they are useable, then it drops off a cliff, so I use battery management to control a relay to cut at 3.2, probably the most used voltage range in digital audio.

but I still use linear and shunt regs for many things where even the massive energy density of these is not high enough, or just isnt convenient. if I need to regulate down to another voltage, I just use a regulated DC supply to begin with unless portable. heatsinking isnt an issue either, which is another bonus

but when someone is already asking about using SLA battery power, IMO there simply is no comparison WRT to performance and usefulness.

[star882]

Perform a loopback test to make sure the connection is error free. Done properly, it will catch even the slightest error. Another trick is to try loosening the connection and note how far it can be pulled out before the link drops completely, an easy way to check signal strength margin.

[qusp]

huh?? is that directed at me? I didnt say anyyhing about transmission errors, the jitter issue with spdif optical has nothing to do with the transmission strength, but in the conversion to and from optical from electrical. as a transmission scheme its excellent. not gonna get me to change to optical though. I still install it in most dacs I build, but unless I do something with optical USB I cant see me actually using it for anything. oh actually no I do use it on my portable dac with some sources, but given a choice I wouldnt.