Yes I want to remove the SPDIF transformer because as I said, I use a LL1572 before the buffalo dac.
Is it a good idea?
Yes, putting them in parallel via a switch will firstly balance them each to the same voltage & will enable you to charge them with a 3.3V charger. However, this may be a problem for the charger using 4 or 6 batteries in parallel as you now have (4*2.3A) 9.2AmpHours or (6*2.3A)13.8Ampshours to charge & it may take too long from low charge. You could organise it that when you switch off the units the charger automatically starts to charge them & then you are just topping up the batteries rather than charging them from low charge.
Prooptiki, doesn't seem like a good idea to me - I don't believe LL1517 is suitable as a SPDIF transformer but I may be wrong
I think you're right. Switch off/charge.
So let's use the filament as an example. I have two double battery packs. One side to + and the other negative. I have a connector to top and bottom which parallels them making its connection via a switch. Correct?
And if I have three packs?
I don't know why I can't visualize it. And sorry for getting off track on the M2Tech thread.
So let's use the filament as an example. I have two double battery packs. One side to + and the other negative. I have a connector to top and bottom which parallels them making its connection via a switch. Correct?
And if I have three packs?
I don't know why I can't visualize it. And sorry for getting off track on the M2Tech thread.
With these types of batteries its not good to keep charging them past a certain point (even trickle), also there is a minimum charge rate for when they are drained. Best bet is to use a charger designed for them. Have two banks that switch between charge & in use, based on a timed relay. Power off should turn off the charger.
Regal. I talked to a battery company and expressed what batteries I would need a charger for. They claim a $100 charger is the best - ouch. They did say they had to be wired so that the charger could see each battery and monitor it.
I was hoping to avoid going through a rely. I did have a bank of relays last time but even the relays need something to energize them. IE more things that have hum or dirty power potential. I was hoping to design something more elegant this time around.
I was hoping to avoid going through a rely. I did have a bank of relays last time but even the relays need something to energize them. IE more things that have hum or dirty power potential. I was hoping to design something more elegant this time around.
Who said anything about charging them past their 3.7V maximum? A LiFePO4 charger turns off automatically when fully charged. The switch should disconnect the charger from the batteries when it is turned on i.e the batteries are connected to the circuit.
Pharord, Forget about the salesman - he's correct but not creative. You don't need a balanced charger if you think about your needs.
Why not get this single cell charger for $12 & if you need another one or two get them - still less than $100 "3.2V 2A Smart Charger for Single Cell LiFePO4 Battery (ebay item no 330320891189)" The only potential is it's 2A output - it will take a while to charge up from fully discharged but yours won't be 🙂
New forum opened about a DAC with this usb interface
http://www.diyaudio.com/forums/digi...it-dac-no-oversampling-no-digital-filter.html
http://www.diyaudio.com/forums/digi...it-dac-no-oversampling-no-digital-filter.html
Actually very few of them do. Most people with Litium batteries turn off the charger as soon as turns green, problem is most cheap chargers continue to trickle charge after they are done and this decreases the life and strength of the battery.
You also have to watch min/max charge rates based on the mAH of the battery.
Regal, you seem to have gained some experience with these batteries now - are you using them, what can you tell us about them?
The charger I recommended stops charging when fully charged!
There is a 3 stage charge process in these chargers depending on the level of charge found in the battery - it's a 2A charger & won't be a problem exceeding max charger rate - quite the opposite , in fact.
The charger I recommended stops charging when fully charged!
There is a 3 stage charge process in these chargers depending on the level of charge found in the battery - it's a 2A charger & won't be a problem exceeding max charger rate - quite the opposite , in fact.
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I've been using them in high tech flashlights for almost 2 years! In fact I pointed you to the OEM supplier, the only manufacturer of these in the world. I'll bet a beer that your $12 charger when you think is stopped charging is trickling in mA's to the batteries (not good), use your DMM in current mode to find out.
Yes, but do you remember I told you that these were NOT the batteries I'm using 🙂 Your OEM is not the only manufacturer in the world for this technology - I don't know where you get this idea from?
You may be correct about the trickle current - I'll check it out & put a diode on my charge circuit to stop any over-voltage.
You may be correct about the trickle current - I'll check it out & put a diode on my charge circuit to stop any over-voltage.
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It can overvoltage but the bigger issue is the heat and the constant input of current screws up the chemical matrix. Good idea with the diode I'll have to share that with my flashoholic buddies if you don't mind.
But you are talking mAs of current into a 2300mAH battery or 4600mAH when in parallel - how much do you think this is going to effect it over a 12 hour or 24 hour period?
No problem with the diode - it's yours 🙂
I can tell you that with the older lithium ion technology it really shortened their lifespan, so we all just pull them as soon as the charger turns green. With the new safer lithium ion iron phosphate chemistry I can't say definately, but we are all still pulling them as soon as charged. They can be sensitive to rate of charge as well, not too fast and not too slow as this affects the crystal morphology the way I understand it.
With Nicad batteries, chargers were real simple no brainers, but lithiums can be troublesome with the wrong charger.
Yes, the older Lithium technology was problematic - overheating, fires, etc.
This chemistry is much less reactive & much more tolerant to over/under charging.
I can understand a rate of charge problem if greater than the recommended current but I've never heard about any problem with low current - in fact the first of of the 3 stages I mentioned above is a low current pre-charge stage for batteries below 2.5V.
This chemistry is much less reactive & much more tolerant to over/under charging.
I can understand a rate of charge problem if greater than the recommended current but I've never heard about any problem with low current - in fact the first of of the 3 stages I mentioned above is a low current pre-charge stage for batteries below 2.5V.
Hi John, just an update .... I'm hoping to have a charger working based on the LT3652 that you recommended in the next week or so. From it's datasheet.
"The LT3652 can be confi gured to terminate charging
when charge current falls below 1/10 of the programmed
maximum (C/10). Once charging is terminated, the LT3652
enters a low-current (85μA) standby mode. An auto-recharge
feature starts a new charging cycle if the battery
voltage falls 2.5% below the programmed float voltage."
I'll test to see if it introduces any extra noise when inactive but still connected - if so I'll set up a relay switching scheme. Will post a full schema when done. BTW, can I purchase another battery?
Dan
"The LT3652 can be confi gured to terminate charging
when charge current falls below 1/10 of the programmed
maximum (C/10). Once charging is terminated, the LT3652
enters a low-current (85μA) standby mode. An auto-recharge
feature starts a new charging cycle if the battery
voltage falls 2.5% below the programmed float voltage."
I'll test to see if it introduces any extra noise when inactive but still connected - if so I'll set up a relay switching scheme. Will post a full schema when done. BTW, can I purchase another battery?
Dan
Yes, Dan, I forgot about that - I reckon this might be low enough trickle current in standby mode not to be of concern 🙂 Let me know how well the charger works. Where did you get the chips? Are you using MSOP or DFN package - DIY soldering an issue?
No problem on a battery, but I'm waiting delivery - contact me in 2 weeks or so.
No problem on a battery, but I'm waiting delivery - contact me in 2 weeks or so.
Got the chips from LT. They are 12 pin MSOP parts. As for soldering, I'm getting Tirna electronics to do it for me. I had a go but my diabetic eyes aren't what they used to be.
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