I have been using the hifimediy TK2050 v2 board for some time with a Meanwell 24-27v SMPS 350W power supply and really enjoy the sound. I wanted to up the ante by bringing in battery power.
I know that both power supply setups have been discussed but I want both, in the same box. Switchable mains/battery/charging. Battery for critical listening SMPS for the general duties. The eventual goal is to have my entire system mains free.
I have 2 Yuasa NP7-12 12v 7Ah SLA for a 24v 7Ah power supply and a charger.
My questions are mostly related to wiring up this mess! I would like:
1 switch/knob to choose between battery/OFF/SMPS (switching the mains power not the SMPS output, to save of wasted electricity)
1 switch/knob to turn the mains on/of for the charger
This is going to be a power amp so I need to bypass the pot on the board as well.
Is the battery/Off/SMPS possible?
Also the front panel is american black walnut and I'm torn between a blue LED dc volt meter read out or an analogue gauge gauge to keep tabs on battery supply. What would you choose?
I know that both power supply setups have been discussed but I want both, in the same box. Switchable mains/battery/charging. Battery for critical listening SMPS for the general duties. The eventual goal is to have my entire system mains free.
I have 2 Yuasa NP7-12 12v 7Ah SLA for a 24v 7Ah power supply and a charger.
My questions are mostly related to wiring up this mess! I would like:
1 switch/knob to choose between battery/OFF/SMPS (switching the mains power not the SMPS output, to save of wasted electricity)
1 switch/knob to turn the mains on/of for the charger
This is going to be a power amp so I need to bypass the pot on the board as well.
Is the battery/Off/SMPS possible?
Also the front panel is american black walnut and I'm torn between a blue LED dc volt meter read out or an analogue gauge gauge to keep tabs on battery supply. What would you choose?
Hi JRKO
why don't you use the power supply also as battery charger?
27V is good for recharge 2 * 12V batteries wired in series.
why don't you use the power supply also as battery charger?
27V is good for recharge 2 * 12V batteries wired in series.
There's no charge protection, float charge mode etc. Just don't want to damage them. Besides, I already have the charger specifically designed for them.
I think the multi-way multi-position switches you need (or an half dozen of relays and some driving logic), will cost almost more than a new battery set... IMMO some diodes and a current limiter (for batteries charging) will do the job, without the 12V charger. Less complicated wiring, less weight, less things inside the box prone to failure or fire..... 
Just my 2 cents.
Just my 2 cents.
Is there no 3way switch that can handle the SMPS/OFF/BATT?
I've been looking at a mains rates DPDT ON/OFF/ON (not momentary) toggle switch.
Edit: OK after some more reading it cant be done on a single toggle switch.
I can though have SMPS/OFF/CHARGE can't I, as they have a common mains supply!
Please tell me I can do that
I've been looking at a mains rates DPDT ON/OFF/ON (not momentary) toggle switch.
Edit: OK after some more reading it cant be done on a single toggle switch.
I can though have SMPS/OFF/CHARGE can't I, as they have a common mains supply!
Please tell me I can do that
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You need a DPDT ON/OFF/ON switch like you say.
Example, 10A Toggle Switches : Toggle Switches : Maplin Electronics
in the version
DPDT-F ON-OFF-ON Double-pole locking, 3-pin, centre off
For the charging, I agree with acid_k2. 27V is just about perfect for charging 24V (nominal) worth of SLA. SLA are made with 2.15V cells in series, 2.15V*12 totals 25.8V. 27V pushes the charging reaction just enough, and is reasonably below the gassing voltage. No need for load balancing, may need a current limiter though.
Here is a good web page on charging SLAs: How to charge sealed lead acid batteries.
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I've read the link you provided and have learn't quite a bit about charging. Not enough to want to use the smps for charging and not enough to tell my wife I'm not using the expensive charger 😉
As for heat - none of the 3 separate systems will be on at the same time, as charging will be done overnight (I'm on economy7 - cheap electricity between 11pm and 6am. I run my dryer & washer etc at 2/3 normal cost)
I'm thinking more of 3 switches now - less for me to **** up
1 - SMPS on/off
2 - Battery on/off
3 - Charge on/off
the only thing to work out now is the 12v charging/24v powering thingy....
As for heat - none of the 3 separate systems will be on at the same time, as charging will be done overnight (I'm on economy7 - cheap electricity between 11pm and 6am. I run my dryer & washer etc at 2/3 normal cost)
I'm thinking more of 3 switches now - less for me to **** up
1 - SMPS on/off
2 - Battery on/off
3 - Charge on/off
the only thing to work out now is the 12v charging/24v powering thingy....
She holds the purse strings as, for genuine medical reasons, I can't be trusted with money - think $10k+ bipolar lunacy spending...
ok so how to wire for 24v power from batteries and 12v charging too them?
This is gonna end up being a bit like the RedWine Audio amps - one of theirs does the 12v/24v thing
This is gonna end up being a bit like the RedWine Audio amps - one of theirs does the 12v/24v thing
I'd gear up a multi-pole rotary switch with a four positions:
- everything off
- amp off battery - batteries in series, amplifier connected to battery
- amp off AC supply - batteries disconnected, amplifier connected to power supply
- charge mode - batteries in parallel and connected to battery charger
In the last position, I'd put a low value resistor (1-2 ohms?) in series with each of the batteries. It'll limit a possible current surge between the two batteries if their voltages are different, and it will balance the battery voltages.
I haven't thought about how many poles you need in a rotary switch to pull this off.
- everything off
- amp off battery - batteries in series, amplifier connected to battery
- amp off AC supply - batteries disconnected, amplifier connected to power supply
- charge mode - batteries in parallel and connected to battery charger
In the last position, I'd put a low value resistor (1-2 ohms?) in series with each of the batteries. It'll limit a possible current surge between the two batteries if their voltages are different, and it will balance the battery voltages.
I haven't thought about how many poles you need in a rotary switch to pull this off.
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