New amp with dual power

[JRKO]

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?

[JRKO]

Almost forgot. The batteries will need to be wired as 24v for power but 12v for charging

HELP

[acid_k2]

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.

[JRKO]

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.

[acid_k2]

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.

[JRKO]

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

[elevator]

Originally Posted by JRKO

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.

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.

[JRKO]

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....

[elevator]

Originally Posted by JRKO

Not enough to want to use the smps for charging and not enough to tell my wife I'm not using the expensive charger

Hey, whatever works for you and your wife

[JRKO]

Originally Posted by elevator

Hey, whatever works for you and your wife

She holds the purse strings as, for genuine medical reasons, I can't be trusted with money - think $10k+ bipolar lunacy spending...