Solved Lowest voltage that n64 can take.

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Hi. I'm new, not sure if it is the right place to ask noob questions if not please correct me.

1. I can't find the information what is the lowest voltage that will power n64. I mean, if i connect it to li-poly batteries, at what voltage it will stop working?

2. And since it will be powered by lower voltage that 12V, won't current be higher, and therefore it will produce more heat?
 

GingerOfOz

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I believe you need 7.4v to power an N64. I'm not sure about a lowest voltage, it's probably whenever your batteries drain and your PCB stops the flow of power. And by using something like 2 3.7v batteries in series, current shouldn't be an issue, and it won't really affect your heat very much. It's ok to have too much current, it's when you don't have enough that there start to be problems.
 
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When li-poly batteries discharge, voltage goes down to 3V per cell, is 6V enough to power n64? At what voltage the console stops working?
 

Matthew

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The N64 can be run off 5V. The N64 already steps down anything from 12v (which includes 7.4v)to both 5v and 3.3v. So no the current does not increase and it won't run hotter.

It's ok to have too much current
This isn't exactly true. Loads on a circuit only pull as much current as they need. It's when the voltage is too low to provide enough current or the voltage is too high (or just a variably voltage source) that this isn't true. If you are providing the right stable voltage to the N64 and you have no shorts then you won't have any problems.
 
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Thanks for answers. Last question - how hard is it to get one (UltraVGA)?
 
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cheese

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The dropout voltage on the 5V regulator on the N64 is around 1.7V. So once you power source drops below 6.7V the regulator stops making 5V and you lose power to the DAC. A typical voltage curve on Li-Po and Li-Ion batteries looks like the picture below. So I'd say you loose somewhere around 5%-10% of your battery life. If you are worried about it you could use one the very popular TI 08080 regulators to make 5V. Those have almost no dropout voltage because they are a switching regulator.




N64 only needs 3.3V to run, technically. The on board video encoder requires 5V so your console will boot but you'll have no video. If you use UltraVGA you won't need 5V and can run everything off of 3.3.
As far as I know you still need the DAC on the N64 for the audio. I'm getting close to wiring mine up so I haven't looked into it too thoroughly but I didn't see audio outputs on the UltraVGA.
 

Noah

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As far as I know you still need the DAC on the N64 for the audio. I'm getting close to wiring mine up so I haven't looked into it too thoroughly but I didn't see audio outputs on the UltraVGA.
I'll have to double check the compendium but I think it runs off of 3.3. Could be wrong though.

Anyways I've got an old amp design laying around I never did anything with that has it's own onboard DAC so you pull audio straight from the RCP that I can open source if I ever get around to cleaning it up. It runs off of only 3.3V
 
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If you are worried about it you could use one the very popular TI 08080 regulators to make 5V. Those have almost no dropout voltage because they are a switching regulator.
To be sure - I desolder U13 (178M05 regulator) and connect switching regulator instead, this way my n64 runs of 3.3V and 5V?
 
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To be sure - I desolder U13 (178M05 regulator) and connect switching regulator instead, this way my n64 runs of 3.3V and 5V?
Yeah basically. You don't even have to desolder U13. Just connect 5V to the output leg on it. Its labeled something like VO(+5).

The datasheet for that particular regulator shows a 2V dropout voltage. So thats more like a 30% battery life loss.
 
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