- Jul 30, 2016
- RDP 64
Pictures with the board would significantly help us. It sounds like you are having a short or some sort of problems on your 3.3v line. Check your regulator for issues.Hey all,
I keep having an issue with my portable. I turn it on and sometimes it doesnt come on. Other times, it does come on. And sometimes it will turn on and then freeze a few seconds in.
Ive already tried looking for shorts and I just got done rewiring the cartridge slot to no avail. I keep having this issue and im unsure of what it could be coming from.
Has anyone else had this issue?
Further, If I get a voltage reading from the video out pin (after a board reduction), does this mean that my board is working? even if I dont get video on the screen
this board is so temperamental.. it drives me insane
That’s a very informative post, I was wondering the same thing regarding a one port solution.It's controversial.
The "2 port play and charge concept" was drawn up along time ago in this community when lithium batteries were a new scary technology and nickle batteries where the norm. The original idea with the "2 port play and charge" is to get full cycles out of the NiMH batteries to prevent battery memory. Li-Ion/LiPo batteries aren't susceptible to memory but early on they were known to catch fire. This is because cheap Chinese products are very bad. Early extra capacity Chinese PSP batteries had a reputation for burning people's legs as they carried them in their pockets. And even more recently the hoverboard fad disappeared overnight because the Chinese knockoff batteries and chargers where burning peoples houses down. So the "2 port play and charge" was kept around out of superstition for safety when we all switched to Li-Ion/LiPo batteries. Any way, people in this community have continued parroting this old diagram. It appears on every incarnation of these forums. It's very outdated.
In all modern electronics whether it be your phone, tablet, laptop, etc. are simply directly connected to a battery (with bms) that is connected to a smart charger. There is no disconnecting and isolating the battery to charge. Probe around your laptop or phone with your multimeter next time you have it apart (or am I the only one who is constantly screwing around inside my electronics). This system is exactly what you are looking for, a "1 port play and charge" setup.
This is where things get controversial. This setup is perfectly safe as long as your charging power supply is up to the task. If you cannot supply enough current to simultaneously charge the batteries and power the connected device you can cause a fire. It won't happen instantaneously so don't worry. The problem is if the connected device is drawing more power than you are putting into the battery, the battery will slowly drain and get hot. If you get the battery hot enough it CAN start a fire.
Ever notice how when your phone is below 30% battery and you are actively using it while charging but its not gaining percentage and getting hot? This is because the smart charger provides more amps to the battery at the start and then it tapers off when you get to 70-80% charge. Whereas when your phone is at 70% and you are actively using it while charging but its still able to gain percentage. This is because the circuitry in your phone is able to provide excess current to the phone when the battery is a higher percentage. And when you are at a lower percent more of the current has to go to the battery thus not allowing the phone to get enough power. If the phone isn't getting enough power from the charger it will draw from the battery causing slow to no charging. When you are in this state you can cause your phone to light up.
When considering power for a portable you have to overbuild the charging. The phone/tablet/laptop has the advantage of low power states on the CPU causing it to draw less based on usage. The charging circuitry on the phone/tablet/laptop wasn't intended to provide enough power to charge the battery from empty while powering the phone/tablet/laptop running at full tilt. This is why the phone/tablet/laptop can charge very fast if you leave it alone while charging. Whereas if you are using the phone/tablet/laptop while charging it charges significantly slower. Your portable N64 doesn't have low power states so you have to build the charging portion to be capable of charging the batteries and running the system from a dead battery. If you do this it can be very safe to build the "1 port play and charge" method.
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On my current portable I'm using this board. I haven't fully tested this one but I've used similar boards in the past. The trick to getting enough power to make it play and charge is to use a 12 volt 5 amp power supply. Anything lower and it doesn't provide enough power to make the batteries charge while playing.
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Thank you for this informative reply.... this setup is perfectly safe as long as your charging power supply is up to the task. If you cannot supply enough current to simultaneously charge the batteries and power the connected device you can cause a fire....
...On my current portable I'm using this board. I haven't fully tested this one but I've used similar boards in the past. The trick to getting enough power to make it play and charge is to use a 12 volt 5 amp power supply. Anything lower and it doesn't provide enough power to make the batteries charge while playing....
Ok so I read your previous posts and see that you have tested these batteries (PANASONIC NCR18650B) and their actual capacity is around 2900mah, I may just go with these since they are tested..
The 5 amp requirement on the charger is more of a safety. The red board can only provide so many amps to charge this is the bottleneck. If it was designed for a 2s configuration and you are running at a 2s2p configuration you aren't going to charge the batteries quick enough for a play and charge. I haven't thoroughly tested this particular board for this application yet (so I don't know the max charging amperage). I'm planning on running one board in a 2s2p configuration but if it's not enough charging current then I will go to two boards running 2s each.
You're chosen battery claims to be rated at 5000mah. If you see my previous posts in this thread you will see that there's discrepancies between rated and tested capacity on all batteries. When you charge a battery you generally charge at 0.5C - 1C (some cases as high as 2C). Or in the case of this cell you can charge at 2.5amps to 5 amps. You need two of them to make 7.4v so the smart charger has to be responsible for 5 to 10 amps at 7.4 volts or 37 to 74 watts. A 12v 5amp charger can provide 60 amps. I'm fairly certain the red smart charger board wasn't designed for 5000mah battery packs so it probably can't charge a pack like that at 1C. I bet the red board was designed for two 2500mah cells and it safely charges them at 0.5C. So the red board probably pulls something like 9.25 - 18.5 watts. I plan to test this further.
Regarding your battery pcm, I found one called tp5100 http://m.ebay.com/itm?itemId=181687643612My guess for whether or not the red board can charge a 5000mah cell at 1C is based on the fact that the average REAL cell is 2500mah. The name brand manufacturers are struggling to barely get a 3000mah cell. There is a possibility that the 5000mah LiPo cell that you've referenced is two 2500mah cells glued together. This is fine but some would argue that without a BMS this is unsafe but since they where made together their capacities should be matched and safe enough. Any way, the red board is advertised in the pictures in a 2s2p configuration so it is possible that it can handle 5000mah per cell at 1C. (Looking at it again it's also advertised as "Unlimited Parallel", lol). I'll eventually get around to testing this red board as I've got it in the middle of my current project (in a 2s2p configuration). In the meantime I will look for some specs or a datasheet on some of the parts.
If you can find a better Smart Charging BMS board I'd love to see it. This is the best one that I've found. In the past I have used a BMS to charge the cells. If you apply power to the charging side of a BMS it will charge the batteries at constant voltage and constant amperage. The BMS will charge the cells until they reach 4.2 volts then disconnect the cells (as this is the overvoltage protection feature). The problem with this set up is you can only charge up to around 70% capacity because a Smart Charger will taper off the amps thus reducing battery temperate. (See my charging graph in previous posts in this thread.) I used this as a quick and dirty solution to my Nintendo Sixty 4or the WiN XL portable because this was a portable designed to soak up parts. I used Ultrafire 3000mah rated cells (900mah tested) in a 2s2p configuration and it gets 40 minutes battery life. In my original Nintendo Sixty 4or the WiN portable I used a stand alone BMS and separate Smart Charging PCB. I cannot find this smart charging any more but I do have pictures. In this portable I used Tenergy 2200mah rated cells (1700mah tested) in a 2s configuration and it gets around 105 minutes battery life.
Here's a link of somebody testing N64 power draw:
In that thread it looks like the N64 + 3.5" screen and audio amp at full volume are drawing around 7-9 watts. Also the N64 stock PSU is rated at 18.51 watts (at 120V input) if you do the math or 26 watts if you believe whats printed on it. The N64 psu is overbuilt to prevent voltage drop when the N64 peaks.
Napkin math puts my mention portables at 14 watts for the N64TW XL and 7 watts for the N64TW. That screen on the bigger one is extremely power hungry. I had a lot of trouble with the inverter on it causing electromagnetic interference on everything.
So assuming all of these things lets just for argument sake say your portable requires 12 watts to operate. A 7.4v 5000mah battery pack requires 37 watts to charge at 1C. If the red board CAN supply supply 37 watts then the portable is leaching 12 watts leaving 25 watts for the battery to charge at. So your batteries will then be charging at 0.676C (1 hour 29 minutes play and charge time, from dead to fully charged**). In this scenario the 12 volt 5 amp power supply rated at 60 watts but probably closer to 45 watts (assuming a 75% efficiency rating) should be adequate.
If we assume the red board can only charge a 7.4v 2500mah battery at 1C (18.5 watts). Then the portable is leeching 12 watts leaving 6.5 watts to charge the batteries. This would put the 2500mah pack at 0.35C (2 hours 51 minute play and charge time, from dead to fully charged**) and the 5000mah pack at 0.18C (5 hours 33 minute play and charge time, from dead to fully charged**).
This simplest way to figure the red board's charging rate would be to charge some cells with known capacities from dead to full and measure the time it takes to charge. I do have some ammeters that I can rig up as well. I have all the parts at my disposal to test so I will get to this eventually. The hardest part of this test to waiting around for the red charging led to turn green. I will try to get to this this weekend.
**Assuming none of the charging power if converted to heat, which of course is impossible.
**Also assuming my math is even half correct.
**Probably multiply these times by 1.33333333 to assume a 75% charging efficiency with 25% converted to heat. So more like 2 hours, 3 hours 45 minutes, and 7 hours 20 minutes respectively on the play and charge times from dead to fully charged.
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