• aditya mehrotra.

chip updates: easy charging and tether power for chip [updates]

So, I don't want to buy anything let's start by saying that. But choosing and placing here for reference has no issues. And we need to choose two things. First, we need to choose a power supply for the tether power for chip, and second, we need to choose a charger. We need to do both of these things because the ISDT supply we currently have is too high in voltage and the charger we have is too complicated. So let's see if we can fix that. First, with the power supply.


The power supply we need is something that can provide 480W because that's what the main inverter for chip can provide.

The thing is, a 24V 20A power supply is absolutely ridiculous and there's no way chip even draws that and if it did, it would blow the main supply anyways so we're going to look for a 10A because that's reasonable.


(1) https://www.amazon.com/MEAN-WELL-NDR-240-24-Industrial-Supply/dp/B016APVF66/ref=sr_1_5?dchild=1&keywords=24v+10A&qid=1590525489&sr=8-5 this is an interesting option because it's the same power supply that comes with the Dobot M1 robot arm.


(2) https://www.amazon.com/LEDwholesalers-Power-Adapter-5-5x2-5mm-3264-24V/dp/B074GJ22P6/ref=sr_1_4?dchild=1&keywords=24v+10A&qid=1590525489&sr=8-4 is another if we want to go laptop-y


But I thought of something else, if we want to do the charger and the power supply all in one, which would be good product design, we should look at ISDT.


ISDT has the greatest products I'm really convinced. Here's one for the power supply!



This is the ISDT SP2417 which is a 24V 400W power supply DC which is exactly what we need. It also has two usb outputs that can charge things like the XBox controller. The good news is this is dual-purpose. It can also power a battery charger.


Which brings me to my second point, if we were really to make chip a product we wouldn't be looking for a battery charger we'd be looking for a BMS that could charge the batteries and power the robot on tether at the same time.

But what we really want to do is make charging easy right? Look at this link: https://www.getfpv.com/learn/fpv-diy-repairs-and-mods/diy-parallel-charger-and-balance-board/


This is a parallel charging board it can take two 6S lipos and charge them together from a single charger. Thats what most of these chargers do anyways. https://www.rchelicopterfun.com/parallel-lipo-charging.html according to this link as long as the 6S LiPos are <0.6v difference between them this can be done simply by, literally, hooking everything in parallel. So what we really need is a parallel battery harness (which we have) and a JST parallel harness (which we can get). https://sites.google.com/site/tjinguytech/charging-how-tos/balance-connectors/ according to this link it's a JST-XH plug. Time to go to digikey or amazon. https://www.amazon.com/BNTECHGO-JST-XH-Female-Connector-Cables/dp/B0778F13T4/ref=sr_1_8?dchild=1&keywords=jst-xh+6+pin&qid=1590527156&s=electronics&sr=1-8 and there they are!



If we order a pack of these, we can splice together two and parallel charge two batteries together. You know how I know this will work? Because once, I accidentally switched the JST plugs going into the charger and it was fine hehe. DONT DO THAT. I do want to check the cell voltages though.


And if we take a battery meter to them the difference between any two cells is 0.02 at best. We just need to make sure we link the right cells together and a well-made harness would let us do just that. So we're actually going to order two of these and try it out and then later get to the discussion of the power supply or charger. Because now we have one large 6S battery instead of two small ones and what that means is we can go find a 20A BMS that will work to charge the battery when we give it some number of volts from a power supply that will also allow us to run the robot at the same time. Something like this:



This system would allow us to charge and dis-charge a Lipo battery from the same port at the same time. This is a very simple and very cheap BMS. We're not actually going to do any of this because if chip was a product we'd design our own BMS and ship it with that. For now we're probably going to stick to the current setup because if we were to use chip as-is. We would get the SP2417 power supply above and then get this charger.



Yes so, I don't really know the current system we're using is completely fine for now, we might get a new power supply that's 24V so we don't need to use the batteries and variably adjustable one but honestly the variable one is fine.


#updates #omgrobots #yay #yeet #chip #ideas #electronics_research

0 views0 comments
© copyright 2019 | aditya mehrotra