11LikesEducumate Me on Batteries
10-04-2018, 03:02 PM
#16
Yes, sorry, that would be 2S.
That would be the SCT, which is a stock SC10 with the sensorless 3300kv system. Would I be correct in assuming sensorless uses less amps? The blinky buggy uses a bit more, but not much. I'm not an aggressive driver (yet).
If my math and understanding are correct, that would be about 125 amps max, which is plenty above what most of these cars draw. Or am I misunderstanding something?
I was mostly looking to save time running or discharging the batteries down, and maybe save some $$$, but maybe I shouldn't be so stingy. I really should weigh my car just for a tuning base, but the track doesn't check so I haven't bothered.
I was mostly looking to save time running or discharging the batteries down, and maybe save some $$$, but maybe I shouldn't be so stingy. I really should weigh my car just for a tuning base, but the track doesn't check so I haven't bothered.
10-04-2018, 03:36 PM
#17
You are correct that a lower capacity battery will charge and discharge in less time. You could probably live with less capacity because you are barely making a dent in your 5000's but you may or may not like the lower weight.
10-04-2018, 04:28 PM
#18
I think that makes sense. I just thought there would be a point somewhere that the overall IR is low enough that reducing it even more would not make a difference. These are fairly new batteries still, so I'll see if they start getting warm as they age.
Yeah, I was disappointed to find out that Protek made a mistake in the user manual for their Prodigy 66 Duo. It lists IR as one of its functions, but actually does not do that. I found a Tenergy 5-in-1 battery checker that does IR for $15. Most of the other functions seem useless on it, but for $15, I think that's better (at least for now) than dumping my almost new charger to drop a couple bills on a new one.
Yeah, I was disappointed to find out that Protek made a mistake in the user manual for their Prodigy 66 Duo. It lists IR as one of its functions, but actually does not do that. I found a Tenergy 5-in-1 battery checker that does IR for $15. Most of the other functions seem useless on it, but for $15, I think that's better (at least for now) than dumping my almost new charger to drop a couple bills on a new one.
10-04-2018, 05:04 PM
#19
well I don't know how good that Tenergy unit is. Might be fine. I have a Protek 625 Due which I like a lot. It seems to measure IR while doing charaging but it was North of $200. I know the ichargers measure IR as seperate function. I have both an i106 and an I306B. But they don't come with power supplies so you would at least need to run them from a 3S lipo. You might consider one of the ISDT chargers likes this one:
https://www.progressiverc.com/isdt-q6-lite.html
It measures IR. I have this older model which is still available and also measure IR
https://www.amainhobbies.com/isdt-sc...AaAk0-EALw_wcB
I run it either with a small 12V Lead Acid battery I have or an old 6S 4000 i had laying around. I mostly use it to charge smaller batteries like RX batteries I have in my gliders. So for a little more, you can have a nice second charger that will also measure IR. You can of course connect it to a bigger battery or DC power supply and run it at full capacity.
https://www.progressiverc.com/isdt-q6-lite.html
It measures IR. I have this older model which is still available and also measure IR
https://www.amainhobbies.com/isdt-sc...AaAk0-EALw_wcB
I run it either with a small 12V Lead Acid battery I have or an old 6S 4000 i had laying around. I mostly use it to charge smaller batteries like RX batteries I have in my gliders. So for a little more, you can have a nice second charger that will also measure IR. You can of course connect it to a bigger battery or DC power supply and run it at full capacity.
10-04-2018, 05:18 PM
#20
you can also look around for chargers with "regenerative discharge". My Protek has this feature but I have never used it. I believe you have to run it from a chargable battery to use that feature. It has a higher discharge rate because the energy goes into charging the power source battery rather than heat in a resistor. So you can connect it to a car battery for example. I have a smaller 14 AH deep cycle battery that I use with my ISDT which would work good. But it wasn't cheap either.
10-04-2018, 06:01 PM
#21
Thanks again. That 106B+ looks tempting with the 7a discharge current on top of the IR readings. I actually have a Pyramid PS26KX (22a 6-15v adjustable) power supply running my slot car track at home. Would that work? I wouldn't drag that thing to the track and back, but it would give me IR readings and quicker discharge at home.
10-04-2018, 11:20 PM
#22
Thanks again. That 106B+ looks tempting with the 7a discharge current on top of the IR readings. I actually have a Pyramid PS26KX (22a 6-15v adjustable) power supply running my slot car track at home. Would that work? I wouldn't drag that thing to the track and back, but it would give me IR readings and quicker discharge at home.
https://www.progressiverc.com/media/...+%20Manual.pdf
You will need something like a 1 ohm power resistor rated at a minimum of 50 watts for a 2S battery. I used a 1 ohm 225W Ohmite resistor. It is about a foot long and 1 inch in diameter. You can buy that sort of thing at Digikey or Newark. But I rarely do it because its a pain. This is why the IDST standalone discharge has become popular. I think the regenerative method is better but then you need a bigger lipo or Lead Acid battery to charge back into.
10-04-2018, 11:43 PM
#23
Assuming you are running 2S that works out to 4.1 and 4.05 Volts per cell. Since I deal with everything from 1S to 12S between airplanes, helicopters, and cars, it is easier for me to think in terms of volts per cell. So again assuming your batteries are 2S, 8.4V is fully charged. You are using very little of your capacity. Hard to believe really but that is consistent with you saying you can run for an hour. 25C seems a bit low but your average current must also be very low based on how little you run your batteries down. You could go to a lower capacity but only if you wanted to lower the full-up weight. That would improve acceleration but might reduce traction. Nothing is simple and everything is trade-offs. Always look up the weight of a battery when considering choices. The higher C batteries do tend to be heavier.
The problem with DIY discharger is that they have no safety features like stopping at a certain voltage or doing any balancing. Just something for the OP to keep in mind. You definitely do not want to ever discharge a lipo below 3V/cell as that can really damage a battery.
The problem with DIY discharger is that they have no safety features like stopping at a certain voltage or doing any balancing. Just something for the OP to keep in mind. You definitely do not want to ever discharge a lipo below 3V/cell as that can really damage a battery.
10-05-2018, 12:16 AM
#24
The problem with DIY discharger is that they have no safety features like stopping at a certain voltage or doing any balancing. Just something for the OP to keep in mind. You definitely do not want to ever discharge a lipo below 3V/cell as that can really damage a battery.
Most important is that all cells are individual checked and the discharging stops when one of them has reached the lowest voltage first. The SkyRC is not doing that.
Yep, my 10-60A (in 10A steps adjustable) homebrew discharger works awesome.
10-05-2018, 09:44 AM
#27
That actually brings up a question. I live in the San Fernando Valley, so they definitely get stored indoors and not in the garage. However, I take my stuff in my car to work and then leave for the race from there. Is that 8 hours in the hot trunk every week doing damage? I could just swing by home after work at the cost of losing about 30 minutes of practice if need be.
10-05-2018, 11:50 AM
#28
That actually brings up a question. I live in the San Fernando Valley, so they definitely get stored indoors and not in the garage. However, I take my stuff in my car to work and then leave for the race from there. Is that 8 hours in the hot trunk every week doing damage? I could just swing by home after work at the cost of losing about 30 minutes of practice if need be.
Here's the case that I use:
https://www.harborfreight.com/18-in-...ase-62271.html
10-05-2018, 07:13 PM
#29
Well potentially to your car, as in burning it to the ground. 2S 5000's are pretty good size batteries and would probably destroy your car if they burst. But why not just put them in a cooler with some ice. A decent cooler can easily go 8 hours in a hot car. Obviously put the batteries in something waterproof or make sure they stay above the melted water.
Dude, I used to like in Encino on Texhoma near WhIte Oak.
Dude, I used to like in Encino on Texhoma near WhIte Oak.
10-06-2018, 03:11 AM
#30
That actually brings up a question. I live in the San Fernando Valley, so they definitely get stored indoors and not in the garage. However, I take my stuff in my car to work and then leave for the race from there. Is that 8 hours in the hot trunk every week doing damage? I could just swing by home after work at the cost of losing about 30 minutes of practice if need be.