Charger question

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minionhunter
Posts: 185
Joined: Fri Nov 04, 2016 5:36 pm

Charger question

Post by minionhunter »

Hi

Does this charger look good? I know it is just for 1s, but I can't find any that I want (isdt or hobbymate) that are sold by Amazon itself right now and I've got a free $15 off $25 for using their photos app that musy get spent. If this is decent for 1s use I might get it just to use the coupon and not waste it. Based on reviews it seems like a good deal for $18 (that's after the coupon).

https://www.amazon.com/gp/product/B071K ... 0DER&psc=1

It is weird but I don't have anything else right now that costs $25+ on its own, that I need that is directly sold by Amazon (everything is fulfilled by or just only sold by 3rd parties), so that is that. Maybe I should just get this charger and have my 1s needs (non-existent at the moment) taken care of.

Aside from needing to use the coupon, I will also likely get an ISDT 608 charger, IDST Q8, ToolkitRC M8S, and then also 4 (and likely 4 more) of the cheap hobbyking chargers also (need to build one block for my kids and one for the girl scouts.
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MarkR
Posts: 375
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Location: Reading Hackspace
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Re: Charger question

Post by MarkR »

Most of the Ant robots use packs with 2 or 3 cells, I don't think that charger will be able to charge such a pack, unless you make a splitter cable and charge one cell at a time, which is very inconvenient. It's not clear from the description that the charger can charge a 2S pack by using two channels - they may not be electrically isolated.

Also this charger supports the "HV" high voltage cells that sometimes drones use for a bit of extra energy, robots don't really need those (although you could use them).

(I think the Fleaweights and lighter often use single cell)

I still think a bank of DC balance chargers would be easier and better, and possibly cheaper if you use the super-cheap Hobbyking ones, with a single suitably rated mains supply, and they will balance-charge absolutely fine.

---

Never assume that any of these (DC) chargers are electrically isolated, I strongly suspect that they mostly wire the negative side directly to their own negative input. If you tried to charge two cells from the same pack at once with two such chargers, you're creating a short circuit (low impedence path) across one cell, which is *very bad*.
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands
minionhunter
Posts: 185
Joined: Fri Nov 04, 2016 5:36 pm

Re: Charger question

Post by minionhunter »

MarkR wrote: Wed Feb 19, 2020 9:41 am Most of the Ant robots use packs with 2 or 3 cells, I don't think that charger will be able to charge such a pack, unless you make a splitter cable and charge one cell at a time, which is very inconvenient. It's not clear from the description that the charger can charge a 2S pack by using two channels - they may not be electrically isolated.

Also this charger supports the "HV" high voltage cells that sometimes drones use for a bit of extra energy, robots don't really need those (although you could use them).

(I think the Fleaweights and lighter often use single cell)

I still think a bank of DC balance chargers would be easier and better, and possibly cheaper if you use the super-cheap Hobbyking ones, with a single suitably rated mains supply, and they will balance-charge absolutely fine.

---

Never assume that any of these (DC) chargers are electrically isolated, I strongly suspect that they mostly wire the negative side directly to their own negative input. If you tried to charge two cells from the same pack at once with two such chargers, you're creating a short circuit (low impedence path) across one cell, which is *very bad*.
Thank you Mark!


Yes I realize that this one is only for 1S.

But OK, maybe I won't get that one then. I keep forgetting that I need to assume the worst about these things. You have to assume that they are not trying to cheat you, but they are trying to cut costs so they will cheap out on these things unless specified. Thanks for reminding me, that is one big reason why I am asking about it.

I do plan on getting the bunch of cheap DC4S balance chargers. I was just hoping this one might satisfy my 1s needs. But that would only happen if I made a wedge wedge wedge clone or something like that I guess.

Sometimes the drive to spend gets out of control. Maybe I'll find a tool that I need instead. You rarely see $15 for free at Amazon.

As long as we are on about battery chargers

Do any of these look decent for charging antweight batteries? Cost aside. I was hoping that one might be decent. These are what I've found after looking for reviews, but they come from Quad copter racing reviews. Cost aside for now, just are they OK for what I need, though likely overkill...

ISDT 608 (the one with the removable power supply)
ISDT Q8
Hobbymate duo AC/DC
ToolkitRC M8S

Side note, my father in law heard about my plans and is looking at mini-milling machines and lathes now. He was a machinist and had a full shop in his basement when raising my wife to provide extra money so they could eat, but he had to give it up about 15 years ago when we got married. Anyway I'm guessing he's going to buy one for me or something similar in the near future because he wants to teach his grandkids about it. So I might wind up with a micro or mini machine shop in my basement... I did metal shop in high school and it was fun, but I haven't worked with anything like that that in 20 years or so. Might be cool....
Tufty
Posts: 105
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Location: North Wales

Re: Charger question

Post by Tufty »

Are there any specific recommendations for chargers? I've scoured Amazon, Ebay and Hobbyking. Apart from a couple of out of stick options on HK, I simply cannot find a charger for a 2s battery.

I'm certain I'm making another noob error here, but it's a bit frustrating when I've managed to find everything else.
Current active ants: Scrooge McDerp | Ply-By-Wire (likely not to see competition) | Grinding Nemo | When Unicorns Go Rogue
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MarkR
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Re: Charger question

Post by MarkR »

If you genuinely can't find a 2S charger (I noticed that some of HK's ones are out of stock) then maybe it is possible to use a 1S charger, if you make up a "Y" cable to connect to the balance port, then just charge one cell at once.

But try to always charge both cells, otherwise it would be unbalanced and discharging an unbalanced pack could ruin it.

It's not a convenient option.

At a push, a bench power supply would charge it, but you'd need to be careful to set it up correctly to avoid Bad Things happening, and I think the EO may take a dim view of using it at an event.
Robots: Betsie - RaspberryPi controlled flipper bot with gyro stablisation - too clever for her own good?
Stacie - tidy flipper; 4wd driven by hair bands
Tufty
Posts: 105
Joined: Wed Jan 29, 2020 9:39 pm
Location: North Wales

Re: Charger question

Post by Tufty »

Finally managed to find one on Hobbyking when I slightly changed the search term. Thank you :D
Current active ants: Scrooge McDerp | Ply-By-Wire (likely not to see competition) | Grinding Nemo | When Unicorns Go Rogue
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