Tutorial - What charger? What power supply?

[Slyster]

You could... but would have to limit the current draw or you blow your lighter socket fuse. Better to open up the hood and alligator clip straight to your car battery directly instead of going through the cig socket.

Then again I just looked and it's only an 80w charger.. You realize how tiny that is right? I'd suggest you at least get this... cheaper and 150W (I owned a bunch in the past and liked them)

Or perhaps save much more money getting a 1000W+ charger now and needing only 2 packs for your helis in the future?

http://www.hobbyking.com/hobbyking/s...dProduct=15166

$46.00

[jbrandt]

Nice find! And no, I didn't realize how tiny that is. Thanks for publicly emasculating me...



Is that charger only available from Hobbyking? I've heard bad things about their service... Like they have the lowest rating I've EVER seen on BBB (F)... I can't find it anywhere but HK...

Maybe this is a good alternative? again only 50W though...
http://www.hobbypartz.com/thac6smbachw.html

I've actually been inspired just now. I'm now considering doing some custom wiring in my RV trailer and my truck, and fabricating a "special" plug (fused of course) that I can use for this charger. Hmmm.....

So does the higher wattages just give you faster charge times?

Originally Posted by Slyster

You could... but would have to limit the current draw or you blow your lighter socket fuse. Better to open up the hood and alligator clip straight to your car battery directly instead of going through the cig socket.

Then again I just looked and it's only an 80w charger.. You realize how tiny that is right? I'd suggest you at least get this... cheaper and 150W (I owned a bunch in the past and liked them)

Or perhaps save much more money getting a 1000W+ charger now and needing only 2 packs for your helis in the future?

http://www.hobbyking.com/hobbyking/s...dProduct=15166

$46.00

[bublik1]

sorry for the newb question and jump thread.
but what for is the DC ground removal? i'v ordered led 360W 12V 30A PSU. do i need to do this ground removal thing?

[soko]

If your charger is sold as an RC charger you dont have to do anything.
The ground removal is just if you buy a used PSU from a computer and want to use it for your charger

[RedOctobyr]

And if you want to run 2 of those supplies in series.

You don't have to remove the ground if running just one (even computer supplies), but you do have to isolate the ground from supply #2 if running 2 in series.

[jbrandt]

Okay, you were right Slyster, I under-bought my charger system. Well sort of. I bought an 80W ac/dc charger, which has proven pretty useful for home use on single batteries, and I plan to keep it, at least for now...

I just ordered a 6 port parallel balance board so I'll be able to charge my 3 3s 2200's at the same time, and still have room to expand. Yes, I realize my 80W charger would be severely limited in the power department for parallel charging my 3s 2200's. At 6amps (max), I can't even charge 1 of my batteries at a full 3C. My plan is to still use it for parallel charging the day before I fly, so I don't care THAT much how long it takes to charge.

For field use, I'm looking to get a deep cycle, something on the order of 35Ah or so, and perhaps a 206B. That would give me around 400+ watts, more than enough to charge 6 3s 2200's at around 2C, right?

If I wanted to be able to charge those same 3s 2200's at 3C, I imagine I'd have to go to something like the 306B, correct?

I guess any way I slice it, even if I go cheap and get the "220W starter combo" from ProgressiveRC (106B and a 220W pc) I'd still be able to charge 6 3s 2200's in less that an hour (if I did my math right), and even less when on the deep cycle. The more I think about it, this might be the ticket (since I'm cheap, lol). Or maybe the "surface combo" since I'm only running 3S batteries...

[RedOctobyr]

Originally Posted by jbrandt

My plan is to still use it for parallel charging the day before I fly, so I don't care THAT much how long it takes to charge.

You can use your chargers however you'd like, of course But I bought my 308Duo and expected to still use my 106B+ for some things. Turns out I just use the bigger charger for everything. I'd say why not use your new one for charging at home, as well as at the field?

For field use, I'm looking to get a deep cycle, something on the order of 35Ah or so, and perhaps a 206B. That would give me around 400+ watts, more than enough to charge 6 3s 2200's at around 2C, right?

The 206B is 300W max. And that's only when providing 17V or higher. Per page 10 of the manual, if feeding it 12V (deep-cycle), you'll get about 220W output.

300W into 3S (12.6V max) is 300W/12.6V= 24A. But, remember that this is a 20A charger. So you'll only be able to put 20A max into your packs, even if only charging 1S.

220W into 3S is 17.5A.

(6) 3S 2200's at 2C would need 26.4A. You will get 1.5C if able to put out 20A (you need 250W, so 14V or higher), or about 1.3C if running off 12V.

If I wanted to be able to charge those same 3s 2200's at 3C, I imagine I'd have to go to something like the 306B, correct?

Yes. Even if you want 2C on all 6 packs.

I guess any way I slice it, even if I go cheap and get the "220W starter combo" from ProgressiveRC (106B and a 220W pc) I'd still be able to charge 6 3s 2200's in less that an hour (if I did my math right), and even less when on the deep cycle. The more I think about it, this might be the ticket (since I'm cheap, lol). Or maybe the "surface combo" since I'm only running 3S batteries...

The 106B+ will give you 10A. Which, for 3S, is only 125W (it's a 250W charger, but only reaches 250W output when charging 6S at 10A). That's 0.8C, and will take right around an hour, based on how long mine took to charger larger 6S packs at 0.8C. More or less time depending on how far you discharge (I only drain about 55%, and it would take an hour).

Buy whatever fits your budget, but do consider that you've already outgrown a setup once. The 106B+ isn't much faster than what you have now. The 206B helps for 3S (20A vs 10A), but if you go to 6S in the future, it's only 50W more than the 106B+. The 306B, on the other hand, unlocks much more potential. 30A/750W charging, 80W discharging, vs 10A/250W charging, 20W discharging, for the 106B+.

I was planning on upgrading from my 106B+ to maybe a 306B/PL6. Then I decided to go for the PL8 instead. Then the 308Duo was announced. I went with that, and have been very happy with it so far. I didn't want to upgrade once, then have to upgrade again. The power is great, and I really like the flexibility of having 2 channels.

If you don't plan to go past a 450, the 206B is a good choice. But if you go bigger, you may find yourself wanting more power. I have (3) 6S 4100s for my X5, they need 318W, 12.6A for 1C. And I want my charging setup to be capable of at least 2C, if not more, for when I want to charge up quickly. The 206B wouldn't quite reach 1C with those.

I'd advise picking a charger. Then look at power supplies. Combos are easy, but you pay for the convenience. Used server power supplies offer much more power for the money, vs commercial hobby supplies.

[jbrandt]

Originally Posted by RedOctobyr

You can use your chargers however you'd like, of course But I bought my 308Duo and expected to still use my 106B+ for some things. Turns out I just use the bigger charger for everything.

True. But you also got a dual charger, so you can charge 3S and 6S simultaneously. I don't see a need for a duo. I have a bunch of 1S batteries for my Nano CPx that my "old" (still my current charger, lol) is more than powerful enough for (paralleling 6 1S 200mAh batteries, for example). I don't see a need for a duo at this point, or really, ever.

I'd say why not use your new one for charging at home, as well as at the field?

I was operating under the assumption I didn't want to buy an external power supply. All I'd need for the field is a 12v battery and the charger. I don't have a generator so the only place I'd use a power supply is at home, or *maybe* camping (though we dry camp a lot so 120v trailer hookups aren't usually available).

The 206B is 300W max. And that's only when providing 17V or higher. Per page 10 of the manual, if feeding it 12V (deep-cycle), you'll get about 220W output.

300W into 3S (12.6V max) is 300W/12.6V= 24A. But, remember that this is a 20A charger. So you'll only be able to put 20A max into your packs, even if only charging 1S.

220W into 3S is 17.5A.

(6) 3S 2200's at 2C would need 26.4A. You will get 1.5C if able to put out 20A (you need 250W, so 14V or higher), or about 1.3C if running off 12V.

Yes. Even if you want 2C on all 6 packs.

The 106B+ will give you 10A. Which, for 3S, is only 125W (it's a 250W charger, but only reaches 250W output when charging 6S at 10A). That's 0.8C, and will take right around an hour, based on how long mine took to charger larger 6S packs at 0.8C. More or less time depending on how far you discharge (I only drain about 55%, and it would take an hour).

Buy whatever fits your budget, but do consider that you've already outgrown a setup once. The 106B+ isn't much faster than what you have now. The 206B helps for 3S (20A vs 10A), but if you go to 6S in the future, it's only 50W more than the 106B+. The 306B, on the other hand, unlocks much more potential. 30A/750W charging, 80W discharging, vs 10A/250W charging, 20W discharging, for the 106B+.

I was planning on upgrading from my 106B+ to maybe a 306B/PL6. Then I decided to go for the PL8 instead. Then the 308Duo was announced. I went with that, and have been very happy with it so far. I didn't want to upgrade once, then have to upgrade again. The power is great, and I really like the flexibility of having 2 channels.

If you don't plan to go past a 450, the 206B is a good choice. But if you go bigger, you may find yourself wanting more power. I have (3) 6S 4100s for my X5, they need 318W, 12.6A for 1C. And I want my charging setup to be capable of at least 2C, if not more, for when I want to charge up quickly. The 206B wouldn't quite reach 1C with those.

I'd advise picking a charger. Then look at power supplies. Combos are easy, but you pay for the convenience. Used server power supplies offer much more power for the money, vs commercial hobby supplies.

Okay, you just said a lot, and it's all helpful. I think my math was a bit off because I was only looking at the "max" wattage of the chargers instead of 12v input. I need to dig a little deeper and re-do my math.

You make a lot of sense out of what is essentially Greek to me (I took circuits 3x in college - not a shining moment for me...). It's getting better, and this helps.

This is making me lean towards the 306B, and no PS for now. So at least for now (with the addition of a single deep cycle, I can create an expandable platform, and max out whatever deep cycle I get.

But just so I understand the calcs:

If I have a single 12v deep cycle with 35Ah, that's 420 watts. That makes 33ish amps, which is more than the 30amp max for the 306B. That'd give me a 2.25C charge rate for 6 3S packs, right?

If that's correct, would there ever be an advantage to say going with 2 deep cycles like Slyster has done for a 24v source setup since I've already maxed the 30amp output with 12v?

[RedOctobyr]

Sorry, I didn't mean to sound like I was pushing a Duo. Merely that you might get value from your new charger at home or at the field, like if you want to parallel charge quickly before heading to the field. But I was assuming you would have a PS for the new charger. Speaking only for me, even if I used a deep-cycle at the field, I'd probably still have a PS for using it at home.

Originally Posted by jbrandt

Okay, you just said a lot, and it's all helpful. I think my math was a bit off because I was only looking at the "max" wattage of the chargers instead of 12v input. I need to dig a little deeper and re-do my math.

You make a lot of sense out of what is essentially Greek to me (I took circuits 3x in college - not a shining moment for me...). It's getting better, and this helps.

This is making me lean towards the 306B, and no PS for now. So at least for now (with the addition of a single deep cycle, I can create an expandable platform, and max out whatever deep cycle I get.

A 306B would be a good choice.

But just so I understand the calcs:

If I have a single 12v deep cycle with 35Ah, that's 420 watts.

The 35Ah only relates to total stored energy (capacity, like a LiPo being 2200mAh), not how fast it can deliver it (the watts of output, more like a C-rating of a LiPo).

A 12V 35Ah may be able to deliver 20A (240W), 50A (600W), who knows. The capacity rating doesn't really describe that directly, how *fast* it can deliver power. It says more that you could get a total of 12V * 35Ah = 420 Watt-hours. That is, it could theoretically deliver 420 watts, for an hour. Or 840W for 30 minutes. Or 210W for 2 hours, etc.

Granted, this is a bit optimistic, based on how these things are rated. Ideally, you don't want to discharge deep-cycles much beyond halfway, as I understand it. So maybe more like 420W for 30 minutes, 210W for an hour.

But just consider that you may be able to get more than 420W from a deep-cycle. Obviously, just the higher the wattage discharge, the sooner the battery will go dead.

That makes 33ish amps, which is more than the 30amp max for the 306B. That'd give me a 2.25C charge rate for 6 3S packs, right?

Again, let's not assume you can only get 420W out of the deep-cycle. Slyster can offer better info on what's reasonable to pull from a deep-cycle. The only thing I can say is that 35Ah sounds like a somewhat small deep-cycle to me, but it may be OK for 450 packs.

But say you *do* choose to pull 420W. You will lose about 10-15% to efficiency losses in the charger. Leaving you with maybe 360W into your packs.

For 3S (12.6V), that's 360W / 12.6V = 29A.

For 6 3S 2200s, that's 2.2C.

Even if you could pull more power, as you said, you'd hit the 30A limit of the 306B, and still get around 2.2C.

If you want more amps, the FMA PowerLab PL6 ($175) would give you up to 40A of charge current.

If that's correct, would there ever be an advantage to say going with 2 deep cycles like Slyster has done for a 24v source setup since I've already maxed the 30amp output with 12v?

Yes, but the distinction admittedly gets less compelling, when only charging 3S, and when output-current-limited.

24V means lower input current to the charger. That keeps your deep-cycle -> charger wiring cooler, and keeps the charger cooler.

Also, due to subtleties of lead-acid batteries, you'll get a little more run-time out of a deep-cycle if your amp draw is lower. I don't just mean the obvious, where less draw means it goes longer before being discharged. I mean that if you double the amp draw, maybe you get 40% of the run-time, not the 50% you'd expect.

If running 2 in series for 24V, you're only drawing half as many amps from each deep-cycle, so you may get a little more out of them.

But for a comparatively-low wattage output (charging 3S, not 6S), you don't see the biggest advantage, which is that supplying 24V allows more total output watts from your charger. Every charger has an input-current limit. For the 306B, that's 50A (for the PL6, it's 40A). So if charging 6S, where you need a lot of watts, if you're providing 12V, the most power you can give the charger is 12V * 50A = 600W (more like 510W of output, with efficiency). But provide 24V, and you can give it 24V * 37A = 880W, and still get the full 750W of output.

This became quite a long reply, sorry. I hope it's helpful. Let me know which things I didn't explain well.

[jbrandt]

I understand you weren't pushing your dually. No worries there. :-)

Thanks for all the info: super helpful! A lot to digest.

The reason I came up with a 35Ah battery is that I wanted to keep it small and light. I'd like to see how light I can go and still get 10 or so (max) charges from it for my 450 batteries. I don't plan on going bigger, but it'd be nice to be able to charge 4 to 6 batteries relatively quickly.

So what you're saying is get the 306B, stick to a single deep cycle unless I go to bigger helis or a 6S setup for my 450.

Again, many thanks.

[jbrandt]

Also, if I do go for a power supply, I think I'd be fine with a relativle low wattage unit (300 + watts). Since I'm not so concerned with speed charging at home, and I could still charge several batteries at a 1C or maybe 2C rate depending on how many I choose to parallel at a time.

[RedOctobyr]

The 306B would get you closest to your goal of (6) 3S 2200's charging at 3C, out of the single-channel iChargers. The PL6, at 40A, would get you there, though maybe not quite on 12V input (it could definitely do 40A into 3S running on 24V).

A single 35Ah deep-cycle would probably get you 10 charges on 450 packs.

To simplify the math, let's take advantage of the fact that a 12V deep-cycle and a 3S LiPo are basically the same voltage. So we can work in amp-hours, rather than needing to convert to watt-hours, like we would if running 2 deep cycles in series for 24V.

Say you discharge by 80%, you need to put back 1760mAh (1.76Ah) into each 2200 pack. Times 10 packs, that's 17.6Ah. If the charger is 85% efficient, you need to pull 20.7Ah from the deep-cycle to make this happen. That's 60%, a little past the guideline of not discharging a deep-cycle below 50%, but still not too bad, for a 35Ah.

For power supplies, feathermerchantrc.com sells 12V, 47A, 575W power supplies for $50, shipped. Those are DPS-600PBs, I have 2 of them. You can get them on eBay for $15-20 and modify them yourself (pretty easy), or just buy his, though you still have to solder on output wires if you buy his. And that's about half of the modifications required. But possibly a way to have more watts available (maybe you run 2 chargers off 1 supply), while still keeping the cost down. Or look at his other options for plug-and-play supplies.

http://feathermerchantrc.com/

[Relisys190]

Heres what confuses me about power.

Say I'm charging at 30amps from my 308 duo on my house power.

How does a 15amp wall socket supply 30 amps to the charger?

Thanks.

[RedOctobyr]

Power = Volts * Amps
or
P = V * I

So 5 amps at 110V transmits the same power as 50 amps at 11V, both provide 550W of power. We need to think in watts, not just amps, when working with different voltages.

Your household voltage is 110V in the US. So, if you could pull 15A from the wall, that means you have 110V * 15A = 1650W available to the charger.

The power supply & charger convert the incoming volts from the wall to the output voltage that's going to your LiPo. Let's say 6S, so 25.6V.

The watts coming into the PS and charger from the wall equal the watts going out to the LiPos, ignoring efficiency losses.

So if you need 30A going into 25.6V (a 6S LiPo), that's only 25.6V * 30A = 768W

The PS & charger converts the voltages internally, so you only need to worry about the power, or watts. Watts in equals watts out to the LiPos.

So if you need to output 768W to your LiPos, how many amps do you need to draw from the wall, which is providing 110V?

P = V * I
or
I = P / V

So to charge 6S (25.6V) at 30A, you only need 768W / 110V = 7A drawn from the wall.

[Relisys190]

Originally Posted by RedOctobyr

Power = Volts * Amps
or
P = V * I

So 5 amps at 110V transmits the same power as 50 amps at 11V, both provide 550W of power. We need to think in watts, not just amps, when working with different voltages.

Your household voltage is 110V in the US. So, if you could pull 15A from the wall, that means you have 110V * 15A = 1650W available to the charger.

The power supply & charger convert the incoming volts from the wall to the output voltage that's going to your LiPo. Let's say 6S, so 25.6V.

The watts coming into the PS and charger from the wall equal the watts going out to the LiPos, ignoring efficiency losses.

So if you need 30A going into 25.6V (a 6S LiPo), that's only 25.6V * 30A = 768W

The PS & charger converts the voltages internally, so you only need to worry about the power, or watts. Watts in equals watts out to the LiPos.

So if you need to output 768W to your LiPos, how many amps do you need to draw from the wall, which is providing 110V?

P = V * I
or
I = P / V

So to charge 6S (25.6V) at 30A, you only need 768W / 110V = 7A drawn from the wall.

[fjoe]

Don't forget to look at balance current! This can really slow you down, especially if you have big packs or parallel charge. That is another good thing about the duo line, 1.2amp of balancing current per cell per channel, I think this is the highest (??) around. Typically I see the bulk charge done in under 10 min from 3.8 - 3.85v and 3C. Then it is another 2-5min depending on the pack size, age, and mode to finish them.

I just picked up a 406 duo (coming from the 306b) and it is great to have two channels, especially if you field charge! With 3 packs I fly constantly with no down time. Also the charger keeps track of how many Ah you pulled from the power source as long as you don't unplug it, so you know when to stop!

I would seriously consider picking up at least the 308 duo over the 306b, the extra channel and over 4x the balance current (1.2A on each channel vs 0.5A) is well worth the $100. Plus you will need less batteries per model!

[Slyster]

I love having a duo charger since now I don't have to parallel charge very often. Typically I will but only the first round.. just to get going. Then the rest of the day I'll use the dual ports singly. Of course a stick pack, being two 6s packs, either requires both ports or a parallel cable still.

BUT.. I did keep my 306b since if I only had the Duo and dropped it I'd be outta luck.

[RedOctobyr]

Originally Posted by fjoe

Don't forget to look at balance current! This can really slow you down, especially if you have big packs or parallel charge. That is another good thing about the duo line, 1.2amp of balancing current per cell per channel, I think this is the highest (??) around.

Very good point. The PL6 and PL8 have 1A of balance current, up from 0.5A on the 306B. Providing a reason even just to consider one of those, vs a 306B.

I tested balancing speed on my 0.3A 106B+ vs my 308Duo, in 1.2A mode, and 2.4A mode. Results are here:
https://www.helifreak.com/showthread...10#post5623810

In my test setup, the 106B+ took almost 5 hours to balance the pack, the 308Duo did it in an hour and a quarter, or 45 minutes in the faster mode. Balance current can definitely make a difference.

If looking at bigger ($$) packs, a dual-channel charger can reduce the # of packs you need to buy to fly non-stop. Kind of paying for itself. For my X5, pack were $100. Instead of buying 4 packs, and field-charging 2 in parallel with a single-channel charger, I bought 3 packs and a Duo ($110 more than a 306B). Now I can do it with 3 packs, and I have a better charger, for the same total price. It also benefits any heli I fly, vs buying more packs for each one.

[Slyster]

Moving from my PL6 to the 4010 Duo helped charging times.. the iChargers don't have that frustrating 2 minute ramp up time and the highest balance current. It really did cut my 3C charging down to 13-15 mins instead of near 20.

[Relisys190]

My best current charger (a 100w x2) has a 250mah balance current.

Cant wait for my 308 to get here!!! lol My PSU's are in Tampa already DSW ROCKS.