What's everyone using to charge high capacity lipo's?

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olds97_lss

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Well, having charged my SMC 9000mah packs 3 times so far on the traxxas dual peak plus id, I'm looking into getting a charger that has a readout that actually tells me something useful about what's going on.

Since I intend on running packs of this size, from what I understand, lipo charge rates are rated in "C" vs "Amp". So, to charge a 9000mah pack at 1C, I'd need to supply 9 amps to it. Granted, I doubt I need to charge them that fast, but if I buy another set or two of those packs, I really don't want to wait 3+ hours to charge each pair. This charger maxes out at 4 amp's per pack when charging 2 packs. Also, it stops after sending 5000mah and I have to reset them and restart the charge.

Anyway, now I'm looking at a new charger. I've had good luck with Dynamite and MRC stuff in the past, so thought I'd start there. I found the DYNC2050 which will charge 10A X 4 packs at a time. I also saw the Venom Pro Quad VNR0686. What I don't fully grasp is that both say 100W x 4, but yet the dynamite says 10A x 4 and the venom says 7A x 4. I didn't see anything by MRC that doesn't require an external PSU.

Trying to find something simple that will handle charging the larger 2S packs (and perhaps 3S at some point, smaller capacity, but higher voltage) at a higher rate than the Traxxas charge that also has a display that tells me volts, time it took, mah sent, balance charge and storage charge capable. Without breaking the bank or eating up a ton of space. I kind of like the venom one due to it's size/standing footprint and the screen faces you vs faces up for where I want to put it, but the 7A vs 10A makes me look at the dynamite charger more.

I know there are other cheaper charges out there and god knows more expensive, but I know a decent priced device can last many years. I've been using the same $50 MRC charger for 10+ years and it's worked perfectly.

If anyone has any experience with either of these or has had good luck with higher capacity packs in other devices, please let me know.
 
Here's something to read to help you understand Watts vs. Amps = http://www.tjinguytech.com/charging-how-tos/wattage-for-charging

Thanks for that. Wish he had talked about pack/cell peak voltage (4.2V per cell) a bit earlier so the stuff made a bit more sense vs just appearing to pull the voltage value out of thin air. Even then, he did it as a sum for a 3S pack (12.6V).

So, with that math:
Cell peak voltage: 4.2V
Assuming a pack can handle 1C for every 1000Mah of a packs capacity (he didn't really dive into that either).
The equation: W = V * A (which hasn't changed since college)
Means wattage per pack for a 2S 9000mah pack would be 75.6W (75.6W = 8.4V * 9A/C).

Is the rule of thumb true for most lipo's that the max input is the total capacity/1000? I see he talks about charging at 2C as well, which suggests some packs can handle 2A input. I sent SMC an email to see what they said regarding that with their packs.

Anyway, seems 100W per pack output would cover my charging needs pretty well to get the charge time down under/around 1 hour.

Still doesn't explain why the 400W venom outputs 7A per pack whereas the 400W Dynamite outputs 10A per pack. Seems like I need 9 amps per channel to get enough to charge a 9000mah pack at 1C. Yes? No?

If the math works out, then it means the Venom isn't really 400W... and neither is the dynamite. If you use: 100W/8.4V=11.9A

So, the venom falls short by almost 5 amps and the dynamite by 2 amps. So, do they throttle the amps out by a predetermined amount?

My head hurts now.
 
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According to the formula shown,your 2s 9000 packs(8.4V * 9a) shows you need 75.6 watts to charge at 1c. So either has the wattage needed. I would assume they are throttled a little for a safety margin on the power supply,so the Venom is throttled to 7a vs 10a on the Dynamite.So actually the Venom won't get to 1c even thought the wattage is there. From what I understand,most batteries will state a maximum rate to charge the battery if it can be more than 1c and if not stated to assume the 1c standard.
I like the Venom better due to it having 4 individual 100w power supplies vs I assume a single 400w in the Dynamite charger. Also Venom customer support was really good when I had one of their chargers. But having said that,I would probably buy the Dynamite since it appears it should hit the true 1c charge rate you need for those packs.
 
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I also like the chargers that display each cell. there are so many that just have lights and shut off ehrn they are done but you have no idea what is going on.
I am looking for a good charger that shows the display. I personally thing 5 amps is fast enough but that's just me.
I have a venom pro charger that has choices.
charge and balance and storage. but I always balance. it may take longer but I think its safer
 
I ended up going with the DYNC2050 10A X 4 / 100W x 4. What stinks is that it's been too cold since I got it to use it. I did use it to charge my micro-t/high roller 2s lipo though.

I bought some balance board extensions because the boards just aren't long enough to make it easy to use. Thinking of making some sort of cheap tilted rack to make it easier to use as well. I don't have a lot of room, but charging 4 at a time is going to be like a game of jenga... pretty sure you don't want lipo's stacked on each other while charging... lol
 
The jenga thing got me! :hehe: We were going thru a nasty cold snap right around this last post. Have you been able to test the charger out? Curious to know how it's working out for you.
 
The jenga thing got me! :hehe: We were going thru a nasty cold snap right around this last post. Have you been able to test the charger out? Curious to know how it's working out for you.

So far, so good. Only used it 3 times. The weather has been awful around here since I got it. I finally did use it to top off two SMC 9000mah packs I got to replace a set of Floreon ones I got off ebay that didn't fit in my truck. Luckily, they did give me a full refund with shipping costs included.

I charged both sets of my SMC 9000mah 2S packs in just under 1.5 hours from the 3.5V LVC cut off I have the revo set to. It did read a bit short on MAH, was 8400-8500 depending on the pack. Guessing that's because of my somewhat conservative LVC setting. I set the charger to 10000mah cut off on all 4 ports and when charging, you choose what the cells are, I set it to 10000Mah so it would charge at 10A, but after I started the charge, I realised I could have set it to 9000mah and 10C... It got to 8.3V/8000mah on all 4 packs in under an hour, but as it charges, it lowers the amperage automatically. Guessing to avoid a false peak and also avoid overcharging/damaging the cells. It took another 20 minutes to finish them off.

I had hoped to use it again on Wednesday, but 10 minutes into my first run, I hit a hunk of concrete hiding in the grass and popped both my ball studs out of my RPM axle carrier on the front. It was 30F, so without tools, it wasn't going back together. By the time I got home and got it fixed, it was dark.

I then used it to discharge all 4 packs to whatever the safe storage voltage is. That took a while, for the life of me, can't remember how long. For some reason, 160 minutes sticks in my head. I think it maxes out at 5A discharge per port, but as it discharges, it also lowers the discharge current automatically.

Like a dork, I too photo's of it. lol
Just started:
2017-0115-DynamiteDYNC2050-01-Start.jpg


Near the 1 hour mark (~56 minutes):
2017-0115-DynamiteDYNC2050-02-At1Hour.jpg


After full charge:
2017-0115-DynamiteDYNC2050-03-FullCharge.jpg


Supposed to get up over 40F out this weekend... will try and get to the skate park before the kiddo's show up. I don't really want to run it at the park... I'm not a fan of mud. Still may go there anyway. Some areas of the park are high enough that they don't stay saturated.

With 4 packs, I should get around 80 minutes of run time. Not sure if that goes up when it's warmer out or not. I was at 42 minutes on the first set and 45 minutes on the second set when I ran them back to back until the LVC kicked in. It was about 32F and windy... my fingers and toes were numb by the time I packed up.
 
That's cool! It seems like a very capable charger. In sure you'll find the settings to trick it out for your particular needs in no time. VERY cool that they set you up with a full refund on those batteries too!
 
Yeah, that return took a few emails. They wanted to refund me partial to keep them. I would have accepted if I had anything else to run them in. I mean, I wasn't out that much money, $50 out of pocket since I had a $20 ebay bucks certificate. I was taking a gamble on the quality as it was. I didn't try to charge them or anything though for fear they wouldn't refund me. I didn't even plug them into anything.
 
I picked up a few high capacity 3s lipos, I just use my same duratrax charger. Even though revolectrix recommended I pick up a high capacity charger all my high cap lipos are charging to 4.35 per cell.
 
Yeah! That would have really sucked if they didn't give you a full refund then! Returning BRAND NEW stuff!!!
 
do those batteries fit in the stock flux battery boxes?
 
@Alexander_0_1. How long does a full charge take with the high capacity battery and that charger? Does it do a full balanced charge?
 
that charger looks an awful lot like my Hitec just a different color and name on it. LOL
 
@Alexander_0_1. How long does a full charge take with the high capacity battery and that charger? Does it do a full balanced charge?

The LiPos got are 3700 mAh, it probably took about 30mins per lipo, but I'll time it tomorrow. I believe it does do a full balance charge, when I checked the the display each counter read 4.35v per cell.

My charger is a Duratrax 235.
 

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