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Old 05-01-2013, 12:34 AM   #271
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4AWG wire is rated at 90-120amps. it is 11mm thick

476 amps would need something nearly 50-70MM thick
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Old 05-01-2013, 12:04 PM   #272
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Today's LiPO packs are being sold under the rediculous claims of 70 - 100C continuous discharge rates. Which equals nearly 700 amps on some packs! It doesn't take an EE degree to realize you can't pull that kind of load through the tiny 4mm bullet plugs most packs have today. The numbers on packs should represent the load that it can handle using the connections and circuit boards that are present on the pack when you buy it.

700A through 12ga wire and a 4mm bullet connector would be over in a hurry!!! lol
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Old 05-01-2013, 12:19 PM   #273
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I agree that the C ratings are a lot of BS these days by many manufacturers. The guy who owns the LHS here rants about this frequently. I do know that some are more accurate than others in their ratings. I purchased some Venom 20C 2S LiPos and discovered that my Novak ESC/motor combo would sometimes cog in my VTA car. Once I used a 25C battery, it would not cog. Novak's site recommends 25C or better batteries with their combo sets for good reason it seems.
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Old 05-01-2013, 12:25 PM   #274
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amperage ratings are for wire in a wall without cooling airflow. In a car, cooling air can and will greatly increase the useful max sustained amps the wire can support. Think about it, a 3.5 turn motor on 2s will draw 100 amps briefly to make its max 750 watts of power, but the cooling occurs for the whole run. Ratings for wire are BS for our application.
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Old 05-01-2013, 12:26 PM   #275
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Quote:
Originally Posted by ShaunMac View Post
Today's LiPO packs are being sold under the rediculous claims of 70 - 100C continuous discharge rates. Which equals nearly 700 amps on some packs! It doesn't take an EE degree to realize you can't pull that kind of load through the tiny 4mm bullet plugs most packs have today. The numbers on packs should represent the load that it can handle using the connections and circuit boards that are present on the pack when you buy it.

700A through 12ga wire and a 4mm bullet connector would be over in a hurry!!! lol
You are probably correct or it is just marketing. In any case, it will certainly handle 40amp charging without any issues. Maybe the cells are capable but the surrounding connectors and wires would melt before you can get to that current. The 700A could be continuous for a millisecond.

I also doubt any 2S or 4S RC car could pull that kind do current before the ESC blows as well. A 4ft+ wingspan plane could pull it running a deliberate lower cell count, thus drawing more current than normal.

In a laboratory set up, you would be able to set up the necessary equipment that can pull 700A to validate the rating.

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Old 05-01-2013, 02:09 PM   #276
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My LHS just got in a Thunderpower TP1430 charger for me, so I will be charging at around 30 amps to see if I see any improvements.
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Old 05-01-2013, 02:20 PM   #277
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Which power Supply will you be using ???
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Old 05-01-2013, 04:20 PM   #278
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I have a pyramid 30 amp, but the thing is a boat anchor. I might be looking into a rivergate if I can find one.
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Old 05-01-2013, 04:35 PM   #279
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I have a pyramid 30 amp, but the thing is a boat anchor. I might be looking into a rivergate if I can find one.
Chances are, it is transformer based and 12V and it will cook if you draw 30 amps from it.

These high amperage chargers like the TP, iChargers and PowerLab requires switching power supplies that can supply at least 40A with 24V-30V. The higher operating voltages enable lower current draws if you are pulling 1000 to 1300 watts.
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Old 05-01-2013, 07:17 PM   #280
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Quote:
Originally Posted by MUDVAYNE View Post
My LHS just got in a Thunderpower TP1430 charger for me, so I will be charging at around 30 amps to see if I see any improvements.
The best thing to do:

If you are using new lipo packs for the first time I would charge no higher then
20 amps for the first few charge/discharge cycles.


Just to be safe the pack isn't defective from the factory.

After that your good to go!!
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Old 05-01-2013, 07:46 PM   #281
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We normally increase it in steps. 1C, 2C, 3C .... during break in and monitor the results.

The packs with good data are reserved for racing and the bad ones....for practice.
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Old 05-01-2013, 09:13 PM   #282
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Quote:
Originally Posted by Team Grid RC View Post
Chances are, it is transformer based and 12V and it will cook if you draw 30 amps from it.

These high amperage chargers like the TP, iChargers and PowerLab requires switching power supplies that can supply at least 40A with 24V-30V. The higher operating voltages enable lower current draws if you are pulling 1000 to 1300 watts.
Agree on not expecting 30A from the Pyramid with any reliability. And it does take a substantial higher voltage power supply to achieve full power from the big boy chargers, but only with high voltage packs.

Full power isn’t needed for the typical 2S, 30 amps from a TP1430 should take somewhere around 300 watts from the power supply. Around 25 amps for a true 12 volt supply, little less for a ~13.8 volt unit. Roughly double for a 4S, about half for a 1S, etc.
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Old 05-01-2013, 11:06 PM   #283
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Quote:
Originally Posted by brendon.matt View Post
4AWG wire is rated at 90-120amps. it is 11mm thick

476 amps would need something nearly 50-70MM thick
You've ignored Pi.
The area of a circle gets much greater with relatively small increases in diameter.
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Old 05-02-2013, 09:51 AM   #284
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Agree on not expecting 30A from the Pyramid with any reliability. And it does take a substantial higher voltage power supply to achieve full power from the big boy chargers, but only with high voltage packs.

Full power isnít needed for the typical 2S, 30 amps from a TP1430 should take somewhere around 300 watts from the power supply. Around 25 amps for a true 12 volt supply, little less for a ~13.8 volt unit. Roughly double for a 4S, about half for a 1S, etc.
I will be charging a 1s pack for WGT. I was thinking the pyramid 30 amper would work, but then again I would like to have the right equipment the first time.
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Old 05-02-2013, 10:06 AM   #285
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Quote:
Originally Posted by MUDVAYNE View Post
I will be charging a 1s pack for WGT. I was thinking the pyramid 30 amper would work, but then again I would like to have the right equipment the first time.
For 1s packs, it will probably do the job. Even though those things say 30 amps, you probably don't want to pull more than 20 or so off of it continually.
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