wowzaz! those are some pricey 1ohm resistors!

Holy beefcake batman.
 

Holy crap for $500 a piece I would think so. I think the idea of this descusion would be to do this without breaking the bank, right? There have to be better ways of doing this.

those are EXACTLY what I am talking about...



ex
http://cgi.ebay.com/Wirewound-Alumin...item4aa34881a9
http://cgi.ebay.com/Wirewound-Alumin...item4aa35c65df

300w, .22ohm
http://cgi.ebay.com/Ohmite-Resistor-...item2796a634dc

Guys, Guys..............

Why are you looking at re-inventing the wheel?

Maxamps has already done the testing to establish that their cells are capable of 75C Continous AND 150C Bursts!

OK, Maxamps.

How did you come up with 75C Continous AND 150C Bursts?

Are there some Graphs laying around there somewhere?

Or did you just pull those numbers out of your.............................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. .................................................. ...........Hat?

I would love to hook up one of these 150c lipos to Pres Obama... See what kind of load that produces!!! A crap load I am sure, ahahahahaha.

Sorry, just could not help drawing a parallel with the kinda of honesty MA provide with the same virtue that our current pres has...

Deet dee dee.... See where it says "50"? :lol: If I had the cash I'd offer him $300. $6 a piece is a good deal for those resistors. The shipping is a bit high, though.

If anyone is interested, I have around 150 (maybe more) 3 ohm 50w resistors not being used. They are all new Dale metal finned case resistors, just be aware that the 50w rating is only valid if mounted on a heatsink and cooled. Just put the resistors in parallel and series arrangement to get the ohmic value you want. I even have some 12v fans to aid in cooling. PM me if interested.

I remember from electronics class in highschool that running resistors in parallel will usually come up with an oddball ohm rating, and there was some confusing math involved with it that i never understood. I know it is easier math when the resistors are the same, but it was when they were different and run in parallel is where it got really strange.

The math isn't overly complex.

For parallel resistors, there are a few methods: If all resistors are the same take the resistor value and divide by the number of resistors. So, if you have 100 X 3 ohm resistors, that would be 0.03 ohms. If using different value resistors (or can be the same), you can use "product divided by the sum" (R1*R2*R3*Rn)/(R1+R2+R3+Rn) or the "conductance" method 1/(1/R1+1/R2+1/R3+1/Rn).

For series, just add them up.

The advantage to using multiple resistors, especially in something that will generate this kind of heat, is the ability to spread out the thermal load. Also, you have much more flexibility in the actual ohmic value.

I was going to make a lipo test station a while back (which is why I have these resistors) and was going to create several 20 parallel resistor banks of 0.15 ohms. Then, just put those banks in series or parallel depending on the desired load and lipo voltage under test. Originally, I was going to use a MMM ESC in high-power brushed mode (can do ~300A for short tests) to regulate the actual amount of power to the resistors. The project never got anywhere because of a few technical details. You can read about it here if interested: http://www.rc-monster.com/forum/showthread.php?t=21478

Whatchu you mad about? With all the new tax cut money we're gonna borrow from the Chinese, we'll have moer to buy more chinese crap? All of our Fiscally Responsible Leaders in DC said its good for us.

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:lol:

Why to keep this post alive?
Maxxamps has no intention to respond to your request.
Their only goal is to keep the discussion alive to "talk about" their products.
It's a basic marketing rule.

I don't know guys but the diesel glow plug seed to have been doing the job easily. It got stupid hot but if you do the test on concrete I don't see an issue. One of them (at least the one I used) managed to pull just a little over 15A so I am guessing that you wouldn't need too many to test a lipo properly. I called one wrecking yard and they said that they wanted $85 for one second hand glow plug like the one I used so that wouldn't be feasible. I also called a truck wrecking yard and asked if the had some cheap glow plugs. They said that there are engines out back that I can have the glow plugs from for $10 a piece but I had to remove them my self. Still I am not all that confident doing this nor do I want to destroy any of my batteries so maybe I should leave this kind of testing to those in the know.

Where are these graphs? I'm still not impressed... I was charging my lipo's at the track on my 1:1 and my battery died. I started my car with a 3S 3300mah Turnigy lipo from my mate.
Not sure why I should pay for a 220$ a lipo that has proven to do the same thing than a 20$ lipo lol.

I can see it.
 

I can see charging a little bit more because of their 3 year 300 cycle warranty if there was a serious problem with there batteries, but from the info shared on these sites over the last two years Maxamps is not providing very much in the way of replacement products anyway. Look at the way CC does business with their motors, and ESC,s and their prices are still reasonable. It seems to me that these guys are doing the greed thing and leaving the customer hanging with substandard procudts. This is merely an opinion, but they still have not come forward with the information proving that these batteries are any better than the cheapo packs that a lot of people are acquiring through HobbyKing for much less. I think Brandon has pretty much given up on trying to prove anything to us here on RCM. If this were my company I would be excited about wanting to provide proof of our companies claims, that is unless they cannot do so. Things that make you go hhhhuuuummmm???

I think the "Others" may have gotten to him... Or perhaps when he asked the "Others" for the graphs, they said: "Is the RCM crew asking again???" :lol: