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Originally Posted by jim76
Sorry, back to the issue of the 20C - 25C again! I now understand about the output of the cells giving upto 100A etc. thanks for that
Just wondered what we currently get from good NiMH cells? Obviously most existing 4wd cars probably won't fit in more than a 3200 saddle lipo, so just wondered if that would be a reduction in punch compared to NiMH (although obviously the reduced weight would compensate).
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Top line Ni based cells will provide about 40 to 50 amps sustained like around 10 or so seconds if my memory serves correct. It has been a while since I even owned a set of Ni batteries. This is one of the reasons that in high powered BL systems Ni batteries just dont cut it. There are lots of problems that show up when you under supply current to the ESC. Now read the ratings carefully on your lipos. Ratings are given in different ways. Company A uses 'sustaned' C ratings and then B uses 'peak' then C says 'continous' and I have seen others. Find out what they mean exactly. Now those that give 'continous' ratings mean that the cell will hold that current till the pack is depleated. Where 'sustaned' generally means 15 seconds or less. So watch those very closely.
Now you may ask what is a high powered ESC? Well basically almost all sensorless units. Mamba, Quark, BK, MGM, MTronics and others. Even the small Mamba 25 and the Quark 33 can suffer problems from Ni batteries not suppling enough current. In testing the Mamba 25 in a Losi Mini T we saw current draws in the 120 amp area. Granted this was for fractions of a second, but they were there none the less.
I have a X10 Perdator and what I did was fit an older Pred cahssis that was made for a stick pack. Everything fit quite well. Now I have made a 4400 mah lipo saddle pack for the new chassis. I have to say that I see no difference in the handeling of the car. But that is most likely my lack of driving skill. Now the new Schumacher CatSX has a lipo ready chassis or a saddle pack chassis. I know that in the US the lipo chassis is selling like 10 to 1 over the saddle pack one. But in europe they are selling the saddle pack chassis in almost the same ratios over the lipo chassis.