Maxamps and Neuenergy lipo testing

[DrKnow65]

hhhhmmmmm seems to me that one could do a better test of load vs. amperage with a carbond pile load tester (used in auto applications to load test a vehicle battery). You could hook it up to a lipo (one cell at a time would be best), then raise the amp load until LVC is reached. That would give you a solid number as to what the cell will put out. Beyond that I think you get into (controlled) tests that could potentialy damage the cells.

[lincpimp]

Well, if any of the batteries let go during my tests, at least I will know what not to buy next time.

I will start off with low gearing and slowly try to creap up on the correct load.

[VintageMA]

Originally Posted by DrKnow65

hhhhmmmmm seems to me that one could do a better test of load vs. amperage with a carbond pile load tester (used in auto applications to load test a vehicle battery). You could hook it up to a lipo (one cell at a time would be best), then raise the amp load until LVC is reached. That would give you a solid number as to what the cell will put out. Beyond that I think you get into (controlled) tests that could potentialy damage the cells.

I agree that this would produce a very "controlled" test, but it's also what you usually see in the graphs that manufacturers produce. (And at that - probably from a brand new cell that is in it's best condition) In general none of our buggies are going to run at over 20A continuous and they really high amp draws will be seen during hard accelerations and at top speeds. It's important to me how the Amp draws at top speed effect voltage drops as that's where you'll feel the most impact.

I kinda like this testing comparison as it's showing what these cells will be doing after being run for a while - a little more real-world.

here is what i just did

i ran my truck and i came in and checked V and both of my 2s packs were at 7.5v , my lvc is set at 12.4 so 3.1v/p/c

i decided for fun to try something, i hooked up my volt meter and it read 15v, my truck is on a stand and the wheels were allowed to free spin, my set-up is a mm/9xl with maxamps 2 x 2s 5k lipos wired together , geared 14/46 with heavy basher badlands

anyway on to the good stuff.............

with basically no load my V dipped from 15v to 11.88v under full throttle

i will try this again once i have recharged my packs and my V will be at 16.8V


i will be tring the neu energy packs or at least something rated higher then these in the future, but as far as i can tell a 30c discharge pack would give great runtime and also be better for the batterys, i guess i am pushing these

Originally Posted by DrKnow65

hhhhmmmmm seems to me that one could do a better test of load vs. amperage with a carbond pile load tester (used in auto applications to load test a vehicle battery). You could hook it up to a lipo (one cell at a time would be best), then raise the amp load until LVC is reached. That would give you a solid number as to what the cell will put out. Beyond that I think you get into (controlled) tests that could potentialy damage the cells.

I have done this on my lipo's and they all have come up short. Maxamps 4s6000mah 20c tests at 70 amps @ 12 volts which makes it 11.66c . Trinity Lipro 2s 4500mah 20c tests at 40amps @ 6 volts which makes it 8.88c. The trinity packs I tried to get the rated 20c (90 amps), 70 amps was max I could get and the voltage went down to 2 I only held it there for a few seconds. Basically you could dead short the Trinity packs and 70 amps would be all you would get. I don't have alot of faith in the manufactures numbers.

[lincpimp]

Originally Posted by Cowboy

I have done this on my lipo's and they all have come up short. Maxamps 4s6000mah 20c tests at 70 amps @ 12 volts which makes it 11.66c . Trinity Lipro 2s 4500mah 20c tests at 40amps @ 6 volts which makes it 8.88c. The trinity packs I tried to get the rated 20c (90 amps), 70 amps was max I could get and the voltage went down to 2 I only held it there for a few seconds. Basically you could dead short the Trinity packs and 70 amps would be all you would get. I don't have alot of faith in the manufactures numbers.

Great info! Any specs, or info about your test gear? How was it setup? Any chance of a pic?

Trinity LiPro's are the worst I have run. fresh pack in a Traxxas VXL will trigger the LVC 50% power mode when punching the throttle to full. Even the MA batteries did not do this. We tested 3 Trinity LiPro's on 2 different VXL's to make sure it was not a isolated issue.

[lincpimp]

Originally Posted by Dewmerz

Trinity LiPro's are the worst I have run. fresh pack in a Traxxas VXL will trigger the LVC 50% power mode when punching the throttle to full. Even the MA batteries did not do this. We tested 3 Trinity LiPro's on 2 different VXL's to make sure it was not a isolated issue.

I had the same issue with a maxamps 4000 pack. When it was fully charged it was fine, but it did it after a few mins.

This is what I'm using. It's very simple. It is just a ammeter and a voltmeter with adjustable load. You just hook your battery up to it and turn the knob. As amps go up volts go down, just watch the gauges. You can adjust it for any load you want. If you want to do a long test like 40 amps for 10 minutes I would put a fan on it

[lincpimp]

Originally Posted by Cowboy

This is what I'm using. It's very simple. It is just a ammeter and a voltmeter with adjustable load. You just hook your battery up to it and turn the knob. As amps go up volts go down, just watch the gauges. You can adjust it for any load you want. If you want to do a long test like 40 amps for 10 minutes I would put a fan on it

Nifty. That looks like a good piece of equipment.

[VintageMA]

Some more MaxAmps 5Ah 3S pack puffing.....

I've got 2 3S MaxAmps 5Ah packs that I've been using for not even a year. They've got maybe 30 - 40 cycles each. Since I've put in the RCM extended chassis on my CRT.5 and went up to 30 series tires my Amp draw has gone way up and runtime gone way down. I know peaks are hitting the high 90s, but the packs are lasting no more that 10 minutes. That's an average of (60/10)*5=30Amps.

30 Amps continuous (really a 6C rating) and at the end of one run a pack was reading 130* and was puffed out on both side. The puffing went down as the pack cooled - but I sat there and watched th pack for about 30 minutes - I was afraid to put the pack in the car for the ride home.

Very disappointing - I have already ordered a 3S 3900 (25C) Neu pack - so we'll see how much better it does when it comes in.