Battery Q

[G.Rose]

I have a 4s. 6200mAh 100c battery.
Can I run battery with the same numbers but from a different manufacturer in series?

[TRUCKPULL]

I would say NO
There is no such thing as a 100"C" battery, every company puts their own "C" on them.

Here are the real "C" ratings, and AMP tests.

Only 4 company's batteries could put out 250A



Larry

[Ivan Kozyakov]

I would say NO
There is no such thing as a 100"C" battery, every company puts their own "C" on them.

Here are the real "C" ratings, and AMP tests.

Only 4 company's batteries could put out 250A



Larry

Thank you! Is it fresh data?

[NativePaul]

No, most of it is still pretty accurate, but it's a couple of years old at least , hoobyking have gone downhill since then, and there are new options.

See the battery forum on RC Groups for more current independent testing.

[Bande1]

This is why its dangerous to under volt a motor to match some silly RPM limit. Say you have a set of 70c rated batteries in series 3s2p thatis outputting a real world 30c on a 1500kv motor rated at 37v @ 3400w. To get to 3400w you're pulling about 140A because you mismatched the motors specs running 6s on an 8s motor. lower voltages at higher amps.

4000mah batteries capable of only 30c IRL - 4A x 30c = 120A
you're going to puff the packs and potentially have a lipo fire

if you match the motor with the proper voltage, 8s @ 1500kv, and not some made up RPM limit (i.e. 25k-30k rpm with a big prop/load) -105A = safe

then if you want to slow the boat down you can current limit through end points even further. Everything runs cool, safe, and batteries arent in dangerous territory.

to the OP - run them if you're not trying the "low RPM" theory but be on top of temps and cell voltages. go 30 seconds and bring the boat in monitoring them closely. if cells are way out of whack and there is a lot of heat, 130f+, stop. If they're cool and the cells are all matched well in both batteries go for 2 minutes and recheck everything.

[Xrayted]

Here is the direct link to the guys doing the testing for more than a decade. The first page is always kept current, and they are in the midst of testing this years packs, as many times packs that were great at one point drop down in quality over time.

https://www.rcgroups.com/forums/showthread.php?1767093-Battery-Load-Test-Comparisons

[Peter A]

This is why its dangerous to under volt a motor to match some silly RPM limit. Say you have a set of 70c rated batteries in series 3s2p thatis outputting a real world 30c on a 1500kv motor rated at 37v @ 3400w. To get to 3400w you're pulling about 140A because you mismatched the motors specs running 6s on an 8s motor. lower voltages at higher amps.

4000mah batteries capable of only 30c IRL - 4A x 30c = 120A
you're going to puff the packs and potentially have a lipo fire

if you match the motor with the proper voltage, 8s @ 1500kv, and not some made up RPM limit (i.e. 25k-30k rpm with a big prop/load) -105A = safe

then if you want to slow the boat down you can current limit through end points even further. Everything runs cool, safe, and batteries arent in dangerous territory.

to the OP - run them if you're not trying the "low RPM" theory but be on top of temps and cell voltages. go 30 seconds and bring the boat in monitoring them closely. if cells are way out of whack and there is a lot of heat, 130f+, stop. If they're cool and the cells are all matched well in both batteries go for 2 minutes and recheck everything.

So how does your theory work for class racing when there are cell/voltage limits?

One of the things you really don't get is that if you run a 1500 kv on 8s, that 105A you claim = safe, gets gone real quick if you over prop, boat runs wet, dunks at full throttle, or some other random issue creates excess load on the motor. Then you may lose motor, esc and battery, if you are lucky a bullet melts off and you just stop.

You have also derailed another post by going off on a tangent far from the ops question just to continue to push your pet theory, in complete ignorance of plenty of advice you have been given by many who have much more experience over decades. Why, just why?

If you want to run high rpm, go for it. But just because it has worked for you in one old small mono, doesn't mean it is the only advice/opinion to be considered. you need to spend some coin on bigger boats and learn the hard way chap.