turnigy

[the badger]

hi guy's would 2x 20c 5000mah hard case be ok for a xblaze super version and what run times would i expect.
thanks badger.

[penz]

They may be enough. I would personally feel more comfortable with 30c+. Run them a little and watch batt temps and for puffing.

[the badger]

the instructions say 20c 4000mah?.
i was using 2x 3s 35c lipos and 1 went poof lol. any ideas why?

[penz]

If the instructions state 20c then your fine. And 5000mah is fine to as long as they fit. Mah is just the run time basically.

What were the mah on the 3s packs you have? Regardless of the c rating if the mah is too low for the application the batts will still puff.

[the badger]

2200 my plane batts ( zagi tazz lipo's ) is it because they drain to fast? i asked my lhs but they had no clue. i am still learning... the instructions said use 3s 4000. but there was a amendment sheet stapled to the front saying only use 2x2s 4000mah 20c as i am only new to fast electrics it was confusing and a right pain in the ass. well i have just learnt the hard way. so if the mah is to low they puff?

[penz]

Yeah 2200 is too low. The equation for figuring out how much amp draw your batery can handle is (c rating)x(amp hours). Just divide mah by 1000 to get ah. So in your case 2.2x35=77. I bet tht boat is pulling close to 77 amps, if not more...

Also check to make sure your low voltage cutoff is properly set so you do not overdraw your battery, this will cause puffing too.

[penz]

the instructions said use 3s 4000. but there was a amendment sheet stapled to the front saying only use 2x2s 4000mah 20c as i am only new to fast electrics it was confusing and a right pain in the ass. well i have just learnt the hard way. so if the mah is to low they puff?

That boat was prob setup to run on 1 3s 4000mah bat, and they changed it to run on 4s by using 2 2s in series. If you had 2 3s batts on there thats 6s, the motor/esc may not be capable of handling that kind of voltage. I would run 4s as they suggest unless you sure the motor/esc can handle more.

[kookie_guy]

It's only a couple more bucks for 40c, why not just go 40c? Just means your batteries will run cooler, plus when it comes time to upgrade (that time always comes, no matter how much you say to youself you'll stay stock) you will have packs that can supply the increase in amp draw.

[the badger]

the esc says 6s on it but its only a 90amp esc? how would i check the low voltage cutoff the manual says:
the thermo protection activated at 120c. lvp low voltage protection engaged when lipo battery per cell drop down voltage 2.9v 1st step. voltage 2.6v 2nd step, see note below(operating cell 2s-6s lipo current raTING 90 A. PEAK CURENT 100amp within 15 seconds. this is double dutch to me.

[penz]

It's only a couple more bucks for 40c, why not just go 40c? Just means your batteries will run cooler, plus when it comes time to upgrade (that time always comes, no matter how much you say to youself you'll stay stock) you will have packs that can supply the increase in amp draw.

Agreed. Its also better to get batterys that can handle at least 1.5 times the max continous amp draw. For example if your boat draws 100 apms constant those 20c bats will do it but be working hard, 5x20=100. So 40c bats with the same mah 5x40=200 thats double, the bats will be happy.

[penz]

the esc says 6s on it but its only a 90amp esc? how would i check the low voltage cutoff the manual says:
the thermo protection activated at 120c. lvp low voltage protection engaged when lipo battery per cell drop down voltage 2.9v 1st step. voltage 2.6v 2nd step, see note below(operating cell 2s-6s lipo current raTING 90 A. PEAK CURENT 100amp within 15 seconds. this is double dutch to me.

Use step 1 2.9v, its safer. Ok well it can handle 6s, but your bats could not handle the amp draw. Sounds like it has lipo auto detect, meaning when you plug in 3 or 4 or 6s it detects it and sets the lvc accordingly. Just make sure you always use fully charged bats with auto detect, if indeed it does have auto detect.

[the badger]

omg lol this is a science in itself i get it sort of. i thought i would get a rtr and it would be easy oh boy was i wrong but like every hobby you learn as you go...is there a book on this for dumbies i feel like a right dumb arse.

[the badger]

ok so the 2.2mah x25c x2=110 amp ?

[penz]

ok so the 2.2mah x25c x2=110 amp ?

Are you talking about the 3s bats? Earlier you said they were 35c? And no that equation is wrong. When you put 2 3s batts in series you increase the voltage but the mah stays the same.
so if your batts are 2200mah 25c its 2.2x25=55.

there is two ways to hook up multiple batterys. 1-series: increase voltage, run time (mah) stays the same. 2- parallel: increase mah, voltage stays the same.

[kookie_guy]

In my opinion, 2.9v/cell is too low of a cutoff point. By the time you hit that, your batteries are over-discharged. 3.4v/cell is a good setting (you don't have that option tho).

You should never run your boat til it hits cutoff. Cutoff is a last ditch effort to save your lipos. It should be based on time. Monitor your voltages the first few times you use your boat. You'll be able to get a good feel of how long it's safe to run the boat.

General rule of thumb is to not discharge your packs lower than 20% capacity. If you have a charger that tells you how much mah got pumped back into a pack after charging, you can figure out how far you went. Then go back to your times, and now you can get a good feel for how long you can run. So a 5000mah capacity pack should not be discharged below 1000mah. Your charger should pump 4000mah back into the pack.