Batt question

[Tony]

Does NiMh batt run times longer than NiCd batt? I have this scale boat which runs on a 8.4v 1300mah NiCd batt. Run time is around 5 min. I also have a bunch of 7.4v 1500mah NiCd batts... Should i run these batt in parallel to get a longer running time? Or, just get some new NiMh batts? I also have some 2s 7.4 lipos, but don't know if it will work with brushed motor or not.

[Flying Scotsman]

Tony, it comes down to voltage and amperage. More volts, possibly more power, higher amperage, a longer run time. Yes, use the LI-PO based on the voltage specs for the motor?

Douggie

[Tony]

Tony, it comes down to voltage and amperage. More volts, possibly more power, higher amperage, a longer run time. Yes, use the LI-PO based on the voltage specs for the motor?

Douggie

Its just a regular 550 brushed motor.

[Flying Scotsman]

Its just a regular 550 brushed motor.

What motor and # of turns, also what scale boat, transmission drive or,? But to answer your basic question LI-PO power is the way to go ,as long as your motor will accept the voltage

Douggie

[Tony]

What motor and # of turns, also what scale boat, transmission drive or,? But to answer your basic question LI-PO power is the way to go ,as long as your motor will accept the voltage

Douggie

Its a 1/20 scale, 2'2" L, 9"W
motor does not have a name, direct drive.

[Flying Scotsman]

Great looking boat, change out the motor, and you are set to go with LI-PO. Some guys will chime in for a motor choice for that hull...I think

Douggie

[Tony]

Great looking boat, change out the motor, and you are set to go with LI-PO. Some guys will chime in for a motor choice for that hull...I think

Douggie

Yea, i thought about changing out the motor to brushless. But, i want it to be able to go in reverse as this will also be use to retrieve my FE cats.

[pmdevlin]

Hi Tony,
nihm batteries are better than nicad. If you assume the volts and amps are equal, nicad are older technology, and have a memory effect. That means that they need to be fully discharged, and fully charged, to be used at their best. Nimh have no memory effect, so can be part charged, and chaged again. As they are later technology, the amps can be higher. If you wire up to double the amps, and keep the volts the same, you will achieve better run times, however, if one of the packs is weaker than the other, the weak one will fail, and the good one will end up feeding the bad one!. If you wire to double the volts, and leave the amps the same, you will get more speed, if the motor and esc can handle the volts, it will be way more fun! but less run time.
The lipo battery is the next generation, more efficient, more power, but need a dedicated lipo charger, preferably a balance charger to monitor the cells, and preferably run with a low voltage monitor, these cost pennies, and plug into the balance lead, as you MUST NOT overdischarge a lipo.
Lipos can be used with a brushed motor, as you have the batteries, its worth experimenting, but if the nicad is an old one is probably ready for the bin!
If you want to go brushless, you also need a different motor mount, and another esc, and reversing ones are a bit expensive, so its down to budget. Depending what performance you want, I would be tempted to get a graupner 700bb turbobrushed motor, another mount for it to fit, make sure your esc is up to the job, then you can experiment with different batteries. If you want brushless, then maybe the racing guys can advise, I was going to fit a feigao 10turn xl into my 4 foot scale boat, but I think your boat would be too light for this set up?
Hope that helps!

[sailr]

No problem running lipos with a brushed motor. Just follow the battery specs the instructions call for. VOLTS are VOLTS regardless of the battery chemistry.

[Flying Scotsman]

If you want to go brushless, you also need a different motor mount, and another esc, and reversing ones are a bit expensive, so its down to budget. Depending what performance you want, I would be tempted to get a graupner 700bb turbobrushed motor, another mount for it to fit, make sure your esc is up to the job, then you can experiment with different batteries. If you want brushless, then maybe the racing guys can advise, I was going to fit a feigao 10turn xl into my 4 foot scale boat, but I think your boat would be too light for this set up?
Hope that helps!




Laddy here is my reply

Another point of view

Rubbish, the Scotsman

Douggie

[Tony]

Hi Tony,
nihm batteries are better than nicad. If you assume the volts and amps are equal, nicad are older technology, and have a memory effect. That means that they need to be fully discharged, and fully charged, to be used at their best. Nimh have no memory effect, so can be part charged, and chaged again. As they are later technology, the amps can be higher. If you wire up to double the amps, and keep the volts the same, you will achieve better run times, however, if one of the packs is weaker than the other, the weak one will fail, and the good one will end up feeding the bad one!. If you wire to double the volts, and leave the amps the same, you will get more speed, if the motor and esc can handle the volts, it will be way more fun! but less run time.
The lipo battery is the next generation, more efficient, more power, but need a dedicated lipo charger, preferably a balance charger to monitor the cells, and preferably run with a low voltage monitor, these cost pennies, and plug into the balance lead, as you MUST NOT overdischarge a lipo.
Lipos can be used with a brushed motor, as you have the batteries, its worth experimenting, but if the nicad is an old one is probably ready for the bin!
If you want to go brushless, you also need a different motor mount, and another esc, and reversing ones are a bit expensive, so its down to budget. Depending what performance you want, I would be tempted to get a graupner 700bb turbobrushed motor, another mount for it to fit, make sure your esc is up to the job, then you can experiment with different batteries. If you want brushless, then maybe the racing guys can advise, I was going to fit a feigao 10turn xl into my 4 foot scale boat, but I think your boat would be too light for this set up?
Hope that helps!

Hi, thanks for taking the time to explain the differences in batts.
I think a 380 brushless will fit in this one. But, i have to find an esc with a reverse...
This guy on youtube has one with a brushless.

http://www.youtube.com/watch?v=BY9P7YNDo9E

[Tony]

If you want to go brushless, you also need a different motor mount, and another esc, and reversing ones are a bit expensive, so its down to budget. Depending what performance you want, I would be tempted to get a graupner 700bb turbobrushed motor, another mount for it to fit, make sure your esc is up to the job, then you can experiment with different batteries. If you want brushless, then maybe the racing guys can advise, I was going to fit a feigao 10turn xl into my 4 foot scale boat, but I think your boat would be too light for this set up?
Hope that helps!




Laddy here is my reply

Another point of view

Rubbish, the Scotsman

Douggie

I don't want to turn this boat into a speed demon. Just want it to run atleast 10 min or more at a scale speed. I have plenty of 2s lipos, and a spare esc w/o reverse for a 380 brushless motor. Maybe, i should try NiMh batt first, and go from there.

[pmdevlin]

Hi Tony, I know what you mean regarding scale speed, its a nice looking boat, and the point I was trying to make (dont really know what douggie means by his response?) if you get it going too fast, it will be unmanageable and unstable, that hull could be difficult to turn, its certainly taller than a racing boat hull. I have a 3 foot scale boat, that is going way over scale speed on a brushed setup, and its very difficult to turn unless you slow right down, the profile of the hull rolls a lot!
A friend of mine has 2 mystery brushless esc's in a twin screw scale boat, they are on fleabay, (and quite cheap) might be worth a try with the brushless motor you have, and they are reversing.
You might need a programme card to set it up, we had to change all the factory settings to have soft start, and soft reverse etc . Also make sure that the esc will do fiorward AND reverse, there are a few out there on the net that are a little misleading with the description, forward, OR reverse (naughty!) if unsure mail the seller for confirmation!
Best of luck

[785boats]

Here's a couple of reasonably priced reversing ESCs. Watercooled & with BEC.
Haven't tried them myself but I have got other Turborix gear that works just Fine.
I have also burnt an older Turborix reversing ESC (older model) but that was totaly my fault.

http://www.r2hobbies.com/proddetail.php?prod=rcps81712_60

http://www.r2hobbies.com/proddetail.php?prod=rcps81712_90

Cheers.
Paul.

[Tony]

Here's a couple of reasonably priced reversing ESCs. Watercooled & with BEC.
Haven't tried them myself but I have got other Turborix gear that works just Fine.
I have also burnt an older Turborix reversing ESC (older model) but that was totaly my fault.

http://www.r2hobbies.com/proddetail.php?prod=rcps81712_60

http://www.r2hobbies.com/proddetail.php?prod=rcps81712_90

Cheers.
Paul.

The 60amp esc bi directional is what i'm looking for. But, its out of stock.