26 replies to this topic

[Nerfguy2002]

Does any one know if this battery NiMH Battery Pack: 12V 1600mAh NiMH Battery (10x2/3A flat ) Packs EDF would work with rhino motors. I can't find any thing about the current and I don't want to use a lipo or trustfires, just good old NiMH.

[shandsgator8]

It will probably work, but will probably overvolt the Rhino motors decreasing their life (although I don't know by how much). Rhinos are designed to run off of 3S packs, I believe. A 10 cell NiMH battery pack hot off the charger will probably be around 14-15 volts, which is probably a few volts higher than a 3 S LiPo hot off the charger.

 

There's no need to go above 8 cells with a NiMH battery pack when using Rhinos.

[ruggerroo]

A 10 cell NiMH battery pack hot off the charger will probably be around 14-15 volts, which is probably a few volts higher than a 3 S LiPo hot off the charger.

Partly true, but as stated here, Cells HOT (and I mean burning hot) off the charger will be at max 1.49v, meaning that your cell (unless charged with a specialised charger) will charge up to around 1.3v before the charger turns off (All of my chargers do this, some old ones might not cut off power?). But MTB Rhinos should be able to take the 13-15 volts because they have a nominal voltage of 12v.

Spoiler

The nominal voltage is 12Volts so it would be able to handle 13v-15v easily because, in theory, a nominal voltage is a safe to handle voltage for each motor. The motor life will decrease slightly if it happens a few times (over charged) but could impact the lifespan of the motors terribly.

Also for futher reference for commonly used Motors from this hobby, the 'database' most people refer to is here: https://docs.google....AwW7vg/htmlview

 

-ruggerroo

Edited by ruggerroo, 22 February 2016 - 02:41 AM.

[shandsgator8]

Rugerroo,

 

Are you saying that if the OP runs a 10 cell NiMH with MTB Rhino motors he will get the same motor life as if he ran an 8 cell NiMH pack? And whether he does or doesn't, is it your position that running MTB Rhinos with a 10 cell NiMH pack will give better performance than with an 8 cell NiMH pack?

[Nerfguy2002]

I have a smart charger, but I could take the battery off when it starts to get warm. I also have a voltage checker for batteries and I can see what its getting.

[shandsgator8]

FYI: When charging nickel chemistry cells, they should not be very hot when done charging. The cell's temperature will depend on the charging rate, but if you charged a 3000mah NiMH SC stick pack (commonly used in RC cars) at a 2C rate (6 amps), the pack should only be moderately warm. It certainly should not be "burning hot."

[jwasko]

Actually Rhino motors are specced (is that even a word?)to 12 Volts.
They are most commonly powered using a 3S LiPo which, when freshly charged is ~12.6V (4.2volts per cell).

Also, I've recently seen some people running Rhinos on 4S (14.8-16.8volts) either for a second stage of flywheels, or (if I remember correctly) for a rapidstrike pusher.

So I don't think you will kill them on a 12V nominal NiMH...I would probably recommend a 10.8V NiMH pack minimum (assuming that you are going for maximum dart velocity from a single flywheel stage). If you drop it down to 9.6volts (2 cell NiMH) then you'd only be getting ~28,000rpm which is just barely what is needed for maximum fps.

Edited by jwasko, 22 February 2016 - 12:31 PM.

[bdelong498]

The Rhino's should handle this pack just fine.  I've run a pair at 16 volts (4S) for a while now in the second stage of a four flywheel setup and had no problems.

 

That said 12-13 volts is a bit higher voltage than is optimum for Rhinos, IMO.  I'd offer that an 8 cell NiMH pack at 9.6 volts would be just about right for a two flywheel setup.

[Nerfguy2002]

So running two of these with the battery I linked would work, I have been looking like crazing but I can't find any thing else that would work with these.

[shandsgator8]

So running two of these with the battery I linked would work, I have been looking like crazing but I can't find any thing else that would work with these.

 

What do you mean you can't find anything else that will work with Rhinos? Already assembled 6,7, and 8 cell NiMH battery packs (using AA size cells or larger) can be found at practically any R/C hobby website. The only issue becomes where you can get the best deal or what battery pack has the lowest internal resistance. Speaking of IR, if the cell is SC size or larger, you'll be fine with practically any battery pack. AA sized packs are ok, too. However, you'll have to be sure it's a high quality cell (like Eneloop) and the pack's wiring and/or plug can handle the 10+ amp current draws just fine.

 

Lithium cells seem to be the future of R/C, but NiMH isn't going away just yet.

[Nerfguy2002]

Well I herd that the AA batteries would not have a good rev up speed so I have been looking for non AA, otherwise I can find them every were.

[shandsgator8]

Well I herd that the AA batteries would not have a good rev up speed so I have been looking for non AA, otherwise I can find them every were.

 

Who said that? As long as the AA batteries aren't alkaline and are a good quality nickel cell (like Eneloops), they can work just fine with Rhino motors.

[Nerfguy2002]

I don't know what a envelope battery looks like but heres a link 12V, - 16.8V NIMH Battery Packs - BatterySpace.

[shandsgator8]

What the heck is an envelope battery pack?

[Nerfguy2002]

Wait, I am so confused. I am making a little project that does not have a battery tray so I need a pack.

[shandsgator8]

You need to answer the following questions first:

 

1. How many cells do you want?

2. What cell capacity do you want?

3. What cell size do you want?

4. What pack configuration do you want? (I presume you will be buying an assembled pack, not loose cells and making your own pack)

I don't know what a envelope battery looks like but heres a link 12V, - 16.8V NIMH Battery Packs - BatterySpace.

 

What is an envelope battery?

[Nerfguy2002]

Ok, I don't know much about batteries, I know they give the motors or lights power, if you give to many volts to the motors it will burn out your motor, and if you short them out, you have fireworks, and now I relies I made a spelling error, their not envelops, their eneloops. Is this what they are 12V.

[shandsgator8]

No, these are Eneloops:

 

https://en.wikipedia.org/wiki/Eneloop

[ruggerroo]

Rugerroo,

 

Are you saying that if the OP runs a 10 cell NiMH with MTB Rhino motors he will get the same motor life as if he ran an 8 cell NiMH pack? And whether he does or doesn't, is it your position that running MTB Rhinos with a 10 cell NiMH pack will give better performance than with an 8 cell NiMH pack?

No,

What I am saying is depending on your use, using a lower voltage isn't necessary (most cases). It would be common sense (I hope) that using slower motors isnt better, that is, unless you want superior lifetime. Im sure running rhinos on 10 cell wouldnt break them so suddenly and last long enough for the average user.

[shandsgator8]

Using slower motors (or running faster motors at a lower RPM) can be MUCH better. But apparently it's a preference thing. Some prefer 95-105 FPS with darts that are relatively accurate (say 1/2 of darts consistently hit a target the size of a standard door at 30 feet) while other want 120-130 FPS, but don't care if they literally can barely hit the broad side of a barn at 45 feet. I don't get how anyone wants the latter, but apparently most people do.

 

Case in point - the first 10 seconds of this video:

 

 

I don't recall what his FPS is, but when I run an 8 cell NiMH pack with Rhinos, my Stryfe shoots like Rob's. When I run a 6 cell NiMH, my darts are much more consistent and precise, but a minimal decrease in range.

 

You aren't Rob, are you?

Edited by shandsgator8, 23 February 2016 - 06:15 AM.

[Nerfguy2002]

Will I need new switches for the gun if I use that 12 volt or can I use stock switches. Also, to get good rev up speed should I get two of these and hook them up in parallel to get double the amps, or is that to much for the motors?

Edited by Nerfguy2002, 24 February 2016 - 06:11 PM.

[shandsgator8]

I don't know for sure, but I think it's a good educated guess to conclude that if you plug a 10 cell NiMH pack (of AA sized cells or larger) to 2 Rhino motors, you need to upgrade the switches. At the very least, you're dealing with a large amount of electrical inefficiency by not upgrading the switches. I would guesstimate that the startup draw from those motors at 14-15 volts will be about 12-15 amps, at least. Someone can correct me if I'm wrong.

 

You can hook up two 10 cell NiMH packs in parallel, but I don't know why you'd do that. If you want the increase in capacity or current potential, just get a larger cell pack. So no, it won't be too much for the motors by putting something in parallel. In series, then two 10 cell NiMH packs will probably fry the Rhinos fairly quickly.

Edited by shandsgator8, 24 February 2016 - 04:49 PM.

[Nerfguy2002]

Ok, thank you. What kind of switches would use. Theirs like a million different kinds.

Edited by Nerfguy2002, 24 February 2016 - 06:10 PM.

[Felix the cat]

Omron ss10s work well and have a 10amp rating in a small form factor.

[shandsgator8]

I used the Omron V-156-1C25 switch in my Rhino'd Stryfe. It's basically the same switched used by Ryan here:

 

 

(I basically did this mod but tweaked it slightly for my purposes)

 

I've got some extra for sale, if you want a few.

Edited by shandsgator8, 24 February 2016 - 07:25 PM.