Battery capacity

This topic is empty.

Viewing 9 posts - 1 through 9 (of 9 total)

Author

Posts
20 January 2011 at 16:33 #29512
Jeremy
Participant
@jeremy15845
I am using a Graupner speed 600 Race 7.2V motor on my Slo-mo-shun. Can I use any 7.2V NiMh battery with this motor. Will a 5000mah battery give me 66% more run time than a 3000mah battery? It sounds like it should but is it as simple as that? Picture of Slo-mo on the water below.

As always, your advice is appreciated
Jeremy
Advert

20 January 2011 at 16:33 #5105
Jeremy
Participant
@jeremy15845
20 January 2011 at 17:28 #29515
ashley needham
Participant
@ashleyneedham69188
I recon yes. As long as the battery is capable of delivering the current that your motor is drawing at full throttle to the first question, and yes to the second question,more or less.

Is this full or part throttle on your slo-mo?

Ashley

Edited By ashley needham on 20/01/2011 17:30:36
20 January 2011 at 17:46 #29517
Jeremy
Participant
@jeremy15845
Hi Ashley

Thanks for the advice.

The motor kept cutting out, maybe because I hadn’t fitted interference suppressors. The RC looked OK because the rudder responded even when the motor didn’t. The suppressors are now fitted but I will have to wait till the next visit to the lake to see this solves the problem. I don’t think the photo was taken during a period of sustained running. The blurred photo below (one hand on a camera and the other on a transmitter doesn’t work for me) probably was and is maybe a better indication of how fast the boat will go. I will post more pictures when she really gets going.

Jeremy
23 January 2011 at 11:12 #29563
ashley needham
Participant
@ashleyneedham69188
I have a few models whereby the r/c compartment is fairly cramped, with wires everywhere, but occaisionaljittery throttle probs can normally be cured by fiddling with positions of equipment, wiring runs and ariel wire location.

As long as a few basics are observed you shouldnt have too much trouble.

Ashley
23 January 2011 at 12:11 #29565
Jeremy
Participant
@jeremy15845
Thanks Ashley

However, I still have a problem. I have fitted suppressors to the motor and an external whip aerial but the motor still cuts out. It’s a bit more than jittery, sometimes requiring several seconds before it will run again. Photo of hardware set-up below. The speed controller (Mtronics Viper 25 watt) is at the upper right hand (to the rear of the left sponson). The position of the receiver is a bit constrained as it has to connect both to the rudder servo at the stern and to the speed controller. I ran the aerial wire behind the top battery before linking to the external aerial – as far away from the power cables as I can make it. All connections seem to be sound. Could there be a problem with the ESC – would it cut out if overloaded?

Any suggestions as to what else I can do would be appreciated.

Jeremy
23 January 2011 at 14:56 #29569
Telstar
Participant
@telstar
Hi Jeremy Do you mean Mtronics Viper 25A?If I remember correctly this range of ESC does have a build in thermal cutout which if you are approaching its working capacity (25A or so) and it has no ventilation at all could cause your problem. I would try to see/feel how warm the ESC is when these problems arise, if so move it to a position where the air can circulate

Cheers Tom
23 January 2011 at 17:24 #29573
Jeremy
Participant
@jeremy15845
Hi Tom, Ashley

I think I may have identified the cause of my problem. According to the LED’s on my RC transmitter, the batteries are running low. Changing the batteries has given me the green light I require but it will be a couple of weeks before I can return to the lake to see if this resolves the problem. I will report back then.

Who was it said that, as you grow older, you grow wiser? I think I must be the exception…..

Cheers Jeremy
7 February 2011 at 09:28 #29757
Jeremy
Participant
@jeremy15845
As suspected, the batteries or, more to the point, my stupidity were to blame. With these replaced, Slo-mo runs well if not exactly like the wind.

Thanks to all for their help.

Jeremy
Author

Posts