Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: Chris on November 01, 2008, 05:05:30 pm
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Hi Folks,
I hope you can help me with this problem. I am building the AnjteII and using the Robbe geared motor with the Ripmax Xtra BS10 ESC. I have wired everything up carefully with a switch and fuse in the positive from the battery as per advise from you guys. On switch on the servo for the rudder works fine but the motor is not working properly. On applying some forward on the stick nothing happens and then it pulses a few revs and stops then it may run a few revs maybe 2-3 seconds. I have removed the motor from the prop linkage just in case the alignment was not good but I get the same effect! Do you think I have a faulty ESC? I have had it some time so it is well out of the guarantee period. The transmitter is a Futaba Attack 2ER with R122JE receiver.
I would be grateful for any advice, Thanks
Chris
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If you connect the battery direct to the motor does it spin and appear all ok?
Bob
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Yes Bob, it spins OK with direct connection from the battery.
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Hi there Chris
Quick question Sir, do you have 4.5 battery connected into your RX ? as well as your main battery supply connected to the speed controller ?
The reason I ask, according to the web, your particular speed controller contains a BEC - battery eleminating circuit - which means you don't require a 4.5 battery connected into your receiver.
Just a thought....
aye
John e
bluebird
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Hi John,
No I don't have a separate battery because the motor is run from channel 2 of the receiver.
Chris
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Hi Chris
Is your battery fully charged as the BEC requires 5V to operate ?
Silly question ?
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Hi Richard,
Yep, the battery is fully charged.
Chris
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Was just about to say that Richard.
It could be your battery hasnt got enough guts to turn the motor whats the Mah rating?
Even though you have the rudder working the battery wont have enough power to turn the motor
Jay
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Chris, this may sound a stupid question, but does your receiver have more than 2 channels? If so, have you tried channel 3? Pete M
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Chris,
Do you turn the Transmitter on before the reciever?
Bob
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There is only 2 channels on the Rx and I did turn the receiver on before the Rx.
The battery is a Powertech 3-XM-4 (6v, 4Ah/20HR)
Standby use: 6.8V - 6.9V
Cyclic use: 7.35V - 7.5V
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Chris,
The ESC is a microprocessor controlled unit, without a Transmitter signal it will seek one and if it doesnt find one shut down.
You should always turn on transmitter before reciever.
Try it with the transmitter on first.
Bob
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Sorry Bob, my fingers are not receiving from my brain %% !!
I did turn on the Tx before the RX
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I have sent you a pm.
Bob
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... poor read on my part, never mind... %)
Lets see, does the rudder work when plugged into the other channel?
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Chris,
To get right back to basics is there any way you could post a pic of the complete set up?
Bob
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Chris.
You need to use a 6 Cell pack.
Regards
Sandy
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i have had this with an m tronics speed controller . some how i had but it in to programing mode. if your esc is programable this might Be the problem. check your Manuel that came with your speed controller
john
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May i ask which Robbe geared motor you are using?
John the ESC in question can run from 6v and has auto set-up so the SLA in my eyes cant be the problem. The radio set doesnt seem to be the problem either as the rudder works via Tx.
Sounds very much like the motor has either pulled too many amps and killed the ESC or its far too power hungry in which case i would try more volts.
Jay
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Going back to basics here, but what you describe sounds like interference from the motor operation on the receiver. I've had this before on a couple of vessels with exactly the effect you describe. I placed tw3o condensors on the motor, one from each of the positive and negative terminals to ground. Cleared the problem right up. Sparking on the commutator on the motor sets up a radio signal that interferes with the revceiver. In extreme cases I've even seen the rudder twitch uncontrollably when the motor runs.
John
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Hi Guys,
Thanks for all your replies.
This is the motor I'm using: http://at.robbe-online.net/rims_at.storefront/490d74ee000244bf271e3e0dc146060d/UserTemplate/1/?ISID=490d74ee000244bf271e3e0dc146060d
I also put the battery back on charge for a while and I'm now getting the motor to run but it cuts out at full throttle. It maybe that I just haven't charged it enough. However the battery charger instructions says that the battery is charged when the charging indicator light is flashing, which it is.
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Chris,you really nead a higher voltage battery with that speed control!
The minimum is a 6 cell rechargeable
A 6 volt lead acid battery will not work.
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Chris that ESC cuts out at 5V so it would appear you need more voltage.
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Thanks chaps for all your help and advice.
It looks to me that I have to buy another battery for this ESC. The motor is rated at 6-9.6 v and the blurb on the ESC says the input voltage is 6 to 12 cells ?. Does this mean that I can use a 12v lead acid cell!?
If not what battery should I use.
Sorry for my ignorance on this but this is my first attempt at radio control and it is proving to be quite challenging!
Chris
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Hi Chris one cell is 1.2 V.
6 cells is 7.2V
12 cells is 14.4V.
:-))
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A 12 volt would work but the bec would be hotter.
That is OK but it may be prone to thermal cutout.
I can't say for sure but the answer may be in the "blurb"
Perhaps if you scanned and posted with a 150k JPEG image attachment of instructions then folk with wider experience - but not with your esc - could chip in.
Regards
Sandy Calder
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Sandy,
Here is a link to the info on the Ripmax site which gives some info:
http://www.ripmax.com/item.asp?itemid=P-XTRA-BS10&ItemsPerPage=100&selectedtab=060&Category=060
Chris
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Chris,
Are you a member of a club so you could borrow another speed controller and check if that works?
If not pm me.
Bob
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Lord Bob!
There's nothing wring with it.
It has a low voltage cutout to stop the receiver voltage falling so low it forgets the neutral.
It's not meant for less than 6 cells which is 5.4 volts (0.9 per cell) under load and 1.35 volts per cell charged,no load.
PM coming to you Bob
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Sandy,
Here is a link to the info on the Ripmax site which gives some info:
http://www.ripmax.com/item.asp?itemid=P-XTRA-BS10&ItemsPerPage=100&selectedtab=060&Category=060
Chris
Hi Chris.
I think a few of the posters already googled the model number and got this info a day ago.
Just in case someone can come up with an alternative to a 6 or 7 cell battery,more detailed instructions might show if it is permissible,say,to add a receiver pack and prevent the low voltage cutout.
That,for example,would be a pointless suggestion if the cutout measures the bec input rather than the 5 volt side dropping out.
The 12 volt idea would be ok if you could limit the throttle setting but.........who knows?
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Sandy,
I will scan in the instructions that came with the ESC when I get home later.
Thanks for your info.
Cheers, Chris
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Sandy,
Attached is the scan of the instructions for the ESC, not a lot of help I suspect.
Cheers, Chris
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Hi Chris.
It's what in the model trade is known as an "entry level" controller
At least it revealed to others here that it is for car use.
Large displacement model tug users may tell you the peril of heading to port without sufficient reverse power in reserve.
I was looking to see if you could use a receiver pack to get around the low volt cutout.I suspect a technically competent person could see if that is OK and where to scratch a track and insert a bec cut off switch but it looks like the easiest option with this is keep it in reserve where you can use a NiMh or a 12 volt battery.
A 9.6 battery is actually about 12volts so whack on a smaller prop,or a 12 volt motor.
Regards
Sandy Calder
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Hi Sandy,
Thanks again for your input. It looks like I'll just have put the ESC in the spares box for some future project. I'm just a bit miffed that I was sold a complete package for this boat by a model shop who don't understand the subject very well.
I will have to look at getting a new ESC etc, I may go for the gear that Robbe recommend for this model although it's not cheap!
Thanks again,
Regards, Chris
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Chris, give me a ring - I've sent you a PM with my No.
Martin.
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Hi Guys,
Just to let you know that I ditched the Ripmax ESC and bought an Mtroniks as advised by fellow Mayhemers (Thanks !) and the motor is now running OK. But I still have a question I'm afraid!
When I first connected it all up, the motor still struggled to run so I check the battery voltage disconnected. It was showing approx. 5.6 to 5.7v so I put it on charge for about an hour. The Powertech auto charger LED was flashing showing a trickle charge as soon as I switched it on. When reconnecting the motor ran ok. What I'm asking is it seems that there is little drop in voltage needed to cause the motor to hesitate. Is my battery really powerful enough?? Or do I need to leave it on a trickle charge for longer.
Sorry about my ignorance in this subject but the books I've read never seem to give quite enough information. So I've come to the experts. Glad I found this site.
Cheers, Chris
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Chris,you have listened to a bum steer.
I don't know how loud you have to shout on this forum but there was nothing wrong with the Ripmax one.
You don't have enough voltage.
Look at your powertech instructions regarding what flashing means.
Regards
Sandy Calder
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Sandy,
I've kept the Ripmax ESC for future when I understand what I'm doing!
The flashing on the Powertech battery charger LED means that it's gone into trickle charge mode.
Chris
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Easily proved about the voltage by linking any 4 1.5 dry (Evereyready/Duracell) type batteries.
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Sandy,
I've kept the Ripmax ESC for future when I understand what I'm doing!
The flashing on the Powertech battery charger LED means that it's gone into trickle charge mode.
Chris
It was possibly a Powertech box where I read that the flashing LED indicates charging rather than trickle.Internet search suggests otherwise.I won't be able to look at the same box until Sunday.
Why not post a specific question to owners of said chargers.
If you have a multimeter you can measure the charge rate and the voltage when it switches to trickle.
I am more familiar with Yuasa and leisure battery chargers.
Correctly matched to the battery capacity,these bulk charge at the c/5 rate and switch to a "float voltage" at c/33 rate.
They have a voltage and a current limit and the charge cycle for a 10 amp hour battery on a charger recommended for it would go like this:-
The 2 amp current limit is in operation for maybe 30 minutes and the output voltage reflects the battery state.
While charging at 2 amp,the voltage rises up to the regulated voltage limit (14.5 or 7.3 volts).
The battery charges at 14.5 or 7.3 volts until the current falls to the trigger level of c/33 at which point the voltage steps down to 14.1 or 7 volts which will not damage a battery left on standby.
Your charger outputs a maximum of .5 amps
That is down to economics of supplying stuff from Asia at £3 each.
Charging is possibly 80% efficient so you would need to charge a flat 4.5 amp hour battery for 10 hours at .5 amps.
Regards
Sandy Calder
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Sandy,
With your knowledge of SLA batteries do you have any comments on my setup please? I am (intermittently) building a Fishery Protection vessel of 1940's vintage and the main batteries are 4 x 4.5ah Cyclon batteries in series giving a nominal 8 volt output. At the moment I use an old Flair Varivolt pulse charger which seems to do the job of charging them but I have never been able to find an SLA charger that is directly suitable for an 8v installation. The switchable types are all 12/6v. I think there are some gee whiz chargers that wll tackle anything about but they seem to cost an arm and a leg.
Any thoughts?
Colin
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Hi Colin.
I've got racks of components at arms length so I'd just make up a simple adapter to fit onto a 12 volt charger.Maplin used to do little action-like kits based on LM317's and I recall one which had the three stage action above.I am sure the internet is crammed with such diy projects all based on that chip.
You could probably do, on vero stripboard ,one of the two circuits on page 7 of the SGS LM317 datasheet http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXwqrz.pdf (http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXwqrz.pdf)
The simple one would be fine as long it is near the float level.You can get quite extensive info on the recommended rates from manufacturer websites.Three components would do.No vero needed.
It has been a while since I had anything to do with chargers and the technology has moved on a bit.The golf and leisure business is flooded with small Chinese made sealed chargers with a switch mode power supply and I have never had a reason to open one.
If you browse to an industrial catalogue like RS,Farnell,Rapid rather than Maplin you might get a few with the search facility.
I got some 4 cell Cyclon batteries from Proops but split them into 6volt packs.If they are ex-equipment cyclons I'd dispose of them.
Regards
Sandy Calder
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Thanks Sandy, I will follow up your links. My Cyclons are brand new. The boat's hull is very round bilge and they are the best fit in the space available. They are stacked under the speed controllers in the picture.
Colin
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Hi Colin.
{-) I couldn't identify that picture out of context.
http://www.euroenergy.co.uk/DbFiles/file274.pdf (http://www.euroenergy.co.uk/DbFiles/file274.pdf)
http://www.batteryuniversity.com/ (http://www.batteryuniversity.com/)
http://www.yuasa-battery.co.uk/industrial/np.html (http://www.yuasa-battery.co.uk/industrial/np.html)
The SLA vs NICD debate: http://www.sheldonbrown.com/marty_sla-nicad.html (http://www.sheldonbrown.com/marty_sla-nicad.html)
This correspondence describes the difference between a trickle and proper float charger quite well http://myreader.co.uk/msg/12713184.aspx (http://myreader.co.uk/msg/12713184.aspx)
I think Cyclon batteries are like deep discharge batteries in that they are less tolerant of overcharging and should be charged by a float charger.I can't remember off the top of my head.Perhaps it's worth looking to see if there are special requirements for that type.
A switchable 6/12 could be adjusted down to 4 cell with a switch and resistor.
Regards
Sandy Calder
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Colin
I use these batteries in an 8v configuration.
To charge them I simply connect them to a standard power supply, set the voltage at approx 9.6v. (This is the key issue in charging these, too high and they will get hot very quickly and overcharge, too low and they can take ages to charge.) They will initially take a huge current which I limit at 1 amp. Subject to the amount of re-charging required this will remain for a while, then the current will drop to a trickle and eventually be a around 10ma. (They are designed to be recharged very quickly 95% in a hour.)
I am also very careful not to leave them unattended for more than a couple of hours. If they are failing or left on for too long then they will get hot, at which point one of the cells is usually dead.
I also had a problem finding a charger and eventually settled on this method as the most reliable.
PM sent.
Best wishes
Jules64
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Thanks Jules, do you use a specific charger - you imply that it has an adustable voltage control - or is it one of the "step" type?
Colin
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Hi Colin.
Jules is right on all counts.It's there in the first link of the previous post.
A simple circuit with an lm317,2 voltage setting resistors and a diode(to prevent backflow) onto any 12volt charger would suffice if the limit was not 1.5 amp on the lm317.
You can get a 5 amp version of that device and also externally limit the charge current but that idea gets complicated.
A variable power supply would do.The step to float just means that you can leave unattended.
Sandy Calder
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I'm afraid electronics is closed book to me although i did build a Maplins ESC once. I need to puzzle over it a bit more.
Colin
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Colin and Sandy
I use a standard bench power supply. 0-30v and 0-2a. Can also charge SLAs etc (With monitoring!)
Best wishes
Jules
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Either that or a 6 &12v switched charger adapted for 6 & 8v by a suitable trimpot would do.
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You may have sorted it out already, A Swallow charger will charge any SLA batery 2-4-6-8-10 or12 volts it will also charge all other battery chemistry's you might have, I set mine for 0.2 c of capacity, charges them in about 6 hours fully automatic, 40 quid I guess trying to convert.
Regards
Nick