Santa needs help (RC car build question)
Discussion
So Santa was extremely generous to my son Joe (who is reading this thread) and brought him a LRP S10 Twister which we have just spend the last enjoyable 48 hours building. Until we reached the penultimate stage and tried to attach the pinion cog to the brushless electric motor and found the worlds smallest grub nut needing the worlds smallest allen key. Which obviously I didn't have. Cue trip to Maplins today.
Car now fully assembled bar power and shell and lovely it is too. The ABS plastic is really tough looking, much tougher than the black stuff my Tamiya Hornet was made from (back in the eighties). Joe was thrilled with it and dad pretty happy too.
Cue latest problem and wobbling eight year old lip: There appears to be no way of charging the lipo batteries with the B6 charger
nor of connecting the ESC to the battery.
Finally, the receiver-sized plug coming off the battery doesn't fit the receiver.
This is all despite Santa's long hard research into checking that these sort of things should not have been a problem!
So, can anyone advise of the solutions and the quickest way of getting these things sorted? We live near Thornbury (M4/M5 junction) so Bristol is close-ish (45 mins usually) or there is of course mail order. Amazon are probably back to being quick now Christmas day has passed?
Car now fully assembled bar power and shell and lovely it is too. The ABS plastic is really tough looking, much tougher than the black stuff my Tamiya Hornet was made from (back in the eighties). Joe was thrilled with it and dad pretty happy too.
Cue latest problem and wobbling eight year old lip: There appears to be no way of charging the lipo batteries with the B6 charger
nor of connecting the ESC to the battery.
Finally, the receiver-sized plug coming off the battery doesn't fit the receiver.
This is all despite Santa's long hard research into checking that these sort of things should not have been a problem!
So, can anyone advise of the solutions and the quickest way of getting these things sorted? We live near Thornbury (M4/M5 junction) so Bristol is close-ish (45 mins usually) or there is of course mail order. Amazon are probably back to being quick now Christmas day has passed?
Brilliant. That's saved a cock-up!
There would appear to be only one plug coming off the ESC that could plug into the receiver though? If that's the power, where is the control signal wire? i.e. How does the RX tell the ESC what to do?
Also, have figured out that the lipo battery has 4mm HXT connectors. Are you saying I connect the pack using the crocodile clips to the HXT? As in, open the clip up, stick half in the HXT and then let go? What about with the male side?
Last one - Good place to buy HXT connector quickly? ebay is saying weds, anywhere sooner?
Edit: reading here http://www.rcgroups.com/forums/showthread.php?t=14...
it would appear that the esc plugs into the throttle port of the rx and powers it from there. FFS none of this is in any of the manuals.
There would appear to be only one plug coming off the ESC that could plug into the receiver though? If that's the power, where is the control signal wire? i.e. How does the RX tell the ESC what to do?
Also, have figured out that the lipo battery has 4mm HXT connectors. Are you saying I connect the pack using the crocodile clips to the HXT? As in, open the clip up, stick half in the HXT and then let go? What about with the male side?
Last one - Good place to buy HXT connector quickly? ebay is saying weds, anywhere sooner?
Edit: reading here http://www.rcgroups.com/forums/showthread.php?t=14...
it would appear that the esc plugs into the throttle port of the rx and powers it from there. FFS none of this is in any of the manuals.
Edited by marcg on Sunday 27th December 00:38
That is correct, the small connector goes to the throttle channel (normally channel 2) of your rx and the ESC will provide power to the rx through the connector as well. Channel 1 of the rx goes to the steering servo.
Now regarding charging and connecting the battery to the ESC. You will need to solder a connector to the red and black wires from the ESC (I assume the other 3 wires will connect to the brushless motor). Looks like you have a deans connector for your B6 charger, so I would be inclined to buy a male and a female deans connector. Solder one to the red and black ESC wires and replace the battery connector with the other. You will then easily be able to both charge the battery and connect it to the ESC.
Here is a link to male & female deans connectors so you can check that this will fit your charger leads:
http://www.modelsport.co.uk/overlander-deans-style...
I hope this makes sense. It isn't the only solution and others may reply with a better one, but it should work.
Now regarding charging and connecting the battery to the ESC. You will need to solder a connector to the red and black wires from the ESC (I assume the other 3 wires will connect to the brushless motor). Looks like you have a deans connector for your B6 charger, so I would be inclined to buy a male and a female deans connector. Solder one to the red and black ESC wires and replace the battery connector with the other. You will then easily be able to both charge the battery and connect it to the ESC.
Here is a link to male & female deans connectors so you can check that this will fit your charger leads:
http://www.modelsport.co.uk/overlander-deans-style...
I hope this makes sense. It isn't the only solution and others may reply with a better one, but it should work.
marcg said:
Brilliant. That's saved a cock-up!
There would appear to be only one plug coming off the ESC that could plug into the receiver though? If that's the power, where is the control signal wire? i.e. How does the RX tell the ESC what to do?
Also, have figured out that the lipo battery has 4mm HXT connectors. Are you saying I connect the pack using the crocodile clips to the HXT? As in, open the clip up, stick half in the HXT and then let go? What about with the male side?
Last one - Good place to buy HXT connector quickly? ebay is saying weds, anywhere sooner?
Edit: reading here http://www.rcgroups.com/forums/showthread.php?t=14...
it would appear that the esc plugs into the throttle port of the rx and powers it from there. FFS none of this is in any of the manuals.
Where are you Marc, you could really do with a local PHer to help you set it up especially regarding the lipo.There would appear to be only one plug coming off the ESC that could plug into the receiver though? If that's the power, where is the control signal wire? i.e. How does the RX tell the ESC what to do?
Also, have figured out that the lipo battery has 4mm HXT connectors. Are you saying I connect the pack using the crocodile clips to the HXT? As in, open the clip up, stick half in the HXT and then let go? What about with the male side?
Last one - Good place to buy HXT connector quickly? ebay is saying weds, anywhere sooner?
Edit: reading here http://www.rcgroups.com/forums/showthread.php?t=14...
it would appear that the esc plugs into the throttle port of the rx and powers it from there. FFS none of this is in any of the manuals.
Edited by marcg on Sunday 27th December 00:38
If OP hasn't yet burned his house down I think you need to do some research into lipo batteries; safety, use and storage. Worrying as these things become more mainstream that they're falling into hands of unfamiliar users. Especially seeing as those are soft-case lipos too!
As above, if you're local I or anyone else would happily take you through the basics. Apologies if any of this post comes across as condescending, it really isn't meant to!
As above, if you're local I or anyone else would happily take you through the basics. Apologies if any of this post comes across as condescending, it really isn't meant to!
Many thanks for the help and offers of help. In the end we went to Antics in Bristol and got some good advice. By the 27th we were up and running!
Nevertheless, I'd like to double check the conclusions with you, just to be sure. I'd also like to share the info for other newbies...
The connectors were 4mm HXT bullet connectors. Antics sold them in store but their online shop gave no indication of this. If I'd stuck with google I would have had to order from ebay or Hobbyking. I de-soldered the crocodile clips from the supplied charger leads and soldered on the HXTs with matching polarity but reversed plugs; so red for red but male into female. I did the same for the ESC.
Next I had to figure out the Imax B6 charger or did I? I checked the voltage with a meter and found both batteries were at 7.6V. Enough to go out for fun. Later i found out this was probably a storage level of charge but it worked and we'd been waiting for days.
So, unpainted shell and part-charged batteries, off we went up the cotswold way:
Kids loved it, dad loved it, dog didn't stop barking for a solid hour. Even only part-charged, each 3600mah lipo lasted 45 minutes. When I was a kid, my Hornet would only go for 20 mins on a nicad and only the first 10mins of that were any good. These went for 45mins full power then ran out. Brilliant. The car is tough, it ran full pace into a few trees and no damage. It also climbs through piles of leaves and power slides around on mud.
So the evening after that, I managed to sort out charging. The imax B6 needs a DC adaptor between 11-15V and I managed to find one in the house that fitted (off the scalectrix). Plugged that in and on came the charger. We'd bought a lipo sack from Antics so in went both batteries and the first plugged into the charger - balance lead to the 2S port, main HXT plugs to the newly soldered leads.
Next question, what settings? Please check this:
Lipos charge at 3.7V per cell
Max input current is 1C = 1A per 1000mAH capacity unless manufacturer states it is higher.
Hobbyking website stated max 2C
So our 2S 3600mah must be charged at 7.2V but up to 7.2A
The imax can charge at up to 5A so I set that, pressed start (you need to hold down the start button for 3secs) and confirmed the 2S that it detected by pressing enter for yes.
Immediately I got a "input voltage error". Which made no sense to me as the adaptor clearly noted 15V DC.... at 1.2A. Only a tiny little adaptor really.
So I changed the input voltage to 1.2A to match the adaptor and success. 2.5 hours later, fully charged battery showing 8.4V on the charger and 8.36 on my meter. I think I can correct the B6 metering in settings somewhere but near enough for now. And the batteries didn't even get warm during charging (not surprising at that current).
I charged both batteries and we went off to play on a private driveway to a school before pub. I realised I had turned the throttle down to 85% on the controller so put it up to 100% to see. Bloody hell, it flies. On wet tarmac it basically spins its rear wheels on a hair trigger meaning drifting galore. More fun up in the woods though. After 45 mins, we still hadn't run out of power but had run out of light so went to the pub!
So all that remains is to finish painting the shell. That's been a bit messy - we used magic tape to mask off bit and there's been a bit of over spray here and there but the colours are totally the kids' design and it has all been part of the fun.
So other than the settings, last question - we have one fully charged lipo in a sack and one part charged left in the model. Should these both be in the sack until next time?
Nevertheless, I'd like to double check the conclusions with you, just to be sure. I'd also like to share the info for other newbies...
The connectors were 4mm HXT bullet connectors. Antics sold them in store but their online shop gave no indication of this. If I'd stuck with google I would have had to order from ebay or Hobbyking. I de-soldered the crocodile clips from the supplied charger leads and soldered on the HXTs with matching polarity but reversed plugs; so red for red but male into female. I did the same for the ESC.
Next I had to figure out the Imax B6 charger or did I? I checked the voltage with a meter and found both batteries were at 7.6V. Enough to go out for fun. Later i found out this was probably a storage level of charge but it worked and we'd been waiting for days.
So, unpainted shell and part-charged batteries, off we went up the cotswold way:
Kids loved it, dad loved it, dog didn't stop barking for a solid hour. Even only part-charged, each 3600mah lipo lasted 45 minutes. When I was a kid, my Hornet would only go for 20 mins on a nicad and only the first 10mins of that were any good. These went for 45mins full power then ran out. Brilliant. The car is tough, it ran full pace into a few trees and no damage. It also climbs through piles of leaves and power slides around on mud.
So the evening after that, I managed to sort out charging. The imax B6 needs a DC adaptor between 11-15V and I managed to find one in the house that fitted (off the scalectrix). Plugged that in and on came the charger. We'd bought a lipo sack from Antics so in went both batteries and the first plugged into the charger - balance lead to the 2S port, main HXT plugs to the newly soldered leads.
Next question, what settings? Please check this:
Lipos charge at 3.7V per cell
Max input current is 1C = 1A per 1000mAH capacity unless manufacturer states it is higher.
Hobbyking website stated max 2C
So our 2S 3600mah must be charged at 7.2V but up to 7.2A
The imax can charge at up to 5A so I set that, pressed start (you need to hold down the start button for 3secs) and confirmed the 2S that it detected by pressing enter for yes.
Immediately I got a "input voltage error". Which made no sense to me as the adaptor clearly noted 15V DC.... at 1.2A. Only a tiny little adaptor really.
So I changed the input voltage to 1.2A to match the adaptor and success. 2.5 hours later, fully charged battery showing 8.4V on the charger and 8.36 on my meter. I think I can correct the B6 metering in settings somewhere but near enough for now. And the batteries didn't even get warm during charging (not surprising at that current).
I charged both batteries and we went off to play on a private driveway to a school before pub. I realised I had turned the throttle down to 85% on the controller so put it up to 100% to see. Bloody hell, it flies. On wet tarmac it basically spins its rear wheels on a hair trigger meaning drifting galore. More fun up in the woods though. After 45 mins, we still hadn't run out of power but had run out of light so went to the pub!
So all that remains is to finish painting the shell. That's been a bit messy - we used magic tape to mask off bit and there's been a bit of over spray here and there but the colours are totally the kids' design and it has all been part of the fun.
So other than the settings, last question - we have one fully charged lipo in a sack and one part charged left in the model. Should these both be in the sack until next time?
For safety, keep them in the sack at all times when not in use - at thr very least, I've gone so far as to put the batteries inside the sack and inside an old munitions box I got from an army surplus shop - I've seen an NiMh cell explode and that's enough to make me paranoid!
Personally I don't charge my cells at anything greater than 1C, so for a 4000mAh I would charge at 3.9A - giving a little room as the balance charge process sometimes requires a little more than you specify. This is nice and safe, but should always be monitored.
Lipo batteries should not get hot, ever, really, as that suggests an internal current flow problem.
Personally I don't charge my cells at anything greater than 1C, so for a 4000mAh I would charge at 3.9A - giving a little room as the balance charge process sometimes requires a little more than you specify. This is nice and safe, but should always be monitored.
Lipo batteries should not get hot, ever, really, as that suggests an internal current flow problem.
You need a proper power supply, something like this:
http://pages.ebay.com/link/?nav=item.view&id=2...
It's only 8 amps but will be enough for charging.
BTW it's the start of a slippery slope. Running around in the woods is fun but racing 9 other people is much more fun! Then you'll upgrade everything to the point there's nothing original left.
http://pages.ebay.com/link/?nav=item.view&id=2...
It's only 8 amps but will be enough for charging.
BTW it's the start of a slippery slope. Running around in the woods is fun but racing 9 other people is much more fun! Then you'll upgrade everything to the point there's nothing original left.
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