Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: Rich griff on November 03, 2021, 11:03:07 am
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Hi electric mayhemmers...
Can a lipo be used with a bobs board and brushed motor please ?
I will have to get a lipo or two to replace a nicad car racing pack type of battery, unless nicad car racing packs are still available ?
Thanks.
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LiPos are just batteries the same as NiMhs or SLA, they don't care what they are being used to power so a Bob's board and brushed motor will work OK. What you will need is some form of voltage warning device to make sure that they are not discharged too far. An esc compatible with a LiPo will have a low voltage cut off that cuts power to the motor when the voltage reaches the minimum.
Jim
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Thanks, will see if nicad racing packs are still available...if not then it's down the fiery lipo route.
Model boat burnt down to the water line by lipo fire, then it explodes due to water, what fun !
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Nicads are not available now but Nihms are and are
a direct replacement, voltage, size etc, but without
the Memory problem of Nicads. They would be ok
with a Bobs Board as you will not be wanting the
high current delivery available with Lipos.
Component Shop amongst others will be able to
supply your needs.
Ned
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As Ned says, check out Component Shop and Howes Models etc. for a wide selection of NiMH packs. (sizes and voltages) No need to even consider LiPos if you are using a Bob's Board. In fact using an electromechanical device like that probably adds to the fire risk as if there is a short circuit the effect on the LiPo pack will be spectacular....
Colin
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Always fit a fuse.
ESC's can go short circuit too.
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Thanks, so a lipo could fry the bobs board more easily than a nicad or NiMH. No fuse fitted to the existing set up by the previouse owner, but will be fitted by me !
Will research component shop by they may not be allowed to deliver mail order ?
Thanks for the replies. Lipo's do seem to be a bomb waiting to go off !
Impossible to put out if on fire and toxic fumes, progress eh.
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They're more capable of supplying large current, but so are many batteries especially when large in capacity.
All batteries can give off toxic fumes if abused. I've been using lipos for twenty years without issue. That and LiFe PO4 are the only batteries I bother with these days.
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Remembering the width of the tracks on a Bobs board you don't really need a fuse, the tracks will burn away before any fuse will blow. %) %) Jim
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Thanks, so a lipo could fry the bobs board more easily than a nicad or NiMH. No fuse fitted to the existing set up by the previouse owner, but will be fitted by me !
Will research component shop by they may not be allowed to deliver mail order ?
Thanks for the replies. Lipo's do seem to be a bomb waiting to go off !
Impossible to put out if on fire and toxic fumes, progress eh.
Component Shop do mail order and they are close to you in Bangor North Wales. Give them a ring and you can call in to collect!
https://www.componentshop.co.uk/ (https://www.componentshop.co.uk/)
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Always fit a fuse.
ESC's can go short circuit too.
..But you have to try really hard to get a short circuit with a Bobs Board which is very likely to be its own fuse anyway.
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For low voltage/low amp setups Bob's Boards could be remarkably responsive and you could SEE them working. They were ingenious devices for their time.
Colin
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I have a Bobs Board in a long-unused Billings Kadet I built with my daughter when she was about 5 (in her 30s now) and most of the track has de-laminated from the board. If I ever re-commission the boat, I'll use a small Mtronics ESC.
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Hi Rich Griff
Just wondering why are you using bob's boards in this day and age?
Happy boating madboats
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Hi Rich Griff
Just wondering why are you using bob's boards in this day and age?
Happy boating madboats
Reading the OP - "I will have to get a lipo or two to replace a nicad car racing pack type of battery, unless nicad car racing packs are still available ?" - it seems that an old boat that worked well is being resurrected. If the Bobs Board is still doing its job as required, why change?
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Having looked at the state of my old Bobs Board, the lifting of the copper tracks from the board would be a cause for concern - as the arm wipes across them, they are quite likely to become a tangled useless mess with the potential of causing a short circuit. Considering that a small ESC is under £20, I wouldn't risk an old Bobs Board in a model myself.
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Yes, an old boat, krick Avanti 2. I have captain Tillie's to seal the hull seam but waiting for blanking grommets so have access to the voids.
Was thinking, when sealed, for pouring in white foam geads, a belt and braces approach.
It came with an old nicad pack and bobs board that looks ok but not yet tested.
I have one good serviceable nicad racing pack but ideally need a new matched pair.
I have a modern battery charger.
I am just waiting for bonfire night to be over so I can go out and collect rocket sticks for spars etc. Then my model making can start in earnest.
Anyone interested in the Avanti before I start to prepare it for use ?
Pm me if you do, it has its original box etc..
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A fast electric on a bobs board- really?!
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Yep, that's what we had to use pre "Pompey" etc. And then went through (and still do) failing Fets. Still got a NOS Bobs board and fittings in a sealed poly bag.
We had it tough
Regards Ian.
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Yeah, they don't know there born, servo reversing ( what's that ! ), Tx mixing ( what, in a food blender ? ), 3 phase motors ( what like the big compressor ? ) and ESC ( we had bobs boards, they were revolutionary when they came out ) etc...
In my day we had to walk to school, in the wind and rain and snow.....we never had it so good, or so we were told. 🤧
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I'm old enough to remember and use Bob's boards, but I'd confine them to the museum now. They certainly weren't much cop in anything powerful, i tend to use a simple on off switch or a buggy type resistance controller for anything a bit more powerful.
I would personally fit out the boat with a small brushless outrunner and esc and use lipo's. Will totally transform the performance and be much more reliable.
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One thing in their favour that is regularly forgotten about resistance controllers is that at full speed they are at least as efficient as modern electronic ones, even if a lot more bulky. Less efficient at lower speeds, and they do need to be a very good match to the motor to get decent control.
Two things - they are quiet - so many queries on here about the "whining noise" with ESCs.
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If you're worried about the windings singing, choose an esc that pulses in the higher or very low frequencies. Also helps if you softly mount the moor, so the hull doesn't act as a resonator.
Having used both technologies over the years, I'll take esc's any day, whine or no whine.