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| S. Heslop:
Couple of little things. Started making another box for the batteries and electronics (i'll probably put holes and a fan underneath to try keep the batteries cool), and reassembled the bike after previously making the left handed thread for the left hand side, as well as replacing the thin bearings with some thicker ones that'll hopefully hold up. If they don't i'll probably make a third aluminum plate to support that shaft above the roller. Funny thing about the handed threads is that I totally screwed them up, and now the nuts on both sides will be able to work themselves loose! Rather than remake the shafts I think i'll just loctite them on, i'll have to check that the loctite I bought is the sort you can heat to release through. It's extremely strong stuff. I'd like to have gotten more done today but I couldn't do too many noisy things since we're looking after my brother's very cute baby daughter. Edit: Oh! I just realised I can just switch the idle/ drive arms around to get the threads on the right side. Edit 2: Now i'm wondering if the idle wheel would work the same as a drive wheel in terms of tightening/ loosening the nut since the wheel will be turning the roller. All this handedness is really confusing! I think i'll just go with loctite. |
| vtsteam:
Not sure since I don't use it that much, Simon, but I think Loctite can always be loosened with heat, Some loosening types can be broken free with a wrench -- maybe that's what you're thinking of. The new bike box and rollers look good! :thumbup: |
| S. Heslop:
I'm getting ready to give the bike a real stress test till the batteries fun flat (or something fails!). I've got a theoretical 10 miles with the current batteries but it'll probably wind up way less than that. Took a good while to get the charger working. For starters, it turns out its a fake clone of the real Imax B6 and risks overcharging the batteries, so i'll need to keep an eye on the voltage with a multimeter as it charges. Kinda frightening with LiPo... The hard part was finding a power adapter that'd work with it. It can accept 12-18 volts input but all my power adapters were providing up to about 24 volts when they were without a load. I'm no electronics expert, so I might be doing something really silly here, but I ended up wiring a car bulb in parallel with the charger to give about 16 volts when the charger was idle. Then when initiating the charge, I switched off the bulb. Took a few tries to get a charge rate setting that kept the voltage under 18 volts. It's now charging at a rate of 0.7A. 12 minutes later though and the voltage has risen about maybe .01 of a volt. It's currently at 11.53 volts and needs to reach a target of about 12.6 volts so it looks like it's gonna be a long one. This is only one cell of two as well! In other news, i've still had no luck finding laptop batteries at boot sales. I need to move on to other stuff though so I suppose i'll have to save the batteries for later, whenever I find any. |
| vtsteam:
Simon, don't run those batteries down more than 3.7 volts per cell -- that's the usual alarm/ESC cutoff voltage of about 1/8 capacity. That works out to about 10.95 volts for a 3 series cell pack. Fully charged would actually be about 12.45 Volts for the same pack, not 12.6. When you say "one cell of two" I think you mean one battery pack of two, yes? Each battery of yours is, I believe 3 cells, internally.. Why do you say that your charger "clone" will over-charge? I suspect it will work fine, unless you have a definite known reason why it won't. Your charger is designed to work with an automotive 12V system -- those vary in voltage as the car alternator does vary its output, hence the "range" of 12-18 volts. AC auto adapters for home use may run high in voltage if the output is open circuit. What matters is the output under load. How many amp hours are your battery packs in capacity, and how much current can your charger output? - You should be able to charge at a rate to get a pack fully charged from empty in an hour. Assuming the charger and the adapter can handle the current requirements. Example: For 2000 mah lipos, you would set the charge rate at 2000 ma (ie. 2 amps). Assuming your charger is capable of 2 amps, and your AC adapter can handle the input requirements of the charger (usually marked on the charger box or in instructions). You can also make a high amperage 12V power supply very simply from a used computer power supply -- there are many instructions for doing this on the internet -- just do a search. I use one of those with my lipo charger. |
| S. Heslop:
The balance charger claims to be able to charge at a rate of up to 5 amps. The battery packs are 5000mAh so am I right in thinking they could handle that 5 amps charge current (assuming I wanted to charge the batteries as quickly as possible. I hear it's generally better for the batteries to charge them slower). The current is limited by the wall adapter i'm using though. Would a car battery charger work better as a power source for the balance charger? It's probably one of those things I could ask any neighbor to borrow. I might even have one hidden in the garage somewhere! I'll probably have to find and older one without fancy circuitry though since I hear those cause trouble. As for cell/ battery. I know better but it's a mistake I keep making when i'm not paying attention. The two RC batteries I bought are a 3 cell and a 4 cell. The one currently charging is the 3 cell. Also, I forgot to actually hit the post button and this has been sitting here for a while. Charged the first battery to 12.45 volts and now i'm starting on the next one. It's getting late though so i'll probably have to save riding the thing till tomorrow. |
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