Phone car mount + speakers + battery? - Page 1
Forum section: electronics / general

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: June 14, 2014, 08:50:48 pm
content: I'm looking for something to play music on my phone while riding my bike, but also has the capability of keeping the phone charged at the same time.Sure I could go out and buy a car mount and some bluetooth speakers, but I have enough problems with my headset cutting out at random. (damned 2.4ghz overcrowding)Plus, my phone barely lasts half a day if I'm using it for anything other than phone calls, and those 13,500mAh emergency chargers are quite bulky.Is there anything out there that can do it all in one go?edit:If only I was in the US... damn you Amazon. (I checked the Canadian site, the speakers are $80 alone)

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 15, 2014, 12:59:31 am
content: What about a little generator coupled to the wheel with a small battery for buffering?

author: Rerouter
author_rank: Super Contributor
timestamp: June 15, 2014, 01:14:30 am
content: http://www.ebay.com.au/sch/i.html/_W0QQ_sopZ12?_nkw=bicycle%20phone%20charger&_fromfsb=0&_trksid=m270.l1313plenty of options on ebay, aim for a lower wattage, as a higher wattage means more oomph just to move, equally with most you have to be moving at a certain rate for it to actually work,

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: June 15, 2014, 01:17:54 am
content: Quote from: NiHaoMike on June 15, 2014, 12:59:31 amIt would only slow the bike down. Thanks though.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 15, 2014, 02:25:20 am
content: You could add a switch on the brake lever to only enable the generator when braking. In that case, you might find it an advantage to use a generator and battery pack that can handle high peak currents. You could even take it further and make it into a full fledged hybrid system.BTW, a good way to implement the charge control (assuming a small 3 phase alternator) is to have 3 MOSFETs on each phase to ground with a Schottky to the battery bank. Then use a PWM controller to drive all 3 MOSFETs together (recommend 33R gate resistors) at about 15kHz, with the voltage limit set to whatever maximum charge voltage of the battery. (For proper operation, the battery voltage range should be above the peak voltage from the generator at maximum speed.) Have the brake switch enable the controller when activated. Then adjust the brake cable so the mechanical brakes come on well after the regenerative braking is activated.http://techno-fandom.org/~hobbit/cars/boost-hack/

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: June 15, 2014, 02:31:16 am
content: I'm really not interested in modifying the bike at all, aside from possibly drilling a couple holes for the phone mount. When I bought the bike, I asked about regen braking and they said implementing it would increase the weight of the bike too much. The SLA's in there already weigh enough, not to mention my fat behind.

author: JonnyBoats
author_rank: Regular Contributor
timestamp: June 15, 2014, 04:09:11 am
content: If you ride primarily on sunny days would a small solar panel be an option?

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: June 15, 2014, 05:19:30 am
content: To charge the bike? I would need 4 to get to 48v, and the battery pack is 20AH, so recharging it via solar would take forever. Plus, I'd have nowhere to reasonably mount the panels.

author: NiHaoMike
author_rank: Super Contributor
timestamp: June 16, 2014, 07:20:15 pm
content: Quote from: justanothercanuck on June 15, 2014, 02:31:16 amThat's incorrect. The difference between a motor inverter (VFD) with regen and one without is more or less just software. In fact, you actually have to go to length to prevent a motor inverter from regening. What is true is that SLAs (not flooded lead acid) can't take high charge current, but using high current lithium would make it weigh less, not more. (If used a lot, lithium is actually cheaper than lead acid nowadays.)

author: justanothercanuck
author_rank: Frequent Contributor
timestamp: June 17, 2014, 11:33:05 am
content: Quote from: NiHaoMike on June 16, 2014, 07:20:15 pmI calculated that I would lose 36 pounds by switching from SLA to Li-Ion... (SLA is 4x 13lbs, Li-Ion is 120x 45g)edit: SLA is cheaper though. They are $70 each from the bike store, whereas 120 LGABB41865's off Fasttech is almost $450 total.