Advice on my electrical system

Discussion in 'Lighting and Electrical' started by zhono, Aug 24, 2017.

  1. zhono

    zhono New Member

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    As part of my new build, I have an LED headlight, and 2 LED strips(one back and one front) that act as running lights, break lights, and turn signals. I might also add a horn in the future. I plan to power that stuff with a 12v 7ah SLA battery(maybe 2 in parallel), and keep a small charger handy for when I'm near an outlet.

    But obviously, like many, I would like to charge the battery while riding. My current idea is to get a cheap 12v 6w dynamo on ebay, and a rectifier/regulator combo that takes in a range of 12v-18v AC, and outputs 12v DC. So my basic system would be dynamo into the rectifier, out of the rectifier into the battery to charge, and out from the battery to power the lights.

    Anyone have any experience with this? Would this work out? The only thing I don't know how to do(if it's even necessary), is to isolate the charging circuit from the load. i.e. I only want the dynamo to be supplying power for charging the battery and not the lights, and I want my lights to only draw power from the battery and not the dynamo. So ideally the whole system should be self-sustaining, without me having to disconnect the battery for separate charging at a wall socket.

    I would also note that the vast majority of my riding will happen in daylight hours, and so neither the headlight nor the running lights will be powered most of the time. Just brake lights and turn signals for probably 90% of my riding time.

    And extra thought: would it be possible/feasible to double-up, and use two dynamos, each with their own rectifier, and combine that for better charging?

    Various links to the specific parts in question:

    My headlight
    https://www.amazon.com/gp/product/B00XVAEP8E

    My running/brake/turn lights
    https://www.amazon.com/gp/product/B01ITBTSHC

    Load resistors(to make the turn lights actually blink)
    https://www.amazon.com/gp/product/B00L4V9ECY

    My battery(I have 4 of these from a fairly successful e-bike build that I changed my mind about)
    https://www.amazon.com/dp/B003S1RQ2S

    The dynamo I'm looking at
    http://www.ebay.com/itm/BICYCLE-BEACH-CRUISER-GENERATOR-UNIT-12V-6W-DYNAMO-CYCLING-BIKES/262688555528?ssPageName=STRK:MEBIDX:IT&_trksid=p2055119.m1438.l2649

    The rectifier
    http://www.ebay.com/itm/AC-DC-Power-Supply-Module-To-DC-5V-9V-12V-15V-Rectifier-Filter-Voltage-Converter/322598417570?ssPageName=STRK:MEBIDX:IT&var=511587289401&_trksid=p2055119.m1438.l2649
     
  2. Tony01

    Tony01 Member

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    Get your build running first and run a lithium 12v system till then. I'm working on a system using a sturmey Archer dynohub (hds20). Those bottle degerators will blow up quick.
     
  3. zhono

    zhono New Member

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    I was actually looking at dynohubs already, but all the ones I could fine were pretty expensive(for me). I can't even afford a small lithium battery right now, so I'm stuck with my SLA's. Still trying to sell my e-bike conversion kit, but the money from that was going to be used to buy either a 26 inch frame with the integrated gas tank from BikeBerry, or a set of 26 inch heavy steel rims with 11 or 12 gauge spokes.
     

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