Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr solar charge, 20Mi range, Carry 250lb me, lifepo4

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ToyTank
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Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr solar charge, 20Mi range, Carry 250lb me, lifepo4

Hello. This is my first project like this, hopefully it goes well. I'm from Montana, USA. Here's what I am planning on doing and please give any suggestions or feedback. I am all ears, and hoping to get help from the venerated here.

  • Tres Terra Callisto bike minus battery $300 shipped
  • Ebay already bought
    Youtube review

  • FoXXPower lifepo4 36V 10AH
  • Available on ebay. Talked to Zane on the phone, waiting for a quote from him.

    Foxx 36V 10AH

  • 30W HQRP Flexible solar panel
  • HQRP gets high marks everywhere I looked at them. I would like to get 2 of these, so I can get 36V without conversion. I think I will order one for now, I can alway get another later.
    http://hqrp.com/30-watt-monocrystalline-flexible-solar-power-panel-30w-12v-dc-for-battery-charging-by-hqrp.html">30W Solar Panel

    Now I need help. I think I need a charge regulator The panel puts out 18V working voltage. Can anyone recommend a light, effecient charge controller tht works with 12V-18V to charge 36V string? If I hook these in series I should get 36V, and these do have a diode, could I just direct charge as long as I did not overcharge?

    Anyone reccomend a different/better battery?

    What else am I missing?

    Thanks!

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Ok first...
    That battery doesn't come with a charger..
    Add $60+
    The solar panels won't work, because in order to charge the 36v batt you need 43.2v
    You also wouldn't have 5 hrs of DIRECT sunlight in winter.

    20miles is only if you pedal most of the time.
    15ah would give ya 20 easily.
    Great deal on the bike tho.. Did yours come with that "tank"?

    antiscab
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    If I hook these in series I should get 36V, and these do have a diode, could I just direct charge as long as I did not overcharge?

    If the Battery has a BMS that disconnects the charging source when a cell goes high voltage, then no charge controller is necessary.

    Most cheap BMS use a Mosfet as a switch.

    one direction its just like a normal rectifier diode, the other goes high/low resistance depending on what it is driven to be.

    so just hook it up direct IMO.

    Matt

    Daily Ride:
    2007 Vectrix, modified with 42 x Thundersky 60Ah
    Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
    conversion

    strawhistle
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Be VERY Carefull !! I bought 2 batteries from foxx power last winter ! the battery chargers stopped working in less than 5 months!! first one than the other. I sent the first one back and never got the replacement that Zane promised even tho i called and emailed MANY times ! He always promised to get right on it !!!
    because the B.M.S. is in the charger, getting a different charger AND a working B.M.S. Is a BIG challenge !!! I have to charge each cell separately in order to prevent over charging and I am still looking for a b.m.s. that will work well with these cells !!!! LaTeR

    thank GOD I wake up above ground !!!!

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    According to their website, it says that every battery comes with a BMS.
    So make sure you get a BMS with it and NOT in a charger.
    That's why I never bought a battery from them, since a charger is not included.

    Many other eBay sellers give a charger and a BMS with the battery,so you wouldn't have to buy one.

    strawhistle
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    If you look at the pic' of the battery ,it shows a military type of multiple-pin connector that the charger with internal b.m.s plugs into, to balance charge the battery, when the charger fails you lose both charger and b.m.s and have cells you can't use without a lot of grief !!! LaTeR

    thank GOD I wake up above ground !!!!

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Thanks for the interest guys. I bought a 15ah from ebay $299

    One step up(boost) Dc-Dc regulator(120W) ebay $13 Can take that solar voltage and get steady 45 or whatever I want out. Can also charge bike from any 12V source now :-)

    step down incase I want 12V accessoreies. ebay $9

    36V Truck horn new ebay $8 :-)

    Hand full of 3A 240V diodes, 2 15A diodes Radio Shack $4(blocker diodes)

    Total now Bike $300, Battery $299, 30W HQRP Solar(buy.com) $71($150 I had coupon),DC-DC regulators and horn

    Total Gross $783 Net $703($80 buy.com credit)

    Don't know weight yet, I figure bike is 50-60lbs, battery is 12lbs. Not sure on solar panel regulators. Solar panel is 2.5MM thick. Should be lite.

    So far so good. I may use shunt diodes instead of charge controller(36V >$200). I know the BMS should already do this, I will test when I get it. I find conflicting reports of whether a float voltage is harmful to lifepo4 or not when your not balancing. I really like the idea of real shallow charge cycles thanks to solar. I've seen a couple post were people used a small 36V SLA for a buffer, but I would like a more elegant solution.

    Last thing, I can't seem to edit the OP. Can you edit a post on this foru?

    Thanks for the input. I will post pictures as I get marterial.

    antiscab
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    I find conflicting reports of whether a float voltage is harmful to lifepo4 or not when your not balancing. I really like the idea of real shallow charge cycles thanks to solar.

    an hour or two on float isn't much an issue.
    days is.

    I have made cells vent from being floated for days.

    Matt

    Daily Ride:
    2007 Vectrix, modified with 42 x Thundersky 60Ah
    Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
    conversion

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Ok first...
    That battery doesn't come with a charger..
    Add $60+

    You are right. I had a charger though. Never heard back from zane@Foxx anyway. $299 15ah ebay bms & charger.

    The solar panels won't work, because in order to charge the 36v batt you need 43.2v
    You also wouldn't have 5 hrs of DIRECT sunlight in winter.

    Thanks I knew that lol. I found a cheap regulator that takes 3-30V in puts 32-60V out. 92% efficient:/ For now I am going with 30W solar. Eventually I will get 60-90W. Maybe I will make a swinging aluminum frame with 4 mylar aluminized reflectors to concentrate solar on a cloudy day.

    20miles is only if you pedal most of the time.
    15ah would give ya 20 easily.
    Great deal on the bike tho.. Did yours come with that "tank"?

    Someone half my weight would do better ha! No Tank, that bike was surplussed because of bad Li-ion packs. It has no tank or battery. I will have to make mounts. I wanted more of a DIY than that bike, but looking just look at controller and motors are as much as this bike. These Hienzmen(sorry can not spell)hub motors are supposed to be nice.

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    The solar panels will give you some back..
    But @ less than an amp output, it would take a while to charge it from 50% DOD or greater.
    Watching the vid about that motor.. Sheesh that's a bit loud for an ebike motor, but it's a good deal anyways...

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Yeah it's gotta brushes. I need 2 more of those panels. Mainly I want to recharge with them camping/canoeing. I might see if I get extended range running with them on. One hour in peak sun would only get me 30Watts so maybe an extra mile(per panel) in ideal conditions. I also am experimenting with windbelts. Very minimal power though. I think . With the one panel now though it would take 1-2 days to recharge from a deep discharge.

    Real true time solar locomotion is something nature has all but given up on. It must not be easy.

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    I have received the bike . I also found a fairly afforable light, but slightly bulky lifpo4 cells here in the states. After much research and almost buying from apparent criminals from a google search, I bought from elite power solutions I bought 4 X 4cell 20ah packs($508 total.3 day ups). I did that so I can upgrade to 48V if I want, and use the china duct tape pack I bought for my scooter(or sell it) I broke my $1000 limit with these batteries...Oh well I am just barely over budget if I allocate the duct tape pack to another project. Sounds like these are basically 20ah TS cells. The PDF I have says most of your power is 3.6-3.0V range, but the cell can go from 4.1-2.5 safely. I think I'll still set hvc 3.6 and lvc3.0

    I wired a couple power tool batteries to ride the bike. I could get about 500ft before the controller would lvc.

    30W Solar panel arrived and is AWESOME! It must need to degrade to nominal. I can't believe cloudy winter skies still produce usable power. Weighs nothing

    All links are for photos. Sorry Drop Box won't let me link to whole folder...

    Cells from Elite are arriving UPS today, but there is snow on the ground...

    DC-DC Boost and Buck Regulators are still coming from China, so is duct tape battery.

    2 Bantam Wattmeter/6s balancers are coming from New Jersey. I plan to hook one up as inline to the battery, and balance 6s, and have the other stand alone just to balance the other 6s. Should be here any day.

    36V 21A Delta-Q QuiQ onboard/offboard charger. I paid about $120. Seems good, every other seller has them for $400. Voltages for the flooded type algorithms are just about right for lifepo4. Anyone have experience with one of these? Or any Delta-Q charger?

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    For the TS cells 3.7 HVC AND 2.9 LVC will make a huge diff.
    I hope you're not thinking of charging with 21a. Charge most at 10a.. 21a will shorten battery life by quite a bit.

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    For the TS cells 3.7 HVC AND 2.9 LVC will make a huge diff.

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Thanks for the input guys. I am confused. A 3C 20AH should be able to charge@ 20Amp no sweet right? Wouldn't that be charging @ 1C? Sorry I'm still learning.

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    1c IS 20a, however, the faster you charge them, the lower the life cycle.
    Examples.
    SLA Best charge/discharge rate c/6 = 6 hour
    LFP Best charge/discharge rate c/2 = 2 hour
    LiPoly best charge/discharge rate = c/1 = 1 hour

    You CAN charge at higher C rates, but for each C you go up you lessen the lifecycle by a factor of 1
    I had SLAs that I charged and discharge at c/2 and was only getting 2 months out of it.
    I then did c/4 and got 6 months of use.
    I then dropped to c/6 and went a year no problems

    LFP's I was using I did 2c and got 14 mo before it hit 80% of max
    LFP's at 1c got 18 months before 85% of max
    At c/2 I've had for 18 months and I'm still at 100%

    Max is 3.65 and Min is 2.8 and I usually only go to 60% of DOD, but once every 20 or so times I got till I hit LVC.

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Thanks for the input. So does proper recharge current depend on C rating of the battery? I am only charging at 1/3 of it's C rating. I agree if I was charging it at the limit(3C 20AH=60 amp)it would affect the cycle life drastically, but I"m not sure charging at 1/3 max rated recharge current would be bad for life. To me this is very similar to charging a 1C 20AH @ 6 amp. I'd love to get some more input on this. My plan with the 20Amp was to use it on board for fuel emergencies. It would make my Power pack a little chunky @40 lbs.

    antiscab
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    charging at 1C once in a while is fine,
    charging at 0.3C all the time is also fine.

    doesn't matter if you charge slower.

    Matt

    Daily Ride:
    2007 Vectrix, modified with 42 x Thundersky 60Ah
    Vectrix 60Ah Lithium Tyres Fuel Registration Insurance cycle analyst 2 x TC Charger & MC
    conversion

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    I think your confusing ABILITY to actual.
    If it's a 20ah pack, 1c IS 20ah
    C is always 1hr.
    C/3 is 3 hrs to charge
    3C is 20min to charge
    For a 20AH pack....
    1c is 20a for one hour....
    Think about it... Charging a 20AH pack with a 20a charger would take 1 hour (20a X 1hr = 20AH)
    which is a 1C rate.

    Charging a 20AH pack with a 10a charger would take two hours which is c/2.

    Doesn't matter what THEY RATE, they can rate it at anything they want, you would still want to charge between c/2 and c/3.
    Like I showed in my example before charging LiFePo4's at a C/2 - C/3 is best
    If you noticed their max continuous on discharge is 2C, charge best would be less not more.

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    OK. Thanks for the help guys. So I should charge at 1/3c, not 1/3 the C rating? Is C rating indicative of charge ability at all? Why is this different than life packs for RC hobbies? The chemistry is the similar, but I'm getting totally different information here. Either way life of the pack is secondary to function, so I am going to use the charger anyway. Should be seldom I need to quick charge on the road. I know GBS says it is a 3C cell, but still recommends 6 amp charge. I suppose when your talking about a $500 instead of $50 battery rules change a little.

    With any luck I will be riding this badboy in the snow today!!
    (without solar)

    O BTW Total weight looks like about 75lbs with small charger, 80lbs with onboard 20amp charger. It got a bit chunkier with the prismatic cells + rack for them.

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    The lipo packs from the RC world are a bit diff.
    Lipo packs are meant to charge very fast and discharge very fast, that's why they have such high C rates.
    LiFePo4 is meant for longer charge and discharge.
    For racing purposes, most EV's use lipos for the reason mentioned above.
    For longer distances an safety purposes LiFePo4 is better in the long run.

    People are just starting to use lipo's for electric bikes, because of the high energy to weight ratios.

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    OK. lipo is lithium polymer li-poly right? I meant life cells. They are Lifepo4, but your right they have insane C ratings. Same as A123/Dewalt nano cells.

    I have everything ready to go, just balancing the battery. Built a BMS with a couple hobby balancers with lvc/hvc wattmeter. I saved a couple couple bucks, but it was a pain, is not as pretty as it could be, and has a few other issues(200ma balancing). That is what I get for trying to save a couple bucks. Gives a real nice read out of the state of all cells though.

    Solar is not going to fit in the budget. I bought 1 panel, and have a DC-DC regulator as a charge controller, but to get enough watts to reach my charge goal I need 2-3 panels.

    sangesf
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    My point was that lipos were meant for high c rate charge/dischage, and lifes were not.

    Very rarely should you charge at 20a. It's a recipe for disaster.

    10a is even a bit too much.

    And yes 6a is perfect. (and so would a 6a discharge), but that ain't gonna happen.

    ToyTank
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    Re: Solar Ebike! First DIY Goals: <$1000, <100lbs, <8hr ...

    Life cells ARE made for high charge/discharge. I have A123 LIFE cells that are rated for 60 amp. Your point with lipo's are moot, you brought it up to tell me I was confusing li-po with lifepo4. That was not the case, but thanks for your input. Li-po's are popular with cell phones and RC, mainly because high energy density, and they can be made into any shape. I am using the 20 amp charger to quick charge only when needed. I understand it will affect calander and cycle life of the cell.

    Anyway this project is nearly done. Still waiting on the buck/boost regulator for solar charging. I need to get some more ring terminals and 22awg and make the balancers look pretty. I'm still not set on battery layout either. I may eventually mount them around the bike instead of one big block on the rack. I saw another post where someone used saddle bags for a 48V 20Ah bike. It looked heavy and awkward, but more evenly balanced then my current set up. Ha I use looking at the 40AH cells. What was I thinking they would be HUGE!

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