Charging stuff without running my battery dead

Discussion in 'Equipment' started by timeOday, Dec 6, 2017 at 7:36 PM.

  1. timeOday

    timeOday Long timer

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    Does somebody make a relay that shuts off if the input input voltage drops below, say, 12.5 volts? I'd like to be able to charge my devices off of my bike at night without the risk of running the battery dead.
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  2. Snapper

    Snapper Long timer

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    Charge a powerbank off the bike while you ride during the day, then use the powerbank to charge devices at night.
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  3. HarveyM

    HarveyM Been here awhile

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  4. Retired and lovin it

    Retired and lovin it Been here awhile

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    Just buy on amazon Introcircuit charge bank and jump start device. I use to charge my phone, my SENA and when I go to a restaurant I charge it up while eating for another day.
    https://www.ebay.com/i/321974816896?chn=ps
    #4
  5. Grinnin

    Grinnin Forever N00b

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    I agree that charging a powerpack during the day then charging devices from it is a good strategy.

    If you really want that battery protecting device, you may want to search "low voltage disconnect" which is a pretty common name for the device. Knowing the name is sometimes half the battle.
    #5
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  6. foxtrapper

    foxtrapper Long timer

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    An effectively dead battery will frequently have ~12 volts, just no amperage. So a volt sensing shut-off would be of dubious protection, imo.

    So I too agree with the above about using a powerbank to charge stuff at night, and then charging the powerbank via the bike during the day. You can find good ones surprisingly cheap these days.

    You should also be able to install power sockets on the bike that would allow you to keep your electronics charged during the day while you ride. Is there a reason this isn't an option?
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  7. timeOday

    timeOday Long timer

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    The reason is one of my uses for it is unusual. I wanted to leave my commuter bike in the parking lot during the day with my cell phone locked in the top box, plugged in and serving as a WiFi access point for my office because my cellular data reception in there is so bad. I'm just a little worried about riding to work with all my heated gear in the morning, leaving my phone plugged in all day, and then being stranded when I come out after dark to ride home.

    I have tried the solution of charging a jump starter battery during the day on trips so I can charge my devices at night, the problem was I forgot to unplug the jump starter battery from charging every time I stopped the bike. Of course I could make a switched charging lead on a relay for that. I also didn't have a fixed location to store the jump starter while it is charging on my dual sport so I had it in my pack and it got yanked out every time I got off the bike or crashed. The whole set up is just kind of bulky and inconvenient, but it could be okay for trips if I put a little more thought and effort into it.

    I just think having a smarter USB charging outlet that wouldn't happily drain my entire battery would be simpler.
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  8. Snapper

    Snapper Long timer

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    You're asking for your bike battery to handle deep-cycle work like an RV battery - this is a special application. I don't know what chemistry your batt is, but as I was always under the impression regular vehicle batts were made to operate topped up and that deep cycling (even to 50%) would wear them prematurely. Also I wouldn't chance this with a modern fuel pump/injection bike, but a older carb and kick starter bike should be able to bail you out.
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  9. timeOday

    timeOday Long timer

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    Interesting. The battery on my SUV died when it was less than three years old and if I wonder if it was from using it for camping, leaving phones plugged in charging, using the dome lights at night, etc. I know running a car battery way down will kill it, but isn't there some safe voltage it can be used down to?
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  10. Retired and lovin it

    Retired and lovin it Been here awhile

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    I really think your asking to much of your motorcycle battery. You drain it a couple times to almost dead it will never be strong again.
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  11. foxtrapper

    foxtrapper Long timer

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    OK. I'll still vote for a powerbank like this for the job: https://www.amazon.com/Anker-20100m...UTF8&qid=1512663200&sr=8-4&keywords=powerbank

    That should have enough power to run your phone all day. Charge it up at home at night and toss it in the bike when you leave. They aren't big, heavy or expensive.

    I'll agree with the others that with a conventional lead acid battery, you're likely to kill it quickly by perhaps deep cycling it. Yea, I know a cell phone doesn't pull huge power, but a motorcycle battery is also pretty small, and you're talking all day, 5 days a week.
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  12. mouthfulloflake

    mouthfulloflake Not afraid

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  13. Snapper

    Snapper Long timer

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    A second (deep cycle) battery wired in with an isolator (not in parallel) could work - this is essentially an RV set-up. However, the ability to adequately charge the system would depend on the length of the commute.

    I agree with above - just charge a battery bank at home along with the phone.
    #13
  14. RoundTrip

    RoundTrip Unintentional deerslayer

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    K.I.S.S. Take the phone with you into the office. Plug it into a charger in your office. Go home after work. Repeat.

    If you must have the phone on the bike during the day, then get two power banks so that when you forget to charge one, you have a backup.
    #14
  15. Grinnin

    Grinnin Forever N00b

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    Lead acid last longest when they're fully charged.

    Leaving it discharged a little shortens its life a little. Leaving it discharged a lot shortens it's life a lot. It's not that there's some threshold, but that keeping it charged up is always better.

    Deep cycle batteries are not as bad with partial discharge as starting batteries. Even my house's deep cycle batteries will last longer if I keep them charged up and die sooner if I leave them partially discharged more often.

    Your motorcycle has a starting battery.

    Lithium batteries do not have any such trouble. You can leave it charged 25% for ages and it'll still be fine. This means that a lithium power pack can power your phone all day and maybe another day or two and you don't have to charge it to extend it's useful life; you only have to charge it so it has power to run your phone.
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  16. nk14zp

    nk14zp Been here awhile

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    A little of topic but I use a booster pack to power some things at night when camping. My question is would adding a switch so I can turn my headlight off to recharge the booster pack while the bike is running help? This would be done with the bike parked. Bike is a 06 KTM950 Adv.
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  17. timeOday

    timeOday Long timer

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    Then again I just got a lithium battery for my dual sport (and it has a kickstarter), so maybe that situation is a different one.

    Can't really see buying a lithium starter battery for my VStrom though.
    #17
  18. Tripped1

    Tripped1 Bitch called me a feminist.

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    How much are you charging and what size is your battery.

    I ask this because I spent at least 6 weeks this summer charging off of the bike at night, we are talking 3-4 phones/navi devices, plus our sena's, batteries for our lights AND occasionally the pump for our air mattress (no one ever accused us of traveling light)

    The navi was usually close to fully charged, the phones varied wildly, personals plus a "burner" that she uses to take photos on the hoof, generally I would charge the Sena's and whatever the most critical device while we were camped and then throw the kitchen sink at it once we were ready to crash. That is just a 12B-BS....nothing fancy about it.
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  19. aldend123

    aldend123 Long timer

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    Are you trying to use the phone as a wifi hotspot to connect computers from your office to it? Otherwise, I don't follow why you want the phone outside. There's no place near a window with a wall oulet in the office that gets comparable service?

    For those talking about deep cycle lead-acids, I don't see why that would be a better plan than a lithium battery pack. If you really want to get fancy, wire it's charging to a switched 12V source that won't let it charge when you turn the bike off.
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  20. worwig

    worwig Long timer

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    Not really. You generally want to keep a lead acid battery pretty much saturated to prevent sulfating.
    On a similar note, years ago I wanted to run driving lights on my motorcycles. The motorcycle alternators were a bit weak. I designed a device that dimmed the lights slowly if the voltage was below 14 volts even with the engine running. Sitting at a red light, the lights would dim, and save the battery. When the engine revs picked up and the alternator output was higher, the lights would brighten back up.
    In your case I would have the key on (and engine running) charge a separate lithium battery pack. Then use that battery pack to charge the phone with the motor off.
    #20