Charging and storing batteries question

Discussion in 'Electric Bicycles' started by Will Snow, Dec 20, 2009.

  1. Will Snow

    Will Snow Member

    I have been putting together gas motorized bicycles for sometime and now going to give electric biking a try.

    Bought a simple Currie/Izip kit for starters to learn on. I installed it on a mountian bike I had around here.

    Here Come the questions:

    1. The instructions say not to store under 50 degrees F. Is that it? In the winter, even in Fresno, Ca it very easly gets under 50 degrees at night. I'm talking about SLA batteries. Our cars sit in a cold garage all the time and outside as well, they have lead battries. Are these bicycle batterie different somehow and must be brought into the house on cold nights?

    2. Don't charge more than 24 hours say the instructions. I have some battery operated tools and the instructions say I can leave the batteries in the charger all winter if I want to. Different kind of Charger maybe? Maybe different batteries?

    I know a little about electrical stuff but have a ton more to learn if I'm going to get serious about electric bikes. I have read several postings of the electric bicycle minded person on this forum. some, I read, are doing very well with these bikes and seem to know a lot about them.

    Looking forward to your your thoughts.

  2. professor

    professor Active Member

    The sla batterys are just deep cycle, as far as I know. When I am not using a battery (and I have several), they get charged for a few hours once a month. Do not let them get flat. Can't imagine why they said 50 degrees. Seems stupid to me.
  3. johnrobholmes

    johnrobholmes Member

    Below 50F the performance will really sag a lot, so you can't go out cruising if the battery is still cold. Easiest to recommend keeping the battery out of the cold instead of explaining it all.

    Lipo is even more sensitive. Don't want to run them under 70f cell temp.
  4. Will Snow

    Will Snow Member

    SLA battery

    Yes, I think I get the drift of it. I talked to a person with an electric bike that he uses for his only transportation. He brings the batteries in the house at night where he also charges them. But then again, If you are shopping or visiting a friend for a few hours on a cold day, then what? Does that mean your bike is sluggish on the way home and may not reach your destination as on a warm day?

    I wonder how full time users deal with this?
  5. johnrobholmes

    johnrobholmes Member

    use hand warmers and insulation to keep it warm. I can't always bring my pack in either, some builds it is pretty much stuck to the frame.
  6. Will Snow

    Will Snow Member

    hand wamers

    That's interesting, my daughter just gave me two bags of hand warmers for Christmas. In these gas/electric cars, I wonder how they deal with this?

    Well, with the information I'm getting, It at lease gives me a better Idea of how to take care of the batteries and I appreciate it.
  7. ibdennyak

    ibdennyak Guest

    Thanks to your thread I noticed that when using my cordless drills in the cold the batteries have about half the life that they normally do. These were NiCad and lithium ion, but they are affected as well as SLA apparently. :idea:
  8. Will Snow

    Will Snow Member

    Tool Batteries

    Guess what?

    I brought all my tool batteries and chargers in from the shop last night. I see our thinking is the same.

    Thank's to professor and johnrobholmes.
  9. Bobocop

    Bobocop Member

    It's called a Trickle charger or Float Charger. (that you can leave plugged in)
    You should never leave any battery on a charger unattended unless it's a smart charger,
    I don't know if you have ever seen an SLA battery that has bloated out (expanded). but that's from over charging or freezing.
    there are very cheap smart chargers around which will shut off once the battery is charged.

    Yes, it will get sluggish, depending on how cold the batteries get.
    I wouldn't worry to much about 50 degrees F, thou.
    if i'm not mistaken that's about 10 degrees C here in Canada, These past few days it has been around 2 degrees C here and i'm still riding on my SLA's with no problems. they are inclosed in a battery box, so they don't get head wind
    BUT, I do bring the bike inside at night because it gets below 0.

    I have also read that some people use newspaper as an insulation (which is a good insulator) in their battery boxes.

    Always keep them charged up as professor mentioned above.
    ALWAYS charge them after every ride, even if you just went for a 5 minute ride.
    you will do more damage to the battery if you leave it over night (after a ride) without charge then you will charging it 10 times a day.

    Maybe check out
    Some really good info there, like the difference from a car/motorcycle and an e-bike/scooter battery
    Last edited: Dec 30, 2009
  10. Will Snow

    Will Snow Member


    That's pretty cold and certainly a good test for riding in the cold.

    Smart Charge, I have seen that term used somewhere before. So that's it, shuts off when fully charged. Good to know, will probably pick one up. I now bring the batteries in the house for charging and storage. I also plan to check out the battery website you listed.

  11. Bobocop

    Bobocop Member

    You can pickup a 36 volt charger for $13 at T-Power-Moto --> at

    e-crazyman also has very cheap chargers -->

    These are all SLA chargers (above)

    If you need NiMH or NiCd chargers, then All Battery is the cheapest that I know of -->

    Car chargers are good, but most will not turn off when charged, so you must keep an eye on it.

    Sorry, Will Snow, my URL's don't seem to work, (you will need to copy and paste the link)
    Last edited: Dec 30, 2009
  12. JemmaUK

    JemmaUK Guest

    From what I have been told on phone forums - that use the LiPo and LiIon batteries the best way of keeping life in them is not to discharge them below 10% and to store them in cool conditions - around the temperatures you would get in a household fridge are said to be ideal... say 5c..

    However they should not be used in these temperatures if possible since it adversely affects their energy output (the colder the substrates the less activity - the less activity the less output) and running them for extended periods in this condition could damage them..

    However, I have been toying with an idea using a very small 2 stroke/4 stroke motor driving a genny on the bike - if the exhaust gases were flue'd past the battery packs to warm them in cold conditions this might alleviate this problem - this would have to be switchable since in normal operating conditions engine exhaust heat would rapidly cook the batteries and you certainly dont want substantial amounts of hot chemicals anywhere near the groin.

    hope that helped.

    Jemma xx
  13. Bobocop

    Bobocop Member

    I never thought of that (using exhaust to heat the batterries) it will work, just make sure you have a vent for the exhaust to escape, (If the batteries are inclosed)

    I have also been tinkering around with something similar, but instead of a gas motor, i use the actual motor (electric) that powers the bike.
    I use a 36 volt motor at 48 volts, and the motor gives out a little heat at close to full throttle or under a bit of load,
    So i made a tube going from the back of the motor to the battery box, with a little computer fan blowing the heat (that the motor puts out) at the batteries.
    This actually does 2 things, keeps my motor cooler and my batteries warmer.
    (i use a separate 12v NiCd battery pack for the fan)
  14. oldgun

    oldgun New Member

    I will be getting a electric bike this spring, I'm thinking of buying a battry warmer like I use on the car battery, it's like a small electric blanket made for batteries. Anyone see any problem in useing this in early spring or fall? I hope to ride in fairly cold weather, at least until snow makes it unsafe.
  15. Will Snow

    Will Snow Member

    As I get more into the electric bicycle world it seems there is much more to learn than I once thought.

    Well, I now bring the batteries in out of the cold.
    I recharge the batteries no matter how short the ride.
    Good idea to have a smart charger, I now have one.
    I even learned how to use a volt meter ( I know, pretty basic stuff).
    Riding in the cold does not seem to effect the battery that much from what I read. Can not see where insulating the battery is a bad idea either. My tool batteries get warm when I use them and shurly the bike battery would warm up also, and if kept well insulated while out and about!???, what do you think of that?

    I like riding that simple,quiet 15 mph electric test bike, So much so that I'm trying to put something together that will be just a little faster and some good range. Finding it not that easy and can get pretty pricey the higher the speed. Have not given up and still working on doing it.

    I wish the generator idea that Jemmuk and Bobocop have would work out. I to have had some of the same thoughts but don't have the know how to start with, but neat idea anyway.

    Going to try this recumbent trike, should be good to carry the battery, weight. I just hope I have the courage to ride it in the street with traffic. Ive talked with some riders of these trikes and they say it is not the problem it would seem to be. I'm Getting off track a little and begining to ramble, just finding it an interesting challenge.
  16. ibdennyak

    ibdennyak Guest

    UH OH, he's hooked. This is how it all starts. :grin5: Actually, insulating isn't a bad idea. That's what I did on my electric push trailer a couple years ago. I just used SLA's, but I too noticed they would warm up with use, so I wrapped them is foam. Seemed to help especially in below freeing temps. I also had a little home made genset on it. Didn't work bad for what it was. Sure did improve the range.
  17. Will Snow

    Will Snow Member


    Could you give some detail about your generator setup I would be interested in what you did.

    I misread what Bobocop was doing. Thought he also had a generator system going but is warming a battery using a clever idea.
  18. ibdennyak

    ibdennyak Guest

    Hate to admit it, but I don't know how to post a link, but if you go in the electric bike forum and in the "just wondering if it is doable" thread, starting with about post #21 there is a short discussion of what I had. I did develop it a bit more after that, but it is kind of on hold at the moment. I do plan to pursue it with a few modifications in the future. :grin5:
  19. machiasmort

    machiasmort Active Member

    The ammount of available current drops as temperatures decline on a battery due to the slowing of the chemical reaction giving you power. Best way I can put it in easy to understand terms.

    Solution, as previously mentioned, insulate your boxes. I'd look at spray in foam or lite weight coolers.

    Smart chargers have a circut that measure the batteries voltage and switch to a trickle charge. I've been wanting to read this article but havn't had time.
    Not sure if it's a smart charger he's building but I like his way of explaining stuff.