Best way to charge my battery

Batteries, Chargers, and Battery Management Systems.
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PewPew
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Best way to charge my battery

Post by PewPew » Dec 23, 2017 9:04 pm

Hey,

So having recently gotten by bafang 750w kit and loving it to bits I just wanted to get a better idea on how I should charge the battery. I've read the general basics ie don't charge to 100% and leave it for long periods, don't drain it completely but in my scenario what's the best way to deal with charging?

So I work shifts and I might be on the bike at 4am so charging immediately before isn't an option as I'll be asleep.

Initially I was charging to full and leaving it for the morning until I realised this might not be the best practise as above.

Nowadays I'm charging to say guesstimated 80% and then topping it off as I bumble around the house in the morning getting breakfast ready etc.

So my question is should I do this extra top up or just leave it be? I just prefer having the battery at close to max when I leave for the day in case I can't be bothered putting in effort on the cycle home after a 12hr shift. BTW I'm not totally clued in with the battery type itself. It was a 52v 13.5ah shark pack from Lunacycles.

Thanks for any guidance. Not sure if I'm really overthinking the entire thing.

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tomjasz
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Re: Best way to charge my battery

Post by tomjasz » Dec 24, 2017 4:17 am

Buy thi# charger, and be don3 with charger issues. Itll do it all.

http://www.ebikes.ca/product-info/cycle ... cycle-life

Read this headin* for best explanation.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Best way to charge my battery

Post by PewPew » Dec 24, 2017 4:56 am

That's a fair whack of cash though. $445 Australian Dollaredoos give or take. I don't know if I can justify that sort of money on a charger when I could spend it on more sensible things like vodka :)

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Re: Best way to charge my battery

Post by tomjasz » Dec 24, 2017 5:15 am

PewPew wrote:
Dec 24, 2017 4:56 am
That's a fair whack of cash though. $445 Australian Dollaredoos give or take. I don't know if I can justify that sort of money on a charger when I could spend it on more sensible things like vodka :)
Jebus $50 shipping! No AU dealerships? Emax?
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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dogman dan
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Re: Best way to charge my battery

Post by dogman dan » Dec 24, 2017 6:44 am

You need to ride your bike in the real world. This may mean charging in the evening, and unplug when you go to sleep. If its full by then fine, if not, finish in the morning. Damage to the battery will be less if its cooler, so better than sitting in a hot garage full for a month for sure.

Topping off if you ride right away should do little harm at all to your battery lifespan. The bottom line is you can't be a slave to your battery to get an extra year, or less, out of it. Using it daily, you will wear it out a bit sooner, but also more than get your moneys worth from it. Just figure your budget on it lasts 2 years. It might last double that, but after the second year it will be a lower capacity battery, suitable for carrying on longer rides. Only if you always do a short ride will it still be big enough by year three, in most cases.

There are chargers out there for less than a satiatior, that have a three position switch to charge half, 90%, and 100%.

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Re: Best way to charge my battery

Post by dustNbone » Dec 24, 2017 7:40 am

I'd get a charger that can be set to 90%, charge it to that before bed, and top it to 100 in the morning while you get ready if you think you'll need the additional range.

Being able to do a 90% charge at work before your return commute would be really nice. If it sits at 90 for a couple of hours before you ride it I don't think you're looking at any serious harm to it's lifespan, and it's probably better for it than draining it to nearly empty on your ride home.

If you do need to almost drain it to get home, make sure you charge it back up to at least 50% as soon as practical, because sitting empty is also not good for cycle life/capacity retention.

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Re: Best way to charge my battery

Post by PewPew » Dec 24, 2017 7:14 pm

Yeah the grin is pushing the budget a bit. I can get an 80% 90% charger cheaply enough but I suppose I really wanted to know if the morning top off was reducing the life of the battery. If this isn't the case I'll carry on doing this top off.

Cheers for the advice.

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fechter
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Re: Best way to charge my battery

Post by fechter » Dec 24, 2017 10:28 pm

In a commute scenario, the charge level isn't going to be the life limiting factor. I would just give it a full charge in the time frame available. What you want to avoid is fully charging it and letting sit in a hot place for a month. If you're using it the next day, the full charge isn't going to cause significant deterioration. You'll wear the pack out from cycles before aging. Slightly less than full (90%) might help cycle life slightly but not if that results in a full discharge on every cycle.
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Re: Best way to charge my battery

Post by 999zip999 » Dec 26, 2017 2:00 pm

Just use it and don't run down to lvc as the rule. Check your charger voltage and battery with a multi meter now and then. Know your shit.

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Re: Best way to charge my battery

Post by 999zip999 » Dec 26, 2017 8:11 pm

52v luna pack is 14 series x 4.2 volt = 58.8 volt . Your charger should not be higher. Check it. Check the voltage of your pack after fully charged. 4.1 volt for longer life. But the bms may not balance at that low a charge. So don't run it to cutoff as at this voltage the pack will unbalance more and more over time.

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Re: Best way to charge my battery

Post by e-beach » Dec 26, 2017 9:15 pm

Sounds to me like the information is getting a bit loose here. As I understand it, it is not the discharge that shortens the life span of the pack (provided it does not exceed the battery manufacturers specification), it is the top of the charge that shortens the battery life. This also seems to be expressed by the Cycle Satiator graphic from the Grin website.
CycleSatiatorGraphic.JPG
CycleSatiatorGraphic.JPG (135.82 KiB) Viewed 480 times
If you are going to follow the path of charging for pack longevity, then do not charge your cells over 4.05 volts and do not discharge them past the manufactures limits. That means you have to know what cells are in your pack, and if you are running a bms then it must be able to balance at your (low) top end limit. Or, you only balance charge every once in a while....Like once a week or so. As stated above running to LVC can cause your pack to get out of balance more quickly. Especially as the pack gets older.

If you are going to work on a daily basis and know the route you are taking then after a few round trips you should know how much of a charge your pack needs. So topping off the charge just before you leave may not be necessary. What might get you is if you unexpectedly have to go farther then you had planned when you left to go to work. Having a charger with you, or an extra one stashed at work is a good idea in case you have to top off at work.

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fechter
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Re: Best way to charge my battery

Post by fechter » Dec 27, 2017 12:34 am

e-beach wrote:
Dec 26, 2017 9:15 pm
Sounds to me like the information is getting a bit loose here. As I understand it, it is not the discharge that shortens the life span of the pack (provided it does not exceed the battery manufacturers specification), it is the top of the charge that shortens the battery life. This also seems to be expressed by the Cycle Satiator graphic from the Grin website.
The graph isn't telling the whole story. I'm sure it's true for charging the pack to whatever level, then running it into the dirt.
If the pack is not fully discharged on every cycle (like most all of my rides), the cycle life will be much higher. I rarely use more than 70% of my capacity and may times less than half.

The time the pack sits around at full charge and temperature play big part too.
Cycle life graph.gif
Cycle life graph.gif (28.47 KiB) Viewed 472 times
"One test is worth a thousand opinions"

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Re: Best way to charge my battery

Post by PewPew » Dec 27, 2017 4:37 am

Thanks for the replies. I'm going to get one of those 80/90% jobbies for charging.

As someone else mentioned on the thread I don't particularly want to be a slave to the battery. I'm not trying to eke out every last drop of longevity from it rather I was more concerned that my actions could be drastically shortening the life of the battery. I don't really understand the chemistry? behind it all and whilst I'd read numerous articles saying not to leave a pack fully charged none of the articles ever really clarified exactly how long you could leave it fully charged nor what sort of impact doing so really had. I was also worried that doing the top off in the morning was sort of like..... double charging the battery so I was concerned I was effectively doubling the rate at which I was wearing it out.

Noob questions really :)

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Re: Best way to charge my battery

Post by e-beach » Dec 27, 2017 10:58 pm

fechter wrote:
Dec 27, 2017 12:34 am
...........The graph isn't telling the whole story........
Especially when the chart says that if you never discharge your pack you get 100000 cycles out if it... :shock: ... :lol:

Your are right about the graph not telling the story.

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Favorite Quote: "This is L.A., sugar. There is no 'over the top." --- Chris Erskine

Current build: Liahona w/ cheap front suspension and suspension seat post. Yescomusa 36v 800w generic front hub motor. 15ah Headway triangle mounted pack. Tronsung 30 amp,

Previous Build:1992 Trek Antelope 800 - Bone Crusher (no suspension) - Yescomusa 800 watt 36 volt front wheel kit. Don't do it! Get suspension!!!

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Re: Best way to charge my battery

Post by dogman dan » Dec 28, 2017 9:07 am

In your case, the 90% charge before bed would be good. But for now, I'd just charge full as you can before sleep, 100% if possible, and then get the rest in the morning if you don't have time to get it full before sleep.

Don't sleep on a charging battery.. Waking up to your house on fire can be exiting. I don't want to scare the crap out of you, but personally, I will never charge a bike battery in my house again.

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Re: Best way to charge my battery

Post by tomjasz » Dec 28, 2017 4:07 pm

dogman dan wrote:
Dec 28, 2017 9:07 am
I will never charge a bike battery in my house again.

I started again, but with a fire safe enclosure, early alarms, backup alarms, and a proper extinguisher is ordered. It's impossible to manage batteries in weather that's below freezing for at least 4 months. But there is excellent cold storage for unused winter batteries. Safety cabinets go on sale often and can be found in auctions.

If I had your experience I'm certain I'd have the same attitude regardless of any other opinion. To talk about fire and live through one are vastly different experiences. Fire is horrifyingly final.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Best way to charge my battery

Post by 999zip999 » Dec 28, 2017 7:28 pm

The point I was making in the middle of the pack everything's fine and dandy when you hit lvc the cells will show their differences in capacity and overtime will unbalance. Guaranteed. Losing ampere hours and ride time plus performance
Do put your pack and leave it on the original charger to bring it up to a level with a BMS can balance the cells once a month. Pick a date maybe your birthdate and give it a full charge every month.

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Re: Best way to charge my battery

Post by PewPew » Dec 31, 2017 2:19 am

dogman dan wrote:
Dec 28, 2017 9:07 am
In your case, the 90% charge before bed would be good. But for now, I'd just charge full as you can before sleep, 100% if possible, and then get the rest in the morning if you don't have time to get it full before sleep.

Don't sleep on a charging battery.. Waking up to your house on fire can be exiting. I don't want to scare the crap out of you, but personally, I will never charge a bike battery in my house again.
Sleeping was definitely out of the question but I was sort of expecting the firehazard batteries to be the ones that were homemade or Chinesium. Hmmm... I see some people charging in an oven? Seems to be a good poor mans safety box until I can get one.
999zip999 wrote:
Dec 28, 2017 7:28 pm
The point I was making in the middle of the pack everything's fine and dandy when you hit lvc the cells will show their differences in capacity and overtime will unbalance. Guaranteed. Losing ampere hours and ride time plus performance
Do put your pack and leave it on the original charger to bring it up to a level with a BMS can balance the cells once a month. Pick a date maybe your birthdate and give it a full charge every month.
Yup, thanks. I understood it was good to balance it every so often.

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Re: Best way to charge my battery

Post by tomjasz » Dec 31, 2017 2:34 pm

PewPew wrote:
Dec 31, 2017 2:19 am
I see some people charging in an oven? Seems to be a good poor mans safety box until I can get one.

Zero does sales on safety cabinets. I picked one up for 40% off and free shipping. Patience and watching pays off. I aid less than used prices and shipping is crazy expensive on something as big and heavy. Midway the gun supplier for a large ammo can that holds two 20Ah triangle packs. Again watch for lowball sales. They happen!
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Best way to charge my battery

Post by fechter » Dec 31, 2017 5:48 pm

Ovens, barbeque grills, ammo cans, small refrigerators all make good fire resistant battery containments, especially if outdoors.
"One test is worth a thousand opinions"

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tomjasz
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Re: Best way to charge my battery

Post by tomjasz » Jan 01, 2018 2:28 pm

fechter wrote:
Dec 31, 2017 5:48 pm
Ovens, barbeque grills, ammo cans, small refrigerators all make good fire resistant battery containments, especially if outdoors.
You fellas have an advantage, sadly outdoors in MN is not practical if you are a cold weather rider.
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Re: Best way to charge my battery

Post by amberwolf » Jan 01, 2018 11:46 pm

Sure it is--just put a heater in there, too. :)

(preferably with a thermostat)

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Re: Best way to charge my battery

Post by tomjasz » Jan 02, 2018 1:09 am

amberwolf wrote:
Jan 01, 2018 11:46 pm
Sure it is--just put a heater in there, too. :)

(preferably with a thermostat)
You’vebeenin the desert to long. Heat at -15F isnt a cakewalk. VBG
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Re: Best way to charge my battery

Post by amberwolf » Jan 02, 2018 1:30 pm

It is if you're using a BBQ as containment. :P

Or a BBQ inside an old fridge (as insulation in case there's too much wind--might need an oxy bottle as well as propane, though). :lol:


More seriously, if it is possible to reverse a refrigerator's compressor cycle (or swap coil connections?) it would then be a heat pump, although I don't know if that works down to those temperatures.

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