10A charging of a 36V 15Ah Hailong battery?
- Thread starter SkipperDK
- Start date
hailong is just a case style.
there's two limitations.
the bms charge fets are setup for a specific max charging current, beyond which they heat up too much. (whcih can cause anything from simple fet failure preventing any charging at all, to heating them so much that they desolder themselves and either slide around the board shorting stuff out, or fall off and short against other things, or drip solder in places that short things, and the shorts can lead to other damage, potentially including fire)
the cells themselves have a max charging current, beyond which they heat up too much (and other stuff happens chemistry-wise). (heating up too much can be anything from a little lifespan-shortening, to so much heat that they become a fire risk, depending on the charge rate per cell and the cells' actual capabilities). remember that the heat produced by charging is still there when you discharge (ride), assumign you're doing the fast charging so you can ride right away and/or keep riding if you stop to top off somewhere, and the riding (discharging) is *also* making heat to add to the existing heat.
you'd have to find out what cells are actually in it, and find their spec sheet, for the latter. and / or put thermal sensors in there to monitor temperatures while you charge and ride.
you'd have to find out what bms is in it, and find it's spec sheet, for the former. (and / or put thermal sensors....)
there's two limitations.
the bms charge fets are setup for a specific max charging current, beyond which they heat up too much. (whcih can cause anything from simple fet failure preventing any charging at all, to heating them so much that they desolder themselves and either slide around the board shorting stuff out, or fall off and short against other things, or drip solder in places that short things, and the shorts can lead to other damage, potentially including fire)
the cells themselves have a max charging current, beyond which they heat up too much (and other stuff happens chemistry-wise). (heating up too much can be anything from a little lifespan-shortening, to so much heat that they become a fire risk, depending on the charge rate per cell and the cells' actual capabilities). remember that the heat produced by charging is still there when you discharge (ride), assumign you're doing the fast charging so you can ride right away and/or keep riding if you stop to top off somewhere, and the riding (discharging) is *also* making heat to add to the existing heat.
you'd have to find out what cells are actually in it, and find their spec sheet, for the latter. and / or put thermal sensors in there to monitor temperatures while you charge and ride.
you'd have to find out what bms is in it, and find it's spec sheet, for the former. (and / or put thermal sensors....)
you have to put the thermal sensors where the heat comes from, because you want to know when those actual parts are getting too hot.
if you want to monitor the bms for charging, you must put it on the charging fets. (not just sitting there, but direclty mounted to the fet metal tab as close to the fet body as possible, you want to measure the actual fet temperature).
if you want to monitor the cell heat, i would put multiple sensors around the pack, but if you can only put one, it needs to go in the center of the pack among the cells, attached to the cylindrical part of a cell wall directly. (not just stuck between them in the air gap; you want to measure the actual cell temperature, not the air inside).
measuring a fet temperature will have a small delay before you see the heat, but measuring the cell will likely have a longer delay, because the cels are larger and take longer for heat generated inside to make it to the outside. the more layers of stuff (including air, glue, etc) between the sensor and the cell, the longer it takes for heat to reach the sensor and tell you the cell is hot.
if you want to monitor the bms for charging, you must put it on the charging fets. (not just sitting there, but direclty mounted to the fet metal tab as close to the fet body as possible, you want to measure the actual fet temperature).
if you want to monitor the cell heat, i would put multiple sensors around the pack, but if you can only put one, it needs to go in the center of the pack among the cells, attached to the cylindrical part of a cell wall directly. (not just stuck between them in the air gap; you want to measure the actual cell temperature, not the air inside).
measuring a fet temperature will have a small delay before you see the heat, but measuring the cell will likely have a longer delay, because the cels are larger and take longer for heat generated inside to make it to the outside. the more layers of stuff (including air, glue, etc) between the sensor and the cell, the longer it takes for heat to reach the sensor and tell you the cell is hot.
as a couple of examples: i have an old 20ah a123 cell pack that can easily take 10a charge, doesn't even get warm. neither do my 20 and 40ah eig cell packs.
but a little 10ah 18650 pack gets warm at even a 4a charge rate, even with the pack opened up rather than in a case or in shrinkwrap. (it also gets hot, over 100f on the *outside* of the pack, under just a 2c (20a-ish) discharge rate (with short peaks up to 50a), when it is supposed to be a 50a continous discharge rate pack--but it does have a note in the original specs page saying not to do it). turns out the cells in it are actually only meant for 2c max discharge, so the pack was built and sold around a lie. (not surprising, and it happens quite a lot in the ebike battery industry). i don't seem to have the temperature data posted from the charging, just the discharging on the one test ride posted about.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=81108
i used to have a lifepo4 18650 pack, and i recall heat as a problem in it, too, but i haven't had it for years (stolen) and no longer remember much about it, though there is a repair thread for it in my posts under vpower / cammycc or something like that.
but a little 10ah 18650 pack gets warm at even a 4a charge rate, even with the pack opened up rather than in a case or in shrinkwrap. (it also gets hot, over 100f on the *outside* of the pack, under just a 2c (20a-ish) discharge rate (with short peaks up to 50a), when it is supposed to be a 50a continous discharge rate pack--but it does have a note in the original specs page saying not to do it). turns out the cells in it are actually only meant for 2c max discharge, so the pack was built and sold around a lie. (not surprising, and it happens quite a lot in the ebike battery industry). i don't seem to have the temperature data posted from the charging, just the discharging on the one test ride posted about.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=81108
i used to have a lifepo4 18650 pack, and i recall heat as a problem in it, too, but i haven't had it for years (stolen) and no longer remember much about it, though there is a repair thread for it in my posts under vpower / cammycc or something like that.
John in CR
100 TW
SkipperDK said:
If they say "max", then I'd go even lower for daily charging.
that's probably even optimistic, and as john in cr said, i'd charge at a lower rate for everyday use. my guess is the seller probably recommends a 2a charge normally, and it probably comes with a 2a charger. most likely, the pack will last a lot longer at the original charging rate than a higher one. (without knowing what's in there, i wouldn't even make any bets it would survive a 10a charge once, much less everyday charging like that).SkipperDK said:
but unless you know for sure what cells are actually in it (and remember the labels inside may be fake), and what the bms specs actually are, or you test to the point of potential damage or destruction, you can't really know what the pack is capable of.
keep in mind that many 18650 cells have pretty low charging rates, as little as 0.1c to 0.2c. a 15ah pack at 0.1c is 1.5a. at 0.2c is 3a. 5a is 0.34c. 10a is 0.67c. some cells can take that, and some can't. some can take much higher rates...but not most of them, and the cheaper the pack is, the cheaper the parts used in it usually are, which usually means low charge and discharge rates.
With even a top-shelf battery personally I stay below 0.4C for longevity.
When the cells are hot from ambient warming you can go faster without much "damage" (lost lifespan cycles).
When getting cooler than T-shirt weather, then need to go much slower
below 15°C my limit reco is maybe 0.2C
I'd start pre-warming below 10° if going over 0.1C
Now, I do coddle my cells, low C-rate discharge, low charge Vtermination, high LVC
If yours are being abused anyway, perhaps unavoidably in your use case, then maybe the reduced lifespan from "faster" charging will not be significantly greater anyway.
Too many variable to really quantify cause & effect.
When the cells are hot from ambient warming you can go faster without much "damage" (lost lifespan cycles).
When getting cooler than T-shirt weather, then need to go much slower
below 15°C my limit reco is maybe 0.2C
I'd start pre-warming below 10° if going over 0.1C
Now, I do coddle my cells, low C-rate discharge, low charge Vtermination, high LVC
If yours are being abused anyway, perhaps unavoidably in your use case, then maybe the reduced lifespan from "faster" charging will not be significantly greater anyway.
Too many variable to really quantify cause & effect.
999zip999
100 TW
What does your charger charge at now ?
Thank you, I'll keep that in mind.John in CR said:
john61ct said:
Well, sorry to say, I really do abuse my battery, it gets fully charged, and almost fully decharged at max rate. I need a bigger capacity and dicharge rated battery and it's on my wishlist.
I hear what all of you are saying. I'm thinking on getting a 5A charger only for when I need a fast recharge and then use the 2A charger as much as possible.
amberwolf said:
Thank you, I actually thought i could treat a 18650 battery with a little higher chargerate as with LIPO, but I see now that not the case.
2A, mate.999zip999 said:
dogman dan
1 PW
Good plan. My current battery does not really state the max charge rate, but it seems to be at least 5 amps, based on the chargers the retailer sells with it. It might be able to handle more, but I seriously doubt its bms is good for 10 amps.
My charger is a satiator, which I can set to 7 amps max. I do use that setting, but only when I need a quick jolt, often enough not even to full. My normal charge rate is a 3 amps charge, used when not in a hurry, or not needing to just top it up a bit quicker. In a top up, the charger will not run at 7 amps anyway, since the flow slows down as the battery nears full. So if I store the battery at 56v, then I can run the 7 amps to fill it to 58v without it really ever getting to 7 amps flowing.
Neat thing about the satiator, it shows on its display what the actual flow rate is, which varies as the battery fills up. Slower at the end. While so pricy It took me years to get my satiator, its worth every penny I paid. Should have gotten one years ago.
My charger is a satiator, which I can set to 7 amps max. I do use that setting, but only when I need a quick jolt, often enough not even to full. My normal charge rate is a 3 amps charge, used when not in a hurry, or not needing to just top it up a bit quicker. In a top up, the charger will not run at 7 amps anyway, since the flow slows down as the battery nears full. So if I store the battery at 56v, then I can run the 7 amps to fill it to 58v without it really ever getting to 7 amps flowing.
Neat thing about the satiator, it shows on its display what the actual flow rate is, which varies as the battery fills up. Slower at the end. While so pricy It took me years to get my satiator, its worth every penny I paid. Should have gotten one years ago.
Worth is an opinion,
But
true charger with current limiting, also terminates when full, unlike a raw rectifier/PSU or DC converter
adjustable setpoint across a large V range, can be used with a variety of packs
adjustable current rate
Multiple units can be put in series or parallel
decent display
reliable, Grin is a well trusted North American vendor, support is available, warranty
Sent from my Nexus 6 using Tapatalk
But
true charger with current limiting, also terminates when full, unlike a raw rectifier/PSU or DC converter
adjustable setpoint across a large V range, can be used with a variety of packs
adjustable current rate
Multiple units can be put in series or parallel
decent display
reliable, Grin is a well trusted North American vendor, support is available, warranty
Sent from my Nexus 6 using Tapatalk
the first thing is that it is designed and built to be able to be carried around or mounted on the bike or vehicle, so it can handle the banging around and vibration and weather, where it's a crapshoot with the cheap (or even expensive) typical chargers on the vibration/banging around, and pretty much none of them can be in wet weather.SkipperDK said:
because of the sealed design it's also fanless, so it's silent.
ends charge when current drops below a settable point, and disconnects it's output from the battery (whcih is very handy if you mount it on the bike and connected to the battery all the time).
if you have a thermal sensor in the battery, you can wire it to a threee-wire charge port so the satiator can monitor battery temperature, and can shutoff charge above a preset point.
you can setup multiple charge profiles, that can be setup for a main default one, and button select the others. so in a use case like yours, you don't need multiple chargers to have slow and fast charging rates, just the satiator.
it also tracks usage in each profile, so you can see how many wh / ah each one has charged up over time.
the profiles can be setup by hand on the charger itself via the menus, or via usb (with the adapter cable) from a computer.
that feature can also be used if you have multiple bikes or battery packs with different properties, but doesn't sound like it applies to your case.
it also has a warranty and actual customer service / help if you ever need it (though grin sometimes takes quite a while to respond via email, you can always call them), and spare parts are available for it if it does break. that includes firmware updates whenever improvements are made to the control software inside it (or the computer based setup software).
adapter cables exist for several common ebike charging port connectors.
the money you spend on it pays for development of other handy new ebike devices, and improvement of existing ones.
everybody doesn't need one. but if the features above sound like stuff you'd prefer over your existing setup, it might be for you.
john61ct said:
amberwolf said:the first thing is that it is designed and built to be able to be carried around or mounted on the bike or vehicle, so it can handle the banging around and vibration and weather, where it's a crapshoot with the cheap (or even expensive) typical chargers on the vibration/banging around, and pretty much none of them can be in wet weather.SkipperDK said:
because of the sealed design it's also fanless, so it's silent.
ends charge when current drops below a settable point, and disconnects it's output from the battery (whcih is very handy if you mount it on the bike and connected to the battery all the time).
if you have a thermal sensor in the battery, you can wire it to a threee-wire charge port so the satiator can monitor battery temperature, and can shutoff charge above a preset point.
you can setup multiple charge profiles, that can be setup for a main default one, and button select the others. so in a use case like yours, you don't need multiple chargers to have slow and fast charging rates, just the satiator.
it also tracks usage in each profile, so you can see how many wh / ah each one has charged up over time.
the profiles can be setup by hand on the charger itself via the menus, or via usb (with the adapter cable) from a computer.
that feature can also be used if you have multiple bikes or battery packs with different properties, but doesn't sound like it applies to your case.
it also has a warranty and actual customer service / help if you ever need it (though grin sometimes takes quite a while to respond via email, you can always call them), and spare parts are available for it if it does break. that includes firmware updates whenever improvements are made to the control software inside it (or the computer based setup software).
adapter cables exist for several common ebike charging port connectors.
the money you spend on it pays for development of other handy new ebike devices, and improvement of existing ones.
everybody doesn't need one. but if the features above sound like stuff you'd prefer over your existing setup, it might be for you.
These are some very compelling arguments, it sure sounds like a good buy. I think i might get one, so I can treat my next battery with much more care. Thanks for the advice, guys.
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