Henry111
1 kW
dogman dan said:
Thank you dogman.
Yes, it is in a metal case. The only time I open one is to change a bad key or replace the key mechanism.
ebike-kit is lucky to have you.
Henry111's free tech support thread
- Thread starter Henry111
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Thank you dogman.
Yes, it is in a metal case. The only time I open one is to change a bad key or replace the key mechanism.
ebike-kit is lucky to have you.
Henry111
1 kW
Can I use a LI-ION charger to charge a LiFePO4 battery?
Both batteries are 36V, 12Ah.
Both batteries are 36V, 12Ah.
Takemehome
1 kW
Henry111 said:
LI-ION : 10 cells at 4.2V = 42V
LiFePO4 : 12 cells at 3.65V = 43.8V
It will charge it but not completely.
42V for 12 cells = 3.5V per cell ( IF your pack is balanced.)
Voltron
1 MW
Yes.... but it won't charge it high enough to make the BMS balance the cells. Fully charged "36v" li ion= 42v, lifepo = 43.6. But there might be an adjuster in the charger that could turn it up to the 43.6 if you open it up....but research it first of course.
999zip999
100 TW
What charger I don't see a charger ? How about a pic ?
agniusm
1 MW
You can. That's what I am doing. Open up the charger and adjust the pot to correct voltage.
Voltron
1 MW
Just a fyi on charger adjusting.. I just did three. One had a nice obvious pot that went clockwise to turn the voltage up. The next one had a nice obvious pot, with some goo on it to keep it from changing by accident that had to get pried off, that went counter clockwise to turn it up. The next one had a big blob of goo..that was so hard to pry off that I slipped and yanked out a nearby wire.. And under the goo was nothing....Just bare circuit board. Finally found it under a heat shield that takes total disassembly to reach.... crazy how three similar black boxes that do the same thing are unpredictably different.
Henry111
1 kW
I have an e-skate with 36v/10Ah SLA batteries.
What would happen if I took these out and replaced them with two 18V/5Am LiPos wired in series.
This e-skate already has Dean connectors, commonly used in RC.
What would happen if I took these out and replaced them with two 18V/5Am LiPos wired in series.
This e-skate already has Dean connectors, commonly used in RC.
chaka
1 kW
You would have a 36v 5ah pack. Depending on the C rating of the pack it should work fine but you will have half the range of the old battery.
sl33py
10 kW
it's been done a few times and should work well! much much lighter!
GL!
GL!
Henry111
1 kW
chaka said:
Thank you for your info.
I will hook up two in series and two more in P and have a 36V/10Ah setup.
Have I got that right?
Weight: These three SLAs weigh 25 lbs. How much will I save by going to four LiPos?
Also:
My packs are rated at 20C. What does that tell me in terms of range on the above setup?
Again, thanks, I sincerely appreciate your advice.
markz
100 TW
Are the Greentime chargers adjustable?
What if I have LiFePO4 in 16S 58.4V (3.65Vmax) and 18650 25R in 14S 58.1V (4.15Vmax)
For the BMS to balance it needs to be what % of max V?
What if I have LiFePO4 in 16S 58.4V (3.65Vmax) and 18650 25R in 14S 58.1V (4.15Vmax)
For the BMS to balance it needs to be what % of max V?
sl33py
10 kW
a couple 5s batteries in series for 5Ah or 4 for 10Ah will be hugely less weight.
Just a quick glance at some 5s batteries - 4 would be about 6lbs to compare. so 2 would be 3 lbs.
Here's the ones i pulled up in a quick search:
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=15008
As for range - you have a brushed motor so i don't think our usual calculations will apply (less efficient than brushless).
BUT if you get the same Ah rating it should be close to what the original board claims - with about 20lbs less weight which can only help!
Just a quick glance at some 5s batteries - 4 would be about 6lbs to compare. so 2 would be 3 lbs.
Here's the ones i pulled up in a quick search:
http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=15008
As for range - you have a brushed motor so i don't think our usual calculations will apply (less efficient than brushless).
BUT if you get the same Ah rating it should be close to what the original board claims - with about 20lbs less weight which can only help!
Henry111
1 kW
sl33py said:
Thanks. I'll let everybody know how it goes and maybe post some pics.
With the SLAs this board weighs 41 lbs.
chas58
10 kW
So does that mean I shouldn't use a LiFePo4 charger to charge LI-ION batteries?
I'm tired of dragging around heavy LiFePo4 cells when I can get LI-ION batteries (Samsung INR18650 type) for about 1/3 the size and weight.
I'm tired of dragging around heavy LiFePo4 cells when I can get LI-ION batteries (Samsung INR18650 type) for about 1/3 the size and weight.
Hillhater
100 TW
chas58 said:
Well, the simple but safe answer is,..
..it CAN be done, but if you don't understand the issue, you SHOULDNT do it, get the correct charger for the pack. ,!
999zip999
100 TW
If me I would go to Luna cycles and get a Samsung 25r pack and his charger. Oh yes he's in California.
I love my lifepo4 24s 20ah 730cycles good as new. Heavy battery. Oh did I mention heavy ? Many use 12ah. But would never carry less than 15ah. Battery Questions ?+? ' s
I love my lifepo4 24s 20ah 730cycles good as new. Heavy battery. Oh did I mention heavy ? Many use 12ah. But would never carry less than 15ah. Battery Questions ?+? ' s
dogman dan
1 PW
Whatever you are doing, the chargers voltage needs to match your packs top of charge voltage.
Lifepo4 and most other lithium have very different full charge voltages. Lifepo4 is 3.5v per cell, but often charges to 3.65v per cell to balance better.
most of the others charge to 4.2v per cell. So it's not very often that a lifepo4 charger is set to the same voltage as other lithium types.
If you can adjust the voltage of your charger, then you can tweak it to run with either type.
Lifepo4 and most other lithium have very different full charge voltages. Lifepo4 is 3.5v per cell, but often charges to 3.65v per cell to balance better.
most of the others charge to 4.2v per cell. So it's not very often that a lifepo4 charger is set to the same voltage as other lithium types.
If you can adjust the voltage of your charger, then you can tweak it to run with either type.
markz
100 TW
I read about "Charging Profile"
The charging profile is the same then with LiFePO4 and Li-Ion.
The charging profile is the same then with LiFePO4 and Li-Ion.
Hillhater
100 TW
Well yes and no.!markz said:
Most are basicly a CC/CV profile, ..but.
... "profile" is a very descriptive term to characterize several factors,.... such as, final fully charged voltage, charge current, finishing current, balance current, etc etc.
Ideally, all these parameters will be optimized and pre set for each different chemistry ( Lipo, LiCo, LiFepo, NMC etc etc)
http://low-powerdesign.com/article_meng_he.htm
999zip999
100 TW
Always best to have a charger that matches the battery. What can work ?
dogman dan
1 PW
Absolutely, the charge profile should be perfect for each type of cell. That would be ideal.
I just have little faith that it is adjusted perfectly, when the charger is a relatively affordable "bike or scooter" charger.
I would also think that since lifepo4 is more tolerant of an overcharge, a li-ion charger used for lifepo4 would not do a lot of harm.
If you want a charger that does have different profiles for different types of lithium, RC chargers should have that, and also the satiator.
I just have little faith that it is adjusted perfectly, when the charger is a relatively affordable "bike or scooter" charger.
I would also think that since lifepo4 is more tolerant of an overcharge, a li-ion charger used for lifepo4 would not do a lot of harm.
If you want a charger that does have different profiles for different types of lithium, RC chargers should have that, and also the satiator.
chas58
10 kW
Ok, the advice here doesn’t seem to add up or fit what is on the market.
Specifically
High end chargers sold by EM3ev and Grin (ebikes.ca) can be set to charge to 80% max. So can anyone explain how voltron can be correct when the top vendors are recommending something else?
And, back to the original question:
Why not use a lithium ion charger for a lifepo4?
BMSbattery’s
Li-Ion charger will charge to 42v
LifePo4 charger will charge to 43.8V
Both at 2 amps.
So, to the OP’s question, he will be getting to 95% of charge. Per ebike.ca data, this will increase the life span of the battery by about 50% (from 500 to 750 charges). Am I missing something?
Specifically
Voltron said:
High end chargers sold by EM3ev and Grin (ebikes.ca) can be set to charge to 80% max. So can anyone explain how voltron can be correct when the top vendors are recommending something else?
And, back to the original question:
Why not use a lithium ion charger for a lifepo4?
BMSbattery’s
Li-Ion charger will charge to 42v
LifePo4 charger will charge to 43.8V
Both at 2 amps.
So, to the OP’s question, he will be getting to 95% of charge. Per ebike.ca data, this will increase the life span of the battery by about 50% (from 500 to 750 charges). Am I missing something?
999zip999
100 TW
Why because lifepo4 can walk off balance over time. And as you are not using top quality lipo4, yours will unbalance and die an early death. Not 2,000 cycles.
You will need a way to monitor and be able to keep in balance. Can you check each cell after each charge.
Em3ev chargers are designed for nmc, nca or lico chemistry cells, with a switch for full charging and balancing. With needs to be done ever so often to balance.
I also found that quality in a cell is best thing you can do for yourself.
It also depends on rate of discharge and depth of discharge. So what is these battery for.
You will need a way to monitor and be able to keep in balance. Can you check each cell after each charge.
Em3ev chargers are designed for nmc, nca or lico chemistry cells, with a switch for full charging and balancing. With needs to be done ever so often to balance.
I also found that quality in a cell is best thing you can do for yourself.
It also depends on rate of discharge and depth of discharge. So what is these battery for.
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