Adjustable voltage ebike charger

[JackFlorey]

Oh interesting. Would they be ok for charging lithium cells? Do I need to worry about the switching thing(mentioned above)?

Yes they would be fine. You can NOT leave them to charge for a few days; you have to unplug them after 2-12 hours so the batteries do not sit at 4.2 volts forever. (That's bad for them, and if you have a defective cell, can eventually cause a fire.)

However, many "factory" chargers do exactly the same thing. The old Radbikes charger I have never terminates either - just keeps charging at 4.15 volts per cell forever. This has a little bit of advantage in that the pack's BMS gets a chance to top balance, but you have to disconnect them manually at some point, and you have to know when that point is.

Better chargers, like the Satiator, will terminate automatically for you.

Personally I use a Satiator when I charge in my garage. I use an old Meanwell as a "road charger" because they are super light, cheap and I am not at risk of forgetting and leaving it plugged in for a week.

 

[LewTwo]

See this thread:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=110754

Riden RD6006 power supply to use as a battery charger for Lithium Ion batteries

 

[bj97301]

Got it. Thank you.

 

[machuni]

Anyone know of a good adjustable charger? I am looking for something that can do 42-100.8v or I’ll settle for 42-84v.

Get a few Meanwell HLG supplies. They are cheap and are sold as LED ballasts. For example, the HLG-60H-C700AB will do 50-100 volts, both voltage and current are adjustable. There are lots of voltage ranges available. (And since you can adjust current, odds of overheating go way down.)

Is there something with that range that puts out more amps? It seems like all the models I googled that have at least a couple of amps either go up to 60v or go down to 60v without a crossover of 52-72v.

 

[JackFlorey]

Is there something with that range that puts out more amps? It seems like all the models I googled that have at least a couple of amps either go up to 60v or go down to 60v without a crossover of 52-72v.

Well, the easy option is to just parallel them.

There are chargers like the Huawei R4850G2 that are super cheap but require more knowledge of electronics.

 

[Chalo]

You can NOT leave them to charge for a few days; you have to unplug them after 2-12 hours so the batteries do not sit at 4.2 volts forever.

Here's a question I've never found a good answer for: Is there a downside to leaving a pack on the charger for a relatively long time at say 4.05V per cell? Versus charging to 4.05V/cell and then unplugging?

I'm not talking extended storage here-- just having the battery ready to rock. Since I have the convenience of two e-bikes, one of them might sit for days at a time unused, but still on the charger. Sometimes I remember to unplug it and sometimes I don't. Sometimes I want to leave the battery plugged into the controller so I don't spark the connector when I reattach, but the controller will apply a small parasitic drain. In that case, leaving the charger attached keeps the voltage from dropping while it waits.

Is this a problem? (To judge by the longevity of my batteries, it isn't.) If it is a problem, then why?

 

[gobi]

You can NOT leave them to charge for a few days; you have to unplug them after 2-12 hours so the batteries do not sit at 4.2 volts forever.

Here's a question I've never found a good answer for: Is there a downside to leaving a pack on the charger for a relatively long time at say 4.05V per cell? Versus charging to 4.05V/cell and then unplugging?

I'm not talking extended storage here-- just having the battery ready to rock. Since I have the convenience of two e-bikes, one of them might sit for days at a time unused, but still on the charger. Sometimes I remember to unplug it and sometimes I don't. Sometimes I want to leave the battery plugged into the controller so I don't spark the connector when I reattach, but the controller will apply a small parasitic drain. In that case, leaving the charger attached keeps the voltage from dropping while it waits.

Is this a problem? (To judge by the longevity of my batteries, it isn't.) If it is a problem, then why?

1. A true batt charger turn off current when the current reaches say 0.2 amps in CV
2. If you get a "zap" then your charger is probably set in a power supply mode.

I use a Riden RD to charge my batts, my highest volt batt is a 14s, so my 57v PS tied to Riden works well for my needs.

If I connect the Pos lead to the PS terminal I get a zap when I touch the terminal,
If I connect the Pos lead to the charger (green) terminal, no zap ever.

I will post a pic later tonight.

Leaving a batt connected to a power supply and say it keeps charging at 0.2 amps, I read will stress out the battery, what is that? not sure,
I am sure the cells will probably degrade if they are kept on a constant voltage and some current.
[I curious, I will research what "stress" means for a lithium batt]

 

[Chalo]

It's self-evident that once the battery's voltage rises to the same as the charger's maximum voltage, the charging current will diminish to approximately zero (actually to whatever the battery's self-discharge current is, plus the current consumed by the BMS or balancer).

My direct experience demonstrates that this isn't a big problem, but is it any kind of problem-- if you assume say 85% charge level and a balanced pack?

 

[JackFlorey]

Here's a question I've never found a good answer for: Is there a downside to leaving a pack on the charger for a relatively long time at say 4.05V per cell? Versus charging to 4.05V/cell and then unplugging?

It is WAY WAY better than leaving them at 4.2 volts.

That being said, if you remove the battery from the charger that is charging them to 4.05, they are going to drop a bit - to say 4.0 or 3.95 volts. And that's even better. The guideline is 3.8 volts per cell or less for maximum life.

Storing a li-ion cell at a lower terminal voltage will always prolong its life (as long as it's above about 3 volts, of course.) Whether it's noticeable to you is going to depend on how much of your battery's capacity you need.

Here's a table from Battery University:

CelV	Cycle life   	Capacity remaining
4.20	300–500		100%
4.15	400–700		90–95%
4.10	600–1,000	85–90%
4.05	850–1,500	80–85%
4.00	1,200–2,000	70–75%
3.90	2,400–4,000	60–65%

 

[999zip999]

Chalo iit depends on the chemistry even though it says lithium ion which lithium ion as there are many many different chemistry, but if it is lifepo4 yes you can hold on at 3.41 v for 12 hours one day should not hurt it. Oh A123 stop I mean high-quality lifepo4.
Just don't do what you're doing and pass out. I know what you're doing. As you can't fool me or your mother.

 

[SafeDiscDancing]

I use four 11 volt to 13 volt (adjustable by pot I added) power supplies in Series.

The last of the four has a long wire where I put the potentiometer out far enough that I can reach it easily.

Each charger can pull about 38 amps.

So the math is roughly 50 volts * 40 amps or about 2000 watts "in theory".

But in reality my garage circuit cannot handle more than about 1500 watts before the breaker flips.

I watch:

Voltage
Current
Watts
Watt Hours

...then my "wildcard" is a single cell voltage on my known weakest cell.

All I do is charge as hard as I can until I reach about 4.18 volts on the weak cell then stop.

Total charge time is about 20 minutes on my pack.

On a busy day I can run through seven charge - ride - charge cycles.

The pack is small at only 300 wh. (SPIM08hp)

So a heavy riding day means 300 wh * 7 or about 2100 wh for a full day of riding. (and I'm exhausted)

I own a second pack that is 600 wh and with double the range I seem to get MORE tired out than with the more frequent 300 wh pack. Something about those 20 minute rest breaks that gives you time to recover for more.

In other words I actually like the rest breaks.

 

[calab]

What chargers are you using in series and did you modifty them for isolated grounds?

I use four 11 volt to 13 volt (adjustable by pot I added) power supplies in Series.
The last of the four has a long wire where I put the potentiometer out far enough that I can reach it easily.
Each charger can pull about 38 amps.
So the math is roughly 50 volts * 40 amps or about 2000 watts "in theory".
But in reality my garage circuit cannot handle more than about 1500 watts before the breaker flips.
I watch:VoltageCurrentWattsWatt Hours
...then my "wildcard" is a single cell voltage on my known weakest cell.
All I do is charge as hard as I can until I reach about 4.18 volts on the weak cell then stop.
Total charge time is about 20 minutes on my pack.
On a busy day I can run through seven charge - ride - charge cycles.
The pack is small at only 300 wh. (SPIM08hp)
So a heavy riding day means 300 wh * 7 or about 2100 wh for a full day of riding. (and I'm exhausted)
I own a second pack that is 600 wh and with double the range I seem to get MORE tired out than with the more frequent 300 wh pack. Something about those 20 minute rest breaks that gives you time to recover for more.
In other words I actually like the rest breaks.

 

[SafeDiscDancing]

What chargers are you using in series and did you modify them for isolated grounds?

I bought them used on eBay. (not sure what brand, but they are NOT the cheap chinese stuff because I've done those)

They seem pretty decent and have held up for a couple years of heavy abuse.

Each power supply gets the same split from the garage plug so there is no weird stuff about how they are in Series.

Let me add... I built a "full splitter" that looks like spaghetti that takes the garage plug and does the split BEFORE it is spread out evenly to the power supplies so I think I can imagine an error where one might run power in Series which might not work too well. (the drain would be uneven)

They are well built with built in current limitation (under 40 amps... about 38 amps) and it seems they are pretty well designed to resist just about any stupid thing I might do like to connect the battery before turning it on and it forgives my error. (reverse surge protection)

I have upgraded the surge resistors that prevent the startup spike to new ones and they have been very reliable for the last year since I did that. Apparently the original surge resistors were cheap clones that did not live up to the spec.

And I even have extra "over rated" surge resistors if I want to go higher, but those have not been needed.

NTC-5D is stock and I bought some NTC-8D as backup.

Basically they have been rock solid for a long time.

I do 1500 watt charging as my daily routine.

------------------------------

Update :

12V 480W 40A Driver Adapter Switch Power Supply Converter for LED Strip Light

Found on ebay. They are this brand.

$35.99

https://www.ebay.com/itm/12V-480W-40A-Driver-Adapter-Switch-Power-Supply-Converter-for-LED-Strip-Light/252400487518?pageci=cebf4074-9958-43f5-85f4-7811814aea56&redirect=mobile

Chinese, but not their worst stuff.

Features:
12V 480W Single Output Switch
Widely ranged input voltage , steady & precise output voltage
Full load burn-in test.
Over current, over voltage, short circuit protection.
Low output ripple.
Warranty: 1 Year.

Specification:
Input voltage: AC110V
Input frequency: 50/60hZ
Output voltage: 12V
Output current: 40A
Screw Terminal Number : 9
Protections: overload/ over voltage/ short circuit

 

[calab]

Meanwells are adjustable but most arent made for mobile use unless you go with the l.e.d. versions and those meanwells you can plug in series rsp's and such. One of my chargers is not adjustable and it only charges to 20.20v yes its a split pack, 2 chargers and battery has an series adapter. Lets see now 4 years I must've been doing that, got a few 9ah ryobi's from home depot.

 

[SafeDiscDancing]

Meanwells are adjustable but most arent made for mobile use.

Mine are very land based. In fact I built a little wood container that puts them upright with the fans at the bottom lifted a few inches off the ground. This allows air to be blown upwards increasing heat as it is pushed out of the front of the power supplies.

That trick seems to improve cooling a lot.

Plus these have two fans at the back so they really push the air compared to the cheaper Chinese power supplies that do not include current limiting. In my experience it is the LACK of the current limiting function that dooms the cheap power supplies to a quick death because you never know when you might have drained the battery low enough to get that "no resistance" startup charge surge.

And my ebike really is a "sport" machine designed around the idea of very thrilling 20 minute "motos" with 20 minute rest and recharge cycles in between.

The idea of long distance ebiking has occurred to me but it always degrades to a sort of homeless existence out on the road which has lost 99.9% of it's attraction in the last two years.

But... thinking another way... if we start losing our ability to travel by car then maybe the ebike will one day be our freedom machines.

Hard to guess right now. Mobile ebike and endless travel.... Hmmmm...

 

[calab]

You need more watt-hours :wink:

 

[SafeDiscDancing]

You need more watt-hours :wink:

Like I said... I do have an older LiFePO4 pack at 600 wh but that weighs close to 20 lbs.

The SPIM08hp 12S pack is about 10 lbs.

And don't forget my motor is only about three pounds. (peak power about three horsepower)

So my standards for thrills and light weight are very different than others.

A lot of people are content with a big pack and 25 lbs of hub motor smacking the pavement all day.

For the kind of "sport" riding I like 20-30 minutes is plenty of runtime.

And the next "moto" is a quick 20 minute recharge away. (drink water, eat snack, go to the bathroom)

Figure 1200 watts is equal to 100 wh every 5 minutes.

Which means 1500 watts is a little more, but with the taper on the second half of charging it ends up about 20 minutes.

No way you would let some BMS try to control all that... if you want the "hard charging" you need to at minimum be smart enough to manage it yourself.

Let those not "smart" use the "smart charger" and BMS. :lol:

 

[gobi]

To do that kind of range, you need something like a lab power supply. For a lot less cost and size, you can get a Meanwell adjustable power supply that will do its rated voltage plus or minus 10%.

You don't say what you're trying to charge, at what current.

Chalo,

Here is what I found on battery uni,

A continuous trickle charge would cause plating of metallic lithium and compromise safety. To minimize stress, keep the lithium-ion battery at the peak cut-off as short as possible. Once the charge is terminated, the battery voltage begins to drop. This eases the voltage stress.

 

[machuni]

To those who don't want to worry about paralleling and to circle back and answer my earlier question, this is what I ended up getting: Mean Well HLG-320H-C3500A 320W 3500mA 3.5A 46-91V LED Driver IP65 120-277V. It has a range from 46-91 v (which are all the ebike voltages I'm interested in) and you're able to adjust the amperage from 1.65-3.5 with built in potentiometers. And I paid less than $100 for it on ebay!

 

[SafeDiscDancing]

...and you're able to adjust the amperage from 1.65-3.5 with built in potentiometers.

Good for a mobile solution because it's a single fairly lightweight power supply.

For your home charging the way to go is not Parallel but Series.

$36 will get you up to 40 amps per 11 volt to 13 volt power supply:

12 volt --> 24 volt --> 36 volt --> 48 volt --> 60 volt --> 72 volt

The problem is some target voltages for peak charging don't fit too well.

I know that 12S LiFePO4 and 12S Li-ion both work well with four power supplies.

So you need to be a little aware of those gaps if you want fast charging that is cheap.

For me the idea of charging at 2 amps sounds really slow...

 

[SafeDiscDancing]

A continuous trickle charge would cause plating of metallic lithium and compromise safety. To minimize stress, keep the lithium-ion battery at the peak cut-off as short as possible. Once the charge is terminated, the battery voltage begins to drop. This eases the voltage stress.

There was another thread somewhere in which they discussed how a lithium battery actually lasts longer if you can do more intense charging and discharging.

Something about those little "roots" that grow will tend to get pushed backwards if you hit them with a hard current.

But the funny thing is I forget WHICH direction matters most charge or discharge.

All I know is my battery cells (SPIM08hp) simply love to be driven hard.

However, this fact is not true of all cells and the 18650's are probably the worst from what I've heard so if your cells are not equipped for high charge and discharge don't force them.

As a rule the pouch cell design naturally can get energy in and out faster compared to cylindrical.