The poor mans cycle satiator

[CUDAcores89]

[strike]Not sure if anyone has done something like this, but I thought I would share how I charge up my ebike battery at work quickly and cheaply without spending $100+ on a fast charger that still has lots of features found on super expensive chargers like the cycle satiator.[/strike]

Edit: Obviously this has been done MANY times, but this is just my version of a cheap charger that does most of what a cycle satiator can do.

I commute around 16 miles each way (32 miles round trip) every day to and from work. I use a 52v 16AH 14S8P battery made from mixed LG, Sanyo and Samsung 18650 cells salvaged from old drill and hoverboard batteries for a total capacity of 832wh. I've gone about 500 miles on it so far and the total cost to build this entire battery was a little over $50. I spent about $30 a week in gas, so this battery has already paid for itself many times over. I would say well worth my money .

To increase battery life, I undercharge my pack on purpose to 4.05v per cell. I use anywhere from 0.66 to 0.75AH per mile so even after undercharging my pack I still have enough capacity to make it there, but not back.

Now I need to charge the battery while i'm at work. I COULD go out and buy a meanwell power supply, or a cycle satiator. But the meanwell power supply in particular has some disadvantages such as:

1. I can't charge any voltage battery I want (in case I decide to move up to even higher voltage later).

2. I can't charge the battery slow or fast, only at a single set current.

3. I can't monitor the current and current battery charge voltage.

4. The knock-off meanwell power supplies aren't known to have the best quality parts inside.

5. They tend to have a tiny fan that get's really loud.

I looked at buying a cycle satiator, but i'm not going to drop $300 on a single charger, so that seems to be out.

Since I need to recharge the battery at work, I use this monstrosity I have nicknamed "the poor mans cycle satiator":


In principal, it works almost exactly the same as a cycle satiator. I can charge any kind of battery I want from 24v all the way to a 96v battery at any charge current from as little as 100ma all the way to 15A.

To supply the DC power to begin with, I used 3 HP HSTNS-PLXX series 480w Server power supplies connected in series to give me 36v. Now i'm lucky that I live near a scrap metal yard where I can buy all sorts of parts just by weight. A good example was my power tool and hoverboard batteries I bought. I found several of these HP server power supplies and got them from the scrapyard for a dollar each, so the initial investment so far is $3. I picked up a few power cords for free from the same scrap yard to run the power supplies.

to boost the 36v up to whatever battery I want to charge, It uses those cheap Ming He BST900w DC-DC Boost converters you can find on ebay and aliexpress for pretty cheap. Usually around $20:

https://www.aliexpress.com/w/wholesale-BST900W.html?spm=2114.search0104.0.0.62533393MLhG20&initiative_id=SB_20180411184642&site=glo&groupsort=1&SortType=price_asc&g=y&SearchText=BST900W

Then you take each power supply and open them up, and modify them to output 12v all the time:
https://www.youtube.com/watch?v=XwHlO8LHEtw

These power supplies however have their output ground connected to the case, so I opened them up and isolated the case from the ground of two of the units. After that they ran in series just fine.

After that I used some stripped 14AWG solid core house wire (also from the scrap yard) to connect the units together and just hot-glued the boost converter onto the power supplies. Now we have ourselves a charger that costs $25 in parts to build that in effect, can do nearly everything a cycle satiator can do. It can even charge higher voltage batteries than the cycle satiator can. The only thing it can't do is charge any of the nickel type chemistries, but who the hell uses NIMH anymore for ebike batteries? These days it's all lithium or lead on the budget models.

At my house, I have one of these DC-DC converters connected to a 24v Dell server power supply instead. When i'm at home I can charge overnight at lower currents anyway, so a fast charger isn't nearly as important.

I've seen a on of guys on here use meanwell chargers for bulk charging, but I don't see many people using DC-DC converters to do that job. Just thought I would share my work with everyone else.

 

[motomech]

I'm not commenting on your DIY charger, but I would point out that are several versions of Mean Well power supplies and they are different enough that they shouldn't be lumped together.
I use the Mean Well HLG-320 series designed for all-weather use powering LED and neon signage.

1. I can't charge any voltage battery I want (in case I decide to move up to even higher voltage later).

They are adjustable and the Voltage can be trimmed +/- 10 Volts and are available in various top Voltage ranges; for example, My HLG-320-48A will adjust between 42V to 51V. The highest rated is the HLG-320-54A, which will adj. up to 58V, which I use on my 14S (56.4 nom.) LiPoly pack.

2. I can't charge the battery slow or fast, only at a single set current.

They are also Current adjustable, but haven't realized a need to adj. downward from the 7.4 Amps I see w/ the above listed unit.

3. I can't monitor the current and current battery charge voltage.

I added a $5 Ebay Volt meter;

5. They tend to have a tiny fan that get's really loud.

The HLG is potted and dead silent.

They are also CC/CV and as top charge is approached, Current attenuates to miliAmps, where it will sit, neither adding nor subtracting from the pack. These units have proven to be indestructible and when one considers that they will never have to buy another charger, $125 seems very reasonable.

Since I need to recharge the battery at work, I use this monstrosity I have nicknamed "the poor mans cycle satiator":

Sorry, but that name is already taken. I think I was the first to refer to the HLG w/ that moniker aa couple of years ago and others have picked up on it.

Not everyone is skilled enough or inclined to DIY their own charger and I just want to point out the the Mean Well HLG's are a very attractive alternative.

 

[flippy]

The ELG 54v series can go to 58v if needed and are a bit cheaper. I only use ELG or HLG series in all my builds for me or my customers.

 

[Alan B]

I used the Meanwell HLG LED Power Supplies for chargers at work, they are UL listed. As was mentioned they are silent. Voltage/current displays are easily added to show what's going on.

Most workplaces require NRTL (Nationally Recognized Testing Lab such as UL) listed equipment for electrical safety. Not all workplaces realize they are subject to this requirement, and some are not. The place I was working last got very serious about electrical safety a few years ago after some incidents so I had to be "legal" for anything that was plugged into their AC power.

The Satiator is also UL listed. It is pricey but a few weeks of gas savings will cover the cost, and it is very high quality and flexible with programmable memories for different rates and voltages. I didn't use it at work since I had already built my at-work charger before it came out.

Best of luck with your low-cost project. Good to see that the DC-DC converters have been reliable for you, many have noted failures with them. Operating them well within ratings should extend their lives.

 

[neptronix]

I like it. I still have my old Meanwell SP, and have been looking for sort of a higher powered alternative to my cycle satiator. In all honesty, if grin released a >500W cycle satiator, i'd be all over it just for the nice overall package, high efficiency, etc. But this is as close as you're gonna get to a variable high powered charger..

Might build one myself. Thanks for the inspiration.

 

[Hardergamer]

It basically what I'm using, but I use 2 48v PSU's with 2 900w dc-dc's, and them 900w dc-dc go upto 110v 15a, it would be cool if Justin brought out a higher voltage Satiator i would get one 60v 8a is so low.

 

[tomjasz]

“Almost” onl6 counts in horseshoes. Thats a long road from a Satiator, but I salute your creativity. Just dispute the innacurate comparison.

 

[amberwolf]

it would be cool if Justin brought out a higher voltage Satiator i would get one 60v 8a is so low.

You might want to check the http://ebikes.ca page for the Satiator then, cuz theres been a higher voltage version for a while now.

 

[Blueshift]

Nice, though I wouldn't take it near or in any airports, banks and the like.

 

[Alan B]

Nice, though I wouldn't take it near or in any airports, banks and the like.

The homemade one does look like a "device".

The Satiator doesn't have that problem.

 

[fechter]

Here's what mine looks like:



I have 10-turn pots for both voltage and current adjustments. The meter keeps track of volts, amps and amp-hours. The meter isn't very accurate, so I made notes of where I should set it to get the correct actual voltage. I run this one at 5A on my 14s packs. I think it's rated for 6A.

 

[tomjasz]

Here's what mine looks like:

Always a stellar idea from you! Nice!
Mean Well? V?

 

[fechter]

Always a stellar idea from you! Nice!
Mean Well? V?

It's a Meanwell clone. I modified it for variable current and voltage and to get it up to 60v max.

 

[flippy]

what mods did you do? can you make a picture from the inside? these meanwell clones come is a few versions.

 

[fechter]

what mods did you do? can you make a picture from the inside? these meanwell clones come is a few versions.

That's an understatement. I've seen dozens of different layouts.

Current limit adjustment. 2K pot across this resistor:




Increase voltage adjustment range to 60V. 2K across this resistor: I'm sort of guessing on the resistor value since I didn't write it down, but the color code looks like 2k. At some later point I replaced the adjustment pot with a 10-turn of the same value (1K), extended by wires.