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.
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- ... xt=BST900W
Then you take each power supply and open them up, and modify them to output 12v all the time:
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.