Please take note: What I am describing here is not for everyone. You need to NOT screw this up. If you have any qualms whatsoever about doing this kind of electrical wiring work, don’t even try it. Mean Well LED power supplies have been used by the DIY ebike community for years. The concept is not new. The weak link here is you and if you screw this up consequences could be severe, including explosions, fire and destruction. So if you know your way around a crimper, or a soldering iron… great this will be easy. Kid stuff. If not, don’t pick this project as your first learning experience.
Why reinvent the wheel here? What benefit could be gained?
Ebike battery chargers tend to be dodgy. The interwebs are filled with stories of frequent flyers whose chargers keep dying. Its either a dead fan that in turn lets the charger heat up and fry, letting the smoke out of the internals (never a good sign) or perhaps the most common: the charger stops cutting off at its cutoff voltage and keeps on charging … with potentially catastrophic results.
So… what is better? You can see that in a popular commercial battery charger: The Grin Satiator. Its so efficient it needs no fan to cool it (or to fail). It is also largely weatherproof and highly reliable. The only demerits it gets from users - which have largely gone away over time - are programming/firmware issues.
Oh and its cost is US$300+ once you figure in a programming cable, along with a couple of adapters. I bought one. It works perfectly. But with an AWD bike with 2 batteries that I ride every single day and charge both at home and at work, I found convenient charging means walking up and plugging in. Not carrying chargers with me, unloading them, setting them up etc. So 2 batteries x 2 locations = four chargers. $300x4= not happening. And I carry a charger with me in case I get stranded. $300x5=crazy talk.
What to do? Use the same core hardware that gives us the $300 charger but without the fancy user interface. That costs around $40. We won’t have a fancy display screen or onboard memory, but it will still be adjustable with a screwdriver.
I have worked with three different models that can serve my purposes. Remember that volts x amps = watts and this will be important when figuring out what to set your charger for:
Available regularly on Amazon for about US$55
Rated to 150 watts
Rated as adjustable from 40 to 56v but actually adjusts from 39v to 58.1v
Usable as an 83% charger for a 36v battery up to a 96% charger for a 52v battery
Minimum amperage selectable is about 1a
Lower wattage rating means it must be set to lower amperage on 52v batteries (2.5a max for a 52v battery)
Designed for LED lighting and ‘moving sign’ lighting applications
IP65 rated for indoor and outdoor use.
Usable at EU or USA voltages.
Mean Time Between Failure (MTBF): 303,700 hours. Yes, really.
Spec Sheet Here
Available often on ebay for about US$40. Normally on sale in the $65-$75 range.
Rated to 185 watts
Rated as adjustable from 49 to 58v. Actually adjusts from 48.3v to 60.0v
Usable as an 80% to 100% charger for 48v and 52v batteries. Not usable on 36v systems
Higher wattage rating means can be used for faster charges than 150w CLG. Typically this is a good 3a charger for 52v batteries.
Adjustable to very low current (about 0.75 amps) for safest trickle charging, ever.
Ramps power down much more slowly and precisely than 150w CLG as it approaches target voltage.
Mean Time Between Failure (MTBF): 192,200 hours, or almost 22 years of continuous use.
Designed for LED lighting and street lighting applications
IP65 rated for indoor, outdoor and wet/hazardous locations
Usable at EU or USA voltages
Spec Sheet Here
This is the Big Daddy. As in bigger and heavier and more power output.
Essentially same specs as the HLG-185H-54A but is instead rated for 320 watts
Current can only dial down to about 2.0 amps. But the high wattage rating means it can be dialed UP to make it a 5 amp charger (only aftermarket battery plugs are able to safely handle this current level) which is why you’d use this thing.
MTBF: 157,100 hours
Spec Sheet Here
Myself, my bikes have 52v batteries. I do use a couple of CLGs at work for my charging station there but only because I hadn’t found the HLG-185’s yet. The HLG-185’s are ideal chargers as they can charge at levels safe for the Sondors battery plugs (3a max) and can handle any voltage asked of them for a 48v or 52v system. If you have an aftermarket battery that does not use the pin plug as does the Sondors batteries, then you almost certainly have an Anderson Powerpole, an XT60 or an XLR connector. Those plugs can handle the higher amperage the 320 is capable of delivering. I use a 320 as a travel-with charger under the theory that if I am stuck somewhere I want to grab as much charge as I can, as fast as I can. But a 185 is perfectly capable of being a 3a charger and weighs probably half what the 320 does.
So… enough details already. Lets make a charger! Here’s what we need:
A Mean Well power supply. The process is identical for all three models.
A pigtail’d grounded electrical plug. They are sold on Amazon typically as replacements for corded drills and similar power tools. NOTE: I am using a USA standard plug, but these units are made to accept worldwide voltage/current so just go to your local hardware store and choose your local version of a pigtailed, grounded power cord if you live outside the USA. Oh, and read the spec sheet to confirm what I just said applies in your country.
A digital watt meter to tell us what we are outputting to the bike. For almost all of my chargers I use $15 inline watt meters. This is optional but very desirable.
An interface from the charger to the battery. I will use an XT60 as the direct connection, which is what a lot of aftermarket batteries use. You can then plug just about any adapter into that for your Sondors or whatever else you have. Note in the picture above, bottom center just to the left of the little adjustment screwdriver we will keep with the charger, that there is a pin plug adapter for use with Sondors batteries. That one came from Luna Cycles.
A note on battery/watt meters. Here’s the short version: They suck. Or more accurately they are oftentimes off by a bit, and there is no way to calibrate them. Its not uncommon to see a battery meter accurate to within 2%. That sounds ok unless you are charging to 58.8v, which could be 59.98v with a 2% error and that is very, very bad. So you want to take a multimeter or similar *known safe benchmark* (in a pinch the reading on your LCD screen will work once you have disconnected any charger from it) and use it to learn where your chosen meter is in terms of its accuracy. I do this and then I take a labelmaker and make a label telling me how much a battery is + or - actual voltage.
So for example, if my target voltage for a 52v battery is an 80% charge of 55.4v, and my watt meter is reading 0.50v higher than it should be, then I create a label that says
So now, we have our parts in hand and its time to assemble them. In order the steps are
Attach the pigtail’d cord to the input side of the Mean Well unit. For the USA plug and the Hanvex drill cord I have been using the wire sequence is green (cord wire) to green (charger wire) for ground, black (cord) to brown (charger) for AC+ and white (cord) to blue (charger) for AC-. Note that the wire colors are noted on the charger left side, but as ACL and ACN. DO NOT SCREW THIS UP. These are international standard designations and colors which as usual the U.S. does not follow. If you want to check my work, start googling. Myself, I use marine heat shrink butt end connectors to connect the wires. I also use rather expensive electrician’s-grade crimping pliers. There is a big difference between proper crimping pliers and … well, pliers. Use the right tools for the job. After I crimp, I heat shrink the connectors, add heat shrink around each individual wire and then do a heat shrink around that entire assembly. How you do it is up to you (i.e. soldering or whatever). Remember that this is mains power you are fooling with here so get this right.
Attach a battery side plug. In this case I am using a male XT60 which both works for my aftermarket batteries that have female XT60 charge plugs, and my Sondors bottle batteries where I can use my XT60-to-pin-plug adapter. Same procedure as in Step 1 although a little simpler as there are only two wires. Note that some of these charger units do not use red and black wires. If you are not familiar with what the colors mean, the casing on the unit specifically tells you which wire is which (V+ and V-).
When you are done, you will have something looking like this:
OPTIONAL - attach an inline watt meter to the output side of the Mean Well unit. This is your power display. I call this step optional because you could just calibrate your charger output once and not use a meter to monitor progress (easy enough to turn on the bike display during charging, which will hurt nothing). Myself personally, even though meters are pesky insofar as getting them calibrated, I vastly prefer to have a real time progress monitor I need only glance at.
OPTIONAL - make an extended output cord. Essentially one big extension cord on the battery side. You’ll know real fast if you’d like to have one of those as whatever you made doesn't reach. You could just hardwire this to your output lead on the charger. But then you are stuck with that length alone. I prefer to make a cable as I have no problem using a couple of 12 AWG XT60 pigtail ends to make a dedicated extension.
Connect an interface to your battery. For a Sondors, this is a bottle battery connector. For many batteries the generic standard is a male XT60 connector. You can either buy a direct-connect bottle battery adapter (see link) or connect a male XT60 pigtail and then buy an XT60 Female-to-bottle adapter. Doing it the latter way makes your charger able to connect to any battery (if you have another battery with say XLR connectors you can make an XT60-to-XLR adapter via a couple of pigtails). You just swap in the adapter you need. In this case I am picturing a Luna-sourced XT60 female to pin plug adapter. A different source for the same thing is in the parts list below
Go out and buy a little Phillips head screwdriver. This tool will live with your charger forever so you should buy a new one unless you have an extra already. Its a must-have for the next step. Also required if you plan on changing your settings (lets say you want to charge 80% one day and 100% the next).
If you have performed all of the above steps, you now have a parts pile that looks like this (well sort of, the meter and the charger have already been labelled with calibrations but just pretend we haven't done that yet):
Dial in your output voltage. Once you have connected an AC plug, and a battery side connector AND connected the inline watt meter, you simply have to plug the new charger into the wall. Amps will read zero and volts will read whatever the unit is currently set for. See the little rubber whatsits that are capping the voltage (Vo ADJ) and amperage (Lo ADJ) adjustors? Pull those off and stick the screwdriver into the Vo ADJ hole. Twiddle it around gently until you feel it seat into the adjustor. Now turn it first one way, then the other. Watch the voltage readout on your meter. One way goes up, the other down ... and the directions are different on my 185's and 150's vs. my 320 so you figure out what direction does what yourself with your own unit.
Calibrate your meter to reality. Remember what I said above about meters. You need to figure out how far off your meter is from your display. As you can see if you look closely above, this meter is off by +0.50v. Thats a fair bit. The good news is when these types of meters are off, they are consistently off so you just need to know by how much (and if you can find a meter that is consistently accurate tell me. I can't find one at any price). this is a pain but you only have to do it once.
Dial in your output amperage. OK... moment of truth time. You are plugged into the wall. Time to plug into your battery. Maybe you should do this out in a field with a long extension cord. Don't do it in the baby's nursery or in Grandma's bedroom while she's asleep. Plug the battery in and now watch the meter. The voltage switches to now show the battery state of charge. The amperage comes to life and shows the current level (amps) being fed into the battery.
Once again, like you did with the voltage adjustment, use your screwdriver this time in the Lo ADJ socket and twiddle it until you see the safe amperage rate you safely want to safely run your charger safely at. Did I forget to mention safety? And volts x amps = watts ? Pay attention and get this right. If your meter is off - especially if it is reading lower than actual voltage - you will want to find out by what percentage it is off and adjust your indicated meter amperage less that percentage amount.
IMPORTANT SAFETY TIP:
Your meter does not switch its power feed on and then off like a light switch. Instead, it will slowly ramp down its current delivery level (amperage) as the battery approaches your target voltage. So that means if you plug in a battery that is fully charged or nearly fully charge, you will get a really tiny reading of current going into the battery. Because of this, when performing calibrations you must have a battery that is at least a couple of volts low. At least. If you are charging to 54v (100% charge on a 48v battery) then plug in a battery at no lower than, say, 50v state of charge.
If you have a Sondors battery and are using a pin plug, NO MATTER WHAT make sure this value does not exceed 3 amps. The plug can't safely take more. Again, remember that volts x amps = watts. So if your 185w HLG-185 is feeding the max of 3.45 amps, that means at 58.8v it will be sending 203 watts which exceeds its 185w rating and thats VERY bad. Here again. Use your brain and don't screw up. Best to leave a safety margin. For example I have one of these set to a 'full' charge of 58.3v and 3.0 amps. 175 watts.
Add a carrying case? Your basic MOLLE water bottle bag will fit this all beautifully. the slightly larger Condor bags available on Amazon will do so with a little more fudge room. I got two green ones on sale for $5 and $8 respectively. Sometimes they are more. Happy hunting.
In the end what do you have? A charger that you can expect to be reliable literally for years. Not necessarily cheaper, but dependable. If you buy this once you won't have to buy it again in 6 months or a year... and thats the usual story out there in ebikeland for the more demanding users in the DIY world.
Parts (remember oftentimes you can get these chargers for a lot less on clearance on Fleabay). Especially the HLG-185 which is commonly used in street lights):
Mean Well CLG-150-48A http://a.co/4IaEpLU ($55)
Mean Well HLG-185H-54A http://a.co/dy3U4qI ($68) https://ebay.us/H3w74L ($56.50)
Mean Well HLG-320H-54A (84.10) https://www.onlinecomponents.com/mean-well/hlg320h54a-43123431.html
Hanvex 18awg 3-prong AC power cord, 6ft, pigtail’d http://a.co/iNJAOMX ($8.99)
XT60 male and female pigtails (need 5 total if you are using an inline watt meter, extension cable and xt60 lead for battery) http://a.co/fuzw4cM (8.99)
Inline watt meter http://a.co/b0iE00l ($15.99)
Option: Female XT60 to male barrel plug adapter www.progressiverc.com/female-xt60-to-male-barrel-plug.html ($4.99) https://lunacycle.com/xt60-female-to-barrel-male-plug/ ($6.95)
Carrying case for the CLG-150 or the HLG-185H- any similar bottle carrier should do - ($8.95) http://a.co/3ln2fd6
Carrying case big enough for the HLG-320H (really, this is the best case for all of them, especially if you get them on sale😞 http://a.co/d/6bSx1lt