ltx 58.8v charger problems

R

radad

1 W
Joined
Aug 28, 2013
Messages
58
Hello I been lurking in shadows here now for months but this is my first post here so i'm a noob. Many thanks for all the great info here. I couldn't have gotten this far without you all. I built a 14s6p pack based on info found here. I just received a 14s ltx 58.8v charger from em3ev.com. Hooked it up last night and couldn't get it powered up. after some thinking and playing I found it will NOT charge anything over 48v. When I connect to 14s charger will not turn on, 12s no go either, however when connected to 10s charger comes on and charges. output is only 48v regardless of switch (3 position) Battery pack measures about 52v across 14s.
Am I missing something? shouldn't charger output be 53, 56 or 58v as per switch? why won't it charge anything over 48v? do I have a defective unit?
 
Congratulations on your first post, I hope it is your first of many.

When you put a multimeter to the leads, what exactly does the multimeter tell you the charger is putting out?

"output is only 48v regardless of switch " Are you saying that a multimeter tells you that the output is precisely 48v no matter the switch position?

Have you sent em3ev an e-mail concerning this matter?
 
Actually I was somewhat wrong, the multimeter reads the same as the battery voltage no matter were I place it, @ 10th series for example reads 40.8v. Charger will not turn on @ 11,12,13 or 14th series. So the charger turn on voltage is somewhere less than 44-48v. Yes I did send a email to paul, no response just yet. I been working on this project for a month now and I'm dying to ride on a full charge. My girlfriend told me just buy a battery pack, I'm dying to prove her wrong.

GNG 1000w mid-drive
gng stock controller 48v
18650x84 samsung 14s6p
signalab bms 14s li-ion(not wired yet, because i'm unsure of wiring schematic)
Specilized mtn bike
 
I knew this was going to be a big learning experience. Had I the money I would buy a $700+ battery pack. The mechanical part was easy, the electrical is killing me. I think my problem is something in the battery pack. I did drop a washer on one of the batteries and it shorted for a second or 2. All 84 batteries were @ 3.7-3.8 prior to pack build/solder. I even left the pack assembled in parallel only to balance cells for two days, before connecting the series connections.
 
radad said:
dnmun said:
can you measure the charger voltage on the output if it is not connected to a battery?
Click to expand...
No charger won't turn on like that.
Click to expand...

Of course, the battery voltage is going to be the same anywhere you place the multimeter. That isn't the discussion, were talking any leads or wires coming from the charger and only the charger, don't focus on the pack for now.

Plug the charger in, there should be a red light and a green light on somewhere on the charger when you do so. Look at the charger and see the wire coming from the charger that isn't plugged into a wall outlet, I'd guess this wire has anderson plugs at the end of it. Look slowly and carefully at the anderson plugs, identify any parts inside of these plugs that look silvery. Put the multimeter probes on the silver colored surfaces inside of the plugs that come from the charger. You put one probe in one of the plugs, and one probe in another, do not touch the probes together while doing this. You will get some kind of a voltage reading on the multimeter. Remove the probes from the charger, change the switch to a different setting, check the voltage coming from the charger again, is it different? Do this for all three switch positions, and report precisely what the charger voltage output is for each setting, be sure to use a pen and paper for this.

Be sure the electric plug is in the outlet and in the charger fully and well.
 
so this is a battery you built up yourself that you are using the charger on?

do you have a BMS on the battery and did you balance the cells before assembling the pack?

what cells are you using and which BMS?
 
bowlofsalad said:
radad said:
dnmun said:
can you measure the charger voltage on the output if it is not connected to a battery?
Click to expand...
No charger won't turn on like that.
Click to expand...

Of course, the battery voltage is going to be the same anywhere you place the multimeter. That isn't the discussion, were talking any leads or wires coming from the charger and only the charger, don't focus on the pack for now.

Plug the charger in, there should be a red light and a green light on somewhere on the charger when you do so. Look at the charger and see the wire coming from the charger that isn't plugged into a wall outlet, I'd guess this wire has anderson plugs at the end of it. Look slowly and carefully at the anderson plugs, identify any parts inside of these plugs that look silvery. Put the multimeter probes on the silver colored surfaces inside of the plugs that come from the charger. You put one probe in one of the plugs, and one probe in another, do not touch the probes together while doing this. You will get some kind of a voltage reading on the multimeter. Remove the probes from the charger, change the switch to a different setting, check the voltage coming from the charger again, is it different? Do this for all three switch positions, and report precisely what the charger voltage output is for each setting, be sure to use a pen and paper for this.

Be sure the electric plug is in the outlet and in the charger fully and well.
Click to expand...

Yes its an anderson 45pp. Did exactly what you said, all 3 switch positions show 46.9v, must be defective?
 
That certainly sounds like there is something wrong, I asked earlier if you had e-mailed em3ev about this. I don't know if you'd be inclined to open up a charger, but sometimes some people do that sort of thing and someone is able to spot the problem with a picture. I am not capable of such things though.
 
bowlofsalad said:
That certainly sounds like there is something wrong, I asked earlier if you had e-mailed em3ev about this. I don't know if you'd be inclined to open up a charger, but sometimes some people do that sort of thing and someone is able to spot the problem with a picture. I am not capable of such things though.
Click to expand...

Thanks so much Bowlofsalad! Well thats not a bad option. Sending back to hongkong going to cost me, plus it took almost 2 weeks to arrive. I don't want to wait til the snow flies to enjoy. pic's coming shortly
 
radad said:
bowlofsalad said:
That certainly sounds like there is something wrong, I asked earlier if you had e-mailed em3ev about this. I don't know if you'd be inclined to open up a charger, but sometimes some people do that sort of thing and someone is able to spot the problem with a picture. I am not capable of such things though.
Click to expand...

Thanks so much Bowlofsalad! Well thats not a bad option. Sending back to hongkong going to cost me, plus it took almost 2 weeks to arrive. I don't want to wait til the snow flies to enjoy. pic's coming shortly
Click to expand...

: ) If it's really broken the moment you got the charger, I'd hope he would just send you another instead of having you wait around for a couple weeks.

There is the circle of three, good, fast and cheap, pick two. Good isn't often an option in the ebike world, but that depends on how you do things. If you are going to try and go with fast and cheap, you might buy two of things you can afford to. Lots of people have discovered something such as their throttle was broken and were out of being able to ride for some time because they didn't have a replacement on hand. Most of the parts you might have problems with aren't too costly to have a backup, and really it'd be far more costly in time, shipping and headache not having spares (my opinion).

Having a spare of things is also great for a method of troubleshooting. Swap out a single part that you suspect is the cause of a problem, if it works with the new part, you have a pretty good idea on what to focus your time and energy on (if you'd try and fix the part).
 
dnmun said:
but no BMS? i thought maybe the voltage was so far outa range that the BMS was shutting off the charge but it sounds like you have no BMS. but no pictures to tell.
Click to expand...
Bms is not wired yet because I'm uncertain of wiring
 
THANKS EVERYBODY!
I never expected so much help so quickly.
I just finished checking cell voltage's 84 times. I did find 3 bad cells but Im sure the battery charger is defective anyways. I think I finally understand how to wire the bms, so I'll be working on that for now.

My battery pack is 84 samsung 18650-26a 14s6p. I got my design inspiration from others here @ ES. A rectangular box 7x13x2.5" with 28 peices of aluminum bar stock 3/4 x 1/8 x 7" with 3 - 1/8" holes in each piece. Very easy to disassemble, 3 screws to unscrew to access any battery, no solder joints. all held firmly in place by mechanical pressure of the bars being screwed to the box which is just a bit smaller than the battery length. to insure no shorts I had to solder a tiny metal washer to positive terminal on each battery. looks like a xylophone, so far has held up well on the short trips i've been able to make without charging. Soon as I upload my pic's to photobucket I'll post.
 
Please don't ride with it till you charge it. That is a sure way to ruin the pack! First troubleshoot the charger then get the BMS attached correctly. Ot go the opposite way. don't D/c the battery before you charge it and balance it or you will destroy your work!
otherDoc
 
the BMS could be a problem to wire up if you have no solder connections so i understand your problem with it. if it has 15 wires for your 14S pack then the lowest one goes to the bottom of the #1 cell and then sequentially up from there on the top of each of the 14. i thought maybe one of the cells had an open circuit if you had assembled it by soldering to the case.

if you open the charger we can look and see if there is anything obvious and show you where to measure voltages.
 
There is nothing obviously burnt, nothing on the back side looks bad either.
I have to remove cover for batter pack pic's, later.

Here is how I soldered a washer to the top of the 18650, so mechanical compression wouldn't cause a short


and of course the bike
 
I'll tell you if you have the skill to build up that mid-drive you certainly can make that battery work. I just noticed something. Do those cells have some insulation or cover around them? The case is negative, I believe.
otherDoc
 
Paul is the man! and I feel stupid as can be. He just got back to me. The voltage switch default is 240v, i never noticed. Switched to 110 outputs the 3 voltages exactly as advertised. Now I'm charging the entire pack and going for a ride tonight! Hope I didn't damage battery to badly as it dropped below 50v in my haste to ride. The last piece of the puzzle is the bms. Not bad for my first ebike. No instructions for the gng kit, nothing for the bms but a super crappy schematic on the sellers ebay site. Good info here for battery pack construction. My Watts-Up meter came in today, by far the easiest thing to connect, so naturally it came with good instructions. Soon I'll know the fruits of my labor, I'm hoping I get a steady 15-22amps @ 58v when needed.
 
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