Plugged in battery to power supply and fan broke?

B

baltimorebiker

10 mW
Joined
Feb 24, 2015
Messages
20
Location
Baltimore, USA
When I plugged in my battery to power supply , I heard a small pop, I smelled burnt electronics, and my fan stopped spinning.

The charger continued to put out 48V, but it quickly heated up because the fan wasn't running. The charger still works fine, but it heats up quickly.

This happened on two power supplies. I have a 3rd one, but I don't want to risk blowing that fan as well.


I using this BMS with lipos:

http://www.ebay.com/itm/44V-48V-50-4V-12S-30A-Lithium-ion-Li-ion-LiPo-Li-Polymer-Battery-BMS-PCB-System/221274094989?

I am using this 48v power supply:

http://www.ebay.com/itm/131415125791
 
Yes, I plugged it in directly. If I am not supposed to do that, then how do I charge my battery?
 
baltimorebiker said:
Yes, I plugged it in directly. If I am not supposed to do that, then how do I charge my battery?
Click to expand...

You need a "power supply" that will supply constant current with a voltage limit equal to the fully charge battery voltage. That's what a lithium charger is. The one you have is constant voltage. It will overload with an empty battery and never be able to charge anything above 48 V.

http://em3ev.com/store/index.php?route=product/category&path=37
 
tahustvedt said:
You need a "power supply" that will supply constant current with a voltage limit equal to the fully charge battery voltage. That's what a lithium charger is. The one you have is constant voltage. It will overload with an empty battery and never be able to charge anything above 48 V.
Click to expand...
.?? Well, those very same power supplies have been used by countless ES members to successfully bulk charge LiPo packs for many years.
Whilst you cannot adjust the current significantly (without modification) , they do have current limiting, CC/CV charge capability, and easy voltage adjustment (+_10%) so that you can set it to suit your pack.
I don't know why you would be blowing the fans when you connect, but you should be turning on the charger before you connect ?

EDIT:--
I feel I should perhaps say that whilst these power supplies definitely behave in a very effective CC/CV manner...
...IE the current wll hold constant through most of the charge, and as the recharge nears completion the current wii ramp down to milli Volt. levels...
..that is not likely to be the "ideal" charge profile for any LiPo pack ...simply because that ideal is probably unknown anyway, and will also vary depending on the exact lithium chemistry being charged !
Also, users should remember these units never auto switch off, so should not be left connected to a pack after charging is complete.
 
Hillhater said:
I feel I should perhaps say that whilst these power supplies definitely behave in a very effective CC/CV manner...
Click to expand...

Hmm, are you sure about this? Have you tested? I'm not challenging you, but the only reason why I haven't used one of these as a cheap bulk charger, is that I assumed that they were constant power, so that when the voltage sagged, the current went up, and something would blow.

If you have confirmed that they are Constant Current and not Constant Power, I'll be ordering one as soon as you confirm!
 
There are many types of "meanwell clone" PSUs, and only some of them can be directly used as "chargers". You'd have to check the various meanwell threads and posts (with the search function) to see which models from which manufacturers have been successfully used, and then make sure you get the same version and preferably the same *revision*, as functionality could change with a different revision of the "same" model number. :(

There is also a thread by Fechter about a current limiter board (has been recently posted to so should be in the active topics page) that can be used on some of these, but again if its a different revision than one posted there or elsewhere, it could be a very different layout with possibly different functionality.
 
amberwolf said:
There are many types of "meanwell clone" PSUs, and only some of them can be directly used as "chargers". You'd have to check the various meanwell threads and posts (with the search function) to see which models from which manufacturers have been successfully used, and then make sure you get the same version and preferably the same *revision*, as functionality could change with a different revision of the "same" model number. :(

There is also a thread by Fechter about a current limiter board (has been recently posted to so should be in the active topics page) that can be used on some of these, but again if its a different revision than one posted there or elsewhere, it could be a very different layout with possibly different functionality.
Click to expand...

That sounds like a sensible answer. But if it's that much work, I may as well just pay an extra $100 for a real charger.
 
It's only the fan blowing, not the charging circuits, so the charger must be OK for what you're doing. Maybe your problem is something to do with inrush when you connect your battery. If you switch on the charger before connecting, it would solve that.
 
Sunder said:
Hillhater said:
I feel I should perhaps say that whilst these power supplies definitely behave in a very effective CC/CV manner...
Click to expand...

Hmm, are you sure about this? Have you tested? I'm not challenging you, but the only reason why I haven't used one of these as a cheap bulk charger, is that I assumed that they were constant power, so that when the voltage sagged, the current went up, and something would blow.

If you have confirmed that they are Constant Current and not Constant Power, I'll be ordering one as soon as you confirm!
Click to expand...
Tested ? Not exactly but I have monitored voltage and current through the charge cycle, and Certainly the 2 (MW clones) that I have used have worked that way.
I guess to be accurate, they are "current limited", rather than "constant current" ...IE.. The current cannot exceed a set level, but it can reduce, as the battery voltage rises and the difference to the set charge voltage reduces.
(Ohms law at play with voltage differential and internal resistance ?)
.. Maybe Dnmun has a better insight as to how these power supplies function ?
 
Hillhater said:
tahustvedt said:
You need a "power supply" that will supply constant current with a voltage limit equal to the fully charge battery voltage. That's what a lithium charger is. The one you have is constant voltage. It will overload with an empty battery and never be able to charge anything above 48 V.
Click to expand...
.?? Well, those very same power supplies have been used by countless ES members to successfully bulk charge LiPo packs for many years.
Whilst you cannot adjust the current significantly (without modification) , they do have current limiting, CC/CV charge capability, and easy voltage adjustment (+_10%) so that you can set it to suit your pack.
I don't know why you would be blowing the fans when you connect, but you should be turning on the charger before you connect ?

EDIT:--
I feel I should perhaps say that whilst these power supplies definitely behave in a very effective CC/CV manner...
...IE the current wll hold constant through most of the charge, and as the recharge nears completion the current wii ramp down to milli Volt. levels...
..that is not likely to be the "ideal" charge profile for any LiPo pack ...simply because that ideal is probably unknown anyway, and will also vary depending on the exact lithium chemistry being charged !
Also, users should remember these units never auto switch off, so should not be left connected to a pack after charging is complete.
Click to expand...


Ok. Sorry. I have used a lot of MW supplies for different projects but I guess I have never overloaded them to test how they behave.
 
Hillhater said:
I guess to be accurate, they are "current limited", rather than "constant current" ...IE.. The current cannot exceed a set level, but it can reduce, as the battery voltage rises and the difference to the set charge voltage reduces.
Click to expand...

Okay, thanks for that.

I'm not sure I understand the implications of current limiting. Whether that means its self protecting to prevent blowing anything, or it just means it is stressing the components unable to deliver enough power, and will eventually blow...

I'll just wait to see if Dnmun says anything, but as I said before, the price different isn't all that great, so maybe it's best I do get a proper charger - they come in safer cases when there's two little boys who like copying daddy running around anyway.
 
Most of these units have positive current limiting to prevent overload, and normally some form of overload shutdown / restart..referred to as "hiccup" limiting.
It's also common to find a current limit adjustment pot for minor trimming of settings.
If you have the $$s I would go for the quality charger every time , as it will give various additional functions ( auto shut off , status indicators, etc) as well as a safety enclosure with no exposed terminals.
These power supplies are "bare bones" units that will do the basic charging with no frills......but were never intended to be near little fingers or untrained users. :wink:
 
I will open up the power supply and try to identify exactly what went wrong.
For reference, the power supply no longer puts out voltage or power. However, plugging in the battery somehow turns on the the power supply led. I inspected the fan and it still works when voltage is applied so its not the fan that broke.
I did turn on the power supply before plugging the battery in, but it still blew out.
 
Please report back if you figure this out. I'm looking for a reasonable price bulk charger. I have 2 6s lip chargers but they take hours to charge.
 
Don't flame me for what I'm about to say. I don't bulk charge. I use only genuine meanwell power supplies and a good dual channel smart charger. In my own experience, you get what you pay for. (most of the time)
 
dnmun said:
these people never come back. why they even ask for help and never reply is beyond me.
Click to expand...
Sometimes, I think, they post, fry stuff, or do something silly and ditch the embarrassment and chiding. Or have other lives and things get delayed. Regardless, some good information and learning is to be had by those of us learning and gobbling up the ideas you and others put forth. It takes awhile to sort out which old timers and crusty hardened posters ought to be listened to. Often the help given is beyond the scope of those asking the question. Your ease with BMS and their use isn't universal. Sometimes it's just plain confusing. But then I'm pretty much a curmudgeon too, and it rolls off. :wink:
 
I haven't forgot about this thread. Just got super busy after I posted. I ended up buying a bulk charger from http://www.ebay.com/itm/171329014800 It works great for the BMS i posted earlier

I did open up the power supply. Fuse was okay. 3 transistors at Q2,Q3, Q5 were okay. Checked all the shunts and diodes were all okay. (by okay, I mean I checked for continuity with DMM while it was off) Couldn't find a schematic anywhere so it would be hard to debug what went wrong or how to modify so it doesnt happen. No idea what could have broken.

Here''s a pic of the power supply opened up

https://www.dropbox.com/s/1mwzf8tvz5g11f7/2015-09-20%2001.16.29.jpg?dl=0
 
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