Help with DC output cable wiring on 48V 50A Battery Charger

Thread Starter

Chris__H

Joined Nov 7, 2016
19
Hi all I'm Chris, this is my first post and I am a pure novice venturing into the wonderful world of electronics. Today I purchased a used Ericsson 48V / 50A battery charger for $250. I want to use it sparingly to charge a forklift battery that will be connected to my grid solar system. I want the battery to supply inverted AC power when the sun decides not to shine (like during the evenings), or when there is no radiance for extended periods and performing equalising and top up charges to keep my battery maintained. (Pic 1. Pictures of the unit with front cover off)

IMG_4885.jpg


The unit has 3 manual switches for different voltages charges, Float 1 [52v], Float 2 [54v] and Boost [64v] I assume for equalising. I need a little help as I'm not sure how to configure the DC charging leads because there is 4 terminals (see close up in Pic 2)

IMG_4902.jpg
Can anyone suggest how I should proceed Please? Will I need to piggy back the DC ("-") Boost & Float terminals? and what do you think the E terminal is for? Sorry about all the dumb questions but I guess I have start somewhere? I also noticed when I plugged the charger into the AC 240v power supply for the first time that it tripped my AC circuit when I switched the unit on? I checked the fuses and found the AC 20amp fuse had no continuity so I will try to find a new one and replace it tomorrow. Hopefully there is not greater gremlins at work here? I'll keep you posted. Thanks again Chris
 

Dodgydave

Joined Jun 22, 2012
9,459
Looking at the output terminals, i would say +Dc is battery positive common, -Dc float is battery negative, and the boost is for a higher voltage output.
E is earth.

best solution is to measure the voltage using a Dvm across the Dc+ and Dc- float/boost and turn the rotary switch to see what voltages are present.
 

Thread Starter

Chris__H

Joined Nov 7, 2016
19
Thanks, Dodgydave, I checked the rotary switch using a Dvm and you are right, both floats 1 & 2 operate from the one terminal, and the boost operates its own terminal. Correct me if I'm wrong but does that mean I'd join both terminals (Dc- float & boost) together as the black cable and the red cable as the positive (Dc+).

What happens to the E (Earth) terminal? Is it just left unconnected? Under what circumstance would I connect it?
 

Thread Starter

Chris__H

Joined Nov 7, 2016
19
Thanks, Dodgydave :), I'm waiting for the 20A fuse before I fire it up, and hopefully, things will work according to plan! But I wonder what caused the fuse to blow in the first place??
 

Thread Starter

Chris__H

Joined Nov 7, 2016
19
Damn it !!!! bloody Gremlins are getting in the way of a good time :(

OK Folks, New Problem. I ordered some fuses NIT20A rated to 550Vac 80KA gG BS88 . This fuse came with the 2nd hand unit and I didn't check it over before I purchased it ( a typical issue when I buy things on face value - rookie mistake!). Anyway, the mains supply fuse on the charger blew again (this happened twice), and at the same time tripping the Meter box 240 16A circuit (Is that normal?)?? Anyway, So I swapped fuses with a 20A one further up the board, this looked like an original fuse which was a NIT 20A M25 415Vac 80KA "motor circuit protection". This time no fuses on the charger blew but it still tripped the Meter box Mains? So I am now thinking that there is some type of short circuit within the charger,? Can anybody give me some pointers on how to go about troubleshooting this issue, please? I'd be forever thankful. Thanks Chris
New fuse.jpg


Original fuse.jpg


Rs20 & single phase plug.jpg
 

gerty

Joined Aug 30, 2007
1,291
"OK Folks, New Problem. I ordered some fuses NIT20A rated to 550Vac 80KA gG BS88 . This fuse came with the 2nd hand unit and I didn't check it over before I purchased it ( a typical issue when I buy things on face value - rookie mistake!). Anyway, the mains supply fuse on the charger blew again (this happened twice), and at the same time tripping the Meter box 240 16A circuit (Is that normal?)?? Anyway, So I swapped fuses with a 20A one further up the board, this looked like an original fuse which was a NIT 20A M25 415Vac 80KA "motor circuit protection". This time no fuses on the charger blew but it still tripped the Meter box Mains? So I am now thinking that there is some type of short circuit within the charger,? Can anybody give me some pointers on how to go about troubleshooting this issue, please? I'd be forever thankful. Thanks Chris"

One of the things that can cause your fuses to blow like that (assuming you are not connected to batteries) is the rectifier. See if you can get a pic of it/them. Should be connected to the output of the transformer. Maybe if we can see what you have we can talk you through it, if you need the help.
 

Thread Starter

Chris__H

Joined Nov 7, 2016
19
So today I disconnected the 2 yellow leads that are connected to the top of the transformer (TR). I think they are secondary winding wires and I guess this TR steps down the voltage? I managed to turn this (TR) on without it tripping the mains circuit! Yay! The voltage reading from the two wires when tested with the DVM was 90v. I think this may have been AC but my DVM is cheap 'n' nasty. Interestingly it still trips the mains circuit 8 times out of 10, but this is progress. (pic below).

I am beginning to think that at least part of the problem may have something to do with my Mains supply not handling the sudden load of amps? I know the main switch in my Meter box is a Hager SB299T 100 Amp, next in line is a HPM 10kA c16 amp which is the powerpoint I am using. I am wondering if this circuit should be upgraded to a higher kA rating? If anybody knows their stuff about kA ratings out there, I'd sure like some advice on that one?

Update (I am having trouble uploading pics at the moment!!)
 

Thread Starter

Chris__H

Joined Nov 7, 2016
19
"OK Folks, New Problem. I ordered some fuses NIT20A rated to 550Vac 80KA gG BS88 . This fuse came with the 2nd hand unit and I didn't check it over before I purchased it ( a typical issue when I buy things on face value - rookie mistake!). Anyway, the mains supply fuse on the charger blew again (this happened twice), and at the same time tripping the Meter box 240 16A circuit (Is that normal?)?? Anyway, So I swapped fuses with a 20A one further up the board, this looked like an original fuse which was a NIT 20A M25 415Vac 80KA "motor circuit protection". This time no fuses on the charger blew but it still tripped the Meter box Mains? So I am now thinking that there is some type of short circuit within the charger,? Can anybody give me some pointers on how to go about troubleshooting this issue, please? I'd be forever thankful. Thanks Chris"

One of the things that can cause your fuses to blow like that (assuming you are not connected to batteries) is the rectifier. See if you can get a pic of it/them. Should be connected to the output of the transformer. Maybe if we can see what you have we can talk you through it, if you need the help.
Here (Link below) are some Higher Res Photos, Thanks Chris
https://photos.google.com/album/AF1QipOFAmX1FA3ccddBQ3-EetWPXAhC-xJKpDPRn_ET
 

gerty

Joined Aug 30, 2007
1,291
So today I disconnected the 2 yellow leads that are connected to the top of the transformer (TR). I think they are secondary winding wires and I guess this TR steps down the voltage? I managed to turn this (TR) on without it tripping the mains circuit! Yay! The voltage reading from the two wires when tested with the DVM was 90v. I think this may have been AC but my DVM is cheap 'n' nasty. Interestingly it still trips the mains circuit 8 times out of 10, but this is progress. (pic below).

I am beginning to think that at least part of the problem may have something to do with my Mains supply not handling the sudden load of amps? I know the main switch in my Meter box is a Hager SB299T 100 Amp, next in line is a HPM 10kA c16 amp which is the powerpoint I am using. I am wondering if this circuit should be upgraded to a higher kA rating? If anybody knows their stuff about kA ratings out there, I'd sure like some advice on that one?

Update (I am having trouble uploading pics at the moment!!)
Are you saying you're plugging a 20 amp device into a 16 amp circuit? That would explain tripping the breaker, but not blowing the fuse. Do you have another,larger. circuit to plug into?
 

Thread Starter

Chris__H

Joined Nov 7, 2016
19
Finally some success, Thanks to all particularly Dogy Dave & Gerty. I started to take the main front plate off in front of the AC transformer when I noticed a very fine 'sensor type' wire, which was loose!, I tightened it and bam! problem solved......Yippee :) Thanks to all :)

IMG_4971.jpg

Loose wire.jpg

IMG_4966.jpg
 
A lot of those screws/nuts used for electrical connections could come back to haunt you. I re-did an X-ray power supply and a 30 kW e-beam evaporator power supply using Locktite 222 for the threads and everyone was happy, Including me. 222 doesn't need heroics for removal.
 

Thread Starter

Chris__H

Joined Nov 7, 2016
19
A lot of those screws/nuts used for electrical connections could come back to haunt you. I re-did an X-ray power supply and a 30 kW e-beam evaporator power supply using Locktite 222 for the threads and everyone was happy, Including me. 222 doesn't need heroics for removal.
Yeah, I hear you, Those intermittent problems can be the hardest to solve...Locktite the little buggers! :)
 
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