Old 12V Emergency Lighting System

[Sunny_92]

Looking for a few suggestions here...


We have a customer that has three (one on each floor) old Dual-Lite 12V Emergency Charging Systems. Specs below.


Dual-Lite Automatic Charger Battery System
Model: 12-NC-625
Charger: 120V AC Input, 1-Phase, 300 Watts
Battery: 1 Cell, 12V
System Rating: 436 Watts for 1.5 hours


These systems feed 12VDC emergency only (normally off) light fixtures. The issue is that these systems require someone to go around to them every 6 months to crank the knob to equalize the charge, and the owner would like upgrade the system so that they no longer have to worry about performing that maintenance.

It seems to me that this could be accomplished by simply replacing the charger in the unit with a modern 12V float charger, but I'm not sure if that would be the proper way to do it. I can't seem to find a product that would work for a direct replacement, as most central battery systems out now are the inverter type. Our lighting rep is going to reach out to Dual-Lite to see if they have any suggestions, but I have a feeling that their solution may involve replacing the fixtures which seems unnecessary.

Thoughts?

 

[Sunny_92]

A few more images...

 

[mgookin]

What do they feed?
Bugeyes?
Troffers?
Sconces?
Exit signs?

 

[Besoeker]

Dual-Lite Automatic Charger Battery System
Model: 12-NC-625
Charger: 120V AC Input, 1-Phase, 300 Watts
Battery: 1 Cell, 12V
System Rating: 436 Watts for 1.5 hours


These systems feed 12VDC emergency only (normally off) light fixtures. The issue is that these systems require someone to go around to them every 6 months to crank the knob to equalize the charge,

I'm puzzled by the 1 Cell, 12V. Does such a 12V battery exist?
And if it's just one cell, what's being equalised?

 

[Sunny_92]

What do they feed?
Bugeyes?
Troffers?
Sconces?
Exit signs?

They feed a few recessed downlights and sconces.

I'm puzzled by the 1 Cell, 12V. Does such a 12V battery exist?
And if it's just one cell, what's being equalised?

I believe the terminology is just misleading. There is a single 12V battery. When it talks about an "equalizing charge", I believe it's just referring to charging it to account for the leakage current after sitting for a while.

 

[GoldDigger]

They feed a few recessed downlights and sconces.



I believe the terminology is just misleading. There is a single 12V battery. When it talks about an "equalizing charge", I believe it's just referring to charging it to account for the leakage current after sitting for a while.

Since there are six individual cells in a 12V Lead Acid battery, it is technically possible that it would need an equalizing charge occasionally if the internal leakage varied among the cells.
The normal state is with a fixed float charge voltage applied, and this should fully compensate for any uniform self-discharge of the cells in the battery.
It is possible that the float voltage is low enough that the battery needs a higher voltage and current refreshing charge from time to time, but in theory that should be avoidable just by setting the float voltage correctly.

As stated in some other posts on FLA batteries, float service and cycle service are both walking a tightrope between plate erosion and electrolyte boil off on one side and sulfation on the other.

 

[Besoeker]

Since there are six individual cells in a 12V Lead Acid battery

That's what I was getting at. Six cells, not one cell.
Or maybe it could be a type of battery I haven't met.

We did quite a few UPS systems for emergency lighting, mostly in cinemas. Yuasa 12V lead acid batteries and, as you say, six cells.

 

[Besoeker]

I believe the terminology is just misleading. There is a single 12V battery. When it talks about an "equalizing charge", I believe it's just referring to charging it to account for the leakage current after sitting for a while.

Isn't it normally on charge from the 120V supply?

 

[Sunny_92]

Isn't it normally on charge from the 120V supply?

Read the charging description in the image below. Seems like it only charges after a power outage or when the dial is turned.

"1. The solid state charge control in this unit will automatically charge the battery after a power failure. To maintain the battery in prime condition, it should be given an equalizing charge every six months. To do this, turn the timer control knob to the 12-hour mark."

 

[GoldDigger]

Read the charging description in the image below. Seems like it only charges after a power outage or when the dial is turned.

"1. The solid state charge control in this unit will automatically charge the battery after a power failure. To maintain the battery in prime condition, it should be given an equalizing charge every six months. To do this, turn the timer control knob to the 12-hour mark."

Actually, as I interpret it, it only goes into "high rate" charge under those circumstances. The rest of the time the battery is on charge at a Float voltage. Charging at the Float voltage may take 24 hours or more to get back to near full charge after a discharge, so there is a mechanism to increase the voltage to drive the current higher when fast recovery is needed.

A Flooded Lead Acid battery with no charging at all except for periodic manual charging (especially at six month intervals!) would be lucky to last a year before the batteries were boat anchors.

(Along those lines, I worked engineering for a student radio station which had full Bell system surplus backup power. When the administration scheduled a 12 hour outage for the building to replace a service transformer the chief engineer decided to run a 12 hour test to make sure the backup system could maintain adequate station operation. The test worked fine, but he forgot to allow enough time between the test and the outage for the batteries to recharge. :slaphead

 

[Barbqranch]

Personally, I would be tempted to install a 4400 hour timer, plus a 12 hour timer.

 

[Besoeker]

Read the charging description in the image below. Seems like it only charges after a power outage or when the dial is turned.

"1. The solid state charge control in this unit will automatically charge the battery after a power failure. To maintain the battery in prime condition, it should be given an equalizing charge every six months. To do this, turn the timer control knob to the 12-hour mark."

As far as I can tell, that puts it on a high rate charge as opposed to the trickle or float charge it would normally receive when the supply is available.
That's how most of the emergency lighting systems I've dealt with operate.
If you left the battery off charge for six months the self discharge rate would significantly reduce the stored capacity and you might not get the designed autonomy.

To answer your original point, I'm sure you can get a product to meet the customer's expectations. My company used to make them albeit for rather larger systems but we have bought commercially availible units for some applications. I'm in UK so contacts from me wouldn't help.

 

[JFletcher]

How old is the system?

" The issue is that these systems require someone to go around to them every 6 months to crank the knob to equalize the charge, and the owner would like upgrade the system so that they no longer have to worry about performing that maintenance."

what? 20 minutes worth of semi-annual PMs? If it provides emergency lighting, doesnt that have to be tested monthly anyway? Do the 6 month PM at the same time. or tell the customer it's antiquated/legacy equipment that needs replacing. Adding a charger to that seems to me a bit like polishing a...