UC3906 Lead Acid battery charger I.C.

Thread Starter

k7elp60

Joined Nov 4, 2008
562
I am considering using the UC3906 Sealed Lead-acid charger IC for a charger. I would like to here pros and cons about your expericence with this IC/and or chargers built with this integrated I.C.

A little more information. I am working on a system of LED night lights for in the yard. I live in southern Utah where the daytime temperature can reach close to 120°F in the summer and in the winter go below freezing.

This IC tracks the temperature and adjusts the charge voltage the changes. I will be using small solar panels to supply the power. The solar panel I have chosen will produce 283mA at 17.1 volts in full sun light.

Your comments please.
Ned
 

SgtWookie

Joined Jul 17, 2007
22,230
Well, that's a linear IC. If you can handle it, you'd be better off with the UC2909; it's a switching battery charger IC, and rated for a higher temp range. If you design it properly, it'll be much more efficient than the '2906/'3906 linear version. This is going to be an issue with your 120°F summers.

You really need to measure the temp of the internal mass of the battery. The place to take the temp reading is the positive terminal(s). You don't want to base the readings on ambient temperature, as it's the battery temp that is the critical item. It takes a short time to heat up the mass during fast charging/fast discharging/heavy loads, but a long time to cool down.

I haven't used either IC, but I've had the datasheets downloaded for a few years now.
 

Thread Starter

k7elp60

Joined Nov 4, 2008
562
Well, that's a linear IC. If you can handle it, you'd be better off with the UC2909; it's a switching battery charger IC, and rated for a higher temp range. If you design it properly, it'll be much more efficient than the '2906/'3906 linear version. This is going to be an issue with your 120°F summers.

You really need to measure the temp of the internal mass of the battery. The place to take the temp reading is the positive terminal(s). You don't want to base the readings on ambient temperature, as it's the battery temp that is the critical item. It takes a short time to heat up the mass during fast charging/fast discharging/heavy loads, but a long time to cool down.

I haven't used either IC, but I've had the datasheets downloaded for a few years now.
Thank you SGTWookie for the information. I do plan to use the higher temperature range version the UC2906. I forgot about the heating of the actual mass of the battery. The overall project has been a learning expericence for me as all the electronics will be outside near the solar panel. so I have had to check on the temperature characteristics of all the parts I plan you use.
Ned
 
Top