Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

LTC3780 for MPPT solar charger poblems

Status
Not open for further replies.

noob64

Newbie level 4
Joined
Aug 27, 2009
Messages
7
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Romania
Activity points
1,339
Hi there,
I have some problems using LTC3780 for charging an lead-acid battery. I did manage to make a working buck-boost power supply with LTC3780 using the schematic form datasheet(for tests I managed to get 12,7V at 48W from 7-18V supply), but having it charging a battery from PV(power supply simulated) module failed.
The symptoms are:
1) Vin = 18V 1A, Vbat = 11.7V, Vout(set) = 13.8V I connect the LTC and Vin drops at 4-5V 1A, output diode get hot.
2) Vin = 18V 1A Vbat = 11.7V, Vout(set) = 12V I connect the LTC and Vin drops at 11.7V but charge, if load gets above 14-15W the LTC gets again in protection or something( Vin = 4-5V, max amps)
3) any combination where the output power(+ loses ) needed > input power bring the LTC bad working.
I see that the LTC3780 dose not want to drop his output voltage in any case, only about 0.4V max, and if the supply power cannot handle output power needed the LTC gets is some stupid mode.
I want to make the LTC3780 work with any input voltage/current and be able to charge whatever voltage battery have.
Here is my schematic(non populated current control):
https://i41.tinypic.com/2usyfjo.png

Sorry for my bad english.
 

Here my work in Eagle 6.4
 

Attachments

  • booster.rar
    95.3 KB · Views: 122

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top