You probably have a WFCO 8900 series power center, likely with a 55 amp DC converter. You can download the WFCO operator's manual here:
http://wfcoelectronics.com/wp-conten...ors-Manual.pdf
On pages 4 and 5 you'll find the troubleshooting section. Follow those instructions carefully. They will identify any problem that you might have. Don't forget that if you have a battery cutoff switch (usually a big red switch) that it must be turned on for the battery to be charged by the converter.
Let us know what you find when you troubleshoot the converter. Good Luck