Other things you can do is .Clean all the fuses in the fuse box , take them out one at a time . And make sure you put them back in the same place as you removed it from. ..Next is trhe earth points , thats the negative leads that go from engine , and gear box, to the body of the car . Clean up the body of the car under the fixing bolt , and put a little grease on before refitting them .. You can have the best battery in the usa, but if the earth lead is not doing its job 100% it will look as if the battery its low on charge . This is just normal maintenance,, but you wont need to look at these items for years after .