Why do you say that since you have a new battery that it couldn't be the problem?
If you need to jump the car that usually means your battery is drained and doesn't have enough juice in it to start your car. First things first. If I were you I would go out and purchase a battery charger of at least 10 amps. All car owners should have one. If you feel you can't be bothered or don't want to spend the money you will need to go all through the trouble of taking your battery out of the car and bringing it to someone else to give it a charge. Do that enough times and you will see the need to own a decent battery charger. Now if your car starts with a fully charged battery I would next check out that alternator or have someone check it to see if it is good on the car. A good alternator will put back in the electric taken out of the battery during starting keeping it charged while running the car. This is another cost factor if you need to have someone else test it if you don't have a Milton type battery testor around. Another tool worth having with that battery charger.
Another problem you may have here since you mentioned that after a couple of days your battery won't start the car. In this case I am willing to guess that you may have a electrical drain on your battery such as leaving an interior light on, glove box light on etc. Sometimes a short in the electrical system will cause this. If it isn't a interior light that was left on this may be a problem you may not be able to handle. Hope I was some help here.
Before I forget. Some people think that by just having your car jumped that your alternator will put a full charge back into your battery. This is not true. If anything at this point your are putting a strain on your alternator. Only a battery charger will be able to put a full charge back into your battery.
Saturday, August 17th, 2019 AT 5:08 PM