Both of them. They work together and must be strong and fully charged. Do you have green in the sight glass? You should after recharging.
The diesel battery is bigger as it take a lot more to get a diesel engine going. Best bet is to charge the diesel battery using the petrol, connect the 2 and leave the petrol engine running.
Yes, you can start diesel engine even if you don't have battery in!
I have been told by a dealership that you can charge it by using the 'jump start' point under the bonnet but I have tried that and it doesn't seem to charge the battery. I have ended up having to remove the battery (which is located under the front passenger seat) and bring it indoors to charge it directly- then it takes a charge fine. Just bear in mind that you will have to have the stereo code to input once the battery is hooked up again.
When the car doesn't start.
Check your charge in your battery. Just because all things turn on does not mean your battery has enough power to start the engine. Charge your battery or get a jump start.
You can charge or jump the battery from jump start posts under the hood on the passenger side.You can charge or jump the battery from jump start posts under the hood on the passenger side.
NO You have to many AMPS from a car, you can jump start it butdon't charge it.
Start the engine up. The engine will rotate the pulley on the alternator and charge the battery.
like you charge a car battery....use a trickle charger set to 12 volts
Use another vehicle to jump start it, or replace the battery, or charge the dead battery with a charger.
As long as both batteries are the same voltage, you can jump start with the battery. If you want to charge the battery then use a battery charger.
charge the battery, change the battery, use the back up start either a pull start or kick start.