Ady Gancz
Member
Hi all,
I have a Disco 1 1998 300tdi. Because I often drive it into the desert solo I carry a 2nd battery (70Ah) with me under the hood, though it is not connected. The spare battery is charged manually every 2 weeks using a smart charger. On a few occasions when my main battery (95Ah) went flat I had to move the spare to the main port and that worked just fine. It is, however, a bit time consuming and involves some labor to physically switch the batteries, so I thought about wiring the 2nd one too and using a heavy duty kill switch so that I can connect or disconnect it at will - Not that simple as it turns out.
I find it almost impossible to start the car if the starting battery is not sitting in the main battery port and connected to the main wiring. If I disconnect that battery and try to start the car from the other port using either my pre-installed heavy duty cables or external heavy duty (alligator type) truck cables or even a combination of both the car will not start. I will only get some weak attempts and the charge alarm will sound.
I suspect this has to do with the length of the cables from the second battery and/or the connectors at their ends. I estimate the cables to be approx. 1.2m in length and with a cross section of about 80mm square or more. They have heavy duty flat terminals and cross the hood from side to side to attach to the main battery terminals via standard connectors.
Just to clarify, my only interest in carrying a second battery is as a backup. I don't need extra Amps and I want is to stay disconnected 99% of the time. Just want to skip the part of physically moving the batteries when I need to switch.
What am I doing wrong?
Cheers
Ady
I have a Disco 1 1998 300tdi. Because I often drive it into the desert solo I carry a 2nd battery (70Ah) with me under the hood, though it is not connected. The spare battery is charged manually every 2 weeks using a smart charger. On a few occasions when my main battery (95Ah) went flat I had to move the spare to the main port and that worked just fine. It is, however, a bit time consuming and involves some labor to physically switch the batteries, so I thought about wiring the 2nd one too and using a heavy duty kill switch so that I can connect or disconnect it at will - Not that simple as it turns out.
I find it almost impossible to start the car if the starting battery is not sitting in the main battery port and connected to the main wiring. If I disconnect that battery and try to start the car from the other port using either my pre-installed heavy duty cables or external heavy duty (alligator type) truck cables or even a combination of both the car will not start. I will only get some weak attempts and the charge alarm will sound.
I suspect this has to do with the length of the cables from the second battery and/or the connectors at their ends. I estimate the cables to be approx. 1.2m in length and with a cross section of about 80mm square or more. They have heavy duty flat terminals and cross the hood from side to side to attach to the main battery terminals via standard connectors.
Just to clarify, my only interest in carrying a second battery is as a backup. I don't need extra Amps and I want is to stay disconnected 99% of the time. Just want to skip the part of physically moving the batteries when I need to switch.
What am I doing wrong?
Cheers
Ady
but I am sure it can be made to work. After all it's just basic wiring. If it's not working and the length of the cable is not an issue, then there must be a bad contact somewhere. I will find it.
