D4D - start from secondary battery?

[Karl Strickland]

Can you start a D4D 3.0 using just the secondary battery - ie the one not attached directly to the starter motor?

I realise the batteries are wired in parallel, but is the +'ve cable between them good enough to start the car?

Thanks

 

[Simon5030]

This is a very interesting topic!
I was having problems with my 120 starting up, so replaced the drivers side battery (RHD) with a Varta, it never really turned well after that but at least i didnt need to jump start it! after about 3 months the jump starting started again! Just replaced the alternator and checked charging was all spot on.
I checked the drain when stationary and after the ECU booted the current steadied off at 40mA as expected, this then got me thinking that i should have changed both batteries at the same time (pretty sure you would all reccomend this as good practice!), so after alot of deliberation about was i running a 12v starter or 24v starter i worked out it was a 12v system, i then removed the drivers side battery and it booted over fine, then put back the 'New' battery in the drivers side and removed the passenger side battery, solenoid engaged but didnt even try to turn it!
Battery had a 4 year warranty so i decided to buy an identical one from elesewhere, fitted it and ran the same tests again, booted perfectly with either battery and with both it felt like i could run it up and down the street just on the batteries!

The -ve lead on the UK drivers side attaches to the engine block, the LHS -ve is to the chassis and somewhere else, the +ve are joined together so no problem there!

My research told me that the 24v starter systems seem to be more prevelant in the colder countries but nothing concrete?

So my answer is yes unless anyone can shed any further light on this?

Simon

 

[jibberjabber]

This is a very interesting topic!
I was having problems with my 120 starting up, so replaced the drivers side battery (RHD) with a Varta, it never really turned well after that but at least i didnt need to jump start it! after about 3 months the jump starting started again! Just replaced the alternator and checked charging was all spot on.
I checked the drain when stationary and after the ECU booted the current steadied off at 40mA as expected, this then got me thinking that i should have changed both batteries at the same time (pretty sure you would all reccomend this as good practice!), so after alot of deliberation about was i running a 12v starter or 24v starter i worked out it was a 12v system, i then removed the drivers side battery and it booted over fine, then put back the 'New' battery in the drivers side and removed the passenger side battery, solenoid engaged but didnt even try to turn it!
Battery had a 4 year warranty so i decided to buy an identical one from elesewhere, fitted it and ran the same tests again, booted perfectly with either battery and with both it felt like i could run it up and down the street just on the batteries!

The -ve lead on the UK drivers side attaches to the engine block, the LHS -ve is to the chassis and somewhere else, the +ve are joined together so no problem there!

My research told me that the 24v starter systems seem to be more prevelant in the colder countries but nothing concrete?

So my answer is yes unless anyone can shed any further light on this?

Simon

Hi Simon,

Yes, you answerd your own question, you need to replace both batteries, also weak batteries (or one weak battery of the two) will wear you alternator out quickly, and if you have two batteries positive connected to positive then you have effectively one big 12v battery.

Well done, good Luck.

 

[jibberjabber]

Can you start a D4D 3.0 using just the secondary battery - ie the one not attached directly to the starter motor?

I realise the batteries are wired in parallel, but is the +'ve cable between them good enough to start the car?

Thanks

Hi Karl,

Welcome to LCC.

There is no primary or secondary in a dual 12v setup, both batteries should be used to start the engine, if you remove the battery that is connected to the starter motor then you are removing part of the chain, if you just use the batt connected to the starter then you are putting a lot of strain on the batt and the alternator.

Thats my perception of the system, but as Simon says it will work as he has done the experiment.

Good Luck.

 

[Karl Strickland]

This is a very interesting topic!
I was having problems with my 120 starting up, so replaced the drivers side battery (RHD) with a Varta, it never really turned well after that but at least i didnt need to jump start it! after about 3 months the jump starting started again! Just replaced the alternator and checked charging was all spot on.
I checked the drain when stationary and after the ECU booted the current steadied off at 40mA as expected, this then got me thinking that i should have changed both batteries at the same time (pretty sure you would all reccomend this as good practice!), so after alot of deliberation about was i running a 12v starter or 24v starter i worked out it was a 12v system, i then removed the drivers side battery and it booted over fine, then put back the 'New' battery in the drivers side and removed the passenger side battery, solenoid engaged but didnt even try to turn it!
Battery had a 4 year warranty so i decided to buy an identical one from elesewhere, fitted it and ran the same tests again, booted perfectly with either battery and with both it felt like i could run it up and down the street just on the batteries!

The -ve lead on the UK drivers side attaches to the engine block, the LHS -ve is to the chassis and somewhere else, the +ve are joined together so no problem there!

My research told me that the 24v starter systems seem to be more prevelant in the colder countries but nothing concrete?

So my answer is yes unless anyone can shed any further light on this?

Simon

Thanks for the info Simon, much appreciated.

I think some 120's only have one battery (Australia), installed on the UK passenger side.

From what I've read the dual battery setup was specifically intended to give more amps to start the diesel in cold weather, so wasn't applicable everywhere.

Any idea how many amps these things take to crank? Mine has two 850 CCA batteries, which would be 1700 CCA in parallel.... sounds like a lot!

 

[Karl Strickland]

Thanks for that.

BTW the original reason I asked was I need to treat some rust on the battery trays, so was wondering if I could do one battery at a time and if the truck would still be useable. (With the extra +ve lead properly isolated of course!)

 

[Simon5030]

Karl
Cannot see a major issue as a temp solution, assuming the battery is in good condition and we are heading into summer so a bit easier to turn over, last thing you need is to be stuck somewhere, might be worth having the battery strapped in the back with a pair of jump leads just in case?
Battery shelves are a bit prone to rust, did mine on my last car over a weekend, stripped it all out spent ages de rusting, painted and waxoiled, seemd to last ok.

Simon

 

[Juddian]

These engines take some kicking over, same engine in my Hilux only had one battery, but it was a higher output than the matched pair we run on UK Diesel 120's.

Not alone in needing a lot of current, for donkeys years i drove car transporters and any time we needed to jump start something like a 2.5 Transit or Nissan Terrano or similar, even with really high quality jump leads the chances of it turning over fast enough were remote, sometimes needed a second set of leads, in extreme cases even had 2 sets of leads and a jump pack as well before it had enough oomph...note the leads i carried had no trouble jump starting a 12 litre lorry engine via 24v.

Yes i agree renew batteries in pairs when possible, and make sure they are charged up fully individually, one less charged than the other always causes issues, many years ago some lorry drivers would fit a radio wired to one of the batteries to keep it 12v, it invariably caused issues over time.

 

[Karl Strickland]

Karl
Cannot see a major issue as a temp solution, assuming the battery is in good condition and we are heading into summer so a bit easier to turn over, last thing you need is to be stuck somewhere, might be worth having the battery strapped in the back with a pair of jump leads just in case?
Battery shelves are a bit prone to rust, did mine on my last car over a weekend, stripped it all out spent ages de rusting, painted and waxoiled, seemd to last ok.

Simon

Good advice - thankyou!

 

[Karl Strickland]

These engines take some kicking over, same engine in my Hilux only had one battery, but it was a higher output than the matched pair we run on UK Diesel 120's.

Not alone in needing a lot of current, for donkeys years i drove car transporters and any time we needed to jump start something like a 2.5 Transit or Nissan Terrano or similar, even with really high quality jump leads the chances of it turning over fast enough were remote, sometimes needed a second set of leads, in extreme cases even had 2 sets of leads and a jump pack as well before it had enough oomph...note the leads i carried had no trouble jump starting a 12 litre lorry engine via 24v.

Yes i agree renew batteries in pairs when possible, and make sure they are charged up fully individually, one less charged than the other always causes issues, many years ago some lorry drivers would fit a radio wired to one of the batteries to keep it 12v, it invariably caused issues over time.

Thanks for that - kind of puts it into perspective.

Just out of interest, what size battery (CCA) did the Hilux need?

Cheers!

 

[Juddian]

Thanks for that - kind of puts it into perspective.

Just out of interest, what size battery (CCA) did the Hilux need?

Cheers!

Haven't the foggiest recall i'm afraid, but the single battery had some kick to it because the engine spun over very quickly.

Incidentally, anyone noticed how small starter motors are these days, when you remember how big they used to be in the days of Bendix Drives on even a 1600 petrol engine they were about twice the size now used.