Thread: Optima yellow top as starter battery??

Originally Posted by Russrobe

The USI 160 does this... Not sure about the SC80. I think thats the main difference between the two..

I don't really need the functionality via switch but it would be handy to easily rig up the yellowtop as a starter in case of the starter failing in a remote place. My understand is a large lead joining the two positives terminals together would do it. But not sure what has to be done with the SC80 in that situation. I wouldn't take an old'ish starter if going remote anyway so not interested in installing a relay/switch etc for such a rare need.

Scott

Originally Posted by LRD414

I don't really need the functionality via switch but it would be handy to easily rig up the yellowtop as a starter in case of the starter failing in a remote place. My understand is a large lead joining the two positives terminals together would do it. But not sure what has to be done with the SC80 in that situation. I wouldn't take an old'ish starter if going remote anyway so not interested in installing a relay/switch etc for such a rare need.

Scott

Fair enough. When I spoke to Tim ( Drivesafe ) when buying my SC80 I'm pretty sure he said it wouldn't be a problem. If it wasn't Tim then it was someone on here who had done it.

Originally Posted by LRD414

When you say rewire Michael, does this just mean connect the two positive leads together and disconnect the isolator (SC80 in my case)?

I've been meaning to make up a positive lead for that purpose for ages.

Scott

Scott,
if the starting battery is dead, no good paralleling with secondary battery as sum will not start car, jumper lead between positive terminals (or separate lead), and then remove neg lead from starting battery, so it is no longer active. Vehicle is then running from secondary battery only.
or on isolators with high load leads, just bolt them together onto the one post, and still disconnect negative terminal etc

Unfortunately it is a case of the specific situation that will govern how you jump start any vehicle.


If the cranking battery is simply flat, then as long as the Optima is around 12.0v or higher, with an SC80 fitted, a single jumper lead, connecting positive ( + ) to positive ( + ) will normally allow you to start the motor.


Once the motor is up and running, you can remove the lead and the alternator will do it’s job.


If the cranking battery has dropped a cell and is showing 10.5v or less, then you need to disconnect the negative ( - ) terminal as Michael posted above, to allow the Optima to be able to start the motor.


In this type of situation, your must PERMANENTLY fix the cable between the two battery positives ( + ). If the lead between the two battery positives ( + ) comes loose, once the motor is running, and the negative ( - ) lead is not connected to the cranking battery’s negative ( - ) terminal, you can damage major electronic components in your vehicle


I have carried out testing of starting vehicles with low cranking battery voltages. My L322 TDV8 can be started with a cranking battery voltage as low as 11.5v, but I could not turn the motor over with the same battery at 11.3v.


In this test, I simply used a set of jumper lead off an Optima sitting beside the L322.


With an L322, as the auxiliary battery is in the rear, the battery has to be removed to be able to jump start. Whereas with both my D3 or D4, with the two batteries being close to one another in the engine bay, a single jumper lead worked when ever I carried out this test.

Originally Posted by rrturboD

(Vested interest flag ... I sell batteries!) ...

Optima D34 will happily operate as a starting battery. The CCA rating is conservative, and we have found that the battery technology delivers the CCA for longer each start, so a smaller capacity battery will often out perform conventional batteries. Eg Cat D6 Dozer 24v, uses 2x N150 batteries (@1000CCA) (one each side of the driver), 2xOptima D34 (@750CCA) (mounted in 1 box, freeing other for tools) have been starting/running dozer for 6 years now.
I recommend users who have D34 as secondary battery, and panic when out the back of beyond etc their starting battery fails (usually the original Varta in their D3 or D4) , to rewire the isolator to use the D34 as starter ... they have always got home, and sometimes taken few months to replace the original starter.

That's very interesting, did you only try the yellow top ? or did you try the red top or blue top as well ?

I cant see why it wouldn't be a better option to have a dual purpose type battery as a main start in a car with as much electrics as a D3/D4. My start battery is only 9 months old as it was replaced under warranty , but in the temperature conditions up here , I don't expect anymore than 2 years out of a start battery. My Ford Ranger work ute is like clock work with start batteries , every 24 month service it has had a new battery , consistent over 6 yrs now.

Cheers Ean