batteries

If your starting battery stuffs up as you put it then you will have no alternative than using your second battery. Provided you do replace your starting battery as soon as possible then you will not damage your deep cycle job too much.
After all its better than being stranded.

NFD
Why cant you run jumper leads to your "stuffed" (by that i presume you mean flat) and start the tug that way.
If "stuffed" means STUFFED i cant see a problem using the deep cycle battery, but if i am wrong someone is sure to correct me.

Cheers
Baz

Off course you could always have a dual battery arrangement so that you are always ok. They are isolated from each other giving you the best of both worlds, however yes you can, that is swap the 2nd battery in or jump from the other.

Depending on the size of the deep cycle battery there will be few if any problems short term with using it to start off, in fact I did away with the starting battery all together 7 years ago & just crank off two deep cycles in parrallel instead. Possibly the main issue you will have, is often the terminals are on the opposite sides so the cables wont reach.
Cheers Craig.............

When ARB fitted dual battery to mine they put a button in the dash that I press if wanting to start off the second battery.

Onya Crackles!
I recently suggested the same....

Deep-cycles are not good for cranking. (But if big the battery is big enough, the cranking current is within "acceptable" parameters.)
Hence why many with normal isolation systems have a cranker in the engine bay, and a deep-cycle as a secondary (& 3rd & 4th etc).

But adding (usually) two cranking relays to parallel the batteries whilst cranking shares the strain.
In practice where front & rear batteries are used, a 1:2 current split is considered acceptable - depending on batteries & requirements. (IE - a 300A starter; 200A from the front battery, 100A from the rear - merely to limit the size of the rear battery-to-starter cable.)

I replaced my Yuasha 700CCA Starting battery with a 6 yo Delkor (80ah) Deep Cycle battery when I changed over to AGM DC's some years ago.
I ran the Deep Cycle 'Cranking' battery for many months till I was ready to go bush again and changed it only for the security of knowing I was going away with a new battery, not a 7 yo DC starting battery as it was at that time.

Didn’t feel any different starting a 4 cylinder diesel with an old Deep Cycle battery.

Maîneÿ . . .

Gday,
Simple answer is no.
But jumper leads are easier?

Cheers

Get an AGM battery for your second battery - they work well for Deep Cycle and Starting.

It would NOT be a problem at all.

To cut a long story short I put a wet cell deep cycle battery in place of my starter battery to get me home. Once home I was not going on any more trips for a while so I thought I may as well leave the deep cycle battery as a starter until it dies. The battery was 12 months old.
4 years later it finally died.
I was almost going to replace it with another deep cycle I was so impressed.
Regardless of what people believe or say, if you were stuck out in the back blocks wouldn't you try?

Cheers Tony.

I carry a short (about 12") jumper cable with clamps- that I can connect onto the outputs of my solenoid type battery isolator.
Have had to use it a couple of times when the vehicle has been standing for a while- and the cranking battery has lost its punch.

Try it at home before you go. Thats what I use to do - just see if you can crank off your aux battery. Wet cell deep cycles in good nick are fine as cranking batteries - there's really not as much difference as the marketing depts make out.

You can crank off almost any battery....
12V 7AH batteries were used in most "starter packs" until the now common 15AH became standard.
As a rough rule, a 15AH cranker should be equivalent to a 30AH deep cycle in terms of "relative stress".
And 30AH is not big.

But I have cranked off a Yuasa NP7-12 intended for alarms (7AH AGM). Its specs say MAX 45A. Even my present reduction starter takes 140A. My old was around 240A or more. Mind you, I doubt it would last long doing that, and the lack of current limiting upon charging is sure to destroy it quickly. (My previous NP4-12 4AH battery lasted 23 years in a domestic alarm application.)


And as was shown back in the pre-EFI days and before electronic voltage regulators, you could start a car (whose alternator had lost its residual magnetism) with a 1.5V battery.... (Not using the starter motor mind you.)


And I saw last week in Mitre-10 these little emergency starter packs for about $40-$50. Within minutes or hours they will charge "any battery" enough to start "your vehicle". It's obviously equivalent to a 1.2AH or 4AH 12V battery... I'm just wondering if it comes with a dc-dc converter, or if it relies on AGM low leakages. Or maybe its a 14V battery etc? Or LiPo!
Not that it matters - they'll be gone by the time the claims float in.....


The point is any battery will do just about anything.
What most are trying to get across is battery life.
My 40AH "power-eye" flooded cells are 8 years old. Not bad for an $80 battery eh?