SPARE BATTERY (Ne auto sparkys out there)

When out hunting I'm a few ks from any help if I have a problem with a flat battery or the alternator stops charging.Its happens twice over the yrs.So I carry a spare battery 750cranks even tho the 4.2tdi has 2 battery's,12v parallel.Battery weighs 22kgs.
Is there a smaller battery with not so many cranks,but capable of helping turning the engine over a few times if needed.Engine normally starts on 1st turn of the key,has been for the last 19 yrs iv own it.Only needs one battery to be flat and engine will not turn.I put 2 new batterys 4 yrs ago,generally they last about 7yrs.But you never know when something goes wrong.
Any info appreciated,thanks.

I have one of these.
https://www.repco.co.nz/globes-batte...b70/p/A6213555
They come bigger too but I don't need anything larger. I was truely surprised how much grunt these have for such a small unit. A lot lighter and easier to work with than a lead acid battery.

When I had my td42 the battery man said to swap from side to as side yearly as the rh tends to charge higher than the left and they need to balance out or something like that . I nether did and sold truck 3yrs later so cant confirm .

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Originally Posted by Trout

When out hunting I'm a few ks from any help if I have a problem with a flat battery or the alternator stops charging.Its happens twice over the yrs.So I carry a spare battery 750cranks even tho the 4.2tdi has 2 battery's,12v parallel.Battery weighs 22kgs.
Is there a smaller battery with not so many cranks,but capable of helping turning the engine over a few times if needed.Engine normally starts on 1st turn of the key,has been for the last 19 yrs iv own it.Only needs one battery to be flat and engine will not turn.I put 2 new batterys 4 yrs ago,generally they last about 7yrs.But you never know when something goes wrong.
Any info appreciated,thanks.

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I hear what you are saying there, but it gets to a point where you go down on diminishing returns. You should be able if your batteries are good and the system is up to par crank the engine with only one battery connected on the short of the wiring harness with the 12v dual battery setups. I have done this a couple of times (the literal twice) although most of my time is with the 24v series connected import versions of this vehicle.

I would get one of the li-ion jump packs - as noted they do fine at what they need to do and do dual use as a emergency power source for cell phones etc as well as being a lot more resistant to being tipped over and spilled etc etc. They don't like being squashed though. I used to cart a lead acid battery in a box, strapped in with Andersen plug jumper leads set up with an isolating switch on it but the portable jump packs are just better now. I used to leave it connected to one side of the 24v setup for about 20mins, then swap it to the other and start as normal and the jump packs will do this just as well.

My experience of the TD42 setups both 12v and 24v, is the starting system is just as prone to issues as the charging side (which is to say they are both pretty bloody reliable and as you've noted the bits connected to them in the batteries are the weaker point in the system). If you have gotten to the point where you are starting to look for hills to park on to roll-start the vehicle you've got bigger issues than battery reliability haha.

Yeah I carry a jump starter of a similar size - cost about $240 from Super Cheap Auto a couple of years back
has a usb charge port too so good for topping up a cellphone

Might need to check with an autosparky that nothing is draining the charge when parked up?

Had a bit of battery trouble with my nissan the sparkey said theres something that equalises the charge to each battery that needed replacing.
No trouble since.

First time stranded it was the left battery slowly dying.2nd time stranded it was the alternator dying.But no problems in the last 8yrs,but when hunting i always carry the spare 22kg 750crank battery in the back of truck.Just nice to know iv got back up if needed,bloody long way to walk for help.

Other option is to keep a solar panel sitting on the roof to trickle the batteries, that way they should always be in a good enough shape to crank and if you flatten them doing something silly they should charge up enough to go again after a few hours of sun light.

2 of these?

https://www.aliexpress.com/item/1005...Cquery_from%3A

just disconnect the battery when you park it, throw a cheapy solar unit on. issue solved
and make sure the charge controller is mppt not pwm

Was wondering if that might be an option, or possibly just something else to shit itself? You can get remote operated isolation switches, meaning no need to open the hood to operate them and the main part of the switch just connects between the positive of the battery and the positive lead. If I remember right, there is a pair of thin cables that you run back to a switch - these connect a circuit across a relay which closes the main high amperage side of the start and charge circuits. I dunno if you are actually going to gain anything by doing that for a short term park up though, same as solar panels and the like. The emergency start pack is probably the better insurance form and you'll probably be carting one of them anyway even if you do the rest.

My hunting wagon was factory fitted with an isolation switch that cuts the ground circuit, very handy knowing that the battery is fully disconnected like that.