standard dual battery isolation

[JoshsD22]

gday mate dunno bout the starter issue but i have a 2008 d22 with the 2.5 the ones that firstly still came out of japan and it has only one battery so there will be no dramas with isolating the one and as Toby said i wouldnt be getting a deep cycle just yet unless it only runs your fridge for an hour hahah

Josh

 

[Old.Tony]

Your idea about how to configure things is spot on, just remember to fuse the wire that's heading back to the tub (fuse should be nice and close to the battery).

If your second battery is wired directly to the starter, yes I'd be popping it off there and running a heavy (8mm) cable from the main battery across to the Redarc/Projecta/Other isolator. The starter should be close to the rear of the motor. Not sure why they'd wire the second battery to the starter except that it's simple and can then be used as a starter battery as well - definitely no drama getting rid of that setup and going the way you want to.

 

[bods]

Thanks for your posts boys I think I am getting my head around this. I am thinking the following;
1.remove wire between second bat and starter.
2. extend wire between alternater to 2nd batt to allow putting an isolator (such as redarc) in and fixing to something.
3. run power to tub from 2nd batt, for fridge etc.
Am I on the right track?
Problem I see is that the the starter looks to be a bastard to get to, it seems to be at the bottom of the engine on the drivers side and the wiring, works around between the firewall and engine to the 2nd bat. Is that right?

almost on the right track. the "second" battery (the one on the passengers side of the engine bay) is only wired to the alternator. so it's a slightly easier job than getting to the starter motor. apart from that, that's the same plan i have to get power to the tray

 

[Krankin]

I drove mine for a week without the second battery connected (in winter), only driving very short distances. They are normal sized batteries, I would not be concerned about losing one of them. Apparently they were fitted with two batteries due to the cold weather markets overseas requiring more cranking power, and we just got their excess stock of vehicles - it was cheaper to leave the batteries in there than it was to remove them....

Yup.




.

 

[heata]

almost on the right track. the "second" battery (the one on the passengers side of the engine bay) is only wired to the alternator. so it's a slightly easier job than getting to the starter motor. apart from that, that's the same plan i have to get power to the tray

thanks bods, are you talking 2010 model? cause there is definately a second wire coming from the passenger side battery, and it runs back toward the firewall and then down to the bottom of the engine on the drivers side and goes to what I believe to be the starter motor, (the main battery is also connected to this)
but anyhow, I'll be seeing a few forum members this weekend, so I'll clarify it then!
But further to this I have pretty much decided to use one of the ready made kits, (redarc or projecta) which recommend connecting via the main battery not the alternator. Just need to set aside an afternoon!

 

[bods]

yeah, 2010. maybe you're right. I just had another good look and it seems they may be connected at both the alternator and starter... The only difference being, on mine it runs across the front of the motor above the egr pipe and down the driver's side of the motor...

Anyway, I just pulled the factory terminal off the battery and wrapped it in electrical tape (to be properly terminated or removed at a later date) and ran a new wire from the solenoid mounted on the driver's side inner guard, along the firewall with the brake lines to the second battery.

 

[heata]

Hey Bods, I started this job tonight, since I was running power to the tub for the fridge. you are right it just goes to the alt. My mistake. There are a heap of wires in mine that are just suspended by the same support as the +ve from the 2nd bat, and that confused me. So this job will be a bit easier than I thought.

 

[Joshp82]

hi everyone, sorry do dig up an old thread, I've just been given a 50L Ironman coolbox Fridge freezer. If i do the process explained above can i just use the stock battery to power my fridge? It says it draws 0.7A average. I'm guessing about 4A on start up. When the fridge is connected to my ute it will only have to run for a maximum of about 16-20 hours without the car running, does this mean i will need at least a 20Ah battery minimum just to run my fridge over night? I really don't know much about these sort of things, please correct me if I'm wrong.
Ill have some LED strips that i will run off this battery as well. I'll run cable to the tub and have a fuse block and a couple of outlets mounted back there.
The other option is to leave the batteries as they are and put a 3rd battery in the tub.
This will cost more but i assume it will net the same results. Power in the tub to run my fridge and small accessories. If i went the way of a third battery i would probably put an inverter in there too so i can charge my cordless drill, laptop and camera batteries while on the road.
If someone could point me in the right direction your help would save a lot more reading

Thanks
Josh

 

[jap55s]

Reading is good. I have learnt SHITLOADS just from reading as many threads as I physically can.

Sent from my iPhone using Forum Runner

 

[Joshp82]

Reading is good. I have learnt SHITLOADS just from reading as many threads as I physically can.

Ive spent the last 2 hours trolling over pages and cant read much more tonight, ill keep searching but i thought it would be just as easy to ask the questions.

 

[terryc]

hi everyone, sorry do dig up an old thread,

+1 for using the search function.
You will find a lot more information if you keep using it.

Please excuse quick reply as need early night.

I've just been given a 50L Ironman coolbox Fridge freezer. If i do the process explained above can i just use the stock battery to power my fridge?

Not a good idea as you could end up with nothing left to start it.

It says it draws 0.7A average. I'm guessing about 4A on start up. When the fridge is connected to my ute it will only have to run for a maximum of about 16-20 hours without the car running, does this mean i will need at least a 20Ah battery minimum just to run my fridge over night?

20 x 0.7 = 14Ah. you want at least double that. Err 75 AmpHour are common, but if you can stump up the cash, get the biggest you can fit in the space. (125Amphr?) Especially with all the other stuff you are talking about adding/doing with it.

Make sure it is a real deep discharge battery and not a CCA or "Marine" one. Caveat,I've never bush bashed any of my vehicles, so if you do, hen marine (thicker plates) might be better. Basically look for a battery with solely AmpHour rating.

I really don't know much about these sort of things, please correct me if I'm wrong.
Ill have some LED strips that i will run off this battery as well. I'll run cable to the tub and have a fuse block

You want an isolator at the alternator/battery that you tap off. Should only conduct after the main has been recharged after starting. Then you want a fuse or circuit breaker(resetable?) immediately after that.

Initially, for cost saving, just run the really heavy cable, then add the dc-dc charger(in the tub) when you can afford it. The car battery charging system is designed solely for CCA batteries and long term use on deep discharge types isn't good for them(high rates of charge and discharge shorten the life of them, yes even on AGM types.).

and a couple of outlets mounted back there.
The other option is to leave the batteries as they are and put a 3rd battery in the tub.

Ah haa, check your manual, you might find the size of the two batteries isn't that much smaller than the battery in the single battery models, so, in theory, you could use the 2nd battery for you fridge, etc, but they are not designed to be used this way and it shortens their life.

Also, if you eventually replace it with one of the right type, under the hood is HOT and this screws that type of battery and reduces their life.

So going for the third battery in the tub might be the better option over all.

This will cost more but i assume it will net the same results. Power in the tub to run my fridge and small accessories. If i went the way of a third battery i would probably put an inverter in there too so i can charge my cordless drill, laptop and camera batteries while on the road.
If someone could point me in the right direction your help would save a lot more reading

Thanks
Josh

Just a start. Look around, keep reading. Others will give their 2c. Don't be afraid to ask questions.

I never buy deep discharge batteries from the auto shops(SCA, Repco, AB,A1, etc) but always go to my local industrial supplier, the guy that does fork lifts, burglar alarms, etc although he has many "special" automotive batteries now as well.

Hint, buy the basic deep discharge lead acid battery and don't buy any of those "special" types for your first battery. They are far more forgiving.

 

[Old.Tony]

The absolute cheapest option would be to separate your batteries in your tub by an isolator, then run a pair of heavy cables from the second battery into the tub. The second battery has enough capacity to do what you need BUT if your starter is still actively connected to it while you're drawing power (with the engine off) you could be in serious trouble.

From those heavy cables in the tub you can run any 12V stuff including an inverter.

Personally, I put my laptop on the floor behind my seat and run an inverter inside the cabin. I think it's gentler on the laptop, rather than having it thrown around inside the tub as I drive!

 

[fzrr]

I'm also curious about this Josh. Was wondering if it was as simple as installing a Redarc battery isolator and then running all the accessories off the passenger side battery.

Or if its just going to kill that battery cause its a cranker I also read earlier in the thread that D22 starts fine with just one battery connected. So has anyone replaced the passenger side battery with a deep cycle??

 

[Old.Tony]

You're right about the cranker being an issue. They have a reduced capacity for deep discharge - basically it kills the battery rather quickly. They are designed for a high current draw for a few seconds then charge 'em back up.

You can replace it with a deep cycle (NOT a gel battery, it'll cook in the engine bay).

For Josh's purposes - a fairly light draw - the second starter won't die too quickly. If he starts to use it a lot, replacing it with a deep cycle would be the way to go. It's always preferable to have these in the tub (or at least out of the engine bay) so the heat doesn't affect them but once you're stopped the heat leaves the engine bay anyway.

 

[fzrr]

So its doable but not advisable to put a deep cycle in the engine bay?

I'm in a similar boat to Josh I just want to run a fridge off it and also the uhf and stereo so I can have them on while setting up camp or waiting for people to arrive at a meetup and not having to worry about being able to start the car.

 

[Joshp82]

So its doable but not advisable to put a deep cycle in the engine bay?

I'm in a similar boat to Josh I just want to run a fridge off it and also the uhf and stereo so I can have them on while setting up camp or waiting for people to arrive at a meetup and not having to worry about being able to start the car.

That's the plan, just gotta keep my beer cold and the wife's wine chilled.

So but an isolator disconnect the passenger side battery, use the factory battery for now, when it carks it buy a deep cycle to replace it as long as its not a Gel battery, run power to the tub with fuses at both ends??
All sorted, then when i want/need a stronger set up put a bigger and better battery in the tub?

 

[fzrr]

That's the plan, just gotta keep my beer cold and the wife's wine chilled.

So but an isolator disconnect the passenger side battery, use the factory battery for now, when it carks it buy a deep cycle to replace it as long as its not a Gel battery, run power to the tub with fuses at both ends??
All sorted, then when i want/need a stronger set up put a bigger and better battery in the tub?

Sounds like a plan! Let me know how you go with it so I can learn from your mistakes.

 

[heata]

That's the plan, just gotta keep my beer cold and the wife's wine chilled.

So but an isolator disconnect the passenger side battery, use the factory battery for now, when it carks it buy a deep cycle to replace it as long as its not a Gel battery, run power to the tub with fuses at both ends??
All sorted, then when i want/need a stronger set up put a bigger and better battery in the tub?

Thats where I'm at now, just replaced the origional aux battery after nearly 12 months of running a fridge probably had the fridge on for 80% of that.

 

[KraftyPg]

That's good because you'll only get 80% charge in your battery!

 

[FatBoy89]

Which you cannily use 50% of the charge? Mate you have about 7 ah left