Late 2010 D40 Dual Battery System

[maulbeagle]

hey guys how long after starting the car does the alternator output drop to 12v ? on my d22 (2011) I just started it and monitored the voltage at the battery terminals (is this correct ?) and it stayed at 14.1V for at least 10 minutes. I'm just trying to work out if my D22 has this same issue as the D40's mentioned above.
Cheers

 

[ourd40]

I have a 2011 ST and it sits on 14.1 all the time

 

[maulbeagle]

@ourd40

D22 or D40 ? Assuming D40 by your name ? So newer D40's don't have this issue ?

Thanks

 

[ourd40]

Yes it a D40, though mine has the older 120 something KW motor not the newer 140kw

 

[bods]

D22's have a standard charging setup, not a fancy one like some model d40's. You won't have any issues with your setup on a d22

 

[maulbeagle]

thanks for all the feedback everyone.
Hopefully the last question:
given the dual batteries in the D22, where abouts in the circuit would I put the isolator ?

cheers

 

[Old.Tony]

Isolator should go very near the main battery:

Mainbatt -> isolator -> fuse ------------------------------------------------------> fuse -> aux batt

 

[maulbeagle]

Thanks Tony, I don't think I made the question very clear. What I mean is I want to leave the dual batteries as they are, both in parallel for cranking all the time.
I then want to put in an isolator and run the output of that down to an Anderson plug on my towbar, then to a DC-DC charger for the house battery in my van.
Does that change the placement ?

Thanks

 

[mike1303]

It's called a variable voltage alternator.
Those with 2012 models and or 2011 stx550 when installing a dual battery system ill require the redarc bcdc1220LV or low voltage, it's able to pick up the lower voltages and still charge the batteries.

Those with 2011 st and stx or earlier are lucky to not need these model redarcs


That is if your choosing to go that way.

 

[Old.Tony]

Thanks Tony, I don't think I made the question very clear. What I mean is I want to leave the dual batteries as they are, both in parallel for cranking all the time.
I then want to put in an isolator and run the output of that down to an Anderson plug on my towbar, then to a DC-DC charger for the house battery in my van.
Does that change the placement ?

Thanks

Not at all - do it exactly the same way.

The isolator looks at the voltage available on its input. If you have the isolator at the rear of the vehicle, there may be enough voltage drop on the cable from the front of the car that the isolator may never activate.

You still need fuses just off the battery/isolator - this prevents fires, not just damage to components like the isolator.

In order to reduce the voltage drop, use a large cross-section multistrand copper wire. I've been putting 8ga wire in my caravan instead of the 6mm2 stuff that I was using and the drop over 6m is negligible (0.3V).

Yours would look like this:

Main Batt -> isolator -> fuse -------------------------------------------------------> anderson plug ----------> d250S -> battery

 

[maulbeagle]

Thanks, I'll give it a go.

 

[maulbeagle]

Another qu4stion

Hi all,

an auto sparky today told me that the reason these newer cars have 2 cranking batteries is that the computer systems draw so little current that the alternators have reduced output now, meaning that the batteries don't get as much charge. The second battery is there so that between the 2 of them there should still be enough juice to crank the engine over.
Anyone heard this or have any ideas about this ?
Is there an easy way to tell what my alternator output is ? He seemed to think something low like 50A vs the 105A stuff cars used to need.
If that's the case, then the alternator would likely never have enough output to charge the 2 cranking batteries, run the electronics, and charge an auxiliary battery, and a DC-DC charger would be a necessity ?

Let me know what you think.

Cheers

 

[Foxbat]

Dual Batteries

Sounds to me like the Electrician has got his hand on it real hard. With the amount of extra electronics in vehicles these days, air-cons, electric windows, computers (engine, transmission, body) door locks etc, etc, the requirement for electricity has increased 3 fold over the last decade. This has resulted in manufacturuers putting larger alternators in the vehicles to cope with the load. Mine I think is 120 Amps. If you go back a few years you'll find a 60-80 Amp was huge. Holden HQ's were 35 Amp unless you had a Statesman (the V8's I think had a 55 Amp).

Also, if the batteries weren't charged enough they would die a rapid death so the comment about them not getting as much charge is crap too.

What size are the batteries? If they are of a standard size they would hold enough charge and the engine wouldn't need two to start.

Load of crock I say.

Have a look on the alternator and the output is usually written or stamped on them somewhere.

Foxy

 

[bods]

Hi all,

an auto sparky today told me that the reason these newer cars have 2 cranking batteries is that the computer systems draw so little current that the alternators have reduced output now, meaning that the batteries don't get as much charge. The second battery is there so that between the 2 of them there should still be enough juice to crank the engine over.
Anyone heard this or have any ideas about this ?
Is there an easy way to tell what my alternator output is ? He seemed to think something low like 50A vs the 105A stuff cars used to need.
If that's the case, then the alternator would likely never have enough output to charge the 2 cranking batteries, run the electronics, and charge an auxiliary battery, and a DC-DC charger would be a necessity ?

Let me know what you think.

Cheers

You better tell your electrician to change hands... the reason d22s have 2 batteries is because of the colder climates they are sold in. They have 2 smaller batteries instead of one bigger one like the d40 and older d22s had in them. I believe the d22s have a 110a alternator in them. I have a 2010 model which has 2 batteries which I have put a standard type isolator in to isolate the second battery. The second battery has no problems getting charged properly, neither does the main battery. Well, as much as the alternator can do anyway.

Just follow the instructions as posted earlier in this thread and you will be fine, you're not the first one to want to do it and yo won't be the last

 

[Old.Tony]

From memory, D22s had a 90A alternator (and people were dropping the 120A alternator from the Patrol in them when they busted). The D40 has a 130A alternator.

I agree that the electrician is likely to be misinformed. As bods points out, the D22s were sold with two for the extra cranking capacity in cold climates. Krankin tested his - up to 550A drawn to turn his '22 over. That's a large amount of current and it gets worse when the engine is freezing cold (heavy oil = hard to turn over). Two batteries to share the load makes sense.

Battery technology is improving. Take a look at the Optima D31A. I've got one of these suckers in my caravan as a deep cycle battery - but it can deliver 900CCA! Sooner or later we'll probably all be using spiral-wound AGMs, they are SO rugged. The military does.

 

[maulbeagle]

Thanks for the replies everyone.
Tony, you were spot-on, I just checked and the Alternator is 90A.
The batteries are SIAM GS Battery Co. 80D26R & 80D26L, I'm assuming that R & L mean Right and Left ? Also, I can't find (in English) any info on them so I don't know what CCA they are and whether 1 is enough so I can remove the other for something else ?
Is that 90A alternator capable of the additional load of an Engel (only 38L) and/or an auxiliary battery ?

Cheers

 

[bods]

Thanks for the replies everyone.
Tony, you were spot-on, I just checked and the Alternator is 90A.
The batteries are SIAM GS Battery Co. 80D26R & 80D26L, I'm assuming that R & L mean Right and Left ? Also, I can't find (in English) any info on them so I don't know what CCA they are and whether 1 is enough so I can remove the other for something else ?
Is that 90A alternator capable of the additional load of an Engel (only 38L) and/or an auxiliary battery ?

Cheers

In Australia you will be fine with 1 cranking battery. I have had mine as a single cranker for over 12 months now and not had any problems. You can either just put an isolator in and leave the standard battery in or change the 2nd battery for a different type as well. The alternator can easily handle the load. The only time you may run into issues is if you have a heap of spotlights on at night during a storm with the demister and wipers flat out. That is when you will have the most load.

If you really want to know how much draw you have, remove the alternator belt and clamp an ammeter on one of the battery cables, that will show rough draw with no charge going in, unless you can drive with it on there to see load while driving.

 

[Old.Tony]

I wouldn't drive any auxiliary equipment off the same circuit as your cranker, because if you NEED to get out and you've flattened it, you could end up in a dangerous situation. Imagine an evacuation ordered because of bushfire or flood - and we've had BOTH of those in recent weeks! No, isolate the battery as bods suggests and only use the second battery to power auxiliary equipment.

The Siam 80D26 batteries look like they're 70Ah 570CCA 135RC batteries weighing 18.6Kg. The 70Ah is the key figure. That's the number of amps that can be drawn out of the battery over a 20 hour period before the battery registers as "flat" (10.75V). You should only let that battery reach 50% charge as it's a normal battery, not a true deep cycle/agm. That gives you 35A of power - my Engel draws about 1.5A when running, so at a rough guess on a normal (say under 30C) day you should use about 18A in 24 hours.

 

[maulbeagle]

So Old.Tony, based on what you mentioned earlier about how much power is required to crank the engine, one of these batteries is only just enough ?

70AH ? Are they a hybrid battery of some sort ? I would've thought Nissan would've taken the cheap way out and just put pure cranking batteries in ?

Also, AGM batteries (like the Optima D31A you mentioned) - can they go under bonnet ?

Cheers !

 

[bods]

This is the part number equivalent of what's in mine, whether the specs are the same as the stock ones I'm not sure, but the model number is the same, 75d23 r and l for right and left... http://www.centurybatteries.com.au/search/index.php/batteries/ID-51-1483

As I said I've had no issues in over 12 months, it may actually be closer to 18 months now