Low voltage alternator

[itsdave]

Could anyone tell me whether the alternator on the 2.5 D22 is low voltage or not. I'm looking at fitting a dc-dc charger for a duel battery and believe there are different chargers more suited to these alternators.

Cheers Dave

 

[bods]

Nope, not on the d22s... There's barely enough electronics in them as it is...

 

[nofx]

^^^Hmm, I certainly wouldn't fight you over it, as I can only go on what I was told, and I might not be remembering it correctly. But redarc told me (and I think maybe my auto sparky confirmed it, can't remember for sure) that the D22 either has a LV alternator or a variable output alternator. Either way, I don't think the redarc LV or variable voltage DC chargers cost much extra over the standard one (if at all, they just require an extra control wire I think), and they will do the job required regardless. Their standard DC-DC charger however, will not do the job if a LV one is required. That's my recollection anyway.

 

[Old.Tony]

I think it'll depend on the year model of the car too. There are plenty of 2.5L D22s out there with "normal" operating alternators (90A, I think they are).

Don't know what they've done in the latest model of trucks, but in ALL of them there's an easy way to tell what's what. You have to rely on the battery being in reasonable condition and the engine being "easy" to start (ie no more than about 3-4 seconds of cranking). 4 seconds of cranking at 500A = about half an amp-hour, which should take all of a couple of minutes to restore to the battery.

So, get ANY car (doesn't matter what model, make, anything) and start the engine, go for a 5 minute drive. Make it 10 minutes just to be sure.

Stop the car, leave the engine running. Pop the bonnet and put a multimeter onto the battery or use your choice of voltage display in the cabin. Read the voltage.

If the voltage is above 14V, you have a "normal" alternator that doesn't switch off. If the voltage has fallen below 13.5V, you're using one of the new-fangled alternators that require the LV chargers.

 

[bods]

I think they may be getting confused. The d22 is about as old school as you can get in a brand new car.... As Old Tony mentioned above, you can check it if you wish but I'm sure even people on here with 2013 models have checked them and advised that they are a standard alternator... It's not like Nissan need to make the d22 any more fuel efficient....

 

[happy john]

The 22 will put out about 14.2 it's not a smart alternator the dc to dc charger will top up your aux faster but a standard redarc will still work ok.
John

 

[Redneck92]

Got the 1999 D22 navara. Few days ago I changed the alternator because the old one did go bad on me. The old one had arround 12,8 volts output and it was an 60amp alternator. I put a 90amp alternator in wich is producing (as it should be) arround 14,2 to 14,5 volts.

 

[happy john]

Old thread I thought I would open up rather than start a new one. Voltage booster diode, does anyone use these or are they a waste of money. The reason I ask is I am powering 2 120 a/h agm's and the 3 way fridge in the van that draws 10 amps I am getting 13.8volts IMO this is not enough for an agm. I only have a basic redarc isolator with very heavy cable. Should I just grab a ctek dc dc. The claim is .6volts more which should see around 14.4 at the 2 agm's.
HJ

 

[Old.Tony]

John I'm suspicious of those things. A DC-DC charger will treat your battery far better.

The way I look at things is like this: I am depending on that auxiliary battery to provide power to keep my food from spoiling. If my food is bad, I'm going to be quite angry that I could have spent a couple of hundred bucks and avoided the problem, and now not only do I have to go looking for a shop, but my memory of the particular trip is spoiled forever.

 

[happy john]

I think I will fit a ctek I know 2 120ah batteries plus 10amps of fridge is a lot for the poor alternator, I tried running The fridge on 240 with the invertor while travelling and it drew more power. I did have a chat to Robmacca and he is pleased with his diode with 1 battery but I think I am working mine to hard.
Cheers Tony

 

[Old.Tony]

The C-Tek can deliver 20A plus say about 2-3A of its own needs. Your fridge draws 10A? Is it a 3-way? If inverted, that's about 11-12A, so total power draw is 35A. Your alternator may not deliver that, so it will draw it all from the cranker. If you're inverting power, what about using a lower current charger, like 7 or 8A? It might be worth your time using the D250S and whacking a 130W solar panel on your roof!

 

[happy john]

Exactly mate! I was just thinking that the old engel is going as well on extended trips so it's obvious I need more grunt. The old 3 way with 3 computer fans 2 sucking and 1 blowing works well and gets 2 weeks out of 9kg gas. I think I will use your suggestion mate thanks.
HJ

 

[happy john]

This is the "claim" that I was trying to make sense of ?????.
HJ
http://www.hkbelect.com/faq/

 

[Old.Tony]

That's a dangerously misleading web page.

Let's take my own Optima D31A spiral wound AGM battery. It's one of the most robust batteries on the market - it's almost unkillable.

However, it's maximum charge rate is C/2 (total capacity divided by 2) which is 37.5A. If I plunge 60A or more into the battery, the electrolyte - which is suspended in a glass matt between the plates - will start to boil away and that will destroy the battery really fast.

It's idiocy to suggest that lesser batteries will handle the charge being thrust into them. Flooded cell batteries should not be charged any higher than C/3, preferably C/5. Gels should not be charged higher than C/10.

There is a reason for the existence of DC-DC chargers and it's not because the alternator (with or without a diode) is the perfect solution for charging your battery.

They're also not accounting for voltage drop. I've got cables running to the rear of my car to provide power not only to my tub (2x56A rated but capable of 400A) but an additional pair of 56A cables to provide power for the caravan. The first pair might see a total draw of 15A, the second pair may see up to 40A.

On the 40A draw, I'm getting a 0.3V drop over the length of the car. You add their 0.5V and take away 0.3V for a heavy cable (and bucketloads more loss for smaller stuff) and you're no better than you were before.

Just to give you an idea of the size of the conductor inside the cable I'm using - I have to remove some of it so that it squeezes into an Anderson plug. I run both positive and negative to avoid any trouble with poor earths.

There's another point missing from the equations too. In order for your alternator to put out its maximum power, you have to be revving the engine. The YD25 D22 uses a A5TA5372 Mitsubishi alternator (the most powerful available in the Navara D22 series) that puts out 29A at 1300RPM, 76A at 2500RPM and 88A at 5000RPM. Take off the operational power consumption of ECU, instrumentation - maybe 15A during the day, and 30A at night (without the stereo going) and you have about 45A left at cruise, and nothing left at idle (so you're not allowed to stop, ok?).

Magic pills are great, but sometimes I just wish they'd tell the whole story.

 

[happy john]

Yes Tony I knew it was very poorly written, I am running 12mm welding cable and like you had to strip a bit to get into the Anderson plug. The other day when I saw this "claim" I thought *hit it will boil it dry. Now c/tek or redarc bearing in mind I am charging 240a/h of agm plus the 3 way in the van?. This is where I am at, and thanks for your opinion Tony I hoped you would see this and get a shock like I did.
HJ

 

[happy john]

Also some goose told me recently to run the 3 way on GAS whilst traveling. Shows you how moronic some fellow travellers are.
HJ

 

[Old.Tony]

C-Tek will do 20A, so your batteries (if you manage them properly, you'll use up to 80% tops) will take 192/20 = 9.6 hours to charge - probably more, because the DC-DC charger will charge at 20A during the bulk stage, but less during absorption stage which is the last 20% of the charge.

The Redarc BCDC1220 charges at 20A as well, and the BCDC1240 can manage 40A. With the larger Redarc, you'd have to question whether or not your alternator is going to deliver the 42-43A required (I'm guessing at 2-3A for the Redarc device itself). I'd suggest that your alternator is going to be borderline delivering that power, and may draw from the cranker instead (unless it trips the low voltage sensor).

 

[Old.Tony]

Also some goose told me recently to run the 3 way on GAS whilst traveling. Shows you how moronic some fellow travellers are.
HJ

Goose is being way, way too polite. The guy should be on suicide watch.

 

[75 GRC]

Goose is being way, way too polite. The guy should be on suicide watch.

Hahaha.good one Tony,

Cheers Geoff Go the V-6's