Thread: Beware Charging Dual Battery in D4.

Thanks Drivesafe. Had that very situation on the D2, cranking battery died and as the system is made up using HD battery cable the car continued starting without any signs. So also made up a volt meter that can be switched to either battery, so voltages and charging volts can be monitored. The meter is mounted in a small box form Dick Smiths, so it looks ok as well. Will set this up in the D3, only problem is the D2 had a 12 inch battery, so not sure where I can mount this and the battery is quite new. Any ideas?

Hi Drivesafe, a slow reply.. i've been out and about.

The facts remain:

The SC80 PARTIALCHARGER dischargers your main battery. The D4 has a mind of its own when it comes to keeping lights and other accesories running. I still want my main battery as full as possible. The DC-DC charger delivers that.

The SC80 PARTIALCHARGER will never get a battery upto 15.2V because the D4 never charges up to that voltage. This is a FACT as I've witnessed it while driving my D4. The DC-DC charger does as I've also seen that. Are you confirming that the SC80 PARTIALCHARGER will reach 15.2V?

The SC80 PARTIALCHARGER will suffer from voltage drop if the second battery is placed more that a metre or so from the main battery. The DC-DC charger will deliver full voltage as you can place it close to the battery to be charged and it will deliver full voltage.

The SC80 PARTIALCHARGER will provider faster initial charge before it stops when partialcharge has been achieved. The D4 may be able to deliver 180AMP but I never want to go near the upper end of that capacity... I'm not THAT confident in Landrover electronics and computers. I know that the DC-DC charger will never compromise the vehicle electronics because it has a set draw limit. The SC80 PARTIALCHARGER will expose the electronics to whatever is connected.

You are correct that my current DC-DC charger has an issue. I identified that. It is still fully charging my batteries... it is just taking a little longer than it should due to the charge stopping at times due to the D4 voltage dropping below 12.7V. A solution to this is being found but is a refinement.

I'm about to head of for 3 weeks of bush camping... I'll let you know how the DC-DC charger goes... I sure hope I don't come back asking for a SC80 PARTIALCHARGER!

RoverLander, you really have been sucked in by the advertising hype surrounding these DC-DC toys.

I have no idea what your reference to the SC80 as being a partialcharger is about, if anything, that’s what your DC-DC toy is. If your auxiliary battery is low, you will never drive long enough to get your auxiliary passed a partial charge.

If anything, the SC80 should be called a multiple battery BULK CHARGER, and something your toy could never hope to do.

For a starter, if you have “A” low battery, and I emphasise a “single” battery, because that’s all these DC-DC toys could hope to charge, but if you have a low auxiliary battery, you will have a MUCH bigger voltage drop at the auxiliary battery with a DC-DC device than you will with an SC80.

I’ll clarify this point, I am not talking about the voltage drop at the input of the DC-DC device, I’m talking about a large voltage drop at the output of the DC-DC device. This is the voltage at the auxiliary battery.

As posted earlier in this thread, these DC-DC devices CAN NOT deliver high voltages while charging, until the battery is nearly fully charged, so an SC80 does not charge your auxiliary battery with as low a voltage as these DC-DC toys do. Get your FACTS right.

You really need to learn a lot more about the way your toy works before you comment about the SC80 or anything else in this field.

You, like many others, have been conned by the advertising hype.

Also, if you don’t trust the D4, why the hell did you buy one.

The facts remain:



The SC80 PARTIALCHARGER will never get a battery upto 15.2V because the D4 never charges up to that voltage. This is a FACT as I've witnessed it while driving my D4.
the charge stopping at times due to the D4 voltage dropping below 12.7V.

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Hi RoverLander
Have read this post with interest, because I have second battery in car and 315A\H batteriers in van, no troubles in last 4yrs, (in D3,last 10mths in D4),with SC80,so I thought I would check myself, I put up the diagnostic menu on satnav, there is a section for "vechicle readings" then , "battery voltage."
When I first brought up screen (car off) 12.1v, start car voltage worked itself up to 15.4v, then when driving along fairly flat ran at 14.8v-14.4v, after a 55km trip most of it at 100k\h Hiway) stopped turned off, battery voltage at 12.6v., pretty much the same readings on the way home, but there is a big long steep up hill, so I floored up there, even at 3800 rpm, voltage never dropped under 13.7v.
Hence D4 can generate more than 15.2v, and mine never dropped under 13.7v, maybe you have a problem elsewhere.
Cheers Ken

Hi roamer and thanks for that info.

The point is, I have well over a thousand D3s equipped with my gear, both here and overseas, and in all sorts of climates from the heat of the Middle East to countries up in the Arctic Circle and no one has ever reported a problem relating to a design fault.

There are now quite a few D4s fitted out and again, no problems reported.

That gives my gear a 100% success rate, whereas RoverLander has tried one set up with his gear and because of a design incompatibility, it’s not working, so correct me here but that gives his set up a 100% failure rate.

It’s not rocket science to workout which system works and which system is an expensive mistake!

Originally Posted by roamer

The facts remain:

I thought I would check myself, I put up the diagnostic menu on satnav, there is a section for "vechicle readings" then , "battery voltage."
Cheers Ken

Thanks for this Ken... This is very good information. I have searched for "diagnostic menu" on my satnav and can't find it. I assume you are talking about the built in Satnav? I'd like to have a look at my readings. If they are as you say then I've definetly been led up the garden path and I think I would owe Drivesafe a case of beer.

Are you able to tell me how to get into diagnostic mode?

Originally Posted by RoverLander

If they are as you say then I've definetly been led up the garden path and I think I would owe Drivesafe a case of beer.

Hi RoverLander, you won’t owe me anything.

I have been bitching about the misinformation that is being used to promote these DC-DC toys for a couple of years now and while your the meat in the sandwich, you prove my point but I see no reason why should owe me anything.

If nothing else, thanks to your thread, a lot more people will be wary of the short falls in the info being put out about these devices.

Cheers.

Originally Posted by roamer

...I put up the diagnostic menu on satnav, there is a section for "vechicle readings" then , "battery voltage."
When I first brought up screen (car off) 12.1v, start car voltage worked itself up to 15.4v, then when driving along fairly flat ran at 14.8v-14.4v, after a 55km trip most of it at 100k\h Hiway) stopped turned off, battery voltage at 12.6v., pretty much the same readings on the way home, but there is a big long steep up hill, so I floored up there, even at 3800 rpm, voltage never dropped under 13.7v.
Hence D4 can generate more than 15.2v, and mine never dropped under 13.7v, maybe you have a problem elsewhere.
Cheers Ken

Originally Posted by RoverLander

... I have searched for "diagnostic menu" on my satnav and can't find it. I assume you are talking about the built in Satnav? I'd like to have a look at my readings. ...
Are you able to tell me how to get into diagnostic mode?

Anyone else know about this "diagnostic menu" and how to get to it?

This weekend I went camping about 3.75hrs drive each away (combination of tar & dirt, 40-110km/hr, steep hills & long flats, i.e. all terrain covered).
I plugged a digital volt meter into one of the accessory plugs near the D4's transmission lever. The voltage observed only ranged between 13.74 & 13.86V, now matter whether accelerating, braking, coasting, idling, or doing anything else. With the engine off I got a voltage of 12.6~12.7V.
So, either the accessory plug supply is regulated during alternator charging, or I'm getting very different results to Roamer.
I'm confused, can anyone shed some light?

By the way, I've enjoyed the education I'm getting from this thread.