where to fit dual monitor

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Originally Posted by drivesafe

Hi again Kevin and I think it’s best left where this is as you are talking about two different devices.

Isolators and voltage meters are not the same thing and I stand by what I posted, a volt meter is next to useless while driving but this has nothing to do with isolators and how they work.

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Yes its best we do and agreed it is pointess to have them alone, however volt meters do have some significant advantage while driving though, I once had my alternator fail while driving with no charge light indication on the dash if it wasnt for the visual voltage drop on the meter I would not have known until the battery voltage dropped that low it caused other problems, used in conjunction with some form of isolator they make the setup even better.

Cheers
Kevin

Well you were lucky Kevin, but based on my own experience and the feedback from customers, within just 2 weeks maximum, of fitting a voltage monitor of any type, 99% of people no longer pay any attention to these meters while driving.

In many cases it gets moved to where it can be of use while camping, hence my post in the first place.

At the risk of hiacking this thread, does it hurt the second battery (deep cycle) to be continuously charged after reaching full charge, or should one also have a manual isolator in addition to the auto isolator, so one can just do top ups from time to time. My Disco is my daily drive and I don't wish to ruin the second battery in between trips by continuously charging.

Hi Mundy and no you will not harm it.

In fact, this sort of cycled charging is actually good for most batteries because they are not on a constant charge, as like when being on a float charge.

Hey guys,

Love the search function, just a big shout out to Kevin B, Drive Safe and other contributors of this thread, great useful information.

I will run an isolator for combined minimum volt drop across the aux and crank battery, then a dedicated crank battery isolator (like what they run at the mine sites) after the crank battery has automatically been isolated from the aux when reaching minimum volt.

Every thing will be protected then.... I hope haha.

One thing I have trouble understanding (due to lack of knowledge I suppose or my interpretation when reading) is that I have read in this forum alone that it is good to 'cycle' a battery from charged to discharged but also read that it is bad on the same hand.

*** I have a yellow top Optima - Fine to let my two 50lt Waeco's drop the voltage down to 10.2V before they shut off in their 'low voltage protection mode' then charge up via my Redarch DCDC charger when driving ect?

No need to create your own new thread, just use the search function so once again great work on the forum guys, makes be proud to be a fellow land rover owner....

Cheers Lads.

Appreciated

Hi LDS and unfortunately you have cur cum to one of the biggest misunderstandings about your fridge’s low voltage cut-out.

The low voltage settings on fridges are NOT there to protect the battery, it is there to protect the fridge from voltages so low that the motor stalls and burns out.

The lowest you should take most deep cycle batteries and expect to get a decent life span out of that battery, is 11.58v or 20% SoC.

BUT, an Optima ( according to the manufacturer ) can be discharged to a flat state, 0% SoC, but this is 10.5v, not 10.2v.

Constantly discharging an Optima to 10.2v will eventually damage the battery.

Another point, because an Optima can safely take an unlimited charge current ( again according to the manufacturer ), using any form of DC/DC device will actually choke the Optima’s charging capability.

I’ve measured 63 amps during the charging of an Optima D34, 55Ah battery, when the battery voltage was at 11.58v when I started the motor, and this was down 10m of 6B&S twin ( 13.5mm2 x 2 ) cable.

The battery reached 95% SoC in a 1.5 hour drive. No DC/DC device is going to do this.

Cheers Drivesafe,

Essentially you just saved me a whole lot of coin as I will be upgrading from 1 yellow top to 3 and have been promptly told that I will need to upsize my DC/DC charger to a larger amp out put to re charge the three batteries effectively.

I don't remember what amp my D2a alternator pushes out??? but from what you have said and what the manufacturer claims, I can re charge directly off the alternator.

So basically this whole 'wet cell, lead, dry, spiral gel' (6 levels of re charge modes / auto detect battery type) diatribe is merely a ploy to have a consumer as my self fall victim to spend money where money isn't need to be spent.

Quiet simply - Wack 'x' amount of alternator amps into a yellow top for 'x' duration for effective recharge and save $500 on a DC/DC charger.

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Originally Posted by LDS

So basically this whole 'wet cell, lead, dry, spiral gel' (6 levels of re charge modes / auto detect battery type) diatribe is merely a ploy to have a consumer as my self fall victim to spend money where money isn't need to be spent.

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Hi again LDS and I am not trying to throw a spanner in the works but the different charging algorithms can be quite beneficial for different type batteries.

BUT, and there is always a but, the benefit of these differing algorithms is only gained at the end of a charging cycle.

Now if you are only using small amounts of battery capacity between uses, then yes, the specific charging algorithm for that type of battery can be beneficial and an many cases, can result in better charging of the battery than what an alternator can do.

Again, here’s the BUT. As the beneficial or superior charging only occurs at the end of a charge cycle, LDS, in your case ( and most other peoples battery type use ) you sound like you are going to be using some serious amounts of battery capacity.

This is where fiction comes into the argument about DC/DC devices doing a better job.

Whether you use your alternator or a DC/DC device, if you need to replace a fair amount of used battery capacity while you drive, NEITHER charging system will do it.

The problem is that with both charging system, you are highly unlikely to dive long enough to allow either system to be able to fully charge the batteries in the drive time.

Here is another BUT, the more battery capacity you need to replace, in other words, the bigger the user of power you are while camped, the greater benefit becomes for using an alternator as this device adjusts for the increasing demand, while a DC/DC device needs a much long drive time to achieve the same thing.

Now LDS, this may sound strange, but your increasing of your battery capacity actually improves your alternators ability to replace used battery capacity, MUCH quicker than any DC/DC device can.

Last but not least, if you want to do ALL your batteries a good turn, periodically charge them with a good quality 240vac battery charger and leave the charger on for at least 12 hours but 24 is even better.