Thread: where to fit dual monitor

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.