Thread: Battery chat... Andrew St P White.

Tim has already commented on another thread within the last week about how he could have improved/simplified the electrical setup. Given that ASPW is living in Perth now, maybe we can drop him a line and suggest some improvements/mods to his rig.....

Hi John and Cripesamighty, and thanks for the link to that video.


I don’t know the two gents and I think their video was made with good intentions, but at the beginning of the video, one of them states that he has no real vehicle electric knowledge and that is where the video should have ended.


They were making statements that are nothing like reality.


For example, both of them went on about how hard it is to recharge a deeply discharged deep cycle battery. It has been 15 or more years since old type deep cycle batteries suffered from that problem.


New type deep cycle batteries, wet cell or AGMs, will take high currents while charging, even when they are in a low state of charge.


Then they were rattling on about how you can only recharge Optima batteries properly with a battery charger.


Nothing charges an Optima Yellowtop quicker than your alternator, especially when the Optima is in a low state. One of them suggested fitting two 55Ah Optimas but both went on about how well a Ctek can charge batteries.


Well here is some basic comparisons between what a Ctek 20 amp DC/DC device can do and what a D4 alternator can do.


If you have two flat ( discharged to 10.5v or 0% SoC ) Optima Yellowtop 55Ah batteries and you want to recharge them while driving. With the 20 amp Ctek, you will need to drive for around 7 hours to get them back over 95% SoC, and charging them via the D4’s alternator will recharge them in less than 2 hours.


Sorry but I just can’t see how the Ctek is of any use and even if you used a 40 amp DC/DC device, you are still looking a close to 4 hours of driving.

To give my 2c on Optima (etc) batteries, specifically using them as second batteries, I can only give you my experience. To date I have purchased 3 Optima yellow tops. The first one was in 2008, this was used as the second battery in my Defender, to run a fridge, CB etc, and was charged by the alternator via a National Luna Dual Battery Relay.

In about 2014 this battery was donated to the workshop forklift when its battery died and It's still in use today, and as far as I know has never been charged by anything other than an alternator. The second Optima I ever purchased is now in the Defender, connected to the same Dual Battery Relay.

The third Yellow Top Optima I purchased is in the Series 3. It started the S3 after it sat idle for a decade, then again after a 6 week journey from NZ to Australia. It hasn't been in a running vehicle since Nov 2016 and still measures 12.7V at the posts. Long may it live.

Yes they are expensive, and yes some people seem to have had trouble with them, but I like them.

Cheers,

Hi Tim and thanks for your post. It confirms my claims that an alternator will do a far better job of charging auxiliary batteries, than any DC/DC device can do, particularly in Land Rovers, with their high charging voltages.


But even in the case of Andrew’s Toyota, he can “trick” the alternator into running at a higher voltage by fitting a $50 Alternator Voltage Booster Fuse, which will cause the alternator to run at about 0.6v higher than it’s normal operating voltage, and this will keep ALL his batteries at a higher state of charge, not just his auxiliary battery.


Even with the newer Toyotas, where, at this stage, there is no way to “trick up” the voltage, and this means the new Toyotas run at a lower constant operating voltage, but they still charge auxiliary batteries quicker than a DC/DC device can.


This has been proven on the Prado forum, where a member with a new Toyota Prado, who had been running a DC/DC device for about 6 months, and then swapped it out to test one of my isolators.


In a very short time, he found his auxiliary battery was being recharged in a fraction of the time that was possible when using his DC/DC device, but because of the way my isolator works, he also noticed his cranking battery quickly gained a higher settled voltage.


This all means he had far more battery capacity than he ever had with the DC/DC device, but because his cranking battery is now maintained in a better condition, his motor is going to be easier to start and his cranking battery is going to have a longer lifespan.


In the video, it’s obvious Andrew has been fed a load of misinformation and like most people, he has no way of knowing this.

Originally Posted by cripesamighty

Tim has already commented on another thread within the last week about how he could have improved/simplified the electrical setup. Given that ASPW is living in Perth now, maybe we can drop him a line and suggest some improvements/mods to his rig.....

One thing I would say about ASPW. He would welcome the info.

An interesting discussion between two supposedly knowledgeable people (I'm not familiar with either of them, presumably South African/English off road gurus) and I thought the thrust of their discussion was quite good.

Originally I thought this was a (at least) 15 year old video by the comments on deep cycle batteries with no qualifying mention of battery construction or type so I was quite surprised when both Optima and lead crystal batteries were mentioned. This put the whole discussion into a different category, "a little bit of knowledge is a dangerous thing" was my first thought with the outdated and irrelevant specifics they both prattled on with. The intention was undoubtedly good but these two have basically no idea on the specifics relating to modern batterys and their management.

As others have noted there's nothing quicker than a dumb alternator to charge an automotive battery and I am often amused by the overly complex and expensive electronic lengths some go to to achieve this end. Whilst it may be necessary to have smart devices to overcome the multiple battery installations in modern vehicles such as the D3, D4 etc for older Defenders and Discos much cheaper and effective solutions are out there.

DC-DC chargers seem to have become the magic bullet for all charging woes and whilst they are very good devices when used appropriately they are not the answer to substandard or undersized wiring problems and as Tim points out they are inferior to a simple alternator connection when it is appropriate.

I wish I'd thought up the concept of using a diode to boost the alternators output. A very simple and no moving parts solution to gain an extra 0.6 volt (or more ) and particularly useful when connecting a diode type battery isolator. Being able to sell 2 cent diodes with a little bit of packaging for $50 or so is IMO a genuine marketing triumph.

I'm with TimNZ here on Optima batterys, I also bought my first two (66ah blue tops) in 2008 and have done approx. 100,000 Km with them over the best and worst roads, tracks and off road Australia has to offer and they are still in good condition as the house batterys in the Oka. At the same time my mate bought a 66 ah yellow top Optima for his Patrol which he gave me as 'stuffed' but with a little run as the Oka start battery (and alternator charging) it is as good as the other two.

As for CTEK type smart chargers I've only had experience of two. One was a genuine CTEK which had a maintenance type mode which the owner had left connected to his camper batterys. Unfortunately there was no timer on this mode which was actually an equalisation mode and proceeded to cook his otherwise healthy batterys. A very expensive and poorly designed crap charger IMO. The other was a CTEK clone which worked OK but turned itself off every time the power flicked, not very good in rural applications with constant outages. Also a crap charger IMO.

So IMO, from a general perspective its a good video. Unfortunately its out of date and specific examples detract from an otherwise good tutorial.

Deano