Thread: Defender second battery location

Originally Posted by Rexy

Seems like there a few down sides.
1, draws power from starter to 50%. Who would intentionally want their starter at 50%, may as well save on weight and put a swift battery in there.
2, draws power from second battery for starting -a lot/most deep cycles are not covered under warranty for use as a starter, nor are they intended for this purpose.
3, will not give me the required 14.7v that the agm requires.

Im sure its a great system for people running old tech batteries but its really just a fancy vsr close to dc to dc price with no solar ability.

Hi Rexy and it is obvious that no matter what advantages are shown to you, your heart is set on using a DC/DC device, without any regards for having a far better system. So be it, but at least others reading this thread can now make a far better educated choice when trying to decide which system is the best for their needs.

Also, can you please list any AGM batteries that require 14.7v to fully charge them. There are none on the market that I know of?

I choose not to draw down my starter OMG.....I had a traxide in my last defer but have fitted a basic redarc to my current defer. Yep going against the grain whoopie doooo, but this is a personal choice and I’m with the OP on this one.

Re: DC-DC, I have never run one of these and agree that limited the charging rate and I prefer to get maximum out of the alternator.....although a few people I know that run DC-DC (mostly 40amp units) seem to be fully charged each time they pull up to camp. So all hype about batteries won’t recover I haven’t seen, and with nearly everybody having solar I think most out there seem to get by.

Just because the OP doesn’t have the perfect arrangement of components that one seems to have to have in a Land Rover doesn’t mean we need to write him off.

I’ll have to read back through the posts and see how much assistance there has been to optimize his current set up/investment.

Funny thing is...nah won’t go there

Traxide, follow this link ctrl f and search for agm.

https://www.centurybatteries.com.au/...y-charging.pdf

Everything it says about agm your system can't do.

AGM batteries should be charged using a chargerwith a mode switch for AGM type batteries. It is recommended to usea charger, current limited to 20% or 0.2C of the batteries capacity at acharging voltage of between 14.6 – 14.8V following deep cycle use, or13.6V – 13.8V for standby use. Charging should be paused if the batteryor ambient temperature exceeds 50°C.

Everything I can find online says AGM should be charged to over 14 volts.

The ctek does all the things agm require so I should see a lot more battery life and easy recoup the savings over the traxide kit- not to mention the solar ability.


Tombie, Its not me not listening, read the original post. From the outset you've never even answered what Ive asked, just crapped on about a system I do not have nor want. I understand Traxide is trying to sell a product but it does nothing I want and I never asked about it.

If cycling is so good for a traditional start battery why is there the move away from them in stop start. Everyone knows it isn't ideal to run down a starter battery. Run them flat too many times and they wont last at all.

Er whoops, I thought Rexy already had the DC-DC.

If it was me this is what I’d do on a dirty of tdi

- upgrade alternator to a 100amp/hr disco, I did mine when the OEM one failed, if you have the coin that upgrade sooner
- two batteries will fit but I relocated the AUX that previous owner fitted under the passenger seat to the cargo area. A normal size battery won’t fit under the drivers without serious mods
- fit a redarc battery isolator either the basic or the one that allows back charge from solar to dart battery
- fit Victron regulator
- fit Anderson plug somewhere convenient to plug solar into.
- run cable from fridge to load side of regulator
- fit fuse box if want more circuits.

Oh two batteries under the seat doesn’t leave a lot of room for much else....so to answer your main question, it’d be tight adding a c-Tek in there as well and be a pain when you need to work on the system.

The above set up seems to work well for me, give me the capacity I require, leaves the starter alone, seem to get good life out of batteries...although I do swap them out st three years regardless.

Hi W&KO and it is not so much a case of writing the OP off, it is just that there is no logical reason for using a DC/DC device in any Land Rover.

Those using them may or may not achieve fully charged batteries but one of the misconceptions that a DC/DC will treat the batteries better than an alternator can, because they THEORETICALLY go into float mode, is a myth.

If you use even any reasonable SMALL amount of auxiliary/house battery capacity and then drive to recharge the battery with a DC/DC device, it is HIGHLY UNLIKELY that you will ever drive long enough for the DC/DC device to get the battery charged to a state where the DC/DC device can go into float.

Just one of the many myths used to sell a device most people never needed in the first place.

I didn’t say run down, I wrote cycle. Big difference.

AGMs like any Lead/Acid battery can be charged by voltage differential, that’s all it takes.

I didn’t say buy Traxide at exclusion of all others - that’s your choice - I was only pointing out the unnecessary DcDc device - heck, in a TDi a simple solenoid will do the job.

Add a solar controller and you’ll be golden.

AGMs aren’t magic. Or new tech.

I’m not going to waste time typing any more as your google research has given you what you want to hear.

Originally Posted by Rexy

Traxide, follow this link ctrl f and search for agm.

https://www.centurybatteries.com.au/...y-charging.pdf

Everything it says about agm your system can't do.

AGM batteries should be charged using a chargerwith a mode switch for AGM type batteries. It is recommended to usea charger, current limited to 20% or 0.2C of the batteries capacity at acharging voltage of between 14.6 – 14.8V following deep cycle use, or13.6V – 13.8V for standby use. Charging should be paused if the batteryor ambient temperature exceeds 50°C.

Everything I can find online says AGM should be charged to over 14 volts.

Hi again Rexy and not having a go at you but you either have no real understanding of how batteries are charged or don’t quite get what you are reading about.


The link is to how to charge a battery with 230vac battery charger.


Furthermore, 14.7v is not the REQUIRED charge voltage, it is the MAXIMUM SAFE voltage that most AGM can be charged with and all AGMs can be FULLY charged with much lower voltage.


A perfect example is an Optima Yellowtop. It can be safely charged with voltages up to 15.1v but can be FULLY CHARGED with 13.65v and these are the manufacturers specs.


DC/DC devices are regularly peeled as being JUST LINK A BTTERY CHARGER, and they operate initially in a similar manor.


But there is one major, MAJOR difference. Its the time required to charge a battery.


With a 230vac battery charger, there is no real time restraint and a battery can achieve a fully charge state.


With a DC/DC device, as I have pointed out repeatedly you are highly unlikely to ever drive long enough to fully charge a battery with either a DC/DC device or an alternator, but an alternator will always have your battery in a MUCH higher state of charge at the end of a drive and the higher the state of charge BEFORE its next use, is far healthier for any battery.


This following info is for yours and manics benefit. This shows how a DC/DC device REALLY works and makes a mockery of the mythical claims about DC/DC devices and their multi stage charging mythical “BENEFITS”.






WILDESIDE - OPTIMA D34 TEST CHARGE - 06/07/19.
Optima D34 55Ah Yellowtop charged from 30% SoC after being discharged down to 11.71v using a 2 amp load, drawing a total of 35.7Ah from a fully charged state, reached at 08:27, Voltage settled up to 12.67v by start of charging cycle with a Sterling Wildside - 25 amp Battery to Battery Charger -.


The Wildside was powered via a bench power supply, so that there was a constant 14.5v to see how quick the Wildside could recharge a battery in perfect conditions.


The first column is the TIME, the second column is the TERMINAL VOLTAGE at the battery, the third column is CHARGING CURRENT, the forth column is the amount of used battery capacity replaced at each time reference and the last column is the percentage of replaced used battery capacity.


11:02 11:83v 00.00a 0a
11:04 12.67v 19.35a 0a
11:34 13.06v 19.16a 9.591a 25.5%
12:04 13.55v 19.07a 19.160a 51.0%
12:34 14.94v 14.88a 28.285a 75.2%
13:04 15.00v 06.02a 33.270a 88.5%
13:34 15.04v 02.37a 35.216a 93.7%
14:04 15.09v 01.09a 36.027a 95.8%
15:04 15.12v 00.46a 36.723a 98.0%
16:04 15.14v 00.28a 37.083a 98.6%
17:04 15.15v 00.22a 37.326a 99.3%
18:04 15.15v 00.17a 37.518a 99.7%
18:25 15.15v 00.16a 37.579a 100%


The Wildside went into FLOAT at 18:26

EDIT :- here is the graph for the test above and note the time taken before the DC/DC device went into float!

D34.b.jpg

Originally Posted by Rexy

If cycling is so good for a traditional start battery why is there the move away from them in stop start. Everyone knows it isn't ideal to run down a starter battery. Run them flat too many times and they wont last at all.

Rexy I have no idea where you are getting info from but this is the complete opposite to reality.


All cranking batteries can be used in deep cycle application, and before about 2000, the only batteries used for auxiliary batteries in vehicles and house batteries in caravans, motorhome and in marine use, were cranking batteries.


The only disadvantage that cranking batteries have over deep cycle batteries is the the size and weight vs Ah capacity compared to a deep cycle battery.


If you have a deep cycle battery and a cranking battery of the same physical size the cranking battery will have between 10 to 30% less Ah capacity than the deep cycle battery.


But unlike most AGM deep cycle batteries which have charge current limit and the best are just 35% of the total capacity, cranking batteries, regardless of whether they be wet cell or AGM, have no charge current limitation and are self regulating.


This means a cranking battery can be used as a deep cycle battery but can be SAFELY recharge ( faster recharged ) with much, Much higher currents that a standard deep cycle battery can be.


As for the change to STOP/START batteries. This has absolutely nothing to do with older cranking batteries MYTHICALLY not being able to be deep cycled.


STOP/START batteries have an even faster recharge capability and this means they will recharge in an even shorter time than a standard cranking battery.


To further debunk this myth that cranking batteries can not be used as deep cycle batteries. For decades now, European cranking batteries were/are marked with both their CCA rating and their Ah capacity.


This is because the Europeans have and still use cranking batteries as deep cycle batteries, they call them Leisure Batteries.