Discovery 3 - additional dual battery addition - unexpected!

[Aussie Jeepster]

At present I have a D3 4.0L ptrol, fitted with a traxide system, and the additional battery under the hood on the driver side.
Today, I paid $10 on Gumtree and collected an unused Hardkorr battery box which looks like bloody good value for $10!!!!!!
I now trying to figure out how to make the most of it.
Any suggestions? (and "send it to me and I'll give you $10" doesn't count!!!)
I've got the outlet from the Traxide in the rear of the truck, and that is where the Engel plugs in, plus any other goodies I want to add.
I'm thinking of putting a battery in the box, and mounting it in the rear as an extra power supply - but do I need a DC-DC to keep it charged, or can I just plug the battery box into the rear Anderson plug from the Traxide install????
I'm thinking there is room under the top of the box to mount a DC-DC unit, but do I need one???


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Any comments greatly appreciated.

[BigJon]

I'm thinking there is room under the top of the box to mount a DC-DC unit, but do I need one???


No. You don't.

[loanrangie]

Just run another cable from the output side of the traxide controller to the extra battery, earth it and bobs your lbgtqyxz aunty.

[DiscoMick]

Just run another cable from the output side of the traxide controller to the extra battery, earth it and bobs your lbgtqyxz aunty.X2

[drivesafe]

Hi Jeepster, as the others have suggested, simply plug the Anderson plug at the rear, into your new battery box and job done.

In this setup, all three batteries will act as one big battery and will charge together when the motor is running.

PS, that’s a nice looking battery box.

[rocket rod]

My guess is the battery needs to be an AGM to remain compatible with the rest of them?

[drivesafe]

My guess is the battery needs to be an AGM to remain compatible with the rest of them?
Any lead acid battery will be fine. Not just AGM.

Be cause the alternator is the primary charging device, it can be an AGM, wet cell, Calcium/Calcium, gel and it can be a deep cycle or a cranking battery.

ONE WORD OF CAUTION, Jeepster, from your photos and pictures of this battery box elsewhere, it does appear to be totally sealed.

If this is the case, you could put some air holes in the box, both at the top and low Dow on the sides or ends.

For safety reasons. Battery boxes MUST NOT BE TOTALLY SEALED.

BTW, I can not find any info on the size of the circuit breaker, can you check it out?

[DiscoMick]

My guess is the battery needs to be an AGM to remain compatible with the rest of them?Yes, don't use a lithium because that would require a DC-DC charger.
Try to make the new battery the same type and size as the other second battery, so they will charge the same.

[drivesafe]

Yes, don't use a lithium because that would require a DC-DC charger.
Try to make the new battery the same type and size as the other second battery, so they will charge the same.
Hi Mick, because the primary charging source is the alternator, you can have any mix of different types of lead acid batteries and all will be charged properly.

It is only when the primary charging source is a battery charger, a DC/DC device or a solar regulator, that the batteries should be of the same type.

They can still be different sizes.

NOTE, While not ideal, but if you know how to set up a DC/DC device or a battery charger or even a solar regulator, you can actually charge a mix of different types of lead acid batteries at the same time.

[theelms66]

I see the box has a 50 amp charge plug that says VSR BUILT IN . Does this mean this battery wont receive charge until the other 2 batteries have a reasonable SOC?

[drivesafe]

I see the box has a 50 amp charge plug that says VSR BUILT IN . Does this mean this battery wont receive charge until the other 2 batteries have a reasonable SOC?
Again because the primary charging source is the alternator, the battery in the box will start receiving a charge shortly after the motor starts.

Where any potential problem can arise is if the battery in the box has been used independently of the other two batteries.

In situations like where a fridge is powered from the battery box, and the BLACK socket is being used to charge the battery box, the other batteries will not provide any power to the fridge one the motor is turned off.

The battery in the box will continue to power the fridge and will become discharged at a lower level than the other two batteries.

When the motor is again started, because the cranking battery is in a near fully charged state, the D4's BMS will see this and run the alternator at a lower operating voltage.

This will in turn, both cause the battery in the box to charge at a slower rate, if at all, and if the D4 drop the alternator voltage below 12.7v, the battery in the box will not charge at all and as it is likely to still be powering a fridge, it will just continue to be discharged further.

The best operation is to use one of the battery box's GREY Andersons and this will mean all batteries will be used to power the fridge while the motor is off.

When the motor is started, the D4's BMS will see the cranking battery is not in a fully charged state and will run the alternator at a higher voltage for a longer time, and this will result in all three batteries being rapidly charged, in a short drive time.

I am still a little concerned with the visible size of the cables running from the GREY Anderson plugs to the circuit breaker and the size of the circuit breaker.

[Aussie Jeepster]

Following this with interest - and thanks.
Drivesafe, it's a D3, so it is a not so smart alternator.
Alan

[drivesafe]

Hi Jeepster, and while a D4 BMS is a lot smarter, the D3 also has a smart alternator and you get some interesting voltage reading when the batteries are down a little and you start your motor.