Dual battery replacement- Advice needed

[Dagilmo]

Hi All,

I have a yellow top second battery that is Wallaby Ted's brother, Roo....

So I need to replace that. Further when we travel we run the fridge in the car on freeze so the 55 amps struggles to cope (hence its current state, normally I'm very kind to my batteries however this battery might have an argument that I've contravened it base battery rights and subjected it to 'cruel and unusual punishment').

So, I want to increase my capacity and I'm happy to set up a second second battery in the rear. Can I get a yellow top to replace the one in the front and a second AGM of any brand for the back and wire them up? And will this be OK as long as the two batteries are new?

NB: I have a Redarc BCDC set up. I have this as I moved it from a previous vehicle. If I was starting from new I would use one of Tim's Traxide system.

What are peoples thoughts?

[Aussie Jeepster]

I've yet to fit my Traxide kit, but I'll also have one of these in the back - excellent portable backup.
DUAL Battery System Jump Starter 12V Thumper 80 AH Cigarette Anderson Dual USB | eBay

[Vern]

I run 2 yellow tops as my auxiliary batteries with tims kit. I use the yellow tops as they charge quickly.

[Slunnie]

As an Optima fan, I would also recommend against them as a 2nd battery. The optimas are great, but they don't have a lot of capacity for their size.

For the same size battery, you can get a flat plate (rather than Optimas spiral cell) that has all of the same technology, life and chargeability, but with more capacity. For example I run an Optima blue (D31M-75ah) up front and the rear Lifeline (GPL-27T) equivalent holds 100ah. After an eternity I recently replaced the Lifeline (GPL-27T) with another Lifeline (GPL-30HT), and that was 70m taller and 150ah.

Keep in mind that battery life is directly related to the % you discharge the battery.

[drivesafe]

Hi David, and while this is a blatant out and out advertisement for my gear, this post could also save you a lot of money and cargo space and weight.


Simply remove the DC/DC device and fit one of my SC80 isolators.


If you fit a second battery, Optima or otherwise, you will need to fit separate cabling from the alternator to the second battery in the rear and you will also need to fit either another DC/DC device at the rear battery ( because the one at the front battery could not be used to charge the battery in the rear ), or an isolator for the rear battery, to protect the cranking battery if you over discharge the rear battery.


After the cost of cabling, which you will need, no matter what setup you decide on, you are looking at around a minimum of $600 for a small DC.\/DC device and a small Optima, a D34.


This $600 does not include an battery mounting hardware you will need to secure the second auxiliary battery.


This would give you a total usable capacity of your fridge, of around 90Ah, BUT the two batteries would have to be on separate circuit and as one battery discharged, you would need to switch between batteries to be able to get the total 90Ah.


Now if you replaced the DC/DC device with one of my isolators, the cost ( not including the cost of cabling as this would be similar ) would be around $170 and you would still have around 90Ah available.


Also note, by fitting one of my isolators, you will now only need to run much lighter ( thinner ) cabling from the auxiliary battery up front, to the fridge in the rear, another saving.

And you will have the added bonus of being able to better maintain your cranking battery, something no DC/DC device can do.

[BMKal]

I run a Traxide system in my D4, with an Optima yellow top aux battery under the bonnet.

In the back of the vehicle, I have an Engel battery pack connected to one of the permanently powered cigarette lighter sockets that was installed as part of the Traxide kit. The fridge (40L Engel) is in turn connected to the Engel battery pack. We often run the Engel fridge as a freezer, especially on the way home from trips to Perth and Geraldton after stocking up on seafood. The system has never missed a beat. We use this system when camping and on long trips (Melrose and Tassie) run camp lighting etc from the outlets in the rear of the vehicle and the Anderson plug under the rear bumper, with the fridge running all the time - and have never had any problems in about 5 years now. Have also never had to replace any batteries (cranking or auxiliary) since installing the Traxide system - whereas the vehicle chewed through two cranking batteries prior to the Traxide system being installed. In my experience - I would not consider any other system.



I also have a "Thumper" battery pack in the shed which I have previously used in place of the Engel battery pack, but it does not seem to do the job as well and is currently dead, needing some replacement cells.

When I want to give the batteries a bit of a "top up" I simply plug either my CTek or an 80W solar panel into the Anderson plug at the back of the vehicle (part of the Traxide system) - and all three batteries are fully charged in less than 24 hours.

[Dagilmo]

Hi David, and while this is a blatant out and out advertisement for my gear, this post could also save you a lot of money and cargo space and weight.


Simply remove the DC/DC device and fit one of my SC80 isolators.

Thanks Tim. I'll give you a call in the next couple of days. I also use the BCDC as the MPPT solar charger for my non regulated panel. I guess I could still have it set up for this purpose?

[Dagilmo]

I run a Traxide system in my D4, with an Optima yellow top aux battery under the bonnet.

In the back of the vehicle, I have an Engel battery pack connected to one of the permanently powered cigarette lighter sockets that was installed as part of the Traxide kit. The fridge (40L Engel) is in turn connected to the Engel battery pack. We often run the Engel fridge as a freezer, especially on the way home from trips to Perth and Geraldton after stocking up on seafood. The system has never missed a beat. We use this system when camping and on long trips (Melrose and Tassie) run camp lighting etc from the outlets in the rear of the vehicle and the Anderson plug under the rear bumper, with the fridge running all the time - and have never had any problems in about 5 years now. Have also never had to replace any batteries (cranking or auxiliary) since installing the Traxide system - whereas the vehicle chewed through two cranking batteries prior to the Traxide system being installed. In my experience - I would not consider any other system.

Thanks Brian. It's good to hear your experience, especially with the improved life of the cranking battery. I've just had to replace mine after only a couple of years.

[DiscoMick]

I would get a specialised starting battery if I were you.

[Dagilmo]

I would get a specialised starting battery if I were you.

Do mean as a second battery? I've got a specialised starter as the starter. My long winded OP really was asking what's the best way to add capacity to the second battery set up?