PUMA Defender dual battery setup

[Henkules]

Hey

I'm hoping for some sound advice from the Defender community before I reach out to companies to install a dual battery system for me - I am sure they jump at the opportunity to make a few bucks out of all of us (unless you are one, or know one personally, I would gladly take a recommendation - CPT area)

I've been scrolling and searching on the forum for my question before I start a new thread, but I can only find really old, and I guess outdated threads on Dual battery systems in a defender, so I decided to create a new one - It could also help for anyone looking to install their own, or for advice.

I have a 2008 PUMA Defender and I am looking to install a dual battery system. I have two extra batteries that is connected to a solar panel - not fixed to my defender. I usually chuck them in the back if I am going to be away for a long period, otherwise they are in my house and I make use of only the starter battery in my defender.


I want to mount one of these batteries in the battery box under the passenger seat, connect it to the alternator to charge even when I do not use the solar panel. But also have the option to plug it into the solar panel when I am not driving around for long periods #lockdown.


I have 2x Royal 1150K batteries - I want to mount of them


If you are able to help me out, and would be willing to do so I can send you pictures of the current setup to make it a bit more clear what I have and what I need.


What I'll use it for:


Fridge
Charging electronics - phone, cameras etc
Additional plugs for lights and handheld spotlight
Work lights (2 or 3)
Chargeable via solar and also the alternator when driving

*Please forgive me ignorance if I named, or refer to something incorrectly ha!

any advice, or help would be fantastic

Thank you

[DiscoDave]

Hi Henkules,


I did my own DIY dual battery on.my previous 2008 Defender. Some thoughts from the setup.

Battery choice is obviously important. Under the seat is a tight fit and you may have constraints on battery size. Think i only got a 95 amp/hr in? Will have to check.
Insulation is very important as well as ventilation. I used a type of car audio insulation under the seat cover to prevent shorting. Frontrunner battery clamp didn't seem sufficient to me so made a custom bracket housing.

Inside I installed a Cyrix battery combiner to allow bi-directional charging which is similar to what you will require. Cheap effective and small. Had a victron dual battery monitor on a Mud console to monitor the batteries. Lovely piece of kit. Installed additional button to allow paralleling of batteries for winch operation.

Brad Harrison for the trailer out under the chassis and several plugs behind front pax seat for charging solar panel and additional inputs (fridge etc).
Simple and worked well.

At the time most companies wanted to sell their own product, a stand alone battery box or similar. Also costs were extremely high. Plenty of ideas on the net to help you out, especially boating forums. Similar tech used.

Hope that helps

Regards,
Dave

[Dwayne P]

Hi Henkules,


I did my own DIY dual battery on.my previous 2008 Defender. Some thoughts from the setup.

Battery choice is obviously important. Under the seat is a tight fit and you may have constraints on battery size. Think i only got a 95 amp/hr in? Will have to check.
Insulation is very important as well as ventilation. I used a type of car audio insulation under the seat cover to prevent shorting. Frontrunner battery clamp didn't seem sufficient to me so made a custom bracket housing.

Inside I installed a Cyrix battery combiner to allow bi-directional charging which is similar to what you will require. Cheap effective and small. Had a victron dual battery monitor on a Mud console to monitor the batteries. Lovely piece of kit. Installed additional button to allow paralleling of batteries for winch operation.

Brad Harrison for the trailer out under the chassis and several plugs behind front pax seat for charging solar panel and additional inputs (fridge etc).
Simple and worked well.

At the time most companies wanted to sell their own product, a stand alone battery box or similar. Also costs were extremely high. Plenty of ideas on the net to help you out, especially boating forums. Similar tech used.

Hope that helps

Regards,
Dave

are you using the Cyrix ct120 combiner? I am using this in another vehicle, and has worked well for me.

[Henkules]

Hi Henkules,


I did my own DIY dual battery on.my previous 2008 Defender. Some thoughts from the setup.

Battery choice is obviously important. Under the seat is a tight fit and you may have constraints on battery size. Think i only got a 95 amp/hr in? Will have to check.
Insulation is very important as well as ventilation. I used a type of car audio insulation under the seat cover to prevent shorting. Frontrunner battery clamp didn't seem sufficient to me so made a custom bracket housing.

Inside I installed a Cyrix battery combiner to allow bi-directional charging which is similar to what you will require. Cheap effective and small. Had a victron dual battery monitor on a Mud console to monitor the batteries. Lovely piece of kit. Installed additional button to allow paralleling of batteries for winch operation.

Brad Harrison for the trailer out under the chassis and several plugs behind front pax seat for charging solar panel and additional inputs (fridge etc).
Simple and worked well.

At the time most companies wanted to sell their own product, a stand alone battery box or similar. Also costs were extremely high. Plenty of ideas on the net to help you out, especially boating forums. Similar tech used.

Hope that helps

Regards,
Dave

Thank you Dave, appreciate the thorough feedback. It seems that one of the royal batteries will definitely fit the bay, and I'll create additional ventilation through the existing grommet in the bay. As for insulation, some high density foam between the batteries and also a rubber cover over the top to prevent any shorts.

I have a NL battery monitor, it only has a "measurement" for one battery, would it be necessary to have a dual monitor instead?

As for a "smart charger", it would seem that more people on the forum is for this, rather than solenoid setup, or am I missing something?

Options for charger:

Cyrix CT120
CTEK - not sure what model would be ideal

I have one Anderson (Brand Harrison) plug to charge via the solar panel, and I'll have an additional one for the fridge. Then I'd like to wire a couple of "lighter plugs" for lights and charging devices.

thank you in advance

[4x4tripping]

I did collect some solutions for the 2nd battery here: https://www.4x4tripping.com/search/label/Batterie

There are too tips, how to build a 2nd battery solution at yourself.

Personally I too did use the national luna solution for my setup. Not shure if I would do the same again, but it works very well.

A 50wp Solarpanel on the car roof is enough charge the battery - I did notice. At least when the weather is nice and I just charging a phone and empower an engel 12v compressor fridge

Surfy

[Henkules]

I did collect some solutions for the 2nd battery here: https://www.4x4tripping.com/search/label/Batterie

There are too tips, how to build a 2nd battery solution at yourself.

Personally I too did use the national luna solution for my setup. Not shure if I would do the same again, but it works very well.

A 50wp Solarpanel on the car roof is enough charge the battery - I did notice. At least when the weather is nice and I just charging a phone and empower an engel 12v compressor fridge

Surfy

Thanks Surfy - appreciate it! And very interesting platform you have there! Enjoying the read

[DiscoDave]

Cyrix CT120 is what I had, worked like a charm.
Battery monitoring isn't required as long as you understand your system and limitations.

With the cyrix and extended draw from the fridge it will pull your starter battery voltage down as well.
Careful planning will be required on stops even with a solar panel to charge without a voltage reading. Nothing worse than having two flat batteries in the Bush.

Ctek is great (best?) but expensive. DC-DC charger and I'm sure many forumites could provide better information. Will it fit under the seats as well?

Also changing a battery with dual batteries under the seat can be a nightmare. It's a very tight fit.

Sounds like you know what you want already and headed in the right direction.

Keep us informed.


Regards
Dave

[Max Lange]

I have a just upgraded to the National Luna DC - DC system, from the NL solenoid system.

I have both batteries under the seat, bitch to get to but convenient, dont see the need for vents but have some insulation on the outside of the battery box on the exhaust side. I purchased the full kit with monitoring and it includes a temp sensor.

What I have noticed the following main differences, limited use of the DC-DC (because of lock-down)

Almost instant charging of the aux battery as apposed to 10min wait time on the solenoid system
Supports a variety of battery types, i.e. can use AGM and Li batteries (if I will ever be able to afford them)
Solar panel plugs into the NL device no need for an extra solar controller, the NL uses MPPT technology

I went with NL rather than Ctek as they are local.

Hope this helps.

[Max Lange]

Forgot to mention the 1 thing that annoys me with the NL kit, charging the starter battery is an issue as you have disconnect the aux battery when charging the starter battery.

Unless someone has a slick solution...

[4x4tripping]

Forgot to mention the 1 thing that annoys me with the NL kit, charging the starter battery is an issue as you have disconnect the aux battery when charging the starter battery.

Unless someone has a slick solution...

I dont understand (maybe because i`m not native english speaker).

The National Luna PPP (1st Gen) Box just has a link to the starter battery.

The lightengine/alternator will charge both, indipendent if you had a rear battery connected or not. With the additional external battery monitor you even can connect both batteries (for 5 min) for help cranking or using the winch.

Hints:

- If you had an additional Solarcharger connected at the National Luna PPP - the power never reach the starter battery (because of the solenoid).

- If you use a Solar Charger at the starterbattery - the Solenoid (National Luna PPP) will start charging the rear battery after some minutes too

- Correctly connected the wires are very big (because you can link both batteries with full cranking power by the additional external Battery Display Device)

- Modern cars (EURO 6 + and, D+) dont deliver enough power for charging anything else than a normal standard battery. Even that not with enough power. Using AGM or Gel Battery need !!! an additional Powerbooster who use IUIU and 14.2v-14.8v (or what the battery needs).

This is the same on any external battery setup in the rear - to get happy at the end - you need something like this:

https://www.votronic.de/index.php/de...iuou-li-marine



It works well in my setup. I guess it is maybe expensiv to buy and ship to SA (?) - if so - look for a b2b charger with UIUI charging and the option to set the correct charing power for your battery.

So you had to do some rework on that "ready battery boxes" anyway. I had to cut and to rework the wires for MPPT Solar charger and Powerbooster. Considering this - will quick lead to a completely build by your own.

My writeup here https://www.4x4tripping.com/2013/04/...ig-selber.html did not consider the Powerbooster so better plan with it.


Cheap Idea:

Make your box by yourself. If you just use this B2B device and an AGM Battery - you dont need more.



Surfy