[gigy]

I could not figure out how the diode across the contactor is going to help. during starting the contactor is not going to close anyways. The second battery is isolated from starting circuit unless forced with the momentary switch.

[Irfanulla]

Apologize for the off topic post

I was wondering where to get the Redarc solenoid (dual battery charge controller) in Bangalore- or is it best to get from Australia direct.

RGDS
Irfan

[Aroy]

Hi folks,
Just went through the posts. Here is an interesting link Hellroaring Technologies, inc., Manufacturer of Solid State Dual Battery Isolator / Combiners. with a diagram Hellroaring Battery Isolator/Combiner notes for 4 Wheel Drive dual battery applications

From what I understand, dual battery setup acts as follows
1. Both the batteries are isolated from each other
2. Relays ensure that the primary battery caters to starting and nominal vehicle load. Secondary battery caters to all the appliance loads
3. In case of the main battery failing, circuit can switch to auxiliary battery for starting.

There are two types of isolators
1. Diode based. These are trouble free but suffer from voltage drop, and resultant heat build up. In case the diodes go bad, there is no isolation.
2. Coil Relay based. These are more complicated, but suffer no voltage drop, or heat build up.

One thing emphasized every where is that if you require dual batteries, please re calculate the total load and upgrade the alternator accordingly. People often forget to account for high power amp, multiple lights and refrigerator (if there) while calculating load. There should be 20-30% margin while sizing the alternator to ensure that the alternator has ample reserves to charge batteries under full user load.

[jinojohnt]

Just a noob question: Wouldn't high power capacitors serve the same purpose with easier maintenance and longer life? I was thinking of something like the ones given in this link.

http://www.squidoo.com/caraudiocapacitor
What is the main role of a car audio capacitor?
Unlike automobile batteries, the main function of an audio capacitor is to store energy. This stored power will be used on demand (when your amp needs it). This will ensure that your audio system is being used to its maximum capability.
How do I know that I need an audio capacitor?
The first thing you will notice is dimming lights. The light will get weaker each time a heavy bass note sounds. If you installed the right capacitor, your audio system would have received the right amount of power needed.

5+ Farad Capacitors | Car Audio Capacitors at Sonic Electronix

[navin]

Originally Posted by jinojohnt

Just a noob question: Wouldn't high power capacitors serve the same purpose with easier maintenance and longer life? I was thinking of something like the ones given in this link.

5+ Farad Capacitors | Car Audio Capacitors at Sonic Electronix

1. All amplifiers have internal capacitors which in well designed amplifiers should be adequate for the audio needs.

2. If you are faced with dimming lights it means your alternator is not charging your battery as fast as the appliances are discharging it.

3. If you are faced with a drop in the music it is usually because battery's voltage has dropped below the amplifier's threshold operating voltage ( see thread by GTO on his Civic's system). In the Civic for example the alternator is not permitted to charge the battery till's voltage has dropped to 11V ( this is a Civic issue).

A capacitor will resolve the dimming lights but check why the lights are dimming in the first place. To resolve the audio drop it make better sense to get amplifiers with lower threshold operating voltage. GTO for example switched from amps with a threshold of 11.5V to 10V.

Dual battery systems make sense when you have competition level audio systems like LBM has. They are complicated and required regular maintenance. I run 3 STEG amps in my system. There is no need for a capacitor or multiple batteries.

Unless the car you have has electronic control over the battery like the above mentioned Civic, you alternator should charge the battery adequately and you should not see dimming lights. A capacitor is often just a band aid. Getting a correctly speed alternator and fresh battery ( old batteries often do not charge properly) might be a more correct solution.

[wanderernomad]

Sorry for bumping up an old thread but I need to do a dual battery install and am not sure as how to go about it. It seems a lot of people abroad who go off road into wilderness do a dual battery set up. I checked on amazon.com and ebay.com that battery isolators are commonly available. However, couldnot find similar products here.
My purpose is to have a dual battery to accomodate a second battery in the jeep trailer. The primary battery in the engine bay will be used only for the heater and engine cranking while i plan to use this second battery for the charging and lighting in the trailer.
How to go about it? Suggestions/ pointers/ leads ?

[Aroy]

Originally Posted by wanderernomad

Sorry for bumping up an old thread but I need to do a dual battery install and am not sure as how to go about it. It seems a lot of people abroad who go off road into wilderness do a dual battery set up. I checked on amazon.com and ebay.com that battery isolators are commonly available. However, couldnot find similar products here.
My purpose is to have a dual battery to accomodate a second battery in the jeep trailer. The primary battery in the engine bay will be used only for the heater and engine cranking while i plan to use this second battery for the charging and lighting in the trailer.
How to go about it? Suggestions/ pointers/ leads ?

You will first need to upgrade your alternator to a much larger capacity one, say 150 Amps or more. In case there is no space for a larger alternator, then a second one dedicated for your trailer will have to be installed. All depends on the space available in the engine bay.

Apart from a more powerful alternator, you will need battery isolator and of course space for the second battery.

[wanderernomad]

Originally Posted by Aroy

You will first need to upgrade your alternator to a much larger capacity one, say 150 Amps or more. In case there is no space for a larger alternator, then a second one dedicated for your trailer will have to be installed. All depends on the space available in the engine bay.

Apart from a more powerful alternator, you will need battery isolator and of course space for the second battery.

I seem to have a spare groove in the pulley to fit another alternator as well, so if I install a second alternator then I dont need a battery isolator? I intend to fit the spare battery in the rear of the jeep by using longer wires or if it will lead to voltage drops then will find a way to mount it in the engine bay itself.

Are voltage isolators available in India and if yes is it the correct term to use if I go hunting for them?

[Aroy]

Originally Posted by wanderernomad

I seem to have a spare groove in the pulley to fit another alternator as well, so if I install a second alternator then I dont need a battery isolator? I intend to fit the spare battery in the rear of the jeep by using longer wires or if it will lead to voltage drops then will find a way to mount it in the engine bay itself.

Are voltage isolators available in India and if yes is it the correct term to use if I go hunting for them?

1. If you use longer wires, then you will have to use thicker gauge. The guide to wire sizing is there in most cable manufacturer's sites. Just remember to choose a thicker gauge than recommended as the wires will heat up in enclosed space.

2. Voltage isolators are just high power diodes with low voltage drop. They are generally mounted on substantial heat sinks for cooling. A location where there will be constant air flow is advantageous.

here are some useful links
http://www.fridge-and-solar.net/dual_bat.htm
https://www.redarc.com.au/battery-ch...tery-isolators
http://www.powerstream.com/battery-isolator.htm

[wanderernomad]

Originally Posted by Aroy

1. If you use longer wires, then you will have to use thicker gauge. The guide to wire sizing is there in most cable manufacturer's sites. Just remember to choose a thicker gauge than recommended as the wires will heat up in enclosed space.

2. Voltage isolators are just high power diodes with low voltage drop. They are generally mounted on substantial heat sinks for cooling. A location where there will be constant air flow is advantageous.

here are some useful links
http://www.fridge-and-solar.net/dual_bat.htm
https://www.redarc.com.au/battery-ch...tery-isolators
http://www.powerstream.com/battery-isolator.htm

Thanks for the links. But any Local link from where these can be bought or I have to source from outside only?

[Chhanda Das]

Apologies to the admin/s in advance if this is not the appropriate forum and/or thread ...
I intend to install a secondary battery in the engine bay of my 2017 Creta Petrol Automatic with an isolator between the two batteries for running appliances while the engine is off but I am primarily confused as to where and how to mount the battery as I intend to add a single lead-acid battery with the highest possible capacity. My primary requirement is that it should be mounted in the engine bay and not the cabin while the requirement for the highest capacity is secondary. Any inputs in this regard would be very much appreciated. Thank you all in advance

[navin]

Originally Posted by Chhanda Das

Apologies to the admin/s in advance if this is not the appropriate forum and/or thread ...
I intend to install a secondary battery in the engine bay of my 2017 Creta Petrol Automatic with an isolator between the two batteries for running appliances while the engine is off but I am primarily confused as to where and how to mount the battery as I intend to add a single lead-acid battery with the highest possible capacity. My primary requirement is that it should be mounted in the engine bay and not the cabin while the requirement for the highest capacity is secondary. Any inputs in this regard would be very much appreciated. Thank you all in advance

Except for a few SUVs, very few cars have room for 2 batteries in the engine bay. You will need to specify which car you are intending to modify.

[srini1785]

Originally Posted by Chhanda Das

I intend to install a secondary battery in the engine bay of my ... with an isolator between the two batteries for running appliances while the engine is off

What appliance(s) are you planning to connect to this secondary battery?. Like Navin has said, there will be very little/no room for secondary battery under the bonnet. Second question , Why the need for a isolator between two batteries?.

[Rahul Rao]

Originally Posted by srini1785

Why the need for a isolator between two batteries?.

Two batteries connected in parallel tend to discharge each other due to divergence in their potential. Isolater will prevent this type of discharge. The isolator switch should be triggered only by the alternator output, and not be triggered only by switching on the ignition.


Rahul

[Chhanda Das]

Originally Posted by navin

Except for a few SUVs, very few cars have room for 2 batteries in the engine bay. You will need to specify which car you are intending to modify.

Like I have already said in my initial post, I intend to modify my 2017 Creta Petrol AT. As the 1.6 petrol engine is somewhat smaller (dimension wise) than the 1.6 diesel engine, I think there is room to add an extra battery. Moreover, my current stock battery is 45 Ah while the 1.6 diesel comes with 60 Ah battery. So there is room there too. But some guidance as to the exact location for mounting the 2nd battery would be very helpful.

Originally Posted by srini1785

What appliance(s) are you planning to connect to this secondary battery?. Like Navin has said, there will be very little/no room for secondary battery under the bonnet. Second question , Why the need for a isolator between two batteries?.

Firstly, my primary intention is to connect my 45 watt fridge/freezer to the secondary battery. I currently run it only while the engine is on. The same goes for my laptop and my portable fan. To answer you second question, I do not want my car's primary cranking battery to drain if I drain the secondary battery. Hence the need for the isolator or a voltage-sensitive relay. I have figured out the wiring setup and just need some help and/or guidance with mounting the battery in the engine bay. Space shouldn't be a problem as the petrol engine is smaller than the 2 diesel ones (dimension-wise) in the Creta. The battery is smaller in the petrol Creta too. A petrol Creta has the most space in the engine bay compared to its 2 other diesel variants. Any tips on mounting the 2nd battery in the engine bay would be very much appreciated. Thank you in advance ...