Dual Battery - What size?

Submitted: Wednesday, Apr 03, 2013 at 22:14
ThreadID: 101485 Views:2065 Replies:5 FollowUps:0
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Hi all.

I am about to get a 2nd battery installed. I have a current model Dmax. The battery will be in the tray, and used to mainly power our 47litre Engel and possibly some camp lighting. I will be using a Redarc voltage sensitive relay, Mainly used for touring and weekend camping purposes with 1 or 2 nights in any particular spot before moving onto the next.

I was thinking 100amp lead acid battery. Alternator has an output of 90 amp. However I am getting varying advice on battery size, with some auto sparkeys saying only 80amp battery whilst others saying up to 130amp. I am not currently using solar for top up ( maybe later). I have already tried to read what's available on this site. Don't want to risk a fridge of warm beer/ G &T or food,

Over to the forum, and thank you kindly in advance.


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Reply By: Allan B (Member, SunCoast) - Wednesday, Apr 03, 2013 at 23:29

Wednesday, Apr 03, 2013 at 23:29
There are a number of factors that determine the appropriate battery size for your needs and a number of considerations for charging the battery.

The best thing you can do before a variety of proposals are offered to you is to read John & Val's blog, Electricity for Camping. Click here.
Then if you have further specific questions, ask them here.

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AnswerID: 508126

Reply By: bluefella - Thursday, Apr 04, 2013 at 07:01

Thursday, Apr 04, 2013 at 07:01
If it's in the tray away from engine heat, I would use a Century AGM 100 a/h. deep cycle.
AnswerID: 508141

Reply By: Sand Man (SA) - Thursday, Apr 04, 2013 at 07:33

Thursday, Apr 04, 2013 at 07:33
You don't mention how the battery will be contained in the tray of your vehicle, but have you considered an "all-in-one" solution?

Derek (Business Member on this site) has an intelligent Sidewinder Flyer to suit this purpose which comes with its own built-in Isolator to protect the starting battery and includes all cabling, fuse, connectors, etc.

All you need is an accessory bracket and a battery of your choice.
I would suggest a 100Ah AGM battery would suffice for up to two nights, but would suggest you include a low voltage cutout device if the fridge doesn't have one.
For any period longer, the inclusion of solar panel support would extend the time period between charges.


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AnswerID: 508143

Reply By: Corrugate75 - Friday, Apr 05, 2013 at 07:31

Friday, Apr 05, 2013 at 07:31
There are always lots of opinions on this one - we run the same battery as the car starting battery (N70ZZ) as this way the second battery can be used to start the car if there is a faliure of the first battery. We use a 47L Fridge and have had no problems when camping, BUT, we usually go for an couple hour drive every other day to see the scenery around where we are camped - which recharges both batteries. I also have 120Watts of solar plugged into the campertrailer batteries, but the solar pannel can be used to supplement the car batteries if we're not going for a drive.
AnswerID: 508237

Reply By: robert s4 - Saturday, Apr 13, 2013 at 02:27

Saturday, Apr 13, 2013 at 02:27
if you can fit a marine battery its worth looking at i have 80 litre engle 100a/h marine pro 3 years old and 120 watt panel for back up usally use 3 lights beers r cold and freeze the meat if u have to
AnswerID: 508906

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