Deep cycle or starting battery

Submitted: Monday, May 17, 2004 at 16:43
ThreadID: 12943 Views:6958 Replies:10 FollowUps:11
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What is the best 2nd battery for my purpose.

Load is 1 x engel fridge(2-3 amps per hour). 1 x versalite (1 amp per hour).
Usage 1 x camping trip / month for weekend only never completely flaten battery and 1 x trip that / year that involves staying put for 4 to 5 days at a time of which battery will be completely flat.

I have been told that to keep a deep cycle in good condition you must flaten it regulary otherwise it will develop a memory but then on the otherhand I have also been told not to ever flaten a starting battery otherwise it will stuff it.

Are there any battery's out there that will do both.
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Reply By: Member - Jeff M (WA) - Monday, May 17, 2004 at 16:55

Monday, May 17, 2004 at 16:55
Never flattern a Deep Cycle either!
I have a deep cycle as my aux, it is used every day a little because my ineterior lights, car stereo, GPS (which is on 24/7) and UHF all run off it. I also do about 1.5 hours a day of cruising, I find that the battery is getting a reasonablly good charge through general use, however I still hook it up to a car charger the night/day before we take of to go camping. Your deep cycles do not need to be flatterned, in fact it's a sure way to kill any kind lead acid battery, just ensure that you keep it charged, even when not using it. Give it a charge every couple of weeks at least. The most important thing is to keep it cool (don't leave it in a small shed in the middle of summer) and make sure it always has plenty fluid in it. (demineralised water). Unfortunatally the ol' TD engine of mine produces a lot of heat and it will be what kills my battery before anything else, but I just keep a close eye on the water levels and don't let them drop.
A deep cycle would probally be the go for you, if you can help it as mentioned in a previous post don't let them drop below aprox 40% charge and they will last a lot longer than if you flattern them.
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Reply By: Rosscoe - Monday, May 17, 2004 at 17:08

Monday, May 17, 2004 at 17:08
Just my opinion, but I would go deep cycle. Now lots of people will disagree, but from what I've read and from my own experience I'm happy with my set up which is standard cranking battery and an 85 AH deep cycle auxiliary battery separated by a smart solenoid system.
Lead acid batteries do not have a memory as you describe and if they are regularly discharged below about 40% their life is dramatically reduced - months instead of typically 3 to 4 years. Deep cycle batteries are designed to be disccharged regularly but not below 40% if you want reasonable life.
Also with a normal vehicle alternator/voltage regulator set up, the best that you can achieve is 70 to 80% of charge not, 100%.
Some simple maintenance will extend the life of your battery.
a) Try to never discharge your battery below 40%. So on your 4 to 5 day stay don't flatten the battery. Turn it off before the light starts to go dim. You can by a low voltage cut out device for about $20.00 that will do this for you automatically.
b) If possible use a mains operated smart battery charger both when you are storing the battery or before you set out on a camping trip. At 100% charged you have 60% capacity for use. ie 100AH battery will give you 60AH without discharging to an non recommended level. If you only charge by the car you typical on ly have 30 to 40AH.
c) If the budget will allow invest in a correctly sized solar panel/solar regulator system ( about $1200.00 - ouch)

Check out the following web site for lots of good info on lead acid batteries:-
or get a hold of Colyn Rivers' Book(s) on the subject.
AnswerID: 58938

Follow Up By: Rosscoe - Monday, May 17, 2004 at 17:12

Monday, May 17, 2004 at 17:12
To get the best from your appliances it's worth running heavier than standard cable to the rear accessory outlet. Personally, I'd go for 6 mm cross sectional area copper conductors (positive and earth return) but most auto electricians say 6mm auto cable is OK (about 4.9 mm square)
Maybe also worth investing in a Hella or similar quality socket and replace the OEM cigarette type accessory socket.
FollowupID: 320592

Follow Up By: Goona - Monday, May 17, 2004 at 17:39

Monday, May 17, 2004 at 17:39
Thanks for the info. Very good website.

Now next Question what is the best brand of deep cycle to get.
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Follow Up By: Crackles - Monday, May 17, 2004 at 17:49

Monday, May 17, 2004 at 17:49
Trojan are a respected brand for deep cycle batteries and have a 115 amp hour model in the standard NZ70 size if you need to run a bit longer than most without recharging. Cheers Craig...........
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Follow Up By: Troopie - Tuesday, May 18, 2004 at 16:01

Tuesday, May 18, 2004 at 16:01
Something to consider - this comes from a battery shop that actually sells Trojans (spoke to the guy recently - see my other post below). Apparently they, and many of the bigger batteries made in the US, have some difficulties when operating in engine bays that tend to get very hot. Something to do with an accelerated loss of liquid from the battery. This increases the concentration of the acid - which in turn increases the rate at which the batteries wear out.

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Follow Up By: Rosscoe - Tuesday, May 18, 2004 at 16:27

Tuesday, May 18, 2004 at 16:27
Spot on. If the battery has to be mounted any where near the exhaust manifilod you should make sure you use some sort of radiation shield between the heat source and the battery. The general ambient heat in the engine bay will still be quite warm but you prevent the flat black battery case (a very good absorber of radiated heat) from copping a full blast from the exhaust system.

This subject is covered in reasonable depth in Collyn Rivers' books. Worth a read.
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Follow Up By: Troopie - Tuesday, May 18, 2004 at 16:40

Tuesday, May 18, 2004 at 16:40
G'day Rosscoe
Thanks for the clarifications.

In my case the manifold is on the other side of the engine bay to the batteries, so i guess that is a start.... Anyhow, (see my other post below) if I discover 150 amh/hour isn't enough (I suspect it will be plenty) - then I can always upgrade - I have a few friends with boats who could probably use the Besco's
FollowupID: 320738

Reply By: Lynn2 - Monday, May 17, 2004 at 18:13

Monday, May 17, 2004 at 18:13
Depends a little on the budget. Optima are supposed to be good but are pricey. A lot of people on the forum sware by Exide Extreme for value for money. My Century battery in the off-road van is now two years old and still going strong.
Also depends on how much space you have. Go as big as will fit but size is not the answer if your charging routine is not up to par.
AnswerID: 58942

Reply By: Member - Liz- Monday, May 17, 2004 at 19:53

Monday, May 17, 2004 at 19:53
Well this quetion is like Toyota or Nissan. HF or Satellite phone. I can give you my experience. We have a 80 series cruiser 97 mod. We tow a Swan (Jayco) off road camper (off road by name only, serious off road we take a tent. Any thing other then a dirt country road is serious for us!).

I have settled on the following set up after experimenting with many. Like you we do weekend trips mostly. Have 5 people (yep 3 kids all girls so the shower gets a work out).

Anyway I have two ACdelco ( I call them intermediate hight crank amps and can deliver over long period if needed) batteries in the car and a deep cycle in the Jayco. For the car I have a Pirana controller.(all this does is keep the batteries seperated when the car is off) I will explain why I went this way.

In the car we run the following from the second battery, Engle 40 l, DVD and two screens (actually a Sony PS2 with inverter) Satellite phone (charger), GPS and a laptop. The main bat runs the standard stuff in the car.

The deep cycle in the Jayco runs the lights and that is about it. Fridge we never use on 12 Vdc as it is useless.

Now I have had battery trouble in the middle of no where. You try push starting a
a fully loaded cruiser with jayco attached and four worried faces looking at you as say what are you going to do about this fine mess we are in!! So I have gone with two batteries in the truck that will crank but still act like a deep cycle. This is because if a battery dies, and beleive me they can just die instantly I can still crank easily from the other one.

Remember these things only ever happen at the worst time. Your by yourself with a car full of girls at night in the middle of no where. You stop the car for a weeee stop and then nothing!!!! Well that want happen to me again I can tell you.(I will not turn the bloody truck off for a start , ever!!!)

All batteries are charged from the truck. I have never had trouble since this set up and will never go back to a deep and cranking battery again.

The ACDelco are made in the USA. Are no maintenance lead/acid battery. They have a visual indication of condition (in-built hydrometer. green good, red dead etc) they are 100 A/H and cost around the $180.00 mark (worth every cent).

My experience anyway. Good luck. Happy battery shopping.

AnswerID: 58961

Reply By: Peter McGuckian - Monday, May 17, 2004 at 20:23

Monday, May 17, 2004 at 20:23
I have a GU Patrol with the Piranha second battery system. The second battery is an Exide Extreme (standard cranking battery). It works very well. In an earlier vehicle I used a deep cycle and for one extended trip - soon changed to a standard cranking battery. It is too hard to keep a deep cycle fully charged if you are not doing a long run each day.

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Follow Up By: Goona - Wednesday, May 19, 2004 at 14:59

Wednesday, May 19, 2004 at 14:59

I have been told that a deep cycle battery can take up to 8 hours to recharge and that a starting battery will take as little as 1 hours. Is this the case?

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Follow Up By: Peter McGuckian - Wednesday, May 19, 2004 at 15:10

Wednesday, May 19, 2004 at 15:10
That has certainly been my experience. I would only use a starting battery now.

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Reply By: ianmc - Monday, May 17, 2004 at 22:23

Monday, May 17, 2004 at 22:23
Hmmmm! Deep cycle as a second battery?? Will it crank your motor (Deisel?) over if the starter battery fails?? IF not go starter battery for 2nd battery.
As it happens I was at the auto elc. to have my second battery (Delkor 4yo) tested.
It would charge up to 13+ volts but leak down to 10.3 within the week. It was shot and I bought a new n70 for $89 on special.
Very exper. elec. agreed that a starter battery may last just as long or longer than a deep cycle as an accessory battery from his experience.
Also noticed a new battery elsewhere gteed for 18 mos as a marine starter but only 6 as a deep cycler. Story in that somewhere!
AnswerID: 59003

Reply By: Troopie - Tuesday, May 18, 2004 at 10:39

Tuesday, May 18, 2004 at 10:39
G'day All
Have been reading this thread with interest - as from the weekend I have been thrown into the same dilemma again.

I have two things to raise here. I've had a Piranha management system for about 4 years. This system has been great - untill the weekend just gone.... I have three batteries under the bonnet - 1 Centuary Severe Service battery as the cranker - and two AC Delco batteries for running accessories/ fridges etc. So - I was working on something else and noticed the AC Delco batteries were indicating red in the test window - hmmmm.

Anyhow - to cut a longish story short - turned out the Piranha had gone phut. No reason - and no explanation available from the place where I bought it.... Anyhow - call me stupid but I had it replaced. I hope I don't live to regret not buying a more simple solenoid set-up as the Piranha unit cost over $250 clams.....

It gets worse - turns out the 2 AC Delco's are on their last legs.... I have had them for 22 months and are maintained to the best of my ability. My previous vehicle also had an AC Delco as the Aux battery - and it lasted well under two years also. I wont pass comment on the batteries - you can make your own judgements. Some say two years is about all you can expect - others say they should last much longer.

I did the ring around yesterday to all the battery places in town and here's a cut down summary of what I found in terms of deep cycle battery options. There was some variation in the ones over 100amp/hr (100-115amp/hr). Also - beware that some of the bigger batteries aren't in the standard N70 case so may not fit in your fourby....

1. Centuary - 75 amp/hr = $140
2. Trojan - >100amp/hr = $240
3. Motolite - >100amp/hr = $180-$220
4. Federal - >100amp/hr = $240
5. AmpTech - >100amp/hr = $180
6. Champion - 85amp/hr = $130
7. Exide - 80amp/hr = ??

AnswerID: 59052

Follow Up By: Troopie - Tuesday, May 18, 2004 at 16:18

Tuesday, May 18, 2004 at 16:18
G'day Again All
It's later in the day and I'm now another 400 odd clams lighter....

I went to the place that offered the best service following my ring around yesterday - which also had the two battery brands I was interested in for my Aux batteries. In the end it came down to Trojan versus Centuary/Besco.

These were my thoughts:
Trojan: Good reputation; made in US; plenty of amp-hours - over 100; apparently a question mark over longevity when operating in hot environments; pricey at $240 each.

Centuary/Besco: another good repuation; made in Oz; low on amps at 75 amp/hour; apparently - because there are less plates crammed into the space - the water loss issue in hot environments is not as big a concern; good value in a $ per amp measure - RRP was $140 - but I was offered a much better deal for buying two.

Given I will have two, I have 150 amp/hours at a total investment of less than one Trojan - so i bought the Besco's.

The kicker for me was the cranking battery is about 3.5 years old and was also on it's last legs. I'm heading up the Canning in one month so didn't want to take the risk - so I replaced it with an Overlander...

Phew - better get slaving to pay for my batteries......
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Follow Up By: Rosscoe - Tuesday, May 18, 2004 at 16:42

Tuesday, May 18, 2004 at 16:42

I'm interested in how you use your auxiliary batteries. Did you run them until the lights go dim or do you monitor their charge level by a reasonably accurate voltmeter or a hydrometer (specific gravity of the electrolyte) and swith them off when you get to 40% charge.

I am led to believe deep discharging is the single most common cause of premature battery failure.

The comments in the posts above are correct re not being able to charge your batteries above about 70 to 80% in the car.
Simple arithmetic therefore says that if you have a single 100 AH battery all you can hope for is 30 to 40 AH or to be able to run a single fluro (1 AH variety) for 30 to 40 hours. Naturally if you run other electrical equipment and you know their power consumption and can estimate how long you use each device you can calculate how long you can camp without some means of recharging your batteries.

So far the only solution I have found is a correctly sized solar pane/solar regulator but my budget doesn't stretch taht far at the moment.
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Follow Up By: Troopie - Tuesday, May 18, 2004 at 17:12

Tuesday, May 18, 2004 at 17:12
G'day Again Rosscoe
Because I have two deep cycle batteries I had quite a bit of juice. Using your calculations - I would have had around 60 to 80 amp/hr with the two AC Delco's as they were both over 100 amp/hr batteries.

As for usage - I am pretty careful with the whole system and can condifently say that in the 22 months I had the AC Delco's there was only one occaison when they came close to 40% discharged. I know this because I have a quality voltmeter connected to the deep cycles so I can always see what's going on. The AC Delco's also have a very nifty feature - there is a hygrometer built into the top of the battery which can be easily inspected. At any time when I've been stopping a bit longer, we use a gas light rather than a fluro - and we are very careful about not opening the fridge too much.... The reason for going with two deep cycles originally was to reduce the possibility of running the batteres too low when stopped for longer than one night. The idea being to get maximum life out of them - given that we will have to replace two when they give up....

Like you - I'd like a solar set up - but with all the dollars I've already blown recently - I can't do it for our upcoming trip.
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Reply By: Moose - Tuesday, May 18, 2004 at 13:28

Tuesday, May 18, 2004 at 13:28
It is impossible to recharge a deep cycle properly using the vehicle's alternator. This is directly from the seller of deep cycles. He said "mate you could drive from here to Bourke and back and your deep cycle still will not be properly charged". I live in Brisbane! On the other hand a heavy duty starting battery can be fully recharged via the vehicle. I'll go starting as the second battery next time.
As the others have said - if you flatten any lead acid battery a few times they'll be stuffed. Do you have some way of recharging the battery during the 4 to 5 day stay other than the vehicle? If not you may be better off with a starting battery and just go for a bit of a run each day.
AnswerID: 59069

Reply By: -OzyGuy- - Tuesday, May 18, 2004 at 18:01

Tuesday, May 18, 2004 at 18:01
the best battery.............. Deep Cycle
best brand at a reasonable cost.... Delkor

my reasons...

Look at a Delkor and you will see they have two (2) posts as usual to all batteries then you will notice that they also have two (2) stainless steel bolt connections as well.

They are a true DC battery !!
not just a heavy duty cranking battery, they are sealed calcium batteries and have no memory hassles.

the statements regarding not being able to charge a DC to 100% from a vehicle altinator makes me ask those that make the claim this question....

(a) Explain why you can't get a DC to 100% from the altinator

(b) why will a cranking battery recharge 100% and you claim a DC won't

you are suggesting every DC battery system out there is faulty because it is only running at 60 to 80%.

I have no hassles with my DC system and I have checked it days after the altinator has charged it and it still shows 12.8 volts and yes I know of 'surface charge'.
AnswerID: 59122

Reply By: Jimbo - Tuesday, May 18, 2004 at 19:58

Tuesday, May 18, 2004 at 19:58

This is a most interesting topic.

Have a look at Post 12429 and look for Mad Dog's response and hook into his link "faq".

Also try

And have a look at my post 12990.

The first two are from genuine experts, mine is only the result of a layman's research.

AnswerID: 59143

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