Dual Batteries - Deep Cycle v. Normal Cranking
Submitted: Monday, Apr 08, 2002 at 00:00
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michelle
We have just been to Piranaha who suggested we get a deep cycle battery - and as we can only fit it in the tray, they have suggested the Optima battery (>$400) - total installation around $1100. I then rang Opposite Lock who indicated that they would never use Deep Cycle Batteries (they are 'out of date') and instead I think they use just a cranking type battery - have indicated that this is what all of the SES vehicles etc... use. They've quoted around $800. Most of the info that I have read have indicated that we need a deep cycle battery (to run fridge and couple of lights) but now I'm not so sure..... Any help would be much appreciated.
Reply By: Nigel - Monday, Apr 08, 2002 at 00:00
Monday, Apr 08, 2002 at 00:00
if you are using a parallel charge system like piranha's then you shouldn't mix battery types. With an independant charge system, where the batteries are never connected together, you can use a starter battery and a deep cycle. One reason why many people avoid deep cycle batteries is coz the cheap ones are made for stationary applications and fall apart in a 4WD.
Well made batteries like Federal, Trojan and Optima overcome that problem (but be aware that the optima is on 55 Amphour). Another problem with deep cycles is that they don't charge properly from a alternatoras they prefer a slower charge at a higher voltage. I opted for a Federal 105 Amphour for my second battery and use the Rotronics independant charge system. I use an Arlec DC10 (10 amp RMS, 6 amp DC) to top it up after every trip. The system was installed by opposite lock for around $400 (not fitted) and the battery purchased from battery world for $250. The tray was installed by opposite for $250. The Federal runs our EvaKool 70 litre fridge for a long weekend without having to start the car. Another option would be the Century MarinePro 600 battery which is a starter battery with more tolerance for being discharged then most starter batteries, but you will still get a reduced life if you discharge it more than occasionally.
AnswerID:
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Reply By: Jim - Monday, Apr 08, 2002 at 00:00
Monday, Apr 08, 2002 at 00:00
Michelle, I tried for months to sort out dual battery systems. Each person I soke to has a different story. I'm not sure I've got the correct answer - maybe there ain't one. On the basis that batteries suffer sulphation if not reharged fully fairly quickly after draining, I've wound up wiyh a cranking battery and a deep cycle battery. All the systems run off the deep cycle one, and a solenoid is used to isolate them. There is also a switch that will isolate them when engine running, with the object of directing the full charge of the alternator to the deep cycle battery. I am also to charge the battery fully using a charger after each trip, and to watch the state of the batteries by measuring the SG every 3/12 or so. I am told that will ensyre long life. For what it's worth, there gas been no loss of SG since put in in July 2001.
I wish you the best of luck in trying to sort out what appears to ne to a dog's breakfast!
AnswerID:
2692
Reply By: Howard - Friday, Apr 12, 2002 at 00:00
Friday, Apr 12, 2002 at 00:00
I look at what some people spend on dual battery systems and now i know why the vehicles never leave the tarred roads. (they cannot afford the fuel after paying thru the nose for a dual battery system).michelle , fit a deep cycle battery with a manaul isolator switch.should cost about $250 in total.i have used a 75 amp hr deep cycle battery for over 3 years in a 60 series diesel and is now fitted in my 80 series petrol. runs the fridge ok and cranks as
well , to the extent that it was only after a long weekend fishing trip that i discovered that the main starting battery was RS and the deep cycle had been turning the old 2H diesel over thru the
canberra winter with plenty of below zero morning starts.
sure you have to open the bonnet and wind the green knob each night but even with the current price of fuel you are hundreds if not thousands of km's ahead.
AnswerID:
2782
Reply By: Howard - Friday, Apr 12, 2002 at 00:00
Friday, Apr 12, 2002 at 00:00
I look at what some people spend on dual battery systems and now i know why the vehicles never leave the tarred roads. (they cannot afford the fuel after paying thru the nose for a dual battery system).michelle , fit a deep cycle battery with a manaul isolator switch.should cost about $250 in total.i have used a 75 amp hr deep cycle battery for over 3 years in a 60 series diesel and is now fitted in my 80 series petrol. runs the fridge ok and cranks as
well , to the extent that it was only after a long weekend fishing trip that i discovered that the main starting battery was RS and the deep cycle had been turning the old 2H diesel over thru the
canberra winter with plenty of below zero morning starts.
sure you have to open the bonnet and wind the green knob each night but even with the current price of fuel you are hundreds if not thousands of km's ahead.
AnswerID:
2783