Batteries - sealed v un sealed?
Submitted: Monday, Dec 11, 2006 at 13:10
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emortal
We have a 79 Series Turbo Diesel Landcruiser. An auto electrician has recommended we use a low maintenance unsealed deep cycle second battery, because a sealed (AGM) is likely to overheat when located under the bonnet (ie heat from the turbo diesel and from climatic outback temperatures.) Any comments?
Reply By: Mainey (WA) - Monday, Dec 11, 2006 at 13:28
Monday, Dec 11, 2006 at 13:28
emortal,
Sounds like you don't trust the advice of a "qualified" Auto Sparky
why not get a second opinion from another "qualified" Auto Sparky
OR
better still go to a 'specialist' battery
shop for their advice
Outback temps will NOT harm an AGM battery (I have two)
The benefit of an UNsealed battery is you CAN add distilled water IF (yes IF) the battery gets too hot and looses fluid because of the position the battery is placed inside the engine bay.
The real benefit of an AGM battery is their long life and very quick recharge times available from them over a wet cell battery.
AGM Gel is a No No No in the hot engine bay temps.
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209749
Reply By: Member - Gadgets (VIC) - Monday, Dec 11, 2006 at 13:57
Monday, Dec 11, 2006 at 13:57
emortal
not sure about the heat issue. I have an unsealed battery (deep cycle) in the engine compartment and have not had overheating problems when up north BUT I did run into an unexpected problem - leakage on steep inclines.
On some very steep sections of track the acid has leaked from the vent holes and splashed onto the underside of bonnet and around the mounting bracket. now have a problem with dissolving paint in that area and need to fix.
So if you are going to do any rough stuff then a sealed battery may be better.
Cheers
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Reply By: Member - Phil G (SA) - Monday, Dec 11, 2006 at 14:07
Monday, Dec 11, 2006 at 14:07
I have the same vehicle, and I tend to agree with your auto electrician. With the twin battery tray in the 79series, and space/ventilation is very limited - I put a heat shield around them as
well. I use twin wet cell cranking batteries, and change them over every 18mths-2 years, so that I always have a near new battery for cranking. As far as $$$ goes, I'd rather buy a quality $130 cranking battery every 2 years than spend best part of $300 on a Chinese AGM.
I'm not a heavy user of the 2nd battery - only use it for the Engel and lights, and the batteries get recharged every day anyway. The above works for me.
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Reply By: Gerhardp1 - Monday, Dec 11, 2006 at 15:41
Monday, Dec 11, 2006 at 15:41
Two of my travelling companions had problems with wet batteries on the
Cape york trip - both had acid splash out from the corrugations, both batteries underbonnet. One battery died due to the exposed plates.
I had no problems with my 100AH AGM under bonnet, no heat problem, no vibration problem, no leaks, just lots of available amps for the fridge (ran the fridge for 4 days, still started the car) and huge cranking amps (1000cca) as
well.
Yesterday I was driving around in
Melbourne and it was 43 deg; the battery remains unaffected by underbonnet heat, and has now been in the car for 6 or 7 months.
Mine is a petrol Jackaroo so maybe it is cooler under the bonnet than a cruiser turbo, can't say without sticking a memory thermometer under the bonnet of each one.
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Follow Up By: Member - Oldplodder (QLD) - Monday, Dec 11, 2006 at 17:04
Monday, Dec 11, 2006 at 17:04
Batteries can have different design vent caps.
Some are just a simple baffle chamber.
Others can have some sort of filter material in the vent cap, or at least a better baffle.
Have a look next time you buy a battery.
Thats why the century Yausa designed the Overlander for 4wd use.
Lots of little design changes for the extra vibration etc.
Yes, I used to do work for Century Yausa Batteries about 10 years ago.
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Follow Up By: Member - Phil G (SA) - Monday, Dec 11, 2006 at 18:13
Monday, Dec 11, 2006 at 18:13
Gerhard,
The problem with heat is that it shortens battery life. It can have as much effect as sulphation. So a battery in a hot environment may last say 2 years, while one in a cooler environment may last a couple of years longer.
My other observation is that a quality cranking battery comes with a 24 month replacement warranty. This is double the warranty that I've seen on most AGMs. Maybe theres a reason for this??
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Reply By: Sand Man (SA) - Monday, Dec 11, 2006 at 17:04
Monday, Dec 11, 2006 at 17:04
emortal,
I think there is a problem in terminology here.
Low maintenance and unsealed are almost contradictory to each other.
A normal wet cell battery may "evaporate" from exposure to a hot engine compartment.
A sealed, low maintenance wet cell battery is better because the contents are better contained inside the battery. (you can't "top" these up with electrolyte)
An AGM battery is probably the best type of battery for "auxiliary" use, although I have read on this
forum, that some have experienced severe distortion or bloating of the battery. This is more than likely to be caused by "cooking" from an adjacent turbo or exhaust manifold and a similar problem would result with any battery in this location.
So, a low maintenance, sealed wet cell, deep cycle battery is a cheaper choice and its footprint (physical size) will mean you can fit a higher capacity A/H battery in the engine bay than an equivalent AGM battery which are larger in physical size.
An aluminium barrier between the battery and a high heat source may also help.
That is my experience anyway.
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Follow Up By: Member - Oldplodder (QLD) - Monday, Dec 11, 2006 at 18:46
Monday, Dec 11, 2006 at 18:46
Good points Sand Man
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