Mud-club
Chat & Social => The Bar - General Chat => Topic started by: Mark_Solesbury on May 12, 2008, 17:13:48
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Hi
I have 2 battery's in the 90, one for normal and one thats connected to a few spots, radio, and a fridge when we go camping.
The split charge system is basic - a massive relay, starter motor wire from relay to each battery, a ground with starter wire, and a feed from the alternator to switch it. So when the engine is running, the batteries are joined in series; when its not they are isolated.
The problem i have is that both batteries are starter batteries, and ive killed the second one with the fridge. At driffield after many beers, i went to bed and left the fridge on for the whole night which flattened it to about 5 volts.
Im looking to get a new one to replace the leisure one. probably 110Ah.
Anyone got any recommendations? Makes to stay well clear of?
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Are you sure its dead dead?
I left the elise for 4 months and the battery was totally flat, no light on dash, not a click, wouldnt even tick on a booster box, had it on a conditioner charger for a week and its been fine since. Same for our golf we left as well, that needed a 10 min jump start.
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Its not dead dead, but it dont last long as its only a normal starter battery.
Leisure ones should last longer shouldnt they as they give out current at low voltage?
Or is that rubbish!
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Would not reccomend a leasure battery for starting the vehicle as they are not made to run that way.
Leasure batteries as you say run for hours at low voltage ie lights small pumps etc, to start a vehicle takes alot of juice from any battery and are designed differently.
To charge a leasure battery will take alot longer than a vehicle battery so when you think it is charged it most probably isnt and will drain fast without the lengthy charge
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This will be as a second battery
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If they are running in series they will both be used to start the vehicle though or have I read it wrong
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They are connected together in series, only when the alternator is outputting 12volts, so they will only be in series when the engine is running.
When starting, they are not connected in anyway.
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Connected in series? That should give you 24volts
The double battery systems I've come across are all connected in parrallel. Here is a good link of lead acid batteries
http://www.vonwentzel.net/Battery/00.Glossary/
The main differeance between a 'leasure' and 'starting' lead acid battery is the thickness of the plates inside the cells. thinner plates allow a higher CCA (for starting and engine) but thicker plates last longer when discharged.
There are some people on here like dan (aka extreme90) who run twin 'leasure' batteries in parrallel, giving double the CCA of a single leasure battery to start the engine with all other benefits of leasure batteries, The are optima batteries mind and a yellow top (leasure version) has similare CCA performance to a typical lead acid car battery of the same capacity.
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Connected in series? That should give you 24volts
:oops: :oops: :oops: :oops: :oops: :oops: :oops:
Parallel.. :doh:
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I just got my leisure batt from the local motor factor - the biggest that fitted in with the standard battery that wasn't at a silly price. Do not think its much of a known brand but carries a 4 year warranty which it about the rate I replace batteries at anyway.
While out laning on Sunday the leisure battery went flat (~11.9 volts) and even though engine was running my aux equipment wasn't get enough power from the alternator. Turned out the big solenoid I was using the dual charge was losing 2volts across the contacts. Opened it up to find quite a bit if mud and pitted contacts. Have used a normal 30amp aux relay and wiring for the dual charge now. There is no need for heavy cabling on a dual charge unless used for winch or a setup where you may want to switch cranking battery without swapping cables.
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Alright Mark,
I bought a 110A leisure batt from tayna for my 101 (after recommendations in A.F.L). Cant fault it so far - though its only been properly fitted for a week or so! ;)
http://www.tayna.co.uk/L110-Premium-Numax-Deep-Cycle-Leisure-Battery-P2100.html