Discussion
Hi I have a freind whose caterham seems to eat batteries [4 in6/7 years ] it is unmodified,factory built,lightly used all the tricks ,old indian knowledge seems to have made little difference i.e premium battery ,battery conditioner ,remove battery and store indoors in winter.It has a an immobiliser system but he says this does not work ,he tells me it is part of the K series ecu ,he was told this by Cat Mids when he bought the car,no work has been done and the problem still exists ,I know little about the K series ,other than it apparent appetite for head gskts and don't want to delve in and not only damage the car but a very good freindship ,has any one any idea's thoughts etc ,replies will be appreciated
Hook it up to a maintenance type charger when it is parked up.
Accumate do them and there are others:
http://www.incarexpress.co.uk/view_product.php?par...
http://www.halfords.com/webapp/wcs/stores/servlet/...
Accumate do them and there are others:
http://www.incarexpress.co.uk/view_product.php?par...
http://www.halfords.com/webapp/wcs/stores/servlet/...
Personally, I simply fit a 'competition' battery isolator switch.
Isolated batteries lose charge very, very slowly (and if you wish you can hook them up to an Accumate or similar to keep them topped up, anyway) - if the battery is physically disconnected from the car's wiring system, there's no way the immobiliser or anything else can draw current.
If he finds he's still killing batteries even if they are isolated when the car is not in use, then it tends to imply there's something about the car's operation they don't like: either excessive heat/vibration (and I must admit, I've heard anecdotal reports of similar problems with 'Sevens' before, so this might be a possibility), or the regulator isn't working on his alternator (but I assume the first thing you did was to check that the alternator isn't over or under-charging?).
Isolated batteries lose charge very, very slowly (and if you wish you can hook them up to an Accumate or similar to keep them topped up, anyway) - if the battery is physically disconnected from the car's wiring system, there's no way the immobiliser or anything else can draw current.
If he finds he's still killing batteries even if they are isolated when the car is not in use, then it tends to imply there's something about the car's operation they don't like: either excessive heat/vibration (and I must admit, I've heard anecdotal reports of similar problems with 'Sevens' before, so this might be a possibility), or the regulator isn't working on his alternator (but I assume the first thing you did was to check that the alternator isn't over or under-charging?).
Edited by Sam_68 on Sunday 30th October 08:36
I agree with Sam, check the alternator is not overcharging, if you can't find out what is draining the battery fit an isolator switch but make sure you fit a good one and keep the cable lengths as short as possible.
My Tiger (pinto engine, electronic ignition, bike carbs so very simple electrics)has an old battery but always starts, even in the winter after a month sitting in the garage. My friends Westfield SE8 has an injected 4.6 Rover engine, the battery in the back and an isolator on the dash, this is very sensitive to the state of charge in the battery, so much so that the previous owner fitted a battery charger thing as discussed above, he gets through a battery a year just to keep starting reliable.
My Tiger (pinto engine, electronic ignition, bike carbs so very simple electrics)has an old battery but always starts, even in the winter after a month sitting in the garage. My friends Westfield SE8 has an injected 4.6 Rover engine, the battery in the back and an isolator on the dash, this is very sensitive to the state of charge in the battery, so much so that the previous owner fitted a battery charger thing as discussed above, he gets through a battery a year just to keep starting reliable.
Sam is spot-on about using an isolator switch. Until last month my toy had moved about all of 250 miles in 10 months; but the battery started it every time on the nose, every few weeks to run the engine up to temp and check it over. No charging/accumate etc required or applied.
SLA Batteries themselves are pretty dumb objects; when left alone and charged, a voltmeter should show not less than 12.7 on the terminals (12.8-12.9 healthy). As for alternator regulation, with the engine running at all you should see not less than 13.5 -13.6v at idle on average (even for BECs - I have one); and a max of about 14.4V at higher engine speeds. These ideal readings vary but only slightly with temperature and chemistry. eg if you battery reads only 12.5v at best fully charged, it *is* on its way out.
SLA Batteries themselves are pretty dumb objects; when left alone and charged, a voltmeter should show not less than 12.7 on the terminals (12.8-12.9 healthy). As for alternator regulation, with the engine running at all you should see not less than 13.5 -13.6v at idle on average (even for BECs - I have one); and a max of about 14.4V at higher engine speeds. These ideal readings vary but only slightly with temperature and chemistry. eg if you battery reads only 12.5v at best fully charged, it *is* on its way out.
Two things happen to batteries to make them fail. The common one is lead sulphate building up on lead plates inside, and the flatter the battery gets the thicker this layer gets. This process is quite normal, and to reverse the process that battery has to be charged to make the lead sulphate go back into solution. This process fails if the battery gets highly discharged when the layer gets too thick, or if it never gets to a full charge voltage (I think this is about 14.2 volts) so the lead sulphate becomes an insulator and the battery's capacity drops. In really bad cases you will see the battery sides distort and the lead sulphate pushes them out. This is the process that kills batteries even when everything is OK, as not all the lead sulphate dissolves during charging so the layer build up over time anyway. At the other end over voltage charging a battery will cause it to release hydrogen gas, and the electrolyte level will drop, so the batteries amp hour capacity will drop. If you can get the vent plugs out of a failed battery have a look at the electrolyte level and check its above the lead plates. If its not visible the battery is being overcharged. Also if you push to much charge current into a near flat battery the battery can over heat and the lead plates bend and short out. A car alternator does not accurately regulate the charge current into the battery, so it can dump a high current into a near flat battery, so its best avoided on a regular basis.
The process of keeping a battery at its best needs the battery to be cycled up to around 14.2 when it just starts to gas, then dropping the voltage back to a point when it stops gassing. At this point the lead sulphating starts again, so the battery needs to be cycled up to peak voltage again to remove the sulphate. This can be a process over weeks, and its part of what a good battery conditioner will do, unlike a simple battery charger that simply provides a fixed voltage. The worse type of charger is those that dont regulate the voltage accurately, and make the battery gas excessively so the electrolyte level drops too far. As a matter of interest the car battery chargers Lidl do on a regular basis for about £12 work a treat on the correct battery maintenance cycle.
The process of keeping a battery at its best needs the battery to be cycled up to around 14.2 when it just starts to gas, then dropping the voltage back to a point when it stops gassing. At this point the lead sulphating starts again, so the battery needs to be cycled up to peak voltage again to remove the sulphate. This can be a process over weeks, and its part of what a good battery conditioner will do, unlike a simple battery charger that simply provides a fixed voltage. The worse type of charger is those that dont regulate the voltage accurately, and make the battery gas excessively so the electrolyte level drops too far. As a matter of interest the car battery chargers Lidl do on a regular basis for about £12 work a treat on the correct battery maintenance cycle.
Edited by blitzracing on Sunday 30th October 09:07
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