Se7enBTCC Posted September 28, 2022 Share Posted September 28, 2022 Interested to know peoples views on whether it's better to turn it off every time I get out of the car or only if the car is to be left for some weeks?A fellow owner spotted me turning it off when I got out the car on track and told me how it's better for the performance if I leave it on. We didn't go into any detail. I only turn it off by habit after leaving my lights on once and running down the battery.Thoughts? Link to comment Share on other sites More sharing options...
StevehS3 Posted September 28, 2022 Share Posted September 28, 2022 I only fully disconnect the battery when the car is laid-up over winter. The rest of the year I connect a CTek battery maintainer if I am not using it for a week or so. I seem to get very good life out of the Banner battery this way. I have read that on some cars the ECU's [long-term?] fuel trims are lost when power is removed so perhaps that is another reason for not removing the power too often. Link to comment Share on other sites More sharing options...
SM25T Posted September 28, 2022 Share Posted September 28, 2022 I turn mine off every time I get out of the car. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 28, 2022 Member Share Posted September 28, 2022 Drain on the battery at rest differs considerably between Sevens.Jonathan(No master switch, Odyssey PC680, CTEK charger connected whenever the Seven is at home) Link to comment Share on other sites More sharing options...
StevehS3 Posted September 28, 2022 Share Posted September 28, 2022 Drain on the battery at rest differs considerably between Sevens.This is a very good point. Do we know what the battery drain is for various models? I measured the Banner battery voltage after standing for a week powered up with no battery maintainer and the battery voltage hadn't reduced (12.6V from memory). 2017 310R. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted September 28, 2022 Member Share Posted September 28, 2022 Andrew Revill did some measurements of drain. It would be great to have more, and I suspect that there are systematic variations between models. And that these affect the conclusions that have been drawn about batteries and the need for chargers and for isolation switches.JonathanPS: For typical car batteries the battery voltage at rest is a rather insensitive measure of residual energy. Load testing is better. And the only convenient load that most of us have is a starter......Previous discussion of drain:https://www.caterhamlotus7.club/forum/techtalk/how-guide-investigate-parasitic-drainincludes Andrew's conclusions on Ks, and Roger Ford's method of measurement. Link to comment Share on other sites More sharing options...
Roger Ford Posted September 28, 2022 Share Posted September 28, 2022 There's a theory that K-series ECUs lose some throttle position info if you use the kill switch WITHOUT turning the ignition off first, as it saves data to flash memory after the ignition is turned off. But plenty of K-series racers disconnected their ignition switch and only ever used the kill switch to turn off. I guess if it only affected tickover that wouldn't bother them too much.I've never heard of any issue if you turn the ignition off first then use the kill switch. Wouldn't be a very good design to rely on the ECU having a permanent power feed. Link to comment Share on other sites More sharing options...
DougBaker Posted September 28, 2022 Share Posted September 28, 2022 I remove the key every time I park the car in the garage. Before I had the kill switch added thinking "oh I will drive it again in a few days, I don't need to put the conditioner on" was how I killed at least two batteries. Link to comment Share on other sites More sharing options...
GBYellow61 Posted September 28, 2022 Share Posted September 28, 2022 Hi AllWhat's the screw size and thread for the side straps on a half hood? Link to comment Share on other sites More sharing options...
SM25T Posted September 28, 2022 Share Posted September 28, 2022 Might want to ask that in a new thread. Link to comment Share on other sites More sharing options...
SM25T Posted September 28, 2022 Share Posted September 28, 2022 My SoftBits half hood attached with poppers riveted in place Link to comment Share on other sites More sharing options...
Neil Bolton Posted September 28, 2022 Share Posted September 28, 2022 Related question on the battery master key.....during the winter when you put the car on a trickle charger is it still OK to remove the key or does this in any way impact the chargers ability to maintain the battery? Link to comment Share on other sites More sharing options...
John Vine Posted September 28, 2022 Share Posted September 28, 2022 #12:It'll be OK. In fact, removing the key is a good idea as it will prevent drain from the immobiliser.Out of interest, do you connect the charger directly to the battery (say, by crocodile clips), or do you have a permanent connection via a wired-in 12v socket? JV Link to comment Share on other sites More sharing options...
Area Representative Golf Juliet Tango Posted September 28, 2022 Area Representative Share Posted September 28, 2022 Switch everything off, kill the ignition then remove the battery key. Every time. Even when in the garage. Link to comment Share on other sites More sharing options...
Neil Bolton Posted September 29, 2022 Share Posted September 29, 2022 Don't actually have the car yet!!! Due October/November......but have a charger that will connect to the power socket that in the passenger well (at least for newer cars). Link to comment Share on other sites More sharing options...
John Vine Posted September 29, 2022 Share Posted September 29, 2022 #15:Exciting times! In #12, you mentioned "trickle charger". Is yours a conditioning charger (such as CTEK, Optimate or Accumate) that monitors battery voltage and adjusts the charging voltage accordingly? JV Link to comment Share on other sites More sharing options...
GulfSeven Posted September 29, 2022 Share Posted September 29, 2022 I turn my master switch off and remove it every time I get out of the car.I also don't use a battery conditioner for the winter lay-up. So far, both times its been laid-up for 4 months, and both times it's started first time in the spring. Link to comment Share on other sites More sharing options...
StevehS3 Posted September 29, 2022 Share Posted September 29, 2022 Between us I think we have covered every combination :) Link to comment Share on other sites More sharing options...
Se7enBTCC Posted September 30, 2022 Author Share Posted September 30, 2022 Yes every possible option. Thanks everyone, I think the main takeaway is there is no gain from leaving it on! Link to comment Share on other sites More sharing options...
GulfSeven Posted September 30, 2022 Share Posted September 30, 2022 Yes - I didn't have one on my Elise and had to use a battery conditioner in the garage. Having a master switch is so much less faff. Just remember to take it with you when you park anywhere so nobody nicks it and leaves you stranded! Link to comment Share on other sites More sharing options...
Neil Bolton Posted September 30, 2022 Share Posted September 30, 2022 Sorry my bad....yep it's a CTEK One....conditioning charger Link to comment Share on other sites More sharing options...
ChrisC Posted September 30, 2022 Share Posted September 30, 2022 Since it was me that made the comment, I think I should backup my statement with the evidence / observations I have made and the reason behind it.Every time my 420 with a stock locked Caterham MBE 9A4 ECU is isolated the Adaptive Map Output and the Short Term Trim is reset to 0%. This does not happen if the ignition is switch off and back on again. Normally the Adaptive Map Output is -10% (max value) and the Short Term Trim is between -7% and -11% meaning the base map is approximately 20% rich. While running with just the base map, my lambda is voltage is 1.22v, way to high(rich) for the ECU to accept the signal as valid, so it's ignored. The ECU reports it's ignoring the lambda sensor with a faulty code of "Bad AFR Reading" and assumes a value of lambda. During this time the engine is running significantly rich, with all the negative effects that brings. However eventually the coolant temperature compensation brings the lambda voltage into a range that is acceptable (1.1v which is still very rich), at approximately 12 mins after starting and a coolant temperature of 90c. The official warmup time for the lambda closed loop system is 30 seconds and 60c coolant. Therefore an isolation event effectively makes your engine artificially rich for longer, it's difficult to say how rich and for how long because it depends if your coolant is going to reach the temperature needed to bring the lambda into acceptable range. Combine this with a bit of over cooling and you may never achieve closed loop control and adapt the base map.I am happy to provide the data if anyone wants to research this further. Personally since finding this out I isolate less, and only when leaving the my car for more than a day. Link to comment Share on other sites More sharing options...
Se7enBTCC Posted September 30, 2022 Author Share Posted September 30, 2022 Chris fantastic detail, I couldn't remember what you said on track!I do have an issue whereby the car runs too rich at start and doesn't idle without throttle input for 10 or so minutes, warm or cold. Could explain it.The car is only used once a month on track days so isolating the battery is the best bet combined with a battery maintainer. Link to comment Share on other sites More sharing options...
Roger Ford Posted September 30, 2022 Share Posted September 30, 2022 Perhaps we need a new thread : ECU design - best practices What an abysmal design for an ECU for a car which is more likely than not to be fitted with a kill switch. Have they not heard of flash memory? Link to comment Share on other sites More sharing options...
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