Jonathan Kay

Some experiences and warnings. Jonathan

"Maybe coincidence but i have a 620 and a CTEK 5.0 and the battery doesnt like the CTEK , sometimes it works fine , other times it crashes." What's the battery, please? Thanks Jonathan

"I washed it before garaging it for the night and the battery was reading about 12.8v after having the ignition off for an hour or so. I'm not sure if this is good or bad but doesn't seem terrible." The unloaded voltage is a very late indicator of a failing battery. The minimum during cranking, as above, will give you better early warning. Jonathan PS: Is the digital voltmeter (not the multimeter) now showing plausible readings?

"I must admit I thought the Odyssey batteries were gel, had one for 8 years and didn't know they were AGM." Ahem: https://www.google.com/search?q=site:lotus7.club+gel+agm+jonathan : - ) I think that it's the G in AGM that causes the confusion, but it might be the attractive idea of a gel not containing liquid. Jonathan

"CTEK disconnected, all power off: 13.5v Cranking: 10v (It took about 6 goes to start because it's very cold right now) idle: 14.47v 3,000 rpm: 14.8v (after revving it is sitting happily at 14.8v)" Thanks. The charging from the alternator looks fine. That's going to be important in the next stage. 10 V during cranking is lower than desirable. Apart from having enough oomph to turn the engine sufficiently quickly the battery has to power the electronics. On some Sevens problems occur if the voltage drops below 10.5 V even though the cranking seems OK. So I'd measure that minimum cranking voltage repeatedly. The battery might be on its way out and that measure dropping any further would confirm that. And if there are any problems with the engine picking up during cranking that could be the cause. Jonathan

"Are you sure that you didn't disturb the battery connections while adding the CTEK connector?" Same thought, and that's why I asked for the photos. But it looks as if a solution is appearing. : - ) Jonathan

"Is this what you mean from Halfords, might get one just incase I have problems tomorrow... https://www.halfords.com/motoring/battery-maintenance/jump-starters/halfords-advanced-lithium-jump-starter---up-to-2l-677444.html(link is external) or maybe this is better... https://www.halfords.com/motoring/battery-maintenance/jump-starters/gb40-1000a-noco-jump-starter-721898.html" That sort of thing. But I don't have one myself. There are lots of comments and some experiences in the archives: https://www.google.com/search?q=site:lotus7.club+lithium+jump&client Jonathan

The Odyssey batteries used in Sevens are AGM type, not gel type. https://en.wikipedia.org/wiki/VRLA_battery#Absorbent_glass_mat_(AGM) https://en.wikipedia.org/wiki/VRLA_battery#Gel_battery Jonathan PS: Thanks for the voltages... I'll comment asap.

"I think I will buy jump leads but not sure whether to just buy a new battery" I carry fat jump leads in all our vehicles at all times. I'd also consider a lithium battery jump start pack. They're useful for all sorts of things. I wouldn't recommend carrying one routinely as an alternative to sorting out the Seven's electrics, but it might provide some reassurance and will get you home in the meantime. Jonathan

In the absence of proper load testing equipment... once it's recovered I suggest measuring the battery voltage with the multimeter: At restMinimum seen during cranking (whether it starts or not)At 3,000 rpm.and posting the values here. Jonathan

"The battery will come in the house this winter." NB The Banner battery is unsealed so make sure that any acid doesn't go anywhere that it shouldn't. I once made a right Jackson Pollock of the back seat of a Polo because I forgot about this. Jonathan

AGM mode is for Absorbent Glass Mat batteries including that Odyssey. https://en.wikipedia.org/wiki/Lead–acid_battery#Absorbent_Glass_Mat_(AGM) https://www.ctek.com/uk/battery-chargers-12v-24v/mxs-5-0-uk Jonathan

"... an old fashioned charger is likely to be needed to get it going." Definitely worth trying. And you can do something similar by jump starting from another battery or vehicle. As soon as the you've got the engine running check the battery voltage at 3,000 rpm. If isn't charging normally then you need to know asap. Jonathan

Same thought as those above: 00 is very suggestive of something other than a shot battery... bust voltmeter, bad connection... Check the battery voltage with the the multimeter at rest and as you switch the charger on. Jonathan

"I can try and buy a new battery but I'm worried about being able to source one the same day (in Kent or nearby)" I try to keep this thread up to date "Whats the best battery these days". Jonathan

More details, please: How old is the battery? How do you know that it has been "drained to nothing"? Which charger lights came on when you connected the charger the second time? Do you have a multimeter? Have you got another battery or car you can use to jump this one? And please can you add a photo of the connections. Jonathan PS: I once had a CTEK charger which had failed. Took me months to work out what was happening... because the lights came on appropriately and then changed in the usual sequence.

Thanks. Private Message sent. Jonathan

"My 2014 sigma has the same fuse box as the 2017 above." Same layout as post #1? Thanks Jonathan

"If I recall correctly, and this would need to be verified, the o/e Ford ones are 41mm, these are the type Caterham will supply. However aftermarket ones are 41mm/42mm for the LH/RH thread, each side is handed. I also recall some comment that it's recommended to stick to the o/e version." These from Ford are 41mm. But these from Ford are 41mm/ 42mm. Jonathan

And the odd layout is discussed in this thread. And was this: Jonathan

That layout comes from this diagram: 0900167 Sigma TA 2013 Chassis Harness.dwg_.pdfJonathan

"... are the hub nuts on current cars 41mm or 42mm?" The current Assembly Guides (v2.1) do not answer this question. They say that they're handed and need 270 Nm but not their size. https://www.caterhamcars.com/en/aftersales/owners-downloads And this is unusual. For many other fasteners they have a description in the fastener pack and say which tool is needed. Jonathan

If you send me a Private Message with your email address I'll send you the whole diagram from which that's clipped. Jonathan

I suspect that it's this: but unfortunately that diagram doesn't include what each fuse does! In order to work that out we have four main weapons: 1 Someone providing the answer. 2 Someone finding that previous thread. 3 Working through the whole diagram, but at least the wire colours are marked at the fuse box and Caterham generally stuck to the British standard. 4 A combination of pulling them to see what they do, and a list of likely values from other Sigmas, appended. Jonathan

There are two layouts for Sigma engines in my collection of diagrams. And there's one more that isn't in there but which we documented in a previous thread. I'll have a look when I'm free if no-one has solved it by then. Jonathan