Chris W

John The main/dip switch may be faulty. If you swap over the main and dip connections on that switch and you now lose main but regain dip, the switch (or the wiring to it) is the culprit. How have you ascertained the bulbs are OK btw? Chris 2003 1.8K SV 140hp see it here

Duncan You could put 2 of these wired in parallel to provide 100mA charge even in winter. Chris 2003 1.8K SV 140hp see it here

Not at 100mA. That's the same as a battery conditioner, which can be left on 365 days a year. Chris 2003 1.8K SV 140hp see it here

Duncan You need about 40mA min to compensate for the immobiliser so, if the guy's to be believed with 50mA on a winter's day, then your problem is sorted. 100mA will put a slow charge into the battery as well. Chris 2003 1.8K SV 140hp see it here

I also did exactly the same as Guy with the same connectors. Fast, convenient, foolproof connections. Chris 2003 1.8K SV 140hp see it here

Important Do ensure you put a 1 amp fuse in-line in the positive wire to the battery connection if the conditioner lead doesn't already contain one. Chris 2003 1.8K SV 140hp see it here

Amazingly I get around 40mpg from my 1.8K SV even when I drive it hard on country roads. Chris 2003 1.8K SV 140hp see it here

Ron My feeling is that you will most likely be OK. What batteries really don't like is being left discharged which is not what happened in your case. The water evporates which basically increases the acidity of the total liquid in the battery. This, on its own, will not detrimentally affect the battery unless you allowed the liquid content to grossly fall. In fact, in some (very cold area) the acidity is run much higher than we would normally use, to aid starting. When you say "the water level fell below the plates" I am assuming you meant below the TOP of the plates? I don't believe it would fall "below the plates" unless you had some kind of leak which would render the battery useless anyway. So long as you have now topped it up and the battery is charged, you should be OK. Obviously the proof of the pudding etc is to monitor its starting capability over, say, the next month. Chris 2003 1.8K SV 140hp see it here

Best to check the water BEFORE you run it as you may cause more damage by running it without sufficient. Chris 2003 1.8K SV 140hp see it here

The additional connections are usually to determine when the battery is charged. The chargers supplied with all these units (and mobile phones) are very basic chargeres and contain no special battery monitoring circuitry. So to determine when charging should stop, the battery contains within its plastic covering a temperature sensitive switch which opens when the battery gets hot (ie: starting to overcharge), interupting the charging process. This temperature switch is connected to the additional 2 terminals on the battery which are connected in turn to the charging circuit when all plugged together. The charging circuit "latches" when the temperature switch opens - ie: if it is switched off by the temperature switch opening, it stays off even if the switch cools and closes again. To reset the charger, it has to be disconnected from the appliance (eg: mobile phone) and reconnecetd. Most digital cameras, mobile phones, electric drills and PDA battery chargers work this way. Chris 2003 1.8K SV 140hp see it here

Chissy The Draper conditioner is fine for continuous use. It is NOT a trickle charger as someone thought above. I have had one connected continuously to my 7 for almost 3 years and have had no battery problems whatsoever. However you should check the water levels not less than once a month if you are leaving it on a conditioner. When you tried to charge the battery after it appeared not to accept a charge, I am presuming you used a standard charger (which you should) and not by trying to charge it with the conditioner (which isn't man enough for the job other than keeping the battery topped up). The suggestion to jump start the car is a good one as the alternator is the fastest charger you possess and will probably get the battery going again. I do suspect low water levels are the problem however. Chris 2003 1.8K SV 140hp see it here

Graeme Replace the existing switch with an identical one or replace it with a "normal" DPDT (double-pole, double-throw) toggle switch. The terminals on your existing switch tend to corrode as they are untinned copper and the switch is rarely used by anyone. Switching it on and off occasionally simply wipes the corrosion off the contacts. Chris 2003 1.8K SV 140hp see it here

Richard Glad you got it sorted. If it's of any interest, there is a photograph of the internals of the MFU plus a circuit diagram of the same on my website. (click below). You will see it shows the ECU operated switch you mentioned. Chris 2003 1.8K SV 140hp see it here

Richard Do you have a circuit diagram for the 1996 Supersport? If so, I would be happy to take a look at it and try to diagnose your problem. Chris 2003 1.8K SV 140hp see it here

Lancelot There's an internal photo of the MFU unit and a circuit diagram on my website. (Click below) Chris 2003 1.8K SV 140hp see it here

Disconnecting a battery over the winter will NOT prevent its draining. All batteries have a natural internal leakage rate. Do not allow a battery to remain discharged for any length of time as its life will be shortened or, in extremis (a few weeks) it may not recover at all. A conditioner is different than a trickle charger in that a conditioner will only deliver about 100mA when the battery is reasonably topped up and this is perfect for countering the drain from the immobiliser and clock for example as well as keeping the battery fully charged. I use the Draper version and, like others, have an under-dash permanent connection. Mine is ON all year (except when I'm driving the 7 as Draper short-sightedly only provide about 8 feet of cable ). Do check the battery water level every 3-4 weeks just to make sure it's kept up to the proper level. Note however that a conditioner will not deliver enough current to charge a low battery in any reasonable time scale. For this you need a conventional charger/trickle charger. A trickle charger, although delivering less current than a normal charger, still delivers too much current to be left on permanently. To do so would result in the battery's being overcharged at consequent detriment to its life. If you buy an "all-in-one" charger/trickle charger/conditioner ensure it states clearly that the device may be left permanently connected and permanently ON. Chris 2003 1.8K SV 140hp see it here

Postscript If you DO actually get 14v across the battery with the engine ON, AND the charge light is still ON, it could be that the charge light wire has dropped off the alternator (usually brown/yellow) and is touching the chassis. With the ignition ON, this fault would illuminate the charge light constantly. Chris 2003 1.8K SV 140hp see it here

Charlie With the engine OFF you should get about 12.5 volts across the battery. With the engine ON, you should get about 14 volts across the battery. The charge light's being ON indicates that the alternator is not supplying this 14 volts so either the alternator needs repair/replacement or the belt is loose so the alternator is not running properly. Chris 2003 1.8K SV 140hp see it here

If anyone's interested in fitting steering wheel mounted indicator push buttons give me a shout. The circuit works with fixed or Q/R wheels, has microprocessor control to allow push ON, push OFF functionality and auto cancel of one side when doing a LEFT-RIGHT double turn for example. It also has adjustable automatic shut-off delay and an audible buzzer. See photos on my website below (page 1, photos 9 & 10) Chris 2003 1.8K SV 140hp see it here

Julian To determine whether the gauge has a problem, switch ON the ignition, pull the lead from the top of the water temperature sender and short this lead to earth. The gauge should read full over (ie: HOT). If it reads anything but 100% hot, you have a problem with the gauge. Otherwise, it's down to less than perfect senders. Screw the sender in till it's tight but not overtight. Don't force it or you will get problems later as someone pointed out. Ensure the lead on the top is held snugly too and that the top of the sender (the contact) is nice and clean before you push the lead on (try some wire wool). Chris 2003 1.8K SV 140hp see it here

Nick The standard water gauge will cover the temperature needed for both water and oil. Providing you use the identical type sender, the gauge will read correctly (within its tolerances!) for both liquids. Chris 2003 1.8K SV 140hp see it here

Joseph The symptoms you describe suggest the field diodes are failing in your alternator. The purpose of these is to provide some initial small current to magnetise the alternator windings at start-up. Once under way, the field windings provide their own magnetism. If the diodes fail or start to fail, the field windings don't get any initial magnetism to kick the alternator into life so the alternator doesn't work........ ..........HOWEVER............ what happens in practice is that there is almost always some residual magnetism in the alternator which is usually enough to kick the alternator into life providing you rev up hard enough. This situation seems to obtain in your case. As the diodes fail (probably going leaky) you are finding that you need to rev up more and more to get the charging light to extinguish (ie: to get the alternator to start charging). I wrote about this, inter alia, in an article I did for Low Flyer about a year ago in the "Electrickery" series. Chris 2003 1.8K SV 140hp see it here Edited by - Chris W on 25 Oct 2005 18:31:16

Nick If you use an identical sender for the oil as you use for water temp, you can then use your water temp gauge to read water and oil by means of a simple single-pole, double-throw switch. That gives you the option of replacing the old ammeter with a new one. The ammeter is useful in showing charge rate in general and, in particular, initial charge after starting which gives confidence (or not) that the alternator is functioning OK. I drilled and tapped my sump bolt to take an oil temperature sender and it has worked perfectly without a leak for nearly 3 years. It seems a shame to throw away some useful information when you already have a hole in the dash. Chris 2003 1.8K SV 140hp see it here

A fully charged battery should show 12.6v (2.1v per cell) for a lead acid type. It may show higher than this for a few minutes after charging due to the electrolyte's not being mixed properly. Switch on the headlights for 5 minutes and then re-measure; you should find 12.6v. With the engine ON the figure should be around 13.8v to 14.5v depending on the actual alternator and regulator. Have someone crank the engine having disconnected the fuel pump (at the fuel cut-off switch for simplicity) to prevent the engine's starting. Measure the battery voltage whilst cranking. If it's below 9v, the battery needs replacing. Chris 2003 1.8K SV 140hp see it here

Don't forget to have the ignition switched ON when you do this test. Chris 2003 1.8K SV 140hp see it here