Battery drain

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pcatterall

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Following my last post on 'ghost voltage' I have been trying to sort out the wiring especially as there was an obvious drain even when everything was switched off!! ( partly down to the leak to the starter motor detailed below)
I still found some other losses but am uncertain as to their significance as I am usless with my multimeter.
With it set on 10amps there was no drain in evidence.
Using the 200m scale(what is that?) I had a reading of 3.8 with the battery switch off and 40 with it on ( all equipment switched off) I cleaned and dried all the battery tops, the bus bar and all the main connections and then measured ( 200m scale) 0.0 with battery switch off and 7.00 with it on ( all leads on the bus bar disconnected.
When I connected the bus bar leads I believe that due to the drain to the starter ( below) that I may have upset my multimeter as it dont work no more!!
One observation is that although the battery tops were not too dirty I think I could see evidence of 'tracking' to the positive terminal. I am at a loss to see where the reading of 7 comes from unless the on/off/on switch has some sort of 'leak'
Any ideas from you experts and can you explain those current symbols ( 200m = 200 milliamps?? or what)
Many thanks and appologies for 3 posts!!
 
I don't know what switches you have, but on my boat I had to strip down and clean the two main switches for exactly this reason.

Come to think about it....it's a few years ago that I did it. Maybe I should check them when I'm next down on the boat.
 
200m - sure it isn't 20 Ohm (resistance scale)? If so using that scale with the battery connected will very probably have cooked the insides (unless you have a posh meter with a fuse).
 
Yes 200m means 200mA (milliamps)

I think I might ignore 3.8mA but 40mA is a bit too much. Over a month that's

40/1000 X 24 X 30 Amp hours = nearly 30Ah. That's quite a chunk out of the battery.

7mA is not too bad.. Only 5 Ah in 30 days. You should be able to live with that. It may be made up of several small leaks that will be almost impossible to locate.

To put it into perspective there is 10mA drain all the time from my car battery. The clock I think!

You may have just blown a fuse in your meter. worth checking but they are often special small ones (I bought a packet full from Maplin for mine!)
 
200m shou;ld be 200ma or 0.2a so you reading of 7ma is 0.007a and it is quite possible to get that sort of level of leakage accross battery selector switches. To put it in context at that rate it would take over 1 month to drain a 100a/h battery so I would not worry to much unless you are also finding that you anodes dissappear fast. 40ma was a significnt loss and it confirms why its important to periodically clean and check the electrics. I suspect that the reason the meter is now not working is due to a blow fuse. It is very easy to get enough surge on the circuit to blow the fuse on a cheap meter. A much better instrument but rather more expensive is a clamp meter. These measure current by clamping round the wire so you dont have to disconnect it and read high currents so can check full output on the alternator or starter motor.
 
Also just read you other posts, given you level of experience if you are having a range of electrical problems it might be wise toget an electrican to chech the system particularly if it is getting a bit elderly or has had modifications do by previouse owners
 
After you reconnected your Bus bar leads you say that the meter failed.Yes, then you have you have more than 200 Milli amps flowing to your bus bars and your fault lis somewhere there, 7 Milli amps with the starter being fed is very low, probally dampness in wiring or starter cap on the solenoid not much to worry about. next step I suggest it to connect and switch everthing off, disconnect all supplies to non switched items vhf,radioe bildge pumps ect and conduct the test again, this time with your meter connected in the line that feed your distribution board and see what you get. if still there each circuit will have to be disconnected in turn until you find the drain. Make sense to you, if not call in an electrician as suggested. Best of luck.
 
The only other comment is regarding the cleaning of the battery. It is unlikely that you can measure in any way the leakage across the battery top as it is from terminal to terminal and you can't break into the circuit to measure it.
So leakage is likely to be at switches etc. good luck olewill
 
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