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MG Midget and Sprite Technical - Battery power
|My 66 midget is having a very protracted restoration and hopefully nearing the end. The battery has been in it a long time but I regularly charge it . The lamps are very dim and the indicators can hardly manage to blink but to my surprise when I tried to start the car it spins over a lot better than expected. How can it hardly have enough power for the wipers but be able turn the engine over? I was looking to replace the battery but now I am not sure, are there any checks I can do?|
Unfortunately I couldn't get te car started so couldn't check if the electrics improve when running. Any ideas welcome
|The wiper wheelboxes are partially seized?|
|there are a lot of connections between the battery and the lights (plus switches, fuses, fusebox, wires)|
check the battery 'water' level in in each cell
get the battery checked with a hydrometer or multimeter or do a drain test on the battery - this vid may help you - http://www.youtube.com/watch?v=_Uk53AYZ_2o&list=UU40j4KqUJPMVv4FQ29ro-xQ&index=13
|Bad grounds ...|
I would say check the strap between the chassis and the tranny next to the clutch slave ... but if it was.missing, loose, rusted or bad in general... then the engine wouldnt turn over so easily
But I still think its a bad ground somewhere....maybe a rusty connection at the dyno/alt.
|Prop and the Blackhole Midget|
|My few words.|
The loom's bullet connectors get internal corrosion, especially if unused for a while.
They "work" the lights, indicators etcetera and if corroded can lose the power of the battery's lecktrickery.
Body earths around the wings and inner panels get rusty, hence cause heavy voltage drops on those circuits too.
The connections from battery to starter are beefier and if in good condition are far more likely not to misbehave.
A good idea would be to pull all the bullet connectors apart, clean them up with a piece of wet'n'dry then refit each with either a smear of anti corrosive paste or at a pinch vaseline petroleum jelly to keep rot at bay.
Some people use 0.177" brass rifle cleaning brushes to clean them out I'm told.
When I put my car back into service I had to replace some of the female connector blocks completely, the old ones even cracked and slpit apart inside.
A few quid spent on spare one, two, three and four way connector blocks will pay dividends.
|It sounds like the connectors might be the way to go. The engine spinning over makes me think the earth strap is ok. I might try a wire straight from the battery to a lamp and see if it's any brighter, would that prove anything?|
|Try a temporary additional earth wire from the item (headlight?) to earth. For some reason it always seems to be the earth connections, rather than the live feeds.|
|What Guy says too|
To test a unit you need good clean power in and good clean earth out
So a known earth and a known power feed will test the lamps
|Can't add much (if anything) to what Bill says...and what Guy says!|
This thread was discussed between 15/05/2013 and 16/05/2013
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.