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Anon
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Voltage drop / Resistance to starter
Just trying to track down some reluctant starting issues.. with fully charged battery & still slow to turn over. Last year when we were out & about it would still occasionally struggle to turn over for a while and then burst into life.
I'm assuming this is a poor or intermittent connection somewhere leading to high resistance & voltage drop between the battery & starter.
I've tried a jump lead between battery neg & engine block with little effect, although hard to be sure it was making good contact on the engine.
I plan to go to work with the multimeter (when I track it down!) soon...
Question is.... what is a reasonable resistance between battery terminal & start +ve.. or battery terminal & engine earth ?
Say a good battery is 13v... and you still want 12 for a good start.... and starting current is 50A (making these figures up!).... V = IR....R = V / I
= 1v / 50A = 0.02 Ohm .. which seems like an unfeasibly low value given the length of cable run from my battery to my starter.
Cheers... and its good to be back.... lack of action on the van front meant i almost couldnt bare to look in here without a pang of guilt for the old girl !
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 Fri 27 Jan 2012 @ 18:21
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Anon
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Check for voltage drop when starter cranking engine (i.e. connect voltmeter between battery and starter, then engine & battery).
Should be no more than 0.5V drop between starter solenoid and battery positive terminal & similarly between engine & battery negative terminal.
Also check that battery voltage doesn't drop below about 10V when starter cranking engine.
Symptoms sound more like a starter problem though, worn brushes top of the list.
If starter is Lucas M35J type with 4 small screws securing brush end plate to yoke (starter body) then brush gear problems can arise due to excessive armature end float, loose or broken brush holder, weak brush springs, damaged commutator (burnt or loose segment/s, solder throw) as well as worn brushes, or a combination.
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Fri 27 Jan 2012 @ 22:31
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Anon
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I had the same problem with my camper although when testing the voltage at the battery whilst cranking proved the battery to be ok,so it was Phil to the rescue he tested the voltage at the starter when crancking and said its a starter problem. He removed the starter and stripped it down to find quite a few problems, he lent me a spare one he had to keep me mobile and returned a week later with the starter working perfect nice one Phil.
Dave
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Sat 28 Jan 2012 @ 08:48
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Anon
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Dave has reminded me about the quick test for starter problems: check voltage at brushes terminal when starter cranking engine.
Battery & cables have to check out ok first & this test is best done when the starter does run slowly (cold start better than warm start).
Connect voltmeter between brushes terminal (or on solenoid terminal for brushes cable for Delco or Bosch starters). Disconnect coil to prevent engine from firing.
Crank engine on starter & watch meter reading.
Reading dropping much below battery voltage (starter cranking, ~10V) and, or, wandering up and down indicates excess current draw due to brushes problems, or dodgy solenoid contacts if they're well mashed with age.
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Sat 28 Jan 2012 @ 09:29
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Anon
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I have to confess I'll be a bit upset if it's a starter issue after all the pain of replacing brushes & bushes last year 
All a bit academic till i find my multimeter tho. 
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Sat 28 Jan 2012 @ 21:28
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Anon
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Could be as simple as a bad earth, works OK for lower amperage systems but fails when the high amp starter is used.
easy to test, put a jump lead on the battery negative and onto the engine, if the fault is cured then the earth path somewhere is past its best.
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Mon 30 Jan 2012 @ 01:44
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Anon
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MANTAMAN wrote:
Could be as simple as a bad earth, works OK for lower amperage systems but fails when the high amp starter is used.
easy to test, put a jump lead on the battery negative and onto the engine, if the fault is cured then the earth path somewhere is past its best.
thanks.. yes i tried that orginally.... tried it on several areas of the engine block too tho as not always too confident how good the contact being made was.
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Wed 08 Feb 2012 @ 08:35
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Anon
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Battery voltage definitely gets pulled down very low, maybe 0.5v difference when cranking between voltage at batt & voltage at starter.
I'll be miffed if it is the battery as it was new last spring, sadly i don't have a spare just to hook up and check.
Because we're stored in a row of vans it's difficut to get a long enough set of jump leads to the battery down the side but when we have done and it's been jumped to my car battery (+ car engine running) it's never seemed to help a great deal, but again maybe just poor contact for the jump leads.
I'll replace the engine earth strap as looking pretty gunky, probably replace the battery terminal clamps as i've only been recycling the old ones to date.
I've also considered fitting a suitable socket for jumping under the bonnet, with a +ve lead to the main solenoid terminal and an earth to the engine strap chassis side. Which would at least bypass the wiring from battery to engine bay.
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Wed 08 Feb 2012 @ 09:18
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Anon
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Battery location
Good evening to every one, let it be a good year for all also. Well, I know it's not the right place (post) to mention my problem,but I didn't see any similar on a run I did. My apologies,please. Anyway, I haven't so far I own the Beddy done anything with the battery and now that it seems to be low-powered, I cannot locate it.I just remember by the previus owner that it's somewhere away from the engine bay, is this correct? But where? I'd apreciate any answer, thanks!
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Wed 08 Feb 2012 @ 13:48
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Anon
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ed_m wrote:
Battery voltage definitely gets pulled down very low, maybe 0.5v difference when cranking between voltage at batt & voltage at starter.
Battery voltage dropping below about 10V when starter cranking engine: recharge battery & try again.
0.5V difference between battery and starter isn't too bad.
I'll be miffed if it is the battery as it was new last spring, sadly i don't have a spare just to hook up and check.
When jump starting from a car, connect up then run the car engine at fast idle for 15 minutes or so to boost the van battery before starting.
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Wed 08 Feb 2012 @ 14:34
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Anon
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alfaka wrote:
I cannot locate it.I just remember by the previus owner that it's somewhere away from the engine bay, is this correct? But where? I'd apreciate any answer, thanks!
Look underneath the van: battery cradle is attached to the chassis on the opposite side to the fuel tank.
If cradle is empty (camper or other body) then follow main cable from the starter solenoid: battery should be close to where the cable passes through the floor.
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Wed 08 Feb 2012 @ 14:41
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Anon
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My battery is located behinde the passenger seat, under a access panel.
Richard & Judith
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Wed 08 Feb 2012 @ 17:32
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Anon
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i'm pleased to say that i have news...
to eliminate the battery / starter i rigged my battery leads direct to the solenoid & engine earth point.... and it turned over with no problems for well.. a long time.
used spark testers & a bit of easy start to rule out lack of spark as a problem, once it has turned over a got some fuel coming through again all was well.
so now i'll be trying to debug either the +ve supply to the solenoid or earth connections through to the engine.
i've taken the grimy earth strap off and will probably try replacing that as a first step.
thanks for all advice so far
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Sat 25 Feb 2012 @ 20:50
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Anon
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Why not fit a new earth cable between the engine and battery rather that depending on 2 iffy earth straps between the engine and battery
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Sun 26 Feb 2012 @ 12:18
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Anon
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update time.
well the old earth strap came up a treat in the parts wash at work (not that i knew we had such a thing!).
spent yesterday cleaning off all the contact points and progressively moving the battery back to where it should live.
the only issue i suffered was lack of fuel cos the eleccy pump didn't have a good earth until i put the strap back on, took a bit of tracking down but a bit of a *doh* facepalm moment when i realised.
now seems to work as well as it ever has..... fuse 6 blew for some reason in the process & the fan belt is slack and missing a few teeth so i need to find me a new one of them.
engine still leaking oil like a goodun, definitely cam cover which doesn't look too scary...... maybe also the next one down which looks like a bigger job ?
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Mon 26 Mar 2012 @ 08:01
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