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Thread: JCB 3CX - 1986 - Battery not chargung

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    JCB 3CX - 1986 - Battery not chargung

    Hi all - my JCB 3CX is either not charging the battery or it is being drained somehow. It has had a brand new JCB battery and recently a new alternator but still the battery isn't charging. I have had the earth off and made sure there is good earth contact for the earth cable but still no joy. It has had a new starter in the last 12 months too.

    The only other thing I can think of is the earth cable itself isn't good enough or somehow there is a break in the alternator circuit which means the power is not getting back to the battery. Any idea how to test the latter in particular?

    With it being old there are no lights, heaters, fans, wipers etc so I wouldn't have thought pulling fuses would help as they are probably already missing!!

    Thanks

    D

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    Re: JCB 3CX - 1986 - Battery not chargung

    Do you have a battery light when you turn the key on?

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    Senior Member ACE's Avatar
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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by Dunny View Post
    Hi all - my JCB 3CX is either not charging the battery or it is being drained somehow. It has had a brand new JCB battery and recently a new alternator but still the battery isn't charging. I have had the earth off and made sure there is good earth contact for the earth cable but still no joy. It has had a new starter in the last 12 months too.

    The only other thing I can think of is the earth cable itself isn't good enough or somehow there is a break in the alternator circuit which means the power is not getting back to the battery. Any idea how to test the latter in particular?

    With it being old there are no lights, heaters, fans, wipers etc so I wouldn't have thought pulling fuses would help as they are probably already missing!!

    Thanks

    D
    I always get suspicious of starting problems when people say they had a new starter motor

    From you story i interpret the following!

    Had starting problem caused by old worn out starter.

    Fitted new starter
    Still struggling but it starts just.

    After a while it gets worse and worse.

    Having done starter you think must be something else?

    Replace battery and alternator.

    Still having issues suspect leads.

    Fit new leads still not right so tare hair out ask on here

    There or there abouts anyway

    Turns out most of the trouble begins when someone replaces the starter motor!
    Far to many cheap copy starters out there that dont perform and are a waste of money being nothing more than scrap.

    To make it worse not all the copys are cheap to begin with either! I would say theres more rubbish starters out there that will fit a perkins than anyother make of engine!?

    The only starters i recommend are the genuine 3.2kw and 4.2kw iskra/mahle.

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by Dunny View Post
    Hi all - my JCB 3CX is either not charging the battery or it is being drained somehow. It has had a brand new JCB battery and recently a new alternator but still the battery isn't charging. I have had the earth off and made sure there is good earth contact for the earth cable but still no joy. It has had a new starter in the last 12 months too.

    The only other thing I can think of is the earth cable itself isn't good enough or somehow there is a break in the alternator circuit which means the power is not getting back to the battery. Any idea how to test the latter in particular?

    With it being old there are no lights, heaters, fans, wipers etc so I wouldn't have thought pulling fuses would help as they are probably already missing!!

    Thanks

    D
    Anyway. Charging circuit.

    Alternator has 1 possibly 2 heavy wires coming off it on a terminal called B+ (battery live) these wires normally go back and connect to poisitive on starter motor or in modern stuff to a maga fuse and then on to the battery positive.

    Next you have a small wire on a terminal called W. This wire must go back to a ignition warning light. This light then has a switched live feed off ignition switch.

    So you turn ignition on. Power lights up warning light and earths through alternator.
    When you start the warning light triggers the alternator so it kicks in and starts charging and when it does the warning light no longer is able to earth through alternator so it goes out.

    So you see you have to have a warning light lit up on dash when you turn ignition on or its not going to charge.

    Also alternators can still charge but a diode can fail inside so when stood it can slowly discharge battery.

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    Re: JCB 3CX - 1986 - Battery not chargung

    Thanks.

    There is definitely no light on the console so maybe this is an issue. If I charge the battery or jump start it the starter motor spins fine so I am assuming the starter is OK. With a full start on the battery it will start fine so I am pretty sure that it is charging related.

    Gives me a place to start though.

    D

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by Dunny View Post
    Thanks.

    There is definitely no light on the console so maybe this is an issue. If I charge the battery or jump start it the starter motor spins fine so I am assuming the starter is OK. With a full start on the battery it will start fine so I am pretty sure that it is charging related.

    Gives me a place to start though.

    D
    If you don't have a load tester, take your volt meter and put it across the battery - should read about 12.6V for a good battery

    Start the machine (boost it if you have to) and while running test the battery again with the volt meter - it should read 13.6 to 14.5 V (putting a charge into the battery)

    This should tell you if the charging system is working or if you have a battery problem.

    If the battery and charging system check out OK, check the battery connection wires - the one to ground and the one to the starter - I have seen battery cables burn out in the middle

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    Re: JCB 3CX - 1986 - Battery not chargung

    If you have no light on the console it's probably a blown bulb in the console which means it won't charge. Short the smaller of the three wires on the alternator plug to earth and the dash battery symbol light should come on with the key in the acc position. Another issue I see regularly is standalone charging lights on older machines being replaced by one piece LED bulb units which don't let enough current through to get the alternator to charge. I only mentioned that in case someone has moved the charging light out of the cluster unit due to a fault in the cluster unit. You need to use a traditional bulb in the charging circuit or else fit a shunt resistor in parallel with the LED bulb but that's more hassle than it's worth just use a traditional bulb. Any bad connection in the connectors from the dash to the alternator could be an issue. For resolving auto electric problems fast these a re the best test tool on the market in terms of value for money once you master how to use them intelligently. Beats a multi-meter hands down for most things as it will provide power or an earth at the flick of the rocker switch plus a permanent earth from the trailing smaller crocodile clip so it can power items under test independent of the vehicle circuit.

    https://www.ebay.co.uk/p/Sealey-PPX-...-H6/1205258497

    Another useful addition to work alongside is a dolphin type test clip:

    http://cpc.farnell.com/fluke/8525340...ent=Connectors

    https://www.ebay.co.uk/itm/DANIU-Ins...gAAOSw5WNa2xPL

    Using the two together you can pierce and test the state of a wire and then make it positive /negative as desired for test purposes. Obviously you need to know what you're doing but the tester is overload protected so even if you do screw up it generally doesn't end badly. Brilliant for finding dodgy connections in a plug etc. The end of the test proble on the sealey is the right size to fit the standard banana plug connectors.

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    Re: JCB 3CX - 1986 - Battery not chargung

    Thanks all.

    Been out to the digger tonight having a poke around. My mate wobbled a couple of the wires going to the starter and we heard some arcing. Pulled the plastic wire shroud back and found all kinds of horrors. Whilst messing about with all this the ignition lights were coming on so I think I might have found the culprit. Just need to take it all off and put it back properly and hopefully that will sort it out.

    There was all kinds of meltiness going on, so much so I am surprised it ever even started!!

    D

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    Re: JCB 3CX - 1986 - Battery not chargung

    Take care this doesn't catch fire, disconnect battery if not near it.

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by 4wd View Post
    Take care this doesn't catch fire, disconnect battery if not near it.
    Good advice and the last thing I did before I put it to bed. I am really surprised it hasn't been on fire already as it was definitely shorted.

    Looks like there are 5 earths, 3 lives and one solenoid wire but at first it looked like all wires had gone into a single connection!!

    D

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by Dunny View Post
    Good advice and the last thing I did before I put it to bed. I am really surprised it hasn't been on fire already as it was definitely shorted.

    Looks like there are 5 earths, 3 lives and one solenoid wire but at first it looked like all wires had gone into a single connection!!

    D
    All wires replaced but still no battery light and still same sporadic starting symptoms!! I am yet to follow some other advice given in this thread so that is my next step!!

    D

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    Re: JCB 3CX - 1986 - Battery not chargung

    Progress of a sorts......now have the battery light on but the same symptoms.

    The starter I bought was from a reputable place (not off ebay) and is a Lucas and I would have thought would be up to the job??

    If not perhaps I have to fork out again!!

    D

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    Re: JCB 3CX - 1986 - Battery not chargung

    UPDATE - Stripped the starter motor off earlier and took it to bits. It was absolutely filthy and soaking wet inside, there was a lot of corrosion and 3 of the brushes were seized. I gave it a thorough clean and put it back together and it started fine. Not sure why it was in such poor condition though??
    Last edited by Dunny; 20-05-18 at 07:57 AM.

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by Dunny View Post
    Progress of a sorts......now have the battery light on but the same symptoms.

    The starter I bought was from a reputable place (not off ebay) and is a Lucas and I would have thought would be up to the job??

    If not perhaps I have to fork out again!!

    D
    Quote Originally Posted by Dunny View Post
    UPDATE - Stripped the starter motor off earlier and took it to bits. It was absolutely filthy and soaking wet inside, there was a lot of corrosion and 3 of the brushes were ceased. I gave it a thorough clean and put it back together and it started fine. Not sure why it was in such poor condition though??

    Was the starter you bought "from a reputable place" in a red or green Lucas box? Red boxed stuff in the past was coming from India and had was poor quality. If it was a red boxed starter that could also be a clue to having water ingress??
    The best thing about Facebook is the logout button......

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by Footsfitter View Post
    Was the starter you bought "from a reputable place" in a red or green Lucas box? Red boxed stuff in the past was coming from India and had was poor quality. If it was a red boxed starter that could also be a clue to having water ingress??
    It wasn't actually in a box and looks to me, now I have stripped it, that it might have been a refurbed unit. The machine isn't kept under cover and I wondering whether the water is getting in where it bolts to the gearbox. Milky coloured water was also on the flywheel but externally all of the back of the engine is dry. Might need to cover this area it when I put it to bed after use.

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by Dunny View Post
    It wasn't actually in a box and looks to me, now I have stripped it, that it might have been a refurbed unit. The machine isn't kept under cover and I wondering whether the water is getting in where it bolts to the gearbox. Milky coloured water was also on the flywheel but externally all of the back of the engine is dry. Might need to cover this area it when I put it to bed after use.
    Lucas starters are rubbish. There either cheap copies or poor quality Indian built. Indian company bought lucas electrical years ago!

    Check transmission oil if that milky then the transmission oil cooler under the radiator is gone.

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    Re: JCB 3CX - 1986 - Battery not chargung

    Quote Originally Posted by ACE View Post
    Lucas starters are rubbish. There either cheap copies or poor quality Indian built. Indian company bought lucas electrical years ago!

    Check transmission oil if that milky then the transmission oil cooler under the radiator is gone.
    Thanks ACE, I will check.

    D

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    Re: JCB 3CX - 1986 - Battery not chargung

    So, checked the transmission oil tonight and it looks clean if a bit thinner than I was expecting. I also took the inspection panel off the bell housing and there is evidence of water and a thick coating of milky oil on all of the inside surfaces that I can see.

    If the oil cooler was at fault I would assume that the transmission oil would be equally milky but it isn't.

    Any idea what might be causing this?

    Can anyone point me at a schematic of the transmission so I can try and diagnose?

    I suppose it could be that the transmission oil and filters just need changing but I doubt it.

    D.

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