Volvo EC15BXR Drains Battery after 2 hours work

[Muz]

Today the new Alternator was fitted. Battery still gets drained and conks the engine. I despair, totally flumuxed. Not in a happy place, been trying to see what and why for the last 7.5 hours!

See my post earlier about an EC 15 keeping running after turning the key off ? well , I noticed after I left the machine for an hour to cool down , when I checked the starter temp it was still hot .. but it wouldnt restart .. just nothing at the switch ... so I left it another hour and was going to drag it out of the way believing the starter to be dead ... but decided to see if it would start, after 2 hours cooling , and it turned over ! it tried to start but the battery was drained ?,.. now ... previously after 3 weeks in sub zero it started no problem 1st time ? So that seems very odd to me ? It had power at first start in the cold ... but becase the starter had been kept running it drained the battery ... no doubt. Sometimes the solenoid sticks and the engine runs the starter, but on this occasion I believe the starter had been constantly energised

[NAVDDD]

Thank you Muz. The starter doesn't whir to my knowledge, though this will be checked.

I'm looking at everything and anything and will revisit previously assumed as being ok. For example, the workaround for the SW9 and SW10 arm switches and even looking at trying to repair the old switches tat had been there to! ha ha.

[Muz]

Thank you Muz. The starter doesn't whir to my knowledge, though this will be checked.

You cant hear if its engaged or not though (at least I couldnt)

[NAVDDD]

You cant hear if its engaged or not though (at least I couldnt)

Thank you, I understand.

I checked out your tread : Starter Engages
This morning I ran the engine (for half and hour) and slipped my hand around a very hot exhaust manifold and onto the starter which was cool and gave no temperture indication of being constantly engaged.

I've got a "digger mechanic" coming the end of next week to see what can be done. I'm willing to try/check any further suggetions.

[NAVDDD]

Hi,
Just a quick heads up latest. The issue remains. One guy didn't arrive because he had covid. I have another lined up (retired electrics specialist) sometime soon..

[NAVDDD]

Hi,
After a lot of time passing and finally getting the EC15b a thorough look over electrically, a number of issues showed up.

Recently the EC15b engine had run continuously and failed to turn off by the ignition key and after both battery terminals had been disconnected. Shut off finally by disconecting the electrical junction to the fuel pump!

Ok, definately time to call in big help.

The Electrical Specialist went through everything. The continuous running was caused by shorting out wires to the alternator, wires touching the manifold. The alternator's main wire had been put through a heat of sorts and the terminal on the alternator was welded, the nut was. Trying to rescue the alternator was fruitless and the unit was fried. A replacement was obtained. Ok, more. The cable from the alternator to the Starter had been put onto the wrong teminal on the Starter, yep that was the cause of all the hassle. The starter had been replaced after it to had given up the ghost early on when this issue first came to my attention. So I think the Starter had the wires to one of the terminals when I aquired the machine. However the replacement should have been wired right! At this point I should add the Electrical Specialist almost did the same wrong terminal thing. The connections on the Starter and Alternator are hard to get at (alternator socket bust too) and when a socket set tool was used on the Starter's teminals he nearly repeated the fault - glad he didn't. Melted wires were replaced and wiring tested thoroughly and batter being charged.

So, the conclusion: Wire up the Starter Motor to the right terminals or you'll fry alternators, fry a starter too and drain batteries!