voltage loss

[ajv2]

hello
my L4310 keeps draining battery
replaced battery and alternator/regulator;
battery and regulator measure 11.35 volts while running
40 amp fuse and wiring getting very hot when key is on
any thoughts or where to get
a wiring diagram

 

[Kubota Newbie]

Start out by disconnecting the battery cables, cleaning around the terminals real well, charging the battery fully with a charger and then checking it in a day or two to see if it is loosing voltage from within (leave the cables off). You could have a bad cell, causing it to go down. SORRY, didn't notice you'd replaced the batt.
Beyond that you can start by tracing the draw backward from the battery (positive side, ignition OFF) with a digital amp meter. Had the same problem on a cub a couple years ago, ended up being the starter switch, still worked ok, but had enough corrosion that it would draw the battery down over three or four days. RC

 

[Kubota Newbie]

Oh, and it should measure well over that voltage when running at about half throttle which would normally point to alternator/diode, or regulator issues. Sure everything is hooked up correctly?????

 

[ajv2]

yeah
i swapped alternators from my other L4310 and had same problem

 

[aquaforce]

Are there any electronics that are not working or acting strange? That is one sign to follow toward a problem area or item.

The hot wire is also a sign. Does it feed several things or one item? If it feeds several things then connectors can be taken loose one at a time while watching the volt meter and see what connector was taken loose when the voltage jumps up to normal.

Hope some of this helps and good luck.

 

[birddogger]

Just throwing some ideas out there. There's only a couple things with that much draw; the glow-plugs and the starter. The starter you would hear if it was energized. The plugs could be latched on with a terminal in the key switch that was worn out and slipped out of place. I had an occasion that the fuel gauge retaining clamp had rotated enough to just kiss a terminal on the key switch. Or just a pinched wire who knows where.

 

[Stubbyie]

I'll second the vote for checking those items that might draw the most amperage---start with glow plugs.

I had glow plug controller hang 'on' and would keep the battery drawn way down no matter how hard the alternator worked.

Use a needle-type analog voltmeter and start hunting by disconnecting circuits / fuses one at a time. Clean every connection you take apart before reassembling and use a dab of dielectric grease to prevent future corrosion and the same problem later at a new location.

At high-idle checking voltage across battery terminals should give 13.8-vdc plus-or-minus. Just on the off-chance, check battery frame ground connection and cable both ends.

When charging the battery you'll do less damage by charging low-and-slow instead of using the 'EngStart' setting. Let it float at 2-A or less for 24-hrs if you can. Your battery will love you for it.

Concerning new battery: in the last five or six years I've gotten a brand new BAD battery twice under two different brands. Brands mean little as most US batteries made by only two or three manufacturers.

Please post back and tell us what you found and how you fixed it.

 

[Kubota Newbie]

Ya know... one more thought on this. I don't know about the new Kubotas, but my old M series uses an external rectifier for the alternator (or did use, it now has a single wire delco alternator, a worthy conversion if you have room under the hood).
The rectifier is seperate from the voltage regulator and can cause symptoms similar to those you describe if it is bad (especially the low charging voltage). Again, this is only if they still use the external rectifier set-up.

 

[JimmieD]

Sometimes an IOD or 'Ignition Off Draw' can be found by testing grounds of electrical components. Where there's an electrical device grounded to chassis remove it from chassis. Hook one alligator clip test lead to component case & touch other test lead to chassis, with ignition off of course. If current flow is found then it indicates an internal short in component. Some devices have a ground wire connection, same process works there.

Also not unusual for an ignition switch itself to cause an IOD either from corrosion in switch or a mechanical problem within. In many systems lighting housings are grounded directly to chassis instead of having an independent ground wire to vehicle ground system. Same test as above will show if the light is shorting IOD to chassis, possibly because of a faulty or corroded light switch.

Sometimes important to use a properly sized battery rather than oversized. Had a lady friend blow the hood clean off her Jeep CJ when battery exploded! She had fit a larger battery, wanting more CCA power, and when hood closed it touched & shorted across both battery terminals causing battery to explode. Thank God she wasn't maimed or blinded! Hood was repairable but acid damage meant a paint job also. Battery was new so it was filled with hydrogen gas inside during pre-charging, causing the potential explosive force.