Forum:
The last few months I've been having a horrendous time getting my Land Rover w/Daihatsu 2.8L NA DL-42 to hold a charge. I've installed a quick disconnect release on the negative battery terminal and keep it physically disconnected whenever it's not running. Unfortunately, to get it running requires not just a jump (because that doesn't seem to be enough to get it to turn over), but also a booster pack.
Last time I jumped it I let it run a full hour, shut it off, and immediately disconnected the battery, but the battery was flat a week later. Unfortunately, the repair tech who came out, tested the battery, and provided the jump said he didn't need to swap the battery. So, my immediate thought to check the alternator, but could there be something wrong with the battery that prevents it from taking and/or holding a charge?
Any tips on troubleshooting the alternator? I'll borrow an voltmeter, but where do I test and what voltage & amperage should I be seeing? Since mine is the non-turbo Daihatsu DL engine, it's got oil hoses to/from the alternator, anything special there I need to know if I have to remove it? How hard is it to refurbish an alternator, if need be (since I'm in the USA and would like to avoid the shipping fees, not to mention the cost of a new alternator)?
Thanks in advance for any pointers you all can provide.
Could be a number of things,
Could be a number of things, so begin at the beginning.
If the battery is disconnected and not holding charge this is the most likely suspect, drop tests will often miss a number of faults.
Measure the battery voltage at the terminals, this should be over 12.3V, then start the engine and this should rise to over 13.6V, although more likely over 14V if the battery is flat. If it exceeds 14.6V the regulator is faulty and the battery fried so faulty regulator and battery.
If the voltage with the engine running does not rise significantly switch on everything electrical and it should rise, if not its the alternator faulty.
If the alternator is faulty and you are in the US i would swap it for a home bred item which is easily and cheaply available. Go for a 90-160 ampere output model, the normal units are 70 amp, the larger units will allow spare capacity for additional heavy loads such as lights or split charging for electric winches.
Look in the "How It Works" section, there is a more detailed article on alternator swaps, this will give sound advice about alternator swaps and how to do them.
Thank you!
Thank you! I couldn't have asked for a better answer. I'll give these instructions a shot once I have a booster pack & multimeter in hand.
rikuwoiku
Electrical tools in hand...
Okay, multimeter borrowed last night and a battery charger today.
When I tested the battery at the terminals (disconnected) this morning it was 10.52V. Gah! I'm going to charge it over night and see what it's like in the morning. If I can get the truck to start I'll perform the other tests, otherwise I'll swap in the battery from my car to run them and see if the alternator & regulator seem to be okay.
rikuwoiku
And the results are in...
Okay, I'm definitely going to call the battery dead. As I said, it was 10.52V yesterday. After charging for 13hrs it was up to 11.89V, so I disconnected it and let it sit (completely disconnected, of course) to see if it'd even hold that charge. 1/2 hour later it was down to 11.5V and another 2hrs later it was back down to 10.5V.
So, I swapped in my car battery which read at 12.66V before connecting. The truck started with no problem and it read at about 13.66V while running. If I switched on the fan & head lights it went up to about 14.05V. If I also switched on the spot lights & rear work light it dropped back down to about 13.66V.
So, if I'm understanding correctly, all this implies that:
my battery is dead and (b) my alternator & regulator are working properly, but (c) I should probably get an alternator with a higher amp rating to support also running the spot & work lights. Are my assumptions correct?
rikuwoiku
Correct; battery dead and
Correct; battery dead and charging system fine.
Why do you need a larger alternator? if you havelarge loads connected and running it would be beneficial. If it is within the range of your current alternator you will not need one.
Read the "How It Works" section, i have posted several electrical articles in there, including how to calculate the electrical load. This will allow you to determine the load output, and answer the question as to if you need a higher output alternator.
More thanks & one more battery question
Thanks for your clear & concise instructions as well as your confirmation of my results (not to mention the electrical "How It Works" articles).
Regarding my thinking that I need a more powerful alternator, I probably just misinterpreted my readings. I was thinking that since the voltage went down from 14.05V to 13.66V when running all the electrical accessories I could (incl. two Hella aux/spot lights and a Hella rear work lamp, in addition to the regular driving lamps, fans, etc.) that the alternator might not be keeping up. I'll go back and the check the amperage of all the lights and actually do the math to see what it all adds up to.
One last question: Is an 800 CCA (cold crank amps, I believe) battery adequate for the Daihatsu DL-42 NA diesel engine?
rikuwoiku
The battery should be fine
The battery should be fine unless it is working in extremes of cold, 800 CCA is within the range the engine needs.
The voltage drop is normal and well within the scope of the regulator operating correctly, around 13.6 is about what these systems do.
If you have work lights i would advise a split charging system, this would allow your work lights to be used without flattening the vehicles main battery. If you upgrade to a larger alternator it would be an appropriate time to fit one. You could flatten your auxlliary battery and still have the vehicle battery fully charged.
This does depend upon your particular circumstances though, and if you keep your engine running with your work lights on.
"Extremes of cold"?
Excellent suggestion on the split charging system. I'll definitely go that route as I add further accessories and an upgraded alternator. Fortunately, at the moment, I really only use the work lights and such with the engine running, so probably don't need to upgrade the alternator quite yet (although I'll still do the math).
As far as the battery goes, what qualifies "extremes of cold"? During winter it's usually down around 0
rikuwoiku
Optima are a good battery,
Optima are a good battery, but expensive for what they are, i prefer Exide as they are as good and considerably cheaper. In addition there are many good batteries, look at the manufacturers websites for information and suitable suppliers locally.
You are not restricted to fitting the second battery under the bonnet, if you have a suitable aperture, or space in the rear, then fit it there. If you have the capabilities, or access to them; why not make an underfloor battery box to fit the second battery into. Alternatively you may find special shaped batteries which will fit to make a battery pack from 2 volt cells, six required for a 12 volt battery.
You could fit the wiring to the rear and use a battery in a battery box, fit a plug and socket to allow it to be removed if not required. I did this for a friend who required light away from his vehicle, 240V 150watt halogen lights were converted with ceramic bulb holders and fitted with 12v 10W halogen bulbs.
The scope is not inconsiderable, it depends upon your requirements and uses.