Car Won't Start: Alternator or Battery? The easy way to know

good afternoon and welcome back to the channel today is a very sad day it's a sad day because for the first time in the history of me owning this truck they didn't start we're gonna find out why here in just a second not good obviously we know there's something power related going on when I turn the ignition on we get the interior lights the radio comes on overhead and tear lights are on we are getting power but as I try to engage the starter you can hear the starter try to engage and turn the motor but it seems like from what I can hear a lack of power coming from the battery to the starter to turn the engine so we're gonna start their service battery charging system interesting no idea did that so the first thing you want to check is the actual terminals to make sure two things are going on the first thing is that they are tight and snug as well as the condition of the terminals okay so taking a look at the terminals we have our positive side and our negative side typically you would want to pull the negative side off before messing with the positive side because you can be messing with the positive side hit part of your know fender some bare metal it can spark kick and you know give you a little shock maybe kill ya maybe not but always start with your negative side pull that off first and then pull off your positive side as you can see there that's a whole lot of crap that is still out now what that actually does a lot of the time is decrease the amount of voltage to actually gets to your starter that being said our first step is to clean all that crap off and then we'll hook it back up and see if we can get the truck to start let's see if it starts okay ignition is on not all cars have this but this is my battery volt meter's you can see it's still extremely low just above 9 volts so I'm not really optimistic but let's see if it starts nope so as the truck dashboard Rab you barely over 9 volts it isn't always 100% accurate coming from the dash but it shows the battery's extremely low so the next step would be to figure out how much voltage the battery is actually holding so that means we get to go pick up a new toy what we're going to need is a multimeter it's a real cheap simple tool that reads the volts or amperage of an electrical charge so that being said we're gonna run to the store and have a mon-star hawaiian new toy moment so what we have here is a simple multimeter tool you want to do is set it up to DC V or DC volts somewhere around fifteen volts this one we have the option of twenty so we're set to 20 volts you take the positive side and negative side and touch them to the terminals of the battery self explanitory again my battery should be reading somewhere around twelve point six volts it's been sitting for a few days so it might be a little bit lower but again should be around twelve point six volts so we have the positive side we have a negative side as you can see it's reading ten point four volts which is extremely level again looking back to the - it's good to know my dash is printing accurate I was showing just above nine volts so ten point four so now that I know my battery's low my next step would be to jump start the truck get it running that way I can tell how much voltage is coming from my alternator back to the battery as the engine runs the alternator should be recharging the battery so the question as always hey is my alternator bad or is my battery bad because we going to replace your battery and turn your alternator was bad you're gonna drain your battery most likely ruin a brand new battery and then you're out a hundred or so dollars so again the question is always is that this or that is it the alternator or the battery so just to make sure I'm gonna be replacing the correct part I'm gonna jumpstart the truck let it run and see what kind of voltage I'm getting out of the alternator back to the battery but first we're gonna appreciate a quick Hawaiian sunset moment I'm actually gonna pack the car in this would be a first for me back the car and jump from the truck to the truck and see if we can get it started now as soon as the engine starts we are gonna see this number hopefully increase substantially now normally running your battery should be reading around 14 volts anywhere between 12 6 and 13 you're not really recharging your battery around the 14 range is where you want to be 14 to 14 point seven is normal operating above fourteen point seven you're actually doing damage to your battery by overcharging it the cell as soon as the engine starts we should see this number come up hopefully it does that way I don't have to replace the alternator and just need to replace the battery alright we got the thing hooked up right now finally on the Mercedes this should start right up and there it is okay that trucks finally started you can probably hardly hear me but what to do now once the truck is running go ahead and turn all of your accessories on that you do have turn your fan on turn on your radio turn the overhead lights make sure headlights are on we're gonna check the charge coming from the alternator back to the battery it should read between fourteen and fourteen point seven so let's go ahead and hook up this multimeter to the negative and positive side of the battery we'll see what it reads fourteen point three volts while running and again that is absolutely perfect and where we want to be while the truck is running so we now know the problem is the battery unfortunately it looks like either the battery has just gotten bad won't hold the charge and to be honest I kind of assumed that so I could tell over the last few months that battery was getting weaker and I'm going to turn this off so the battery is getting weaker and weaker as time went on I could tell starting it up every time you started the start of a turn over a little bit slower and unfortunately this last time it was down to a point of not being able long story short the battery's bad let's run to the auto parts store grab another battery slap that in there and when we should be good to go all right oh that's a lot of awkward wait everybody decides he's gonna come on in here got a number on the back windshield so obviously a race car at the same time this chick behind me she's been driving it through her headlights off for the past about five miles still hasn't figured it out hey she figured out what her blinker is it's not like these roads are lit either it's pitch black out here but here she comes our batteries should have a twelve point six volt charge so again just came back from the auto parts store and we are at twelve point five six twelve point five seven so call it twelve point six awesome alright alright so quick update the batteries in but I'm not done it turns out I don't even know this the bracket that's supposed to hold this battery secured to the truck non-existent so uh but I pulled that old battery out unhooked him lifted it out of there so what we're doing right right now is building a simple bracket to mount that battery in the truck so if there's any you know sudden terms jarring emergency braking situations the battery's not gonna go flying so so far we're building a little bracket to secure that in place so there we have it battery is installed that bracket right there just fabricated that works just perfect to keep the battery in place and the moment of truth number fourteen that looks good here we go and ladies and gentlemen we are good okay we are just back from our test drive and everything works perfectly and that bracket I was talking about the how to fabricate it's right down there below that red wire holds the battery in real nice and is exactly what we needed the alternator we tested works perfect which is nice to know and it was in fact a bad battery so that being said if you have any questions go ahead and comment below if you enjoyed this video give it a big thumbs up subscribe for more Aloha and have a great night we'll see you next time

Channel: LONESTAR HAWAIIAN

Views: 2,152,422

Keywords: battery, alternator, car wont start, car won't start, truck wont start, silverado, motometal, Moto Metal 962, Lonestar Hawaiian, LSH, alternator or battery, battery or alternator, rough country, lift kit, lifted truck, silverado moto metal, motometal 962, bad battery, DIY, bad alternator

Id: VPdQ7X56F8g

Length: 13min 14sec (794 seconds)

Published: Sat Dec 16 2017