01tibby

ok, so i was supposed to take care of some things today, but my battery is dead and there is nothing around me i can use to charge it with.

but this seems to be a recurring thing. my car never sounds confident when starting up, and this battery is only ~5 months old. i do have tons of sensors with my alarm, but i measured the current draw on the battery when armed and its only 8 mA. that should not be enough to put a dent in a battery rated 50 AH.

my carpc does wait for a bit to shutdown, like a minute running while car is off. its a 120w PS. i also just changed to underdrive pulleys.

but i had weak startup problems before i did either of those, and got this new battery because of it. i distinctly remember having to jump my car one morning. it was running for a good 5 minutes and then i turned it off. wouldn't start back up.

all this is making me lean towards a bad alternator. thoughts?

Sparticus

what type of battery are you using? a standard one or a deep cycle? if not using a deep cycle i would recommend it due to the amount of draining you're putting on it.

01tibby

its regular, but thats the thing. i'm really not putting that much draining on it.

pandy

Alternator.

Been there seen it

MKE

^^^

not necessarily.

if the car runs fine after it was started/jumped, then the alternator is doing what it's supposed to be doing. If it wasnt, then your lights would be extremely dim (after disconnecting the cables), you would lose all your power assisted stuff, and your carpc probably wouldnt run.

i'd say see what kind of warranty came with the battery if it's only 5months old, and/or try a different battery.

i just had this same issue (sort-of) on my g-ma's van. if you jumped it, you could drive it all over no problems. however, if you had to turn it off, you were not going to get it back on without something to jump it.

01tibby

yeah, but im almost positive the battery is still good. i dont think i can go through 2 optimas that fast. i dont have any crazy power needs. i dont even have subs in yet.

car does run fine when after it is started. im thinking it has something to do with the charging ability of the alternator.

DTN

Figure 90A alternator, use 50 for normal driving.

Total up the fuse amps you're using with your carPC, amp, sterio, and other electronics then multiply by .6. (rough estimate method) if you're drawing aproximately 40 or higher amps, then you'll need a bigger amp. I can tell you your carPC power supply is drawing 10A, which leaves only 30 for your amp and whatever other auxiliary electronics you have.



You may need a bigger alternator

01tibby

well, the one amp i have in now is rated at 60 amps, but i doubt that is actually what it is drawing. i havent had time to setup all my software stuff so i have rarely been listening to music. its close to 10 amps on the CarPC too, it's prolly seeing close to 13volts there.

i havent been driving my car a lot, maybe its just that. every once and a while ill make a minute drive to and back from a grocery store, but thats about it. any amount of driving over 5 minutes is very rare(going home or up to b-more).

DTN

There you have it! You probly need a bigger alternator. Idle dosn't really charge the battery as much as full throttle. I bet your lights probly dim at idle as well. Give it some time to charge, get a capacitor (i doubt you don't already have one) and a new battery. My guess is it's probly within limits, but you are barely charging at idle.

01tibby

dinero no mas, especially with christmas.

i'll just have to remember to go on a drive every once and a while. wont be too hard. wink1.gif