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Two questions about seat heater


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Check the fuse for it. It's probably about 1/4 to 1/3 of the fuse rating. If it's a 30 amp fuse it may be quite a bit - like 8 to 10 amps maybe.

 

Heating elements do pull a lot of amps. That's fairly normal.

 

Most meters have a 10 amp inline capacity without using a shunt and clamp-meters that read DC are pretty spendy.....

 

I have used one of these succesfully for measureing draws larger than the 10 amp my meter can handle directly:

 

http://www.harborfreight.com/30-Amp-Automotive-Fuse-Circuit-Tester-67724.html

 

GD

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Thanks GD, I've got a clamp meter here just have to find it. it's just weird that everything hinges on the seat heater thinking how much the starter pulls..

 

It's maybe a half a turn with the heater on and with it off it starts.. Oh well gives me reason to replace the battery anyways.

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I'd be more suspicious of a failing ignition switch than the seat heater draw. If the starter solenoid isn't getting enough power from the ignition switch the draw of the starter motor will pull system voltage down to the point the solenoid releases.

 

I think the chances of a battery being marginal to the point that seat heaters being on or off would affect it to the point it couldn't crank is pretty unlikely.

 

Put it in park/nuetral with the parking brake on and try running a jumper wire straight from the battery termial to the starter relay contact (a spade connector on the back of the solenoid) while having all accesorys like lights, heaters, and blower on and see if it cranks.

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Make sure the charging system is working ok also. If it isn't then replacing the battery isn't going to help much. Make sure the fan belt is tight. With the battery voltage at 10.8 volts unloaded I am surprised you can make anything work, let alone the starter.

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I was looking at Torque today and the voltage at the OBD II port with the car running was between 13V and 13.1V seems a tad low no? My old Legacy was like 14V running.. but it started to give out near the last few weeks I had the car..

 

This one has a Subaru reman alternator.

 

Before I started the car the voltage was 11.8V and that was with the driver's seat heater on as well. The battery is of an unknown age but it can't last forever.. having said that i'm looking for a replacement.. Anyone try those Exide AGM batteries? Or should I just get the interstate again?

 

I wished I could of saved my old one but when the body got hit it pretty much made it impossible to get out.. Sucks less then a year old battery.

Edited by 1-3-2-4
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With no load on the battery, it should be resting well above 12v.

If it never gets above about 13.1 when charging, your alternator is on it's way out. What about when it's running at 2,000+ RPMs? Does it jump up to ~14v then?

 

Charging at 13 is too low, it'll eventually ruin your battery never letting it charge up. Even if you're battery is old/tired, it should still have a system voltage of 14v

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Got curious so I checked the voltage at the battery after 9 hours of rest and had 12.8v with the car running I had 14.1 I had all loads on when starting. The funny thing is when I leave for work early in the morning I have no issue.. when I leave work at 9am and say crank with the seat heater on it only cranks half a crank before it stopped. It must be the battery age.

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what do your battery terminals look like. all gunky?

 

also, rear defrost is a HUGE draw on power, is that on while you are doing it? I mean HUGGGGGGEEEEEE draw.

 

Both are pretty bad I'm going to guess its a little leak in the terminal post area. Also rear defroster not working due to broken lines got cold too fast to fix the rest.

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Repair/replace the terminals also. Those look bad. Water and baking soda are your friends here. The fact that the terminals look like that is a sign that your battery is taking a dive. The acid deposits are a good sign that connections are poor and the battery is old.

 

GD

 

 

yeah that's why I said I was looking for another battery and asked if anyone has used the exide AGM batteries.

 

As far as the terminals I had planned to change them because I was going to put amps in the car.. I wish when people buy a battery they pull the dots of the date of purchase so people can get an idea how old they are.

 

Pretty sure the battery is Group 35?

 

http://www.amazon.com/Exide-Orbital-ORB75DT-108-Automotive-Battery/dp/B0009H516C/ref=au_pf_ss_3?ie=UTF8&Model=Legacy|64&n=15684181&s=automotive&Make=Subaru|13&Year=1997|1997&carId=001

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Yeah it's a group 35. I like Interstate's myself. I get MT35's for $67 and some change.

 

GD

 

Only reason why I would get the one in the link is it's a AGM battery I had a interstate in the old car before it got stuck under the hood but yeah I agree it's one of the better batteries that you can buy.

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I haven't had much good luck with the gel batteries in my vehicles. They seem a lot less tollerant of sitting for long periods which my many vehicles tend to do since I have quite a few and can only drive one at a time.

 

GD

Should not be a problem for me but you are the first i've heard about gel batteries and not wanting to start after sitting awhile.
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I was looking at Torque today and the voltage at the OBD II port with the car running was between 13V and 13.1V seems a tad low no? My old Legacy was like 14V running.. but it started to give out near the last few weeks I had the car..

 

Before I started the car the voltage was 11.8V and that was with the driver's seat heater on as well.

 

A fully charged lead-acid battery at rest should be 12.6v. By the time it gets down to 12v it's like 75% discharged.

 

The alternator will try to pull the system voltage up over 14v, but if the battery is discharged it will be a high load on the system so 13v may be normal. Does it go up to 14v if you bring the engine RPM's up to about 2,500?

 

I've had batteries marginal to the point where I had to put the headlights on for a minute to warm the battery up so it would have enough CCA to start the truck. Never had one where the extra load of an accessory was enough to reliably prevent it from cranking.

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