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Best Replacement Battery?

12 messages,  Last post on Oct 21, 2008 at 8:51 AM

You are in the Subaru Forester Maintenance & Repair Forum.

What is this discussion about? Subaru Forester, Electrical

Messages Page 2 of 2

#11 of 12 Update by garion

Oct 20, 2008 (2:43 pm)

Just a quick update and a question.
 
After trying to jump my car and the car still wouldn't start, we decided it's time to just get a new battery. But right before we were about to leave, my super stops by and suggests that we use his battery charger. (He also tried to jump it with this battery jumper that is suppose to jump 18 wheelers... it didn't work. Nada. We got at least a wheeze from my sister's Passat.) After the failure of his battery jumper gizmo, I just went and got a new battery from Sears. It was just easier.
 
So, altho my problem has been fixed, I'm curious and this might be helpful for others in the future. Would it make sense to try and use the charger. It takes 4 hrs supposedly. I mean, I guess it couldn't hurt. The worst thing is that it wouldn't work and you'd just have to take the battery out again and then finally get a new one, right?

#12 of 12 Re: Update [garion] by bigfrank3

Oct 21, 2008 (8:51 am)

Replying to: garion (Oct 20, 2008 2:43 pm)
Battery chargers work great to slowly recharge the battery. Sometimes slowly is the only way to bring back one that has gone dead, although as I mentioned earlier most current batteries don't like to be run way down. I have seen new ones not recover very well. There are deep-cycle batteries designed for situations were it might get that kind of use. Optima makes a very good one.
 
Chargers usually don't work well to jump start because they aren't designed to provide the current reserve necessary for that. Some are, the one I have has 3 settings, 2 amp, 10 amp, and "boost", but nothing beats a big battery with a lot of reserve for a jump. My charger will also not over-charge the battery. Sometimes I use it on my tractor on the 2 amp setting just to keep the battery fully charged, especially when the tractor is not getting regular use.
 
Don't forget that the whole thing is a circuit, including the connections, so if the battery clamps aren't clean, shiny, and tight there is a lot of resistance created to putting current into the battery. My recommendation for a marginal battery is always to clean up the connections and slowly charge the battery with a charger if time allows. Otherwise a jump from a big battery is the best bet.
 
Also don't forget to check the level in the battery. I have found low-maintenance and "maintenance free" batteries that needed water to be added. Many have caps or covers that can be removed for water addition even though they don't look like it. A battery low on fluid will not provide full capacity.
 
Cables can cause a problem too. I once worked on a car that I couldn't get to start no matter what I did. It had good clean connections, good battery and everything looked fine. I finally took a resistance measurement of the cable that ran to the starter with my ohm meter and got a very high reading. I took a razor blade and slit the vinyl covering of the cable and it was basically 75% powder inside, even though it looked great from the outside. I replaced both cables and that fixed things.

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