Lotus99

We don't drive the car every day, and sometimes when I get in, I see the battery discharged symbol. I figured to be safe, if I'm not driving it for a few days, to put it on a battery tender. Doing so under the hood is straightforward since I can leave the hood open, but I can only do that when I park it in the garage, which is not often.

To connect it in the trunk, is it pretty much a matter of getting the liners out of the way, and I'll see the battery and I can connect to its negative and positive? How long does it take to reach it? Or is there a bunch of removal required and I might need tools to undo bolts? I've not yet accessed it back there. But if it's easy, it would be great, since I can leave the battery charger in the trunk since it's quite bulky.

ptikkala

I`m using this set at winter here in Finland, DEFA / ChargerKit 1204

Lotus99

Thanks. I'm not sure if you can buy it here even. I don't see prices for it when I google it either, so it must be a rare item.


Do you know how to access the battery in the trunk?

luigi524td

Attach the battery tender under hood NEVER to the battery posts.

When I set this up in my e60 I used a piece (about 12') of low-voltage landscape wire to extend a connection, complete with matching plug for my tender, from the under hood post and ground. I coiled the excess under the hood so I could pull it out and connect to the tender that was plugged in to an electrical outlet on my covered outside porch at the end of my driveway. You should also check to see if your car has a glass mat battery - their charging characteristics are different than the older style lead-acid battery and I've read that some automatic battery tenders will not work well with them.

Lotus99

Thanks Luigi. Is the reason you're not supposed to connect to the battery directly because of all the electronics in these cars?

Extending the wires is a great idea! My battery charger right now has alligator clips on it, so I'm thinking whatever wire I use, if I put alligator clips on it, then I can attach it as needed, and not worry about leaving the wire permanently under the hood. I know the car only runs on like 12-14 volts, but the amps going thru the wires I thought are high? The wires on my charger - as I'm typing this, I realize it's a charger I think, and not a tender - are pretty thick. Not thin landscape type.

I called the dealer, and surprisingly, they said they don't know what type my car has, until they see it... Their computer shows 4 different types can fit, including an AGM one.

Cpalacay

I had to replace my battery about a month ago. According to the dealer, the white top battery is the conventional lead acid type, black tops are the AGM types.

You'll need to remove the plastic tray on the right hand side to gain access to the battery. There will be a vent tube you will need to unplug and a bolt for the tie-down to remove. Be warned, the battery weights about 60lbs and space is tight, so it helps to have the wire harnesses tied back.

-Christian

Lotus99

Thanks, I'll try to get at it and see. I find it comical though that even though I give them my VIN, they still can't tell me which one should be in my car. They say it could be any one of 4 that I might have, including an AGM.

I've bought a battery tender/charger in the meantime, and will be hooking it up, to keep it from getting any worse. I bought this one, the CTEK Multi US 4.3, which does all types of batteries. It's water-resistant too, so I'm ok leaving it under the hood in damp / wet conditions, like we have here in the PNW.

CTEK Multi US 4.3 - CTEK Battery Chargers
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norsecarnut

Anyone know if most proper group sizes will work such as one of these : ODYSSEY Batteries - Find a Battery

I have the above brand in huge size as my land rover 2nd battery in dual layout and it's been great for 8 years now. These are AGM type.


Seems like better construction than what dealer sells and for same or less $

Lotus99

So I've been using the CTEK charger above now for the past 5 months, on and off, and for the most part, the car's only been used on the weekends (though for 200 mile round trip highway rides to the mountains). And I've not used it every time I park the car Sunday nights. So maybe only 5 times during this time.

Not once have I seen the low battery warning sign come up. So I'm crossing my fingers it's done some good for the battery, and maybe reconditioned it in some small way.

As far as the AGM batteries go, when I opened up my trunk liner to look at mine, it is a lead acid battery with a 110 amp hours (reserve capacity) and 850 Cold cranking amps (CCA). You can't (if you want to do it properly that is) just pop in an AGM battery in place of a lead acid, as the car's charging system won't be aware of its capacity (even if you register a new battery, which at least tells it to charge differently, vs. if it still thinks it's charging a 5 year old battery).

You need to get the car coded for the new AGM's capacity, etc. Which is more than just "registering" the new battery, which is all you'd have to do if you just popped in a new lead acid battery with the same specs (and as you know, some people have just not bothered).

That's what I've learned. Hope it helps you.

norsecarnut

Yes, regarding coding for a change of battery to new type. BMW Seattle quoted 1hr labor but I'm going to ask around as I can't imagine it takes more than 15 minutes or so.