I have a 2000 528i and a 2005 330Ci that I don't drive enough to keep the batteries charged. I recently purchased a BMW Advanced Battery Charging System from Bavarian Auto. This looks like a BMW part and plugs into the lighter. A couple of friends tell me that the "Battery Tender" is much better and safer because it connects directly to the battery and doesn't charge back through the system. I understand the logic. Any one with experience with these two systems and which is preferable. Lots of computers on board these cars and charging back through the system could be a problem but also, i doubt they would offer a product that would damage the electronics...opinion? Wayne Rasco
Makes sense to me, not sure why it would be sold if it was likely to cause any problems. I haven't used what you have, I have the Deltran Battery Tenders, which work fine. I'm guessing that generally, it's more ideal to connect chargers directly to battery posts. If you keep both cars always parked in close proximity, Deltran makes a two-bank charger - they also sell longer cable leads if needed. Since you have the one already, maybe go for one of the Deltran battery tenders for the other car and compare yourself. But, yes, I'd expect what you have to work just fine. You could search google for any horror stories, or look on other BMW forums such as bimmerfest.com or bimmerforums.com.
Thanks for the reply, several people have recommended the Deltran. I don't like to send things back but this charger from Bavarian is unopened and I think I may be better off with the Deltran system. The cars are parked tandum on the back wall of my garage and the 4Runner is on the oposite side so logistics is alright for the double bank system. I think we may have corresponded earlier about my fuel pump problem on the 528i which is working fine now by the way. The return pump was the problem. Anyway I appreciate the suggestion on the battery charger...thanks, Wayne
Second the battery tender over the charging socket one. Just hook it up to the jump points under the hood and walk away very easy and safe.
So you suggest return the BMW one and order the duel bank Tender. You say use the jump points in lieu of going through the trunk, I was a little anxious of that but there is a disconnect on the Tender wire that you apparently hardwire to the battery and leave the connection lose in the trunk. Either way when you want to get one or the other out to play you have to go through the unplugging process...front or back. I just didn't want wires all over the place and having to un-dock the thing but I guess battery health is worth it. I can have plugs installed on the back wall to accommodate the Tender or Tenders. The duel is almost double the single so I might just order a pair in case I make a change in cars. Thanks for the input, Wayne Rasco
The Deltran comes both with battery clips, and ring connectors you can bolt to the battery, so you can use either. I think it's kind of interesting the BMW charger looks very similar to the Deltran, although BMW did not opt to wire theirs up with plugs that could use different types of connectors - makes me wonder if the only difference in the two BMW chargers is the connectors, or if there's some slight electronic variation for charging through a lighter plug vs. the clips. I don't think it matters whether you connect to battery charging points under-hood or the battery itself, it will get the charge either way - do what's most convenient for you or whatever means least wires in the way to trip over. If you opted for the Deltran long leads, it might save the electrician expense of an outlet & circuit installation (although, not tripping & falling over wires with risk of injury might well be worth that cost). There's always duct tape, universal solution! I think BavAuto & others sell a lighter socket you plug a 9v battery into, which you can plug in temporarily while disconnecting a battery, and keep radio settings, etc. - might save that small hassle if you use the hardwire connector instead of the clips. Two separate chargers are more flexible for placement, etc. I'm a little surprised BavAuto doesn't sell the Deltran in addition to the BMW and CTEK chargers, c'est la vie!
