# Similar battery chargers?



## stonex1 (Oct 10, 2012)

I'm looking at maybe storing my car away next winter and want to keep tabs on the battery.
So, I'm looking at battery tenders/chargers.

The recommended unit from BMW is the "BMW Advanced Battery Charging System".










After some research, some BMW owners seem to like the charger from Deltran.










These 2 units sure seem similar. 
The charging led lights seem to be in the same location, the heat vent slats on top are similar.
I'm wondering if the guts inside are the same?

Any experience/advice on either unit?


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## tim330i (Dec 18, 2001)

I moved your question to our general BMW forum, you'll get more feedback in here. My guess is that BMW charger is just a rebranded charger. 

Tim


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## Doug Huffman (Apr 25, 2015)

Neither of those are chargers. The Deltran Battery Tender is inadequate as a battery charger at nominal 1.25 amps output. It would take roughly a hundred hours to charge a late model BMW's AGM battery from dead.

BMW recommends a rebranded CTEK 7XXX battery charger for about $100 that will work fine as a battery maintainer (float or trickle) and is a fine smart charger.


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## luigi524td (Apr 4, 2005)

*Keeping your BMW battery in a charged state*



Doug Huffman said:


> Neither of those are chargers. The Deltran Battery Tender is inadequate as a battery charger at nominal 1.25 amps output. It would take roughly a hundred hours to charge a late model BMW's AGM battery from dead.
> 
> BMW recommends a rebranded CTEK 7XXX battery charger for about $100 that will work fine as a battery maintainer (float or trickle) and is a fine smart charger.


YES (but) neither of those devices is intended to function as a battery charger - the labeling on the BMW product is most likely done by the product marketing department without knowing the difference.

They are perfect to maintain your BMW's battery at a ready state whenever infrequent or short cycle driving use or extended parking doesn't permit the vehicle's charging system to adequately charge the battery.

If and when the car's battery becomes so depleted that it needs to be resuscitated (brought back from death!) it's more likely there are serious electrical system issues that should be addressed/repaired or a battery failure that in my experience will render the battery a goner!

That said, a proper battery "charger" make a good addition to a complete DIY'er garage.


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## Kamdog (Apr 15, 2007)

When I bought my car I got a coupon for 50% off an accessory under $100. I bought the BMW branded trickle charger, which is labeled "Deltran" on the bottom. The BMW one is far superior because the instruction sheet shows where the underhood terminals are. If you already know that, well, then the cargers are identical.


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## imtjm (Oct 5, 2004)

Given that they both carry PN: 021-0128 on the label, they are the same. It's common for accessories and parts to be a rebranded OE product. As Doug noted, BMW has been rebranding CTEK chargers/tenders. The latest BMW charger/tender (61432408594) is a rebranded CTEK MUS4.3. CTEK is prominently labeled on the BMW one, too.


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## Doug Huffman (Apr 25, 2015)

luigi524td said:


> YES (but) neither of those devices is intended to function as a battery charger - the labeling on the BMW product is most likely done by the product marketing department without knowing the difference.
> 
> They are perfect to maintain your BMW's battery at a ready state whenever infrequent or short cycle driving use or extended parking doesn't permit the vehicle's charging system to adequately charge the battery.
> 
> ...


They are inadequate for maintaining an AGM - VRLA battery as installed in late model BMW's used in short driving cycles. A properly adapted BMW IBS charging system will not adequately charge the battery for battery longevity or maximum capacity.

I live on a 25 square-mile island, five miles in any direction, ten miles is a full day of errands, and a short driving cycle. I charge weekly with a smart-charger that starts the bulk charging cycle at 4 amps and generally runs for about six hours for an estimated (by simple quadrature) 10 - 12 AH or about ten percent capacity.

The cycle life of an AGM battery is correlated with average State of Charge; average SoC >70% implies a cycle life of about 1,000 nominal full discharge-charge cycles or about 100,000 AH use.

One ampere-hour of overcharge damages a starved electrolyte AGM battery by electrolyzing 0.335 grams of water to gases oxygen and hydrogen. When about 3 psi over pressure has accumulated then the excess is vented off and lost from an already starved electrolyte battery.

The BMW IBS will not overcharge its battery as it leaves some headroom of uncharged capacity.

The lifetime of an AGM battery is about eight years, limited by internal corrosion.

BatteryUniversity.com. BatteryFAQ.org.


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## radioactivemike (Mar 22, 2016)

A trickle charger is better than nothing, but I vote for something in the 10-12 amp range. When you have that time that someone has a dead battery, you won't have to wait a few days to charge it. I use yellow tops in my hot rods (I can't say I love them, but it's what I'm geared up for). To go with them, I picked up the Optima charger. It's a great unit that trickle charges as needed and then monthly conditions the battery to keep the sulfates under control. Trick charger that's made my latest yellow top last 3 years with no sign of age, yet. 

I have 3 chargers now. Each slightly better than the last. Skip getting by with a 2 amp and just get a nice one.


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## stonex1 (Oct 10, 2012)

luigi524td said:


> They are perfect to maintain your BMW's battery at a ready state whenever infrequent or short cycle driving use or extended parking doesn't permit the vehicle's charging system to adequately charge the battery.


Thanks for the replies.
This will be my case, with extended periods of parking.
The Deltran is on sale this weekend at my local auto store so was thinking of picking one up.


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## need4speed (May 26, 2006)

stonex1 said:


> Thanks for the replies.
> This will be my case, with extended periods of parking.
> The Deltran is on sale this weekend at my local auto store so was thinking of picking one up.


It works well to keep your battery charged


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## Weaselboy (Jul 7, 2002)

stonex1 said:


> Thanks for the replies.
> This will be my case, with extended periods of parking.
> The Deltran is on sale this weekend at my local auto store so was thinking of picking one up.


I have that exact Deltran model you posted and have used it for years with no issues. It will work just fine.

The "official" models at the BMW web site are now two newer Deltran and CTEK models, but this older Deltran will still work fine.


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## R ODonnell (Dec 15, 2014)

Kamdog said:


> When I bought my car I got a coupon for 50% off an accessory under $100. *I bought the BMW branded trickle charger, which is labeled "Deltran" on the bottom.* The BMW one is far superior because the instruction sheet shows where the underhood terminals are. If you already know that, well, then the cargers are identical.


I've got the BMW one as well and I concur. I've been using it for 9 years as a maintainer and it seems to work fine.

I've also go a 2/10/55A "start mode" charger that I use to charge dead batteries or to keep the battery up when working on the car.


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## M5Fed (Sep 7, 2014)

I'm using the BMW one and have no issues whatsoever. Great for keeping the battery charged when I'm not driving my Beast. Definitely a buy.


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## CapeBimmer (Mar 16, 2002)

Been using a Battery Tender for years to winter store vehicles. Works great. Storing does not require charging, only maintaining.


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## Fish23 (Apr 24, 2012)

I live in a cold climate in winter and have a 335 xi and a 535 xi GT both with the Regenerative Braking System. My dealer had many complaints from owners with RBS who drove only short distances with temperature-compromised batteries that gave "charge battery" warnings. That is the "driver profile" reason that was given but not well understood. 

As a result, all new vehicles are sold by by my dealer with a BMW battery tender installed and listed on the sticker. During delivery owners are advised to plug the vehicle in overnight (especially those parked outside) during very cold weather to have it as charged as possible in the morning. I also use the tender when away from home for extended periods of time.


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