Battery Tender 021-0156 Battery Tender Plus 12V Battery Charger True Gel Cell Model

I just talked to the manufacturer. The regular Battery Tender Plus will charge lead acid, SGM, and Gel cell batteries. THIS model is not a regularly available model from the manufacturer, and should ONLY be used for the TRUE GEL BATTERY that is on the newer BMW motorcyles. This charger is optimized for that battery and is not optimized for other battery types (although it will work, but not optimally since it will not provide the best voltages needed.) A gel cell battery is not the same as a true gel battery, hence the confusion that people are having.

So .. will it work? Yes. Is it recommended by the manufacturer and optimized for other battery types? No.

The above is from my conversation with a representative from Deltran. Please do not flame me if you don't agree with what the manufacturer told me. I suggest you call them if there are disagreements. I just wanted to post this to provide some clarification since I am in the market for the Battery Tender Plus. Deltran's recommendation was to go with model 02-0128 unless I have the appropriate BMW motorcycle.

Thanks.

I purchased this product in February of 2011 and it seemed to work fine. It says that this model can be used as a battery charger and it will change from charge mode to float/maintenance charge mode without damaging the battery like trickle chargers. In July of 2011 it just stopped working while it was connected to my classic car battery in float/maintenance charge mode. Of course I bought this model for its 10 year warranty, but now I find out that in addition to having to pay to ship it to the company, I also have to pay $15.95 for them to do Warranty Evaluation, & shipping & handling fees. When you pay $47.00 for an item and it costs you around $30.00 to pay for shipping & return shipping, what is the point of the warranty? This is supposed to be "the best" of battery chargers and they basically want me to pay for anything done to the unit. I am not impressed!

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This little charger works great and takes up very little space. Product dimensions are incorrectly listed as 11x4x11 inches and 2.4 lb it is aproximately 4x3x3 inches, and can't weigh more than a half pound. It also lists the "Battery Tender 081-0069-6 Ring Terminal Harness with Black Fused 2-Pin Quick Disconnect Plug" as a "frequently bought together" item, but mine came with one. You only need more if you are planning to permanently mount them to more than one vehicle.

There seems to be some confusion as to what batteries this will charge. It is optimized for gel cells, which require a lower charging voltage than AGM or flooded. However, it is compatible with the latter 2 types. If you do not have true gel cell batteries, this is not the charger you want, but if you have a mix of 12V gel cell and 12V lead acid batteries, it will handle all of them. 021-0123 and 021-0128 are optimized for AGM batteries, compatible with flooded (STD), and not reccomended for gel cells. 021-0069 is optimized for flooded (STD) batteries, compatible with AGM batteries, and and not reccomended for gel cells. The 012-0156 does everything.

The only thing this charger won't do that I need is to charge 6V batteries, but at the price, I can't expect them to include that capability, so I'll buy their 6v model also.

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After some correspondence with Odyssey Batteries (Enersys), it ends up that the battery tenders don't have a high enough float voltage for their batteries. This is all very confusing of late (gel cell, lead acid, dry cell, etc). Since the float voltage is not high enough, the battery is only about 90% charged max. I measured my BT+ at 13.24V while in float mode. Odyssey says that the float needs to be 13.5V minimum. Here's a quote from their service department:

"There are many great chargers that work well with most batteries on the market that do not fully charge the ODYSSEY battery so if your charger floats at less than 13.5V then it will sulfate the battery and it will fail premature due to consistent undercharging and maintaining the battery in an undercharged condition. Most Battery Tenders float at less than 13.5V"

So, don't plan on using a BT+ on an Odyssey battery. Now I understand why the engine wasn't cranking over as I thought it should. Time to find a better charger. I wish BT would mention this in their product descriptions/website/etc to save the consumer the hassle. I did find a recommended battery chrager list on Odyssey's website. To be fair, my other BT's have worked great on my lead acid batteries.

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Best little electronic item I have bought recently. Little is what it is. The Battery Tender unit is really tiny compared to the old horse of a charger I was used to using. Very effective and very smart little unit. I tried more for a chuckle to see if I could wake up a scooter battery that showed a .5 volt remaining out of 12.4v initial start. It made up over 10v of relative charge in what was a dead battery. I was amazed and very satisfied with the capability of the Tender. Since there is no line voltage output it is a very safe unit to have around. It will hold your battery at full charge for many years. Any vehicle with a battery in it needs a Battery Tender if it is stored for more than a month at a time.

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