Battery Tender

You can connect to the terminals in the bay but leave your battery switch on.

 

On a 355 you can also just connect them straight to the battery, and fashon a connection inside of the right front wheel well. This will make it easy to plug in when you park your car.

 

Just a note on batteries that have been drained complelely. Once this has happened batteries are never the same, you might want to replace it. They have a habit of holding a charge then all of a sudden they don't. Something to do with the plates grounding themselfs at the bottom of the battery when there is no charge in them. Regards, Vern

 

Vern,
I've only seen that happen when the battery is 4 or 5 years old. My experience is consistent with what you'll get if you go to a battery mfg's web site & read their FAS. It takes quite a while for sulfate deposits to build up to the point that they cause the effect you describe.

Relatively new batteries can survive a half-dozen deep discharges & still work normally for a long time as long as they don't sit discharged for several months. The longer they sit discharged, the more likely they'll give problems.

However, since my 3x8 tends to have long periods of non-use during salt season, & my salt season driver is stored during 'driving season', I just buy deep cycle batteries. They can take something like 10x the deep discharges of a std car battery.

 

Maybe its just me but over the years I have had batteries that I thought were fairly new (2yrs or so on a 5 yr battery)that have gone dead for one reason or another and in a few months after they quit doin' their thing. Regards, Vern

 

I know you want to hard wire it, but it's a lot easier to replace the end clips with a cigarette lighter plug, like on the end of a radar detector. You can get these as replacements at electronics stores like Radio Shack. Then all you have to do is plug it into your cigarette lighter socket! Super easy. That's what I do on my 308, but I use a doubler so I can also put in my simple volt-meter so I can tell the voltage and when it's fully charged.
Image Unavailable, Please Login

 

This would be most convenient for me (328). Do any battery tenders come with the cigarette lighter adapter standard?

 

One of the "battery minder" models comes with a lighter plug, ring terminals and clamp attachments. I use the ring terminals on a motorcycle, and the lighter plug for the 328. The connection in the lighter plug is not the best, though. If you yank on the cable and cock the plug a bit, it tends to lose the connection. Could just be crud in my lighter...I never really looked.

It's kindof pricey at around $100 (don't get it directly from the manufacturer), but the desulfating feature is supposed to work - I tried it on a bike battery that had been sitting dead for over a year...I had to use a normal charger in manual mode on the battery first to get the voltage to a minimum level, then swapped in the battery minder and it did it's thing. Working battery.

Not clear if you need a special unit for optima batteries. The standard unit will definitely charge/maintain the optima, but may not desulfate effectively.

 

I don't know if it would help you at all, but I have a writeup on how to install a battery tender in a 328. Drop me an email if you'd like a copy (it's a 5MB file) at [email protected]

Carl

 

Just go to Radio Shack for a cigarette light adapter plug. Very easy to splice on. If you must hard wire, you can do it to the battery, and run the wire up through the small hatch in the passenger side of the trunk...I run the wire out through the edge of it, so all I have to do it pop the trunk and connect up.

But the cigarette lighter trick is the easiest of all.

I don't care for running the wire through the fender liner, to easy to forget and possible drive off with it still connected!

 

My Optima Red Top Battery (model 34) was less than 18 months old and last weekend, when I went to start my 246GTS it wouldn't start, even using my starter jumper battery and then using jumper cables from another of my cars with the engine running in my other car. The battery check meter indicated that the Optima had a charge of only 6.75 Volts and this is not enough to allow the batter to start to hold a charge. The rest of the starter system and alternator tested just fine, and there was only a very minor drain (from the clock) when everything was shut off. I am more than a little PO'd since Optima adverstises itself for use in cars that are occasionally driven. I last drove the Dino about 4 weeks ago for an extended period at freeway speeds. I replaced the battery and now I am going to check everything again and then review what happened with Optima. Maybe I just happened to get a bad one from Optima. Also, I'm going to try a battery tender too, but short term storage was the reason why I bought the Optima to begin with.

Mark

 

I think it's the yellow top Optima recommends for the rarely used car.

I had the same issue with a new Red Top in my 328. With the recovery system pulling 80mA, the battery went to 6 volts and change and the charger wouldn't bring it back. I unplugged the battery connector in the car and let the battery sit with no load for a week or two, and then put the charger back on it for four hours. It came back. But it will discharge in under two weeks at the "off" load of the car.

I now use a battery tender (Schumacher, from AutoZone).

I bought some inline connectors from Radio Shack so I could change ends. The one I most commonly use is the connection to the cigarette lighter plug. But I want to wire a heavier connector directly to the battery, so I can put the tender on the battery with the battery disconnect pulled off (e.g. over the winter). The heavier connector would be so I could connect the full 10A charger without having to get under the spare tire.

While I like not having to worry about out-gassing during charging, I'm not really impressed with the Optima as a battery.

 

I got that volt-meter at WalMart, but my local one doesn't carry it anymore. Here's an online source: www.scopestuff.com/ss_vmcp.htm ($16)

 

I know this is a old post, but - My 355 has the hard wired connection in the front wheel well. Any certain battery tender you guys can recommend. Would like to buy one. Basically just plug it in and leave it??

 

Personally, I prefer the Deltran Battery Tender.

 

Deltran Battery Tender Waterproof.....

It has a sealed case, small, and 800ma...... Just a bit more power than the BT Jr. and a lot safer than a full charger. I have three of these.

 

They ALL pretty much work the same. Just make sure it says either "smart charger", "fully automatic", "automatic with float mode" or "microprocessor controlled"...those are the key words that identify it as not being a simple "trickle charger", which is what you don't want. The previously mentioned ones will shut off once the battery reaches full charge, and start charging when voltage drops below a pre-determined level.

I have two Detran Battery Tenders; one is the Battery Tender Plus (1.25 amp, another is the Battery Tender Jr.(750 ma, I use on a motorcycle) I also have an onboard NAPA 1.5 amp unit on my 355 (my FNA dealer installed) and a Griot's Garage unit (1.5 amp, manufactured by Yuasa). They ALL work similarly and sucessfully.

The one that looks to be the best deal right now is the Black and Decker 2 amp charger sold at WalMart. Less than $18 and includes several hooks ups, most importantly it INCLUDES a cigarette lighter adapter!! Makes connection very simple.

Details below:

Black & Decker 2-Amp Automatic Float Mode Battery MaintainerSpark Resistant Reverse Hook-Up And Overcharge Protection 2 Charge Rate Settings: 2 Amp For Recharging Motorcycles, Lawn Mowers, Tractors, Atv'S, Snowmobiles, And Personal Watercraft; 1 Amp For Recharging Rv'S, Specialty Vehicles, Antique And Classic Cars, Marine Deep Cycle Batteries E-Z Connect For Battery Clips, Ring Terminals Or Dc Plug Use Includes Battery Clips For Temporary Vehicle Battery Connection Includes Battery Ring Terminals For Hardwire Installation Includes Vehicle Dc Accessory Plug For Internal Car Use 2 Stage High-Frequency Charging Technology Produces High Output Pure Dc Current Charges Battery Automatically Automatically Switches Between Charging Mode And Float Mode Monitoring All Solid State Circuitry 5 Year Limited Warranty Ul Listed

http://www.blackanddecker.com/productguide/product-details.aspx?productid=15572&toolview=4#details

 

BTW, the connector you already have installed in your car is most likely the one that is universally used by Deltran, Yuasa, Griot's, and Black & Decker. But if you get the B & D unit, use the cigarette adapter plug....you will never back out of your garage with it connected!

 

As absurd as this seems, I can almost see this happening as it almost happened to me!

I would hate to see the scratches from the unit rubbing against the body!!

 

http://www.griotsgarage.com/catalog.jsp?L1=L1_2500&L2=L2_4000&SKU=77655



or this


http://batterytender.com/product_info.php?products_id=2&osCsid=28daa7ccc2252d99cdb7038a90e6072f

 

It HAS happened to others on this list...

 

Yes, but if you want the Deltran, get it here:
http://snipurl.com/7cod

Since they all work the same, and the B&D unit comes with the cigarette lighter adapter standard, AND sells for less than $18 at WalMart, I recommend that you seriously consider purchasing it. I noticed the B&D unit also has two charge rate settings, 1 amp and 2 amp, rather than the fixed output of the others. Not a huge deal, but a nice feature. You could buy three of them for the cost of one Griot's unit! (or buy them when Griot's has their "garage sale" at their warehouse, where they sold them "Two for $10!" which is what I paid a couple months ago...sorry, already gave them all away to my friends.

 

No need to pay $60 for one, I stopped by Harbor Freight a few weeks back and stumbled on this special for under $8.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42292
PS - under $8 is the online price, the in-store sale price was $4.99.

Yes, just plug it in and leave it. The voltage regulator measures the battery and if the voltage drops it then charges until the battery is full and then stops charging. It constantly measures and if teh voltage falls again, then it resumes the charging.

I saw that when you bought them and went over to the "$15 each or Two For $10" table, but weren't they missing something like a special power cord?

 

They were missing the cords if you were not first in line ( ), but some connectors and cigarette lighter plugs from Radio Shack and you could get them up and running....but for a couple dollars more, could have saved the trouble and just bought the Black & Decker units!!

That Harbor Freight unit is probably fine... I would clip off those clamps and come up with a cleaner method of attachment, as accessing the battery can be so difficult on Ferraris. You can get cigarette lighter adapters, or make up a connector with a disconnect directly to the battery itself.