rpmooreii

Hi,

My wife and I are fortunate to have two 911s (a 93 RS America and a 73 911T). Both of the cars get driven but sometimes infrequently and on short trips, and as a result, I would like get a good battery tender. I have several questions:

Cigarette lighter battery tenders
I have heard of battery tenders that plug into the cigarette lighter but have not been able to locate any of these.

1. Do they really exist?
2. Do they work?
3. Can someone point me to a web site that sells these?


Permanently attached battery tenders
The 73 911T has had the two battery system converted into a one battery system. The larger single battery is located in the battery well sideways thus eliminating easy access to one of the battery terminals. As a result, the alligator clip style connections are not very convenient (the batter has to be removed from its well to connect one of the alligator clips).

1. Is there any safe way to attach a battery tender/maintainer without alligator clips?
2. Does anybody have any experience with permanently attached tenders, and if so, which brand/style to you prefer?

Thanks, in advance, for the collective wisdom!

...Roger

Roger Moore
'93 RS America
'73 911T (original owners)
'99 Audi A6 Avant
ex-'60 Roadster (street concours)
ex-'74 911 (mexico blue, featured in Leffingwell's latest 911 Buyers Guide)

pwd72s

No brand name suggestion, but you can hook the negative alligator clip to your negative ground cable connection...

p_carfan

rpmooreii-

Dude, you cant beat OEM......Porsche makes a cig-lighter plug-in version. Very handy little device. Try "Sunset Porsche" tell them you want the "excellence" discount. Dealer cost + 15% 1.800.346.0182
You might also consider replacing your batteries with "Optima" red tops next time you replace batteries, they last 3+ times longer than an acid battery and are great for the conditions you describe.

BTW....... It's pretty hard to beat "Sunset" on OEM stuff, you might hang on to their number for when you do price comparisons .

Good Luck!!!

TMH

I use the VDC Electronics Battery Minder in my vehicles (I think that I have about 4 of these units for different vehicles). I get mine through BatteryMart.com as I have found the best prices there. I have no affiliation with either company.

The Battery Minder has a short (12"?) plug that "permanently" attaches to the battery through the cable bolt. It is polarized so you can't plug the charger in wrong, and of course the negative ground on the plug is bare metal while the hot side is insulated from touching the chassis. The main things they say about these chargers are true, based on my historical experience with all sorts of batteries:

1) The worst thing for a lead-acid type of battery is to let it go down. You will get the most life (least sulfation of the plates) if you keep it constantly "topped off"; and
2) "Pulse" mode charging can serve to remove some of the sulfation off battery plates, and give you longer life out of batteries.

Unit is essentially a "wall wart" type charger which goes into pulse mode at a certain battery voltage. So cheap to run that you can leave it charging whenever you are not driving. Easy plug in to plug attached to battery. Need to run a 110 volt extension cord to vehicle, and close your bonnet onto this cord.

It works great for me, even for some of my vehicles which may not run for several months. I started using these when I had to replace big old 8D size batteries in the fire engines at about $150 a pop. Never have had to replace one since I started using maintenance chargers.

Tom

964porschedude

I bought a small battery tender (1.5 amp) and it has a connect plug at the end of the output cable. It was supplied with two mating cables that plug into this connector. One is a set of alligator clips; the other is a connector to attach to your battery cables in a permanent fashion. That way you could connect to car without the alligator clips.

gr8fl4porsche

I use a permanently mounted smart charger that works perfectly - not sure of the brand. The smart chargers monitor the charge and only turn on and off as required as opposed to an always on trickle charger.

I just plug in the car everytime I think it will be a few days between cruises.

greglepore

Get a cheap one-from Harbor Freight etc. Radio Shack sells cig lighter male plugs-take off the clips, put on the plug. Should be around 20 bucks total.

86NOH2O

Just a quick note. I have the cigarette lighter variety trickle charger. The Porsche unit. I saw on this board a few months back some important info. You must turn your key on for it to work! I used mine for awhile and the red light never came on when "charging". Then after seeing the tip on this board I realized the key must be on and now when plugged in the red light shows it's on. Why, I don't know.

I never checked this with my voltmeter, but the light does come on now.
I have an 86' if that matters.