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MG MGB Technical - Battery tender

I plan on installing a battery tender on the 2-6 volt batteries on my 1960 A Coupe. Can I install one 12v battery tender across both batteries or is it better to use 2-6 volt battery tenders separately connected to each battery. Does anyone have any recommendations on which one to buy and recommended methods of permeantely installing them, so you just have to plug it in when in the garage.

Thanks Andy
Andy Preston

Andy I'd use a single 12v tender (presumably a battery conditioner that charges and gently discharges and can be left on indefinitely?). On my B the cigarette lighter is permanently live so I fitted a matching plug on the conditioner. Alternatively hard wire a suitable socket in the car and fit the plug on the conditioner. HTH Michael
Michael Beswick

I'd second Michael's comments, twin 6v batteries are treated in exactly the same way for charging. I caused great confusion amongst some pals by saying I had a cigar lighter plug on my charger, they couldn't see how I could power the charger from the socket as well as charge the batteries ...

Cigar lighter wiring on the B at least varied over the years, at one point it was on the accessories position of the ignition switch which isn't really suitable for unattended charging as it needs the keys to be in (modern cars seem to be like this also), and definitely not if it is powered from the ignition circuit. Where powered from an 'always on' source in the car I'd want it to be fused for safety, even if the plug on the end of the charger or the charger itself is fused, and the same would go for adding a socket.
Paul Hunt

On my '67 I ran the quick disconnect plug to the positive lug on the solonoid and the negative to a good clean ground. It has been in place for 6 years now and keeps my 2 6 volt batteries fully charged at all times. I use a Battery Tender unit, cost around $50 . RAY
rjm RAY

Thanks guys for your recommendations. I thought that it would be ok to use a 12v battery tender but it's nice to have it confirmed by fellow enthusiasts. BTW I thought I was posting to the MGA site but do have more MGBs than MGAs and scan both sites nightly.


67 mgb roadster
60 MGA Coupe
Andy Preston

I think a better choice for a trickle charger is the Battery Minder Plus. The advantage is that this unit offers a desulphation cycle. Sulfate is the primary cause of long term battery failure. These units are available from many sources, just Google.

Here is what the manufacture claims.

Battery MINDer Plus is the first of a new generation of "Computer-On-A-Chip" technology. It conditions "sulphated" batteries as well as automatically charging any type 12 volt storage battery without ever over-charging. Dubbed the charger with a "brain," it is believed to be the first charger of its kind to reverse the primary cause of early battery failure known as "sulphation". "Sulphation" batteries that were once considered beyond recovery can now be brought back to long-term useful condition.

Great for any 12 volt battery. Leave it on any battery/vehicle while in storage and never have to worry about a dead or sulfated (ruined) battery ever again. Works on cars, motorcycles, ATV's, watercrafts, boats, and generators. Brochure Download (PDF Format)

Frank Grimaldi

I second Frank's comments on the BatteryMinder. I got the cheaper (cheapest?) model 12117. My MGB and my truck go long periods without firing up. I saw a marked improvement on both batteries, in terms of output, after using the BatteryMinder for a while. My truck used to need charging every 2-3 weeks. Now I can get in after 3-months or more and she fires right up. In fact, I haven't needed to use the BatteryMinder in over a year. I figure it saved me the cost of two batteries, so more than paid for itself.

Terrence Goodell

Some years ago I bought ten battery Buddys made in the USA. I have never sold em but have used three in various cars. The latest I fitted into my MGB Roadster
68 model. As I have re-designed the boot/trunk somewhat I have a real neat instalation. The EU requires certain items to be carried in the car. fire extinguisher, first aid kit etc. So all my stuff is clamped to the inner trunk bulkhead. Nothing rattling about I have the following. Extingusher, jack, hammer, warning triangle, even a litre of Castrol oil, first aid kit for humans and one for the MGB. I managed to fit the battery buddy also and this is fantastic. It is so well made and actually disconnects the battery from the system when it gets to a low level. Only problems is you have to extend the battery lead and I ended up buying a coil in the UK and spent some time running it through the car underside and into the boot. I don't know of the battery buddy is still made but if you ever get a chance to own one get it. You can park up for months knowing that it'll fire up once you press the reactivate button. I have one 12v battery.
A Chambers

Forgot to mention that I also installed a seperate earth/
ground battery style post as well on the bulkhead. So now if need to I can jump start the car from the boot. It also gives me a great connection for a 500w inverter as well.
A Chambers

This thread was discussed between 10/11/2009 and 20/11/2009

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