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MG Midget and Sprite Technical - Any Battery experts out there

I am having to lay my midget up until next spring, and I was wondering what to do about the battery. I have a trickle charger, but have seen it written that this may sulphate the cells.
Is it worth getting a pulse charger, or just use the trickle charger once a fortnight.

Thanks in advance
Dave
Dave Barrow

a "good" trickle charger is designed to avoid doing that (one with internal circuitry that modulates how the charge is going in, and makes necessary adjustments over time by "listening" to the battery and responding to that).

these guys talk about that a lot:
http://batterytender.com/

I assume that there are other companies who make them with similar thought in mind. I have been using Battery Tender chargers on all of my batteries that get infrequent use, and even managed to get one gell mat battery to last for almost 15 years.


Norm
Norm Kerr

oh, found it!

Hopefully, this will better answer your question: You don't want to use a trickle charger for any extended length of time, instead get a tender that will switch to lower voltage when the battery is charged (or, in a pinch, have some kind of a timer turn off your trickle charger for most of the time, maybe only have it on for 20 min a day or something - the website linked above includes formulas to calculate that if you want to work it out manually).

Here is an excerpt from it describing the difference in more detail:
How is the Battery Tender Plus battery charger different from a trickle charger?

The Battery Tender Plus battery charger delivers 1.25 amperes during bulk charge mode, holds the battery charge voltage constant at 14.4 VDC during absorption charge mode until the battery charge current drops to 0.1 amperes at which time it then automatically switches to a float charge mode. During float charge mode, the output voltage of the Battery Tender Plus battery charger is 13.2 VDC, which is well below the gassing voltage of a lead acid battery. This keeps the battery topped off, while minimizing any detrimental effects to do gassing. The Battery Tender Plus battery charger is able to perform these complex switching functions because its electronic circuitry is controlled by an on board microprocessor.

Although they often appear to be a better economic choice for the typical consumer, trickle chargers do not have the advantage of sophisticated electronic control. Therefore, as they allow the value of charge current to trickle down to what appears to be safe levels, the output voltage of the charger rises well above 15 VDC, sometimes even going higher that 16 VDC depending on the charger type and the battery that is connected to it. Either voltage is well above the gassing voltage of a lead acid battery. If the battery remains connected to this high level of voltage for an extended period of time, even less than 1 day, extreme damage can be done to the battery. What appears to be a cost savings for the charger may actually cost several times the charger price in replacement batteries.



hope this helps,
Norm
Norm Kerr

Probably teaching granny to suck eggs but I would remove the battery from the car completely if trickle charging for that length of period, just in case! Also would recommend leaving the car on axle stands front and rear to save the tyres or blow them up real hard, leave the handbrake off, make sure the front brake pads are free from the discs and have lots of antifreeze in your coolant. Assuming its garaged I'd leave the hood up with the windows part open and the carpets lifted away from the floor. I was quite shocked at just how much needed doing when mine was involuntarily laid up for four months with no prep.
But you know all that anyway!
Matt1275Bucks

as you know I'm an expert on nothing, but -

if you've got a good battery in good condition and your car electrics the same with no immobiliser or alarm on the car then I would just leave it

or get a battery conditioner

check battery for electrode level and top up if required with distilled water before connecting conditioner

tyres - over inflate or remove wheels, possibly hand brake left off and other stuff I can't think of

perhaps put fresh grease in

it would be better if you could get someone to drive it once a month for say 50 miles
Nigel At

Dave, you need one of these
http://www.airflow-uk.co.uk/Battery-Conditioner.html
David Smith

I've got a Carcoon one fom years ago but it's really one of these - http://www.accumate.co.uk/

loads of info on their web site too
Nigel At

I have been storing our midget for extended periods for over thirty years (9 months to 3 years)and have never used trickle charger. Remove battery when fully charged and store in warm place. As said above axle stands and everything free. mouse poison around stands.

Batteries last as long as one in my wife's everyday car or longer and never had trouble restarting when ready for road. oil change immediately before laying up so no internl corrosion

good luck
G Burrow

I've been driving my car a lot recently and just noticed a build up of a whitish, thickish, sticky to hard buildup on the pos. post/cable and also in the middle of the battery hold down bar. The stuff on the bar was hard enough to chip off with a screwdriver and the stuff on the terminal was softer and was wiped off and wire brushed off. Neg. post was clean. I had previously smeared both posts with grease and the crud was mainly around where the clamp bolt goes through the clamp, probably where I did not get a good coating of grease. Is this from the out gassing you're speaking of? Normal or indicative of a problem?
Jack
Jack Orkin

you can use hot water to get ‘fur’ off from around the terminals

or if it’s a big build up pour home baking soda made into a wet paste over the effected areas and clean with an old tooth brush, you can brush clean the whole battery top then rinse down clean water, if necessary use thick paper towels to fully dry before wire brush cleaning the terminals and lead clamps
Nigel At

Thanks guys, I will consider all the options.

Dave
Dave Barrow

What Nigel says!!!

and then use even more water, hot or cold doesn't matter, to washaway the resulting liquid you made from the fur.

This is impure but quite strong sulphuric acid basically and is rather unfriendly stuff to leave lying around

And what GB from Manitoba (GB?, a name is nice to handle G) says about keeping the battery healthy is right

charge it fully
disconnect

reconnect when you need it

a light charge "may" be needed and the battery will serve you for a long time if healthy when charged and disconnected
Bill 1

This thread was discussed between 17/08/2011 and 21/08/2011

MG Midget and Sprite Technical index

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