Solar Trickle Charger Advice Please

Hi guys,

My P38 is only used either weekends or every other week when we want to go out on family trips and the rest of the time it is stood on the drive not doing very much.

I have a little 1.2 Clio I use for commuting to/from work to save the old pennies!

As the RR is sat on the drive the battery drains considerably when left and I often have to jump start it.

If I bought one of these gizmos and permanently wired it to the battery and left it attached to the windscreen in the car, would it provide enough power to keep the battery topped up so I can at least start it when it has been stood a while?

Any advice / suggestions welcome

The two I have seen can be viewed here Maplin > 12V/ 12W Solar Battery Charger
and here
Maplin > Solar-Powered 12V 1.5W Battery Trickle Charger

They are both on offer at Maplins until 10th June

Thanks

Stef

Hi,
Have you looked into why the battery is going flat first? This is usually down to the early RF receivers picking up from various sources causing the car electronics to wake up regularly and so flattening the battery. I had this problem (battery would go flat in 2 days standing) until I fitted the new RF receiver now I don't have a problem with the battery going flat.
mikeateves

I have already replaced the RF receiver to the updated one. I am not sure how old the current battery is although it looks like a fairly recent one.

A couple of months back my wife accidently left the interior lights on all night and it still started OK the next day but recently for whatever reason the charge will not hold for very long.

I don't want to go and spend £90+ on a new decent battery if I can keep the current one topped up enough to start.

Once fired up, the alternator is charging it fine

Hello Stefan,

For the purpose you describe the trickle charger would be fine, except that the battery still has to be in reasonable condition to accept the charge.

If the battery is dying then you can assume it will shortly be dead. Then you are going nowhere.

If you are determined to keep the old battery then the 12 watt charger may be better and just start pumping in the charge a couple of days before you want to take the car out.

Because you are going to keep the old battery, then at least take a few minutes to read this essay on why "only the rich can afford cheap car batteries".

You will then understand what is actually happening to your old battery and plan what to do when it shortly gives up the ghost.

Only the Rich can afford Cheap Batteries


Ramon
Vintage Model Airplane and Rover SD1 3500cc Twin Plenum Vitesse

Excellent link ramon.alban Thank You

I had a look this evening under the bonnet and it is a Maintenance Free battery I have with a little round viewing hole. According to this my battery is OK as per the thumbs up symbol displayed next to it when it is green. Thats what colour the little hole is.

It looks like I may have to do a little further investigation as to why it isn't holding charge very long. I will see if I can borrow another battery from a mate before splashing out on a new one and see if I get the same problems.

If the car is driven and left for the day it still cranks and starts well, only when for a considerably longer time. It's a confusing situation! Like you have stated - All I am after is something to still allow me to start the car. I am planning on going abroad to Eastern Europe later this year and my brother in law can get me any branded car parts at a fraction of the cost here in UK.

Hi Stefan,

If you have an ammeter you could connect it in series with one of the battery cables and see if excessive current is being drawn from the battery (should drop to near zero amps after about 1minute from locking the car). Alternatively, if you don't have an ammeter leave the battery disconnected then reconnect it just before you want to start the car and see if the battery is still okay. I had to replace the battery on my P38 DT even though it was less than 2 years old because it was no longer holding its charge.
mikeateves

Hi Stefan.

My defender only gets used every other week and sometimes not for three or four weeks. My battery kept going flat. In january I bought a 1.5w panel and keep it on my dash (I felt the 5w was a bit big size wise). I have not had a flat battery since.

I have gone and bought one of the 1.5w ones for a tenner and installed it.

Whilst I had it all apart I used my multimeter and it looks like I had a drain of 1A. This was using it in between the earthing strap and the negative bettery terminal with it disconnected. Mind you the interior lights were on with the door being open and the key in.

The battery voltage showed up as 10.6V so I have lost in the region of 2V. The crucial amount needed to crank the V8!

I will leave it for a couple of days as I am working over the bank holiday so won't get to use it until at least next weekend and see what happens.

In the meantime if anyone wishes to add their advice it would be greatly appreciated

Try looking at something called an "optimiser" (try looking in motor bike shop's)it's almost the same as a trickle charger but monitor's the BTY keeping at the correct charge state. I use it on my ser2a and works a treat remember to disconnect it before you drive off though.