Battery Charging on P38

I am not using the car too often and as a result the battery runs down (as they do! ). I have been told that a maintenance charger (Halfords advertise one @ £25) left connected to the battery on the car would resolve this problem. I am aware that charging the battery on the car is a no no. However, is it possible that the low charge rate with these devises is acceptable?

I don't want to screw up the ECU has anybody used one of these devises with their P38?

parranger said:

I am not using the car too often and as a result the battery runs down (as they do! ). I have been told that a maintenance charger (Halfords advertise one @ £25) left connected to the battery on the car would resolve this problem. I am aware that charging the battery on the car is a no no. However, is it possible that the low charge rate with these devises is acceptable?

I don't want to screw up the ECU has anybody used one of these devises with their P38?

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I have been using an automatic charger on my P38 for years as like yourself I do not use the car that often. I leave the charger permanently connected and it switches itself on and off automatically. I use the trickle charge setting.
I have never had any problems whatsoever regarding damage to the battery or any of the ecu's, in fact you run more of a risk of causing ecu problems, especially relating to the Becm by disconnecting the battery or allowing it to go flat......just look at all the countless posts on here relating to flat batteries !!!!!!!

parranger said:

I am not using the car too often and as a result the battery runs down (as they do! ). I have been told that a maintenance charger (Halfords advertise one @ £25) left connected to the battery on the car would resolve this problem. I am aware that charging the battery on the car is a no no. However, is it possible that the low charge rate with these devises is acceptable?

I don't want to screw up the ECU has anybody used one of these devises with their P38?

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your battery should last a good few weeks with out useing it...but like my car your is not going in to sleep mode when its turned off...i sorted mine with a sola panel about the size of a number plate and that seem to do the job its pluged all the time so good at home or away and no need to plug in and out ..you can do wot you was asking but id not trust the halfords crap just get a proper charger and leave on low setting that will be fine. if you have a disel you could remove the air box and get something like a k&n filter. witch will make room for another battery if petrol you could have a extra battery in the boot link that up. and put it on a switch so when your out it will charge and when you get home flick the swtch and it will stay good for weeks..so the long and short of it is yes you can do wot you asked but theres a few other ways aswell but all will work just as good best of luck jamie

I use a Sealey Autocharge 12 and have found it to do what it says on the tin.
If the car is stored in the garage, can't see how a solar charger would help.

Thanks for the replies. I have taken another look at the options and like the idea of a solar panel. Maplins have a variety and not sure which one will be the best option. The range is 1.5W, 2.4W, 4.8W and 12W prices range from £10 to £30 so would be inclined to go for the £30 (special offer). Would appreciate some advice ref the BECM would this 1 Amp charge cause any problems? Would I need to fit a regulator..if so where can I get one?

I have had experience of charging the battery on the car (should have read the instructions first!) which caused an electrician a few hours to sort out the screwed up electricals!

No the charge won't affect the Becm but if the Becm is not going into sleep mode due to RF problems it will probably pull just under 1amp anyway. I suppose a small charge is better than no charge and don't forget that the solar panels are only active in daylight so during the winter months, the Ah produced will be less.

Irishrover said:

I use a Sealey Autocharge 12 and have found it to do what it says on the tin.
If the car is stored in the garage, can't see how a solar charger would help.

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thats fine mate i was just trying to be of some help. i keep mine out side so the sola worked out ok for me. if the cars keeped in a garage you could get one for the roof of the garage ...the way you have it. is good and has worked for you im not trying to knock it mate..do you think adding a nother battery would be a wast of time..

I know I`m late in posting this,but better late than never. As a motor biker too,I found using the Optimate battery charger for bikes was in itself a great asset on the R/R P38. My car lives outside on my drive,so i`ve rigged up a live feed from the house to the Optimate which I leave under the bonnet of the car.This type of charger keeps the battery fully charged at all times,turning off and on when necessary.I also leave a note in line of sight on the dashboard in case I forget to disconnect.(That`s an age thing!!!!)

Dave ( DDLR) 04-08-11

Trust me, as age takes it's toll, a little trickle is better than nothing at all.


It's not bad for the battery either.

Small maplins solar charger sitting on the dash and permanantly connected has sorted all my electrical gremlins for over a year now.

jamie1210 said:

thats fine mate i was just trying to be of some help. i keep mine out side so the sola worked out ok for me. if the cars keeped in a garage you could get one for the roof of the garage ...the way you have it. is good and has worked for you im not trying to knock it mate..do you think adding a nother battery would be a wast of time..

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:behindsofa:

Didn't mean to cause offence or think you were "Knocking it".
The forum is all about people putting their suggestions forward and leaving it up to the poster to decide which way to go.
As we all know, there are two ways to charge a battery...either plug a charger in or use solar power. I also know that the solar chargers are fine in their own environment, i.e. with the car outside. I was just trying to advise the pros and cons.
Personally, I wouldn't go for fitting a second battery, I would make sure that the one I have has plenty of capacity and is in tip top condition. If both batteries are connected in parallel the weaker of the two batteries will pull the other one down.

Irishrover said:

:behindsofa:

Didn't mean to cause offence or think you were "Knocking it".
The forum is all about people putting their suggestions forward and leaving it up to the poster to decide which way to go.
As we all know, there are two ways to charge a battery...either plug a charger in or use solar power. I also know that the solar chargers are fine in their own environment, i.e. with the car outside. I was just trying to advise the pros and cons.
Personally, I wouldn't go for fitting a second battery, I would make sure that the one I have has plenty of capacity and is in tip top condition. If both batteries are connected in parallel the weaker of the two batteries will pull the other one down.

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you have not affended me in any way at all. and hope i have not you. with 2 batterys when you get home both should have full charged by driveing around. id fit battery no.2 on a braker so when parked it would stay charged and when needed just flick a switch and back up battery kicks in. and driveing around will charge them both for free...i will point out he did ask about a charger and your the man who can as you use one....i was just chucking a few other ways in the air like you said if we all put are 2penc in he can take the best way to suit.. wish more people where a bit more like you on here top man

parranger said:

Thanks for the replies. I have taken another look at the options and like the idea of a solar panel. Maplins have a variety and not sure which one will be the best option. The range is 1.5W, 2.4W, 4.8W and 12W prices range from £10 to £30 so would be inclined to go for the £30 (special offer). Would appreciate some advice ref the BECM would this 1 Amp charge cause any problems? Would I need to fit a regulator..if so where can I get one?

I have had experience of charging the battery on the car (should have read the instructions first!) which caused an electrician a few hours to sort out the screwed up electricals!

Click to expand...

I use a 12 watt on the rear parcel shelf with a regulator, but we have a lot more sun here 4.8 watt would probably do it but I would go for the 12 watt It can be left permanantly connected if it has a blocking diode fitted.

Thanks once again for the responses. Lots of good information. I have decided to go along with the solar panel but keeping a weather eye on the mains supply trickle charger option.

Leaving the solar panel charger permanently connected to the battery is an option but where to connect into. The auxilliary socket in the boot seemed a logical solution but the power is off when the ignition is off. Has anybody connected through this socket wiring directly to the battery. Appreciate some advice on where to pick up a permanent live feed to the battery.

parranger said:

Thanks once again for the responses. Lots of good information. I have decided to go along with the solar panel but keeping a weather eye on the mains supply trickle charger option.

Leaving the solar panel charger permanently connected to the battery is an option but where to connect into. The auxilliary socket in the boot seemed a logical solution but the power is off when the ignition is off. Has anybody connected through this socket wiring directly to the battery. Appreciate some advice on where to pick up a permanent live feed to the battery.

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I ran a 4mm live direct from the battery to the rear aux socket with a fuse at the battery. I put the wire in Kopex plastic tube and fixed it to the chassis rail top. Easy job I obviously disconnected the original feed to the socket. I needed the feed for my caravan.

If you go with a small panel on the dash just use the supplied cable along bottom of screen under the door rubber and straight into the engine compartment, crocodile clips to the battery

discomalc said:

If you go with a small panel on the dash just use the supplied cable along bottom of screen under the door rubber and straight into the engine compartment, crocodile clips to the battery

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Or.....to the extreme left (Negative) and extreme r.h. (Positive) screw terminal post on the Becm. You could run two single wires around 1.00mm. sq. and put a female Lucar (Spade) connector on one end of each. Put a matching male Lucar on each wire from the charger, remove the Becm fuse access cover from the seat lower trim and just connect up...Making sure of course that the polarity is correct.

I have my Rangie on charge whenever I am not using it for more than a week. It has no problems with the battery remaining connected and it starts when I need it! If I didn't charge it up, it would be flat in a week.

parranger said:

Thanks once again for the responses. Lots of good information. I have decided to go along with the solar panel but keeping a weather eye on the mains supply trickle charger option.

Leaving the solar panel charger permanently connected to the battery is an option but where to connect into. The auxilliary socket in the boot seemed a logical solution but the power is off when the ignition is off. Has anybody connected through this socket wiring directly to the battery. Appreciate some advice on where to pick up a permanent live feed to the battery.

Click to expand...

id run a live straight to the battery. in to the boot nice and tidy and earth from the body of the car..