Trickle charger for my 80 - 12v or 24v?

[THL]

I'm going to get a trickle charger for the 80 as it does sit for a good few weeks without use, however I don't know if I need a 12V or 24V charger. I've read on here that some 80s are 12v whilst the later models start on 24V then run at 12V. Its a 1998 so I'm assuming it has later start on 24v system but what voltage charger do I need?

 

[Steve Wright]

Hi
As you say there is some confusion, but as far as I can determine that the system is 12 volts and as you say on some there is some switching to make 24 volts but just for starting.
What you need to do is get a DMM and check out to see if the output from the alternator is 12 volts and check if the two battery's are connected in parallel or series.
What you might have to do is connect the 12 volt charger to one battery then the other.
The other thing don't use a old fastened charger as that might cook the battery's, use a smart charger

 

[grantw]

You need a 12v trickle charger and make sure it's connected to 12v battery not the 24v start battery side. You can connect it to both sides as long as you don't start it up whilst the charger is connected. Though 24v on the output side of the charger probably wouldn't do any harm.

 

[THL]

Thanks @Steve Wright and @grantw

So the charge from the 12V side will flow across to keep the 24V side charged/conditioned? I have a CTEK charger (https://www.ctek.com/products/vehicle/mxs-5-0) but I didn't think it would work for anything 24V. I'll leave it overnight on the 12V side and see what happens

 

[Chris]

Just so we don't get confused here. The car runs on 12v but starts on 24v. When it's parked or running it's 12v. Like Grant said, just don't connect the charger across two batteries at once and better not to have it connected when you turn the key. Outside of that the two batteries are connected in parallel; there is NO 24v charging option. There's a cover normally on the near side battery to stop you connecting stuff. So connect to the driver's battery. But, be aware that in essence you are trying to trickle charge one MASSIVE battery and that's going to test any charger. 4 amps isn't going to have any charging effect at all in reality but it MIGHT just keep a well charged pair of batteries topped up in terms of maintenance. To look after mine I use a decent 10A charger and alternate every so often between the batteries, pulling one of the terminals off to make them separate units. Or you buy two chargers of course. Just another reason for going to 12 v start. Then you only need one battery.

 

[StarCruiser]

As Chris says, though the charging would be handled whether the charger puts out 2A or 20A, as long as it charges at the correct voltage (which it will) it will just be a time difference between one and t’ other. Ctek would probably suggest a charger such as the 10A for the combined Ah rating of your batteries.