Installing battery charger

[Houleaux]

I should know this... but how do I connect my new Ctek M200 to my batteries? I've got the usual 1, 2 both battery switch. The negative terminals of the batteries (2 of) go to a common point, but where do I connect the positive output from the charger? Does it just go to the positive post of one of the batteries and then charge both when the battery switch is set to both?

Any help would be much appreciated.

Cheers.

Rob

 

[GrahamM376]

I should know this... but how do I connect my new Ctek M200 to my batteries? I've got the usual 1, 2 both battery switch. The negative terminals of the batteries (2 of) go to a common point, but where do I connect the positive output from the charger? Does it just go to the positive post of one of the batteries and then charge both when the battery switch is set to both?

Any help would be much appreciated.

Cheers.

Rob

I leave the engine battery to charge from the alternator (just like the car) so I would wire it to the domestic bank as that's the one you will be discharging most. If the engine battery needs a charge then switch to both.

 

[Rivers & creeks]

Problem there is you also need a split charge diode to make sure alternator also charges the domestic. Connecting alternator and battery charger to "both" is OK.

 

[charles_reed]

I should know this... but how do I connect my new Ctek M200 to my batteries? I've got the usual 1, 2 both battery switch. The negative terminals of the batteries (2 of) go to a common point, but where do I connect the positive output from the charger? Does it just go to the positive post of one of the batteries and then charge both when the battery switch is set to both?

Any help would be much appreciated.

Cheers.

Rob

A good point and the one on which I rejected the CTek in preference to a charger with multiple outputs.

I'd connect it to the out terminal of the 1-2-both switch.

Reasoning, to work the charger needs to sense the voltage in the battery it's supposed to be bringing up to full voltage, when both batteries are well discharged, OK to charge both as it will be on bulk charge. However for each battery to attain full charge it will need to address each battery in turn to achieve float voltage.
This means you have a non-automatic system, but will be able to intervene to fully charge both.

 

[Pye_End]

I put mine on the domestic bank terminal. If I want to give the engine battery a bit as well then just put the '1-2-both' on to 'both'. Engine battery doesn't drop much so is rarely charged in this manner.

 

[Houleaux]

Thanks all. Now fitted and working.

 

[Houleaux]

I noticed last ttime I used the battery charger that my NASA BM-1 was indicating 15V which seems rather high. It eventually dropped to 13.6V and stayed there.

I'd ended up connecting the positive output from the charger to the positive terminal of one battery with the negative output going to one side of the BM-1 shunt. I always leave the battery switched to "Both", so I reasoned that this should charge both batteries. I may shift the positive to the out terminal of the battery switch as has been suggested above. Somehow that just seems more right - but I'm not exactly sure why!

My batteries (both "Leisure") are a 105Ah sealed and 110Ah that can be topped up. I don't have a separate engine start battery (it's only an 18HP Volvo 2002). The info with my Sterling regulator suggests using a lower voltage setting if you have sealed batteries and with the engine running it never exceeds 14.5V on the BM-1.

Is something wrong? Am I in danger of damaging anything using the Ctek charger (batteries or electronic equipment)?

Thanks.

Rob

 

[robbieg]

If your charger is temperature compensated and it is cold (5-10C) the charger will ramp up the voltage to compensate for the cold. The 14.4v listed in the spec is at 25C-hotter than this you should get less than 14.4v and colder you should get more. My Ctek m300 was charging at 15v recently-but it was only just above freezing. Someone will correct me if wrong hopefully but I think the adjustment is about .02v per degree below (or above) 25c-so at 10c you would expect the charger to be at 14.7v ish and around 15v if just about freezing.

 

[Houleaux]

If your charger is temperature compensated and it is cold (5-10C) the charger will ramp up the voltage to compensate for the cold. The 14.4v listed in the spec is at 25C-hotter than this you should get less than 14.4v and colder you should get more. My Ctek m300 was charging at 15v recently-but it was only just above freezing. Someone will correct me if wrong hopefully but I think the adjustment is about .02v per degree below (or above) 25c-so at 10c you would expect the charger to be at 14.7v ish and around 15v if just about freezing.

Thanks. Nice to know that it's normal! It was pretty cold at the time...