Ctek D250 SE

Trotter

Full Member
I fitted the above a few months go, and TBH it works brilliantly, on lead acid batteries. Shortly after buying it , I was kicking myself because, if I wanted to go the Lithium route, I'd have to buy a different DC to DC charger.
But maybe not so. Looking at the new setting instructions for the Ctek D250 SE, the black pig tail that was used only on Neg -, for AGM batteries, can now be connected to Pos + for Lithium.
If I've got this wrong, or have oversimplified this, tell me, but be gentle.
If by some fluke I've got it right. Would the + be on the + post of the battery?
 

wildebus

Full Member
I fitted the above a few months go, and TBH it works brilliantly, on lead acid batteries. Shortly after buying it , I was kicking myself because, if I wanted to go the Lithium route, I'd have to buy a different DC to DC charger.
But maybe not so. Looking at the new setting instructions for the Ctek D250 SE, the black pig tail that was used only on Neg -, for AGM batteries, can now be connected to Pos + for Lithium.
If I've got this wrong, or have oversimplified this, tell me, but be gentle.
If by some fluke I've got it right. Would the + be on the + post of the battery?
nope, this is right. just connect to a +12V. The Redarc B2Bs use a similar sense cable method of Ground/Float/+12V to provide 3 different charging regimes.
46475

You could use the +12V on the CTEK +ve Stud that goes to the Leisure Battery
 

Okta

Full Member
The current product details say the D250 SE has a LiFePO4 setting. 14.2V is on the low side for some LiFePO4 makes but I doubt it would be a significant problem. For LiFePO4 the desulphation phase of the lead acid/agm batteries seems to have been replaced by a mysterious 5A acceptance phase that lasts for up to 2 hours, this might be an issue. I expect my B2B to whack in 40A from the start so that the battery is fully charged when I only do short trips. It might be worth checking with the manufacturer how long this phase normally lasts because if it is 2 hours and you stop for a comfort break every couple of hours you may never get more than a 5A charge.
 

Trotter

Full Member
nope, this is right. just connect to a +12V. The Redarc B2Bs use a similar sense cable method of Ground/Float/+12V to provide 3 different charging regimes.
View attachment 46475

You could use the +12V on the CTEK +ve Stud that goes to the Leisure Battery
Happy bunny! No immediate plans to change batteries at the moment. But as and when, I now know I don't have to rip stuff out and start over. Thanks again Dave.
 

Trotter

Full Member
Have you isolated the original charge circuit? I pulled fuse at split charge relay.
Not sure what you mean here. Are you talking about the split charge ? If so, not to worry, it was because that had failed, I fitted the Ctek in the first place.
 

nabsim

Full Member
Del if you get the money for Lithium I would look at fitting the Smartpass with it. I think that had lithium setting didn’t it and if so it will put a much higher charge in
 

Wissel

Full Member
Good to see CTEK now do a charger that can charge LiFePO4.

If it were me though, I'd want to know exactly how this works with the Smartpass. This is what my concern is:
d250se.JPG
The 120A continuous bit. LiFePO4 is greedy and will try to suck every bit of power it can. Unless stopped from doing so, it would max the charger out. The Smartpass may be fine with this - but a standard alternator wouldn't last very long I fear :unsure:
 

Trotter

Full Member
Del if you get the money for Lithium I would look at fitting the Smartpass with it. I think that had lithium setting didn’t it and if so it will put a much higher charge in
I'll only think of fitting lithium as and when your old batteries fail. Not convinced I'd need the Smartpass with my current travel style. The 20 amp input seems plenty.
Now, if Nik wanted to go full time................... Who knows;)
 
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