Charging starter and leisure batteries at same time.

[Ayjay]

I usually rely on my solar panel to keep the starter battery topped up via a Ctek 250SA until the weather really turns and we get long periods without sunshine. That's when I plug the leisure system into the hook up cable (Victron Bluesmart installed) and then run a CTek MXS 5 from the 240v sockets in the van to the 12V (lighter) socket in the dash. OR will the leisure battery get a charge from the starter battery if I simply plug the Ctek MXS 5 the mains and then into the 12V socket? Hopefully it's not a stupid question.

 

[Dellmassive]

good questions and answered here:

[Guide] Battery Maintainer (for Starter battery) -- How I Done It --

[Guide] Battery Maintainer (for Starter battery) -- How I Done It -- Right so its that time of year again . . . . . . . . Winter & (Lockdown 2020) The van might be layed up not being used, which will lead to a flat battery in around 3 weeks. The cold weather doesn't help the battery's...

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and here . . .

Charging Starter and Leisure batteries with same charger - Victron

Hi, Inspired by @Deaky build post, I was planning on installing a Victron IP65 Smart charger next to the Starter Battery and a 2nd one to charge the Leisure batter (110AH AGM). I've discovered the CTEK D250SE will still charge the leisure battery as long as the volts on the starter battery are...

www.t6forum.com

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[Dellmassive]

will the leisure battery get a charge from the starter battery if I simply plug the Ctek MXS 5 the mains and then into the 12V socket?

- short cut answer -

YES, BOTH batterys will charge,

provided the mains charger (below 8A) is plugged into a socket that is connected to the starter battery, (above 8A a direct connection is required (12v socket will melt/get to hot))

then once the starter is charged (above 13.0v) - the dc-dc charger will kick in and charge the leisure battery.

you may see the charger cycle on/off a few times - depends on the battery's SOC and the charger current A rating.

 

[VanDamMan]

Hi.. ( Lee just answered my post better than I can ) Luckily our van is parked off road so we simply connect the Mxs 5.0 directly to the starter battery and this as said charges the leisure battery (via 250sa ) ….I don’t have fancy gizmos and simply monitored the leisure via the Victron smart stunt app and use a clamp volt meter on the starter…takes for ages but better to charge slow

 

[Nigel W]

Just a thought because I have a different system but the same might apply.

I have a Sterling DctoDc charger but it sets itself off by voltage not by a run signal.

so…….when I first plug my Noco 5amp charger into the cig socket the Sterling kicks in and both the vehicle and leisure are charged but…..once charged the Noco drops down to maintenance voltage the Sterling cuts out and it will never restart as the maintenance charge to the vehicle never again reaches the voltage to re-trigger it so the leisure battery is out of the loop.

phew….hope you follow.

so I keep the leisure charged by solar panels and vehicle by the Noco

 

[Dellmassive]

Just a thought because I have a different system but the same might apply.

I have a Sterling DctoDc charger but it sets itself off by voltage not by a run signal.

so…….when I first plug my Noco 5amp charger into the cig socket the Sterling kicks in and both the vehicle and leisure are charged but…..once charged the Noco drops down to maintenance voltage the Sterling cuts out and it will never restart as the maintenance charge to the vehicle never again reaches the voltage to re-trigger it so the leisure battery is out of the loop.

phew….hope you follow.

so I keep the leisure charged by solar panels and vehicle by the Noco

Yes . . . @Nigel W that's correct.

The NOCO chargers are a bit too cleaver for there own good. (if you have a constant load ie DC-DC charger or Fridges etc .draining the LB, the NOCO decided that the LB is at fault as the SOC doesn't reach 100% and will show a RED battery error LED after 24-48hrs)

you can easily fix that issue by restarting the NOCO charger every 24hrs. - which resets the error timer.

or swap it out for a Victron charger - or other. (which dont have the battery faulty timer)


see more details and testing here (NOCO,CTEK,VICTRON) :

Noco Genius 10 not working correctly

I have posted this on another thread but its the charger discussion one so i thought id do a separate one to see if anyone else has had this with Noco’s or any other charger. I've been camping this weekend. Running a Dometic CRX50 and a Noco Genius 10. The Noco charges when you turn it...

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[Ayjay]

.......provided the mains charger (below 8A) is plugged into a socket that is connected to the starter battery.

Cheers to all, especially Lee. I was assuming that's the case as the two 12V sockets (front and top of dash) are both permanently live (ie. even with ignition off) and when I plug the Ctek MXS into one of them, it starts charging the starter battery (or am I showing my ignorance yet again?). As the the charger itself, it's 5A so OK for the sockets.

 

[Dellmassive]

On my van, which had factory second battery fitted.

The top dash socket is fed from the LB.

The lower middle socket is fed from the starter battery.

 

[keith baker]

I use a similar method - charge the van battery then the sterling DC/DC will charge the lithium LB. I think I'm going to run a 12v from the ctek to the sterling engine run input to trick it into charging all the time. The same problem as the Novo smart charger mentioned earlier.

 

[Qnapper]

I feed my solar to the leisure battery direct via victron MPPT (115amp AGM) then I fitted Battery maintainer by Sterling Power to vehicle battery. Great bit of kit (fit and forget). Removed it from my motorhome before selling were it was fitted and worked for years.

Link: Battery Maintainer