Battery Charging Advice Please

[Johnb]

After my last service I was told the battery charger was working but not pushing much juice through. Had I been informed during the service I think I would have asked for a replacement but I missed that boat. The battery is quite new and I wasn't told there were any problems with it and, I presume, its state of charge.

I have an electric Thule Omnistore fitted to the van, with hand crank if the motor fails of course, but would like to think that reliable electrical feed is available.

Simple question for members understanding caravan electrics: I have a CTEK smart charger with "croc. clips" to fix to a battery.

Would there be any problems (if charging issues occur whilst away on EHU) with simply attaching the CTEK to the battery with the provided clips and without changing anything else with the van electrics, plug it in to provide a reliable charge?

 

[JTQ]

Though not claiming to be a specialist in this, I would not risk having both the CTEK and inbuilt charger both together trying to charge the battery .
I suspect it will not do any harm, but as said would not invite it to try.

I would contrive one way or other to overnight just have the CTEK charging. A way might be remove the mains fuse in the inbuilt charger, or pull its mains plug if one is used, or even disconnect the EHU from the van and connect it just to the CTEK. Fortunately I can do this at home should I want to.

Before ever doing it I would research if the inbuilt charger is smart and also test to check it is if faced with concerns I had a charging issue.

 

[IanB1485]

Hi JohnB
The charger /PSU wont push much juice into a nearly full or full battery, thats how it works
As the battery voltage rises up to 14.2V ( or on simple 1 stage chargers like the PS276or the Nordelettronica ones 13.8V) the charge current slowly reduces to less than 0.5 Amps . Connecting a CTek charge will not 'upset' the inbuilt charger, it will merely think the battery is fully charged and its output current will fall to 0 Amps the Cteck charger will continue to charge the battery upto 14.2V ( bulk charge) and then let it settle back to 13.8V (float charge)The inbuilt charger will take some current but it won't harm it , its merely running the output circuitry and feedback components , telling the driver stage not to produce any power . The service tech may not have fully understood how chargers work . When checking both the battery and inbuilt chargers I disconnect the battery and place a load of about 100-200A on it whilst observing the the voltage ,if it drops away quickly from about 11 to 11.4V ( say to 10.6V or less) then the battery is on its way out. If it holds at 11V for 30 seconds or more then its OK , but during that test I have taken quite a significant amount of charge out of the battery. Then I reconnect the charger and using a D.C clamp ammeter and digital multimeter observe the charge current and rising voltage , if I get about 9A initially and falling away as the battery voltage climbs back to 13.8V the charger is OK , Usually the inbuilt charger/PSU will fail completely rather than lose output capability( I have several dead ones of various types laying around my workshop). Conversely I have had one or two which have lost regulation and 'boiled' the battery by not shutting off at 14.2V - The usual telltale is the client has reported a 'bad egg' smell near the battery box.Some older charger/PSUs only can supply 12 Amps , where as newer ones like the the PX310 or the Victron Blu smart 12/20 can deliver 20A , but again if just charging the battery , the current will be lower.

 

[Jcloughie]

Once we had a week away in poor weather. Bailey Valencia. The charger failed on day one. I replaced it with my little Aldi charger. It kept the van going for the week.

John

 

[Johnb]

Thanks for the advice - much appreciated.

I'll probably leave the charger as it is until much later in the year.

(Reading the comprehensive reply from Ian above (thank you Ian) then maybe the on-board charger is working as it should - although my service guy is very thorough and certified AWS)

I have holidays planned including the usual extended European trip so to have the option of popping the CTec on is a bonus and will tide me over.

Again help much appreciated.