Fuse on positive leisure battery terminal

[WelshGas]

Ok I found this fuse! Now, in order not to do anything wrong...
- Do I just uncouple the negative of this battery, than the positive and take this fuse out? As the battery's are coupled, is this safe?
- Would I recognise if the fuse is blown?
- As right now we are camping in Slovenia, do you think I would find a replacement?

Sorry if these are dumb questions. I just want to be sure not to damage anything...

Thank you!

Bart

Remember, when you disconnect the Red + lead to remove the fuse, the Red + lead is still connected to the + tve of the Leisure Battery under the Front L Passenger Seat so be careful.
If the fuse is blown it will be obvious. As far as how commonly available, a VW or Motorhome Dealer might stock them.

Do you have Breakdown Insurance. They might be able to source one.

 

[bmassaer]

Ok, thank you for this advice! I'll give it a try!

 

[JohnGuppy]

Best way is to disconnect one battery and measure the voltage on each battery if they are the correct type of battery connect up both batteries and check the voltage turn on the charger and check if voltage is the same would not take much notice of the percentage its the voltage you need to know if you ran your fridge over night it does not run or draw current all the time as I am sure you have ready you should get 2 days out of two batteries not sure running the heater ? all night weather is too hot not to have windows open now so unless you set the heater to a high setting must have been a sauna ?
so many people seem to have so much trouble with there charging and leisure batterys , from the picture above it is easy to test with a ohm meter

 

[bmassaer]

Thank you! I'll try...

 

[Sforza25]

Hoy guys, I have a California t5 and the fuse of the third battery is blow.
I have tried to replacement but it’s too hard, anybody replaced it by yourself? Any advice?

thanks a lot!!!

 

[WelshGas]

Hoy guys, I have a California t5 and the fuse of the third battery is blow.
I have tried to replacement but it’s too hard, anybody replaced it by yourself? Any advice?

thanks a lot!!!

Sorry but I don’t understand. You just pull the battery out of the under wardrobe compartment, undo the nut holding the red +tve lead on. Lift the lead up and then the 50 amp cube fuse. Replacement is the reverse.

 

[Paulro]

Welsh Gas is correct, it’s not difficult.

 

[Hotel California]

Is it thesame on a hightop , as @Sforza25 details say so?

 

[WelshGas]

Is it thesame on a hightop , as @Sforza25 details say so?

Who knows.

 

[TripleBee]

If I may participate:


And the wiring diagram tells me 80A for the leisure battery under the left front seat.
75A for the battery at the back.
And a 100A fuse for the relay.

 

[Sforza25]

Sorry but I don’t understand. You just pull the battery out of the under wardrobe compartment, undo the nut holding the red +tve lead on. Lift the lead up and then the 50 amp cube fuse. Replacement is the reverse.

Sorry but I don’t understand. You just pull the battery out of the under wardrobe compartment, undo the nut holding the red +tve lead on. Lift the lead up and then the 50 amp cube fuse. Replacement is the reverse.

Thanks for the reply!

But how do you lift the lead up from the fuse?

 

[WelshGas]

Thanks for the reply!

But how do you lift the lead up from the fuse?

Take the red cap off and undo the nut.

I suggest you take a photograph,

 

[TripleBee]

Maybe the 50A fuse blows too early, and should be 75A.
In fact, the batteries are 75A DIN batteries, so there is no problem fitting a 75A fuse.
Once your batteries are empty, and you charge them with a decent charger, let's say 100A, the battery will surely draw a whole amount of current, which means 50A is not enough.
And it will most possibly be a slow fuse, meaning it can go over 75A for a short time without blowing.

Mind you, firing up a diesel engine on a cold day, pulls over 80A (on a 4 cylinder car), as the glow plugs will eat 20A a piece.
Tune that up to over 100A for our beloved ancestors (T5 2.5TDI).

You can't go wrong with a 75A fuse on those batteries. As you must know that the crank current is 420A. This means that the battery can deliver 420A in one shot. But then it's dead.

 

[TripleBee]

They do have the same color:

 

[vbk1975]

Maybe the 50A fuse blows too early, and should be 75A.
In fact, the batteries are 75A DIN batteries, so there is no problem fitting a 75A fuse.
Once your batteries are empty, and you charge them with a decent charger, let's say 100A, the battery will surely draw a whole amount of current, which means 50A is not enough.
And it will most possibly be a slow fuse, meaning it can go over 75A for a short time without blowing.

Mind you, firing up a diesel engine on a cold day, pulls over 80A (on a 4 cylinder car), as the glow plugs will eat 20A a piece.
Tune that up to over 100A for our beloved ancestors (T5 2.5TDI).

You can't go wrong with a 75A fuse on those batteries. As you must know that the crank current is 420A. This means that the battery can deliver 420A in one shot. But then it's dead.

The fuse size should be determined by the current rating of the battery cable used from the battery to the spilt charge relay. In the T6, the cable is 16mm2. So i would just be cautious about replacing a 50A fuse with a 75A if the cable size was thinner on earlier vehicles.

Normally loads are fused and the current always flows to the load, so the fuses are always up stream of the load. But because batteries can supply current but also take current, there needs to be a fuse at each end.

I am sorry I don't have the earlier circuits, so I can't check the cable size for those, if the cable is the same size as the T6 then you might be ok to use a 75A. I would say in general that stick with the fuse ratings & type as built, they might be cautious but because there are so many variables they will have landed on the answer for a reason. Also use a reputable make of fuse, it is critical that they perform as intended.

A

 

[Kjetil]

So which is it 50 or 75 amps?

75 amps seems to be a bit high but as @Loz has stated the wiring diagram does show 75 amps.

However, @Paulro and @Geesvw both seem to have had 50 amp fuses fitted.

Unfortunately I can't check for the next few days. Too busy.

Catching up with battery questions; Later Cali SE recommends 75, the earlier models, like mine from 2005, says 50

 

[Freeley]

Take the red cap off and undo the nut.

I suggest you take a photograph,

I'm in a similar position in that I removed my leisure batteries a few months back to charge them separately and then when reattaching the rear battery I accidentally let the positive lead touch a metal part of the wardrobe and sparks flew!
Since then I've noticed that the leisure battery voltage on the CCU has been dropping quicker than usual when idle, as it is most of the time as the van sits on the drive unused regularly.
I suspect the cube fuse has blown so have ordered a new one to fit this week.
I have a couple of questions if you wouldn't mind answering - when replacing the fuse can I do this "live" or should I isolate it by pulling a fuse elsewhere?
The reason I originally removed the batteries to charge them is that when I bought them to replace the original batteries I fitted them without charging them first, I didn't realise at the time how important it was to do this with batteries fitted in parallel. When I replace the fuse do you think it would be a good idea to charge them individually again to make sure that they're both at 100%? And if so could I charge the battery under the seat without removing it by using the hook up whilst the rear battery has been removed for charging separately? I only ask this as it's a bit of a pain removing the front one.

 

[vbk1975]

I'm in a similar position in that I removed my leisure batteries a few months back to charge them separately and then when reattaching the rear battery I accidentally let the positive lead touch a metal part of the wardrobe and sparks flew!
Since then I've noticed that the leisure battery voltage on the CCU has been dropping quicker than usual when idle, as it is most of the time as the van sits on the drive unused regularly.
I suspect the cube fuse has blown so have ordered a new one to fit this week.
I have a couple of questions if you wouldn't mind answering - when replacing the fuse can I do this "live" or should I isolate it by pulling a fuse elsewhere?
The reason I originally removed the batteries to charge them is that when I bought them to replace the original batteries I fitted them without charging them first, I didn't realise at the time how important it was to do this with batteries fitted in parallel. When I replace the fuse do you think it would be a good idea to charge them individually again to make sure that they're both at 100%? And if so could I charge the battery under the seat without removing it by using the hook up whilst the rear battery has been removed for charging separately? I only ask this as it's a bit of a pain removing the front one.

The most sensible approach is to remove the earth strap from all of the batteries (2 camper ones and engine bay one) before you do anything on the positive side. In terms of charging the camper batteries they will balance themselves over a short period.

A

 

[yossarian]

they will balance themselves over a short period.

They will but their ability to exchange current easily exceeds the capacity of the cube fuse and the battery charge / discharge recommendations.

Balance by charging or with a current limiting resistor.

 

[WelshGas]

I'm in a similar position in that I removed my leisure batteries a few months back to charge them separately and then when reattaching the rear battery I accidentally let the positive lead touch a metal part of the wardrobe and sparks flew!
Since then I've noticed that the leisure battery voltage on the CCU has been dropping quicker than usual when idle, as it is most of the time as the van sits on the drive unused regularly.
I suspect the cube fuse has blown so have ordered a new one to fit this week.
I have a couple of questions if you wouldn't mind answering - when replacing the fuse can I do this "live" or should I isolate it by pulling a fuse elsewhere?
The reason I originally removed the batteries to charge them is that when I bought them to replace the original batteries I fitted them without charging them first, I didn't realise at the time how important it was to do this with batteries fitted in parallel. When I replace the fuse do you think it would be a good idea to charge them individually again to make sure that they're both at 100%? And if so could I charge the battery under the seat without removing it by using the hook up whilst the rear battery has been removed for charging separately? I only ask this as it's a bit of a pain removing the front one.

In answer to your charging question, Yes. The onboard mains charger is connected to the front Leisure Battery. So plugging in the EHU will charge the front battery.
Remove rear battery BUT insulate the Red +tve lead inside a “ Marigold” glove and keep away from any body metalwork. Charge for 24hrs and refit. DON’T overtighten the +tve lead with the new Cube fuse. They are fragile.

 

[CaliforniaSeb]

Morning. After some advise on the state of my leisure battery fuse. Just taken a photo of the fuse on my 24 cali. Does this look like it is OK. I.e. not blown?
I cannot get my Victron solar controller to power up. Would rather its a victron issue TBH and my leisure battery is ok.

 

[Paulro]

Morning. After some advise on the state of my leisure battery fuse. Just taken a photo of the fuse on my 24 cali. Does this look like it is OK. I.e. not blown?
I cannot get my Victron solar controller to power up. Would rather its a victron issue TBH and my leisure battery is ok.

View attachment 127725

It looks ok.

 

[JuanVecino2023]

Slightly on topic (apologies for thread hijack otherwise).

Currently fitting solar panels. Have my 6mm wires with 8mm terminals crimped on for the leisure batteries.

Reading above re shorting batteries accidentally, what is best practice when attaching my the leads to the battery terminals and then in turn fixing into the Victron?

Should I disconnect the earth on all batteries?

I’ve sourced this as fuse/isolator for the +ve feed

Inline Audio Fuse Holder 12V-24V... https://www.amazon.co.uk/dp/B09J7W1BPW/?tag=eliteelect-21

 

[CaliforniaSeb]

Roger supplies cables with a fuse. His advice is you can connect either end first, victron or leisure battery, but if connecting to the battery first take the fuse in his cable out until both ends are connected. I tried both scenarios to get my victron working. I have had confirmed no blown fuse on the leisure battery.