B2B getting hot when on solar?

[Wh05apk]

Noticed today that our recently installed victron B2b seems to be switching on whilst the solar is charging, and is very hot to touch (too hot to hold onto) is this safe? I think the long days of sun recently mean we are producing lots of power which is presumably boosting the voltage.
I know previously it was mentioned that it should be wired from the d+? Rather than voltage sensing, but this is beyond me, as a stopgap, can I adjust the cut in voltage somewhere?

 

[Kannon Fodda]

Have you disconnected, isolated the original charger. Does your solar also charge the starter battery. Either can cause issues if B2B is not operating off D+

 

[Lenny HB]

Sounds like you have it set up to switch on with voltage sensing if so what is happening is when solar charging the starter battery & it reaches the threshold voltage of the B2B turns on.
It's always best to wire a B2B so it is switched by the D+ then it will only turn on when the engine is running.

 

[Wh05apk]

Have you disconnected, isolated the original charger. Does your solar also charge the starter battery. Either can cause issues if B2B is not operating off D+

Pass!

I understand the basics and principles but that's it, thats why I had it "professionally" fitted.

The solar goes straight to the battery, and the cab battery gets a trickle charge.

 

[Wh05apk]

Sounds like you have it set up to switch on with voltage sensing if so what is happening is when solar charging the starter battery & it reaches the threshold voltage of the B2B turns on.
It's always best to wire a B2B so it is switched by the D+ then it will only turn on when the engine is running.

It is voltage sensing, can the voltages be adjusted to kick in later?
Also is it a concern that it gets hot to touch?

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[Kannon Fodda]

and the cab battery gets a trickle charge.

There be the problem.

 

[TerryL]

Can't be good, think I would be disconnecting the B2B before it got too hot and maybe cause a fire.
Then if you don't feel competent yourself find a professional who knows what they're doing.
Your solar should look after you for a while during this nicer weather.

 

[Wh05apk]

Can't be good, think I would be disconnecting the B2B before it got too hot and maybe cause a fire.
Then if you don't feel competent yourself find a professional who knows what they're doing.
Your solar should look after you for a while during this nicer weather.

I have turned off via the app, will be calling dealers after the bank holiday, as you say, currently solar keeping us going, even running the 3 way fridge most of the day.

 

[Lenny HB]

It is voltage sensing, can the voltages be adjusted to kick in later?
Also is it a concern that it gets hot to touch?

The early Victron B2B had a rep for overheating supposed to be cured on the newer ones but they do need to be mounted in a well ventilated area with plenty of space around them.

If the voltage is adjustable and you raised if you have a smart alternator it's lightly it wont't switch on with the engine running.
There is only one correct way of wiring a B2B If any other method other than the alternator is charging the starter battery and that is for it to be controlled via the D+.
Should be easy enough to do as most vans have a relay box to distribute the D+ signal to avoid overloading the alternator's D+ output, so you just connect the trigger wire to it.

 

[Wh05apk]

The early Victron B2B had a rep for overheating supposed to be cured on the newer ones but they do need to be mounted in a well ventilated area with plenty of space around them.

If the voltage is adjustable and you raised if you have a smart alternator it's lightly it wont't switch on with the engine running.
There is only one correct way of wiring a B2B If any other method other than the alternator is charging the starter battery and that is for it to be controlled via the D+.
Should be easy enough to do as most vans have a relay box to distribute the D+ signal to avoid overloading the alternator's D+ output, so you just connect the trigger wire to it.

Thanks Lenny, I have switched it off now, and can rely on solar for now, it concerns me, as the space is quite tight where installed, which won't help, photo below:

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[Lenny HB]

Thanks Lenny, I have switched it off now, and can rely on solar for now, it concerns me, as the space is quite tight where installed, which won't help, photo below:

View attachment 760222

It's fitted the wrong way round the fins should be vertical no wonder it's getting hot.

 

[Gromett]

Thanks Lenny, I have switched it off now, and can rely on solar for now, it concerns me, as the space is quite tight where installed, which won't help, photo below:

View attachment 760222

That looks like it is on it's side. Needs to be upright to let air flow upwards through the fins. Also very small cupboard there?

 

[Gromett]

It's fitted the wrong way round the fins should be vertical no wonder it's getting hot.

Beat me to it. Opened thread while wait for kettle to boil, answered without refreshing.

 

[Gromett]

but that's it, thats why I had it "professionally" fitted.

Professionally fitted? ok

 

[Wh05apk]

Professionally fitted? ok

Thats why it was in quotation marks!

Thanks for your help guys, I will be speaking to the dealers (who generally have a very good reputation) and get booked in for our return in 3 weeks time.

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[Gromett]

Also worth noting even if it is upright you still need enough space above and below for convection to happen. At the risk of stating the obvious sorry warm air rises and pulls cool air in from the bottom cooling the fins. If you don't have enough space at the bottom and top then this can't happen.

 

[Gromett]

Thats why it was in quotation marks!

Thanks for your help guys, I will be speaking to the dealers (who generally have a very good reputation) and get booked in for our return in 3 weeks time.

Good luck with that. Hope you get it sorted to your satisfaction.

 

[Tombola]

Tell em to make sure the cables enter at the bottom too when the switch it..just in case

Seriously tho...you can also add a metal/tin large plate between the board and the fins(as big as you can) which will help act as a larger heat sink too.
What's about in that cupboard ..is it poss to drill a few holes and add a grill for circulation.

 

[Wissel]

I can't tell from the photo, but I assume there are 3 wires out of the B2B?

PS - You can add a switch to the loop on the green bit (just pulls out)

 

[Lenny HB]

Also if it's one they have had in stock a while it could be one of the ones prone to overheating.

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[ChrisL]

I don’t have this issue with the B2B turning on with the engine off despite having a battery master, and my B2B is set for voltage sensing, i'd be looking at how many volts your starter battery is getting from the solar it should only be a float voltage.

 

[Wh05apk]

Further photos, it is fitted in a space under the fridge, it does concern me that there is very little ventilation in there.

 

[Wissel]

As others have said, it needs to be mounted vertically. Should also have 100mm above and below.

Does look like the later model though (heatsink is bigger on later one)

 

[Jimbohorlicks]

As a temporary measure you could leave the door open and if you have a small fan (USB type or similar) to provide more air flow and see if that cools it down.

 

[Wh05apk]

Just an update, now running off D+, and has been turned around/moved (prior to doing so, I thought I would run the battery down to allow charging, ran the fridge off battery, but then went out, and forgot to switch off! battery completely flat next morning, but now recharged so hopefully no long lasting damage done) on drive back I was getting up to 45a (presumably including solar).

All seems to be working now, so thanks for everyone's useful advice.

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