Charging oddity - starter batteries not charged when isolator off

[Sticky Fingers]

I’ve discovered that the starter battery bank on my 1999 Princess 460 seemingly does not charge from the AC charger if the ‘Engine start’ isolator switch is off. I’ve discovered this after leaving the boat for 5 months with the leisure isolator on / engine isolator off. Returned to find the leisure batteries in great shape (26v or so) and the starter batteries a bit flat (about 23v).

The charger is a 2 channel Victron unit, there’s two feeds labelled ‘Leisure’ and ‘Engine start’ so I assumed it would be working despite isolating the starter batteries.

Is this normal?

 

[PaulRainbow]

I’ve discovered that the starter battery bank on my 1999 Princess 460 seemingly does not charge from the AC charger if the ‘Engine start’ isolator switch is off. I’ve discovered this after leaving the boat for 5 months with the leisure isolator on / engine isolator off. Returned to find the leisure batteries in great shape (26v or so) and the starter batteries a bit flat (about 23v).

The charger is a 2 channel Victron unit, there’s two feeds labelled ‘Leisure’ and ‘Engine start’ so I assumed it would be working despite isolating the starter batteries.

Is this normal?

Not how i would wire it, for the reasons above.

I suspect if you follow the wire from the charger it's connected to the load side of the isolator switch/solenoid. Just move it to the other side if that's the case.

Which Victron charger do you have ?

 

[Sticky Fingers]

Not how i would wire it, for the reasons above.

I suspect if you follow the wire from the charger it's connected to the load side of the isolator switch/solenoid. Just move it to the other side if that's the case.

Which Victron charger do you have ?

Thanks Paul. That sounds likely!

Pic of charger attached.

 

[Mr Googler]

Been wired wrong hasnt it at the isolator

 

[Sticky Fingers]

I reckon so. As Paul said

 

[PaulRainbow]

Thanks Paul. That sounds likely!

Pic of charger attached.

Bit silly to wire it how it is, the domestic output is 25A and the engine one is just a 4A trickle charge, perfect for keeping your batteries safe when the boat isn't in use.

 

[Sticky Fingers]

Yup. I'll add this to my ever-increasing list of things to do!

 

[PaulRainbow]

Yup. I'll add this to my ever-increasing list of things to do!

You only have one list, i'm jealous

 

[JOHNPEET]

Interesting one this for me also! I have a similar Victron charger except that it is 3 channel and 60amp. The three outputs of which I’ve connected to the load side of the three battery isolators that I have (engine start, house and windlass)
I pondered over this issue for a long time regarding which side of the isolators the charger should be connected to and in the end did the above. I took that approach on the basis that I thought it safer to have the battery isolators do exactly that - isolate the batteries from everything! It does mean that when I’m on shore power, the battery isolators have to be left on so that the batteries are being charged though.
Interested to hear the arguments either way or is there a right/wrong way or just personal preference?

 

[LittleSister]

Interesting one this for me also! I have a similar Victron charger except that it is 3 channel and 60amp. The three outputs of which I’ve connected to the load side of the three battery isolators that I have (engine start, house and windlass)
I pondered over this issue for a long time regarding which side of the isolators the charger should be connected to and in the end did the above. I took that approach on the basis that I thought it safer to have the battery isolators do exactly that - isolate the batteries from everything! It does mean that when I’m on shore power, the battery isolators have to be left on so that the batteries are being charged though.
Interested to hear the arguments either way or is there a right/wrong way or just personal preference?

in my view it would be better to have the chargers connected to the battery side of the isolators, so that they are charged when you are on shore power, but have the isolators switched to off so that there are no loads attached.

Presumably the charger has fuses and/or is designed to fail safe. In the unlikely event you want to completely isolate the batteries, disconnect them at the battery.

(I am open to considering alternative views.)

 

[Refueler]

Interesting one this for me also! I have a similar Victron charger except that it is 3 channel and 60amp. The three outputs of which I’ve connected to the load side of the three battery isolators that I have (engine start, house and windlass)
I pondered over this issue for a long time regarding which side of the isolators the charger should be connected to and in the end did the above. I took that approach on the basis that I thought it safer to have the battery isolators do exactly that - isolate the batteries from everything! It does mean that when I’m on shore power, the battery isolators have to be left on so that the batteries are being charged though.
Interested to hear the arguments either way or is there a right/wrong way or just personal preference?

I have always fed charger direct to batterys or their connectors .... so that even with isolators OFF - the batterys are still charged ...

I do not like idea of having isolator ON to charge - as that means the whole boat is then open to power ... and if a fault develops - even if charger shuts off - the boat still has all that energyu from batterys available. May sound a bit paranoid ... but I've seen boats after electricla faults !
With isolator off - but charger still able to charge batterys - if a fault develops - the charger should shut down ... .... boat then safe.

 

[Sticky Fingers]

That's my thinking too, hence why I turned them off! Only came to light because I'd left the boat for much longer than usual.

 

[Refueler]

That's my thinking too, hence why I turned them off! Only came to light because I'd left the boat for much longer than usual.

Think you misunderstood my post ... I am saying that charger should not be disconnected by isolator switches ... charger should charge independently of switch on / off.

 

[Sticky Fingers]

No I didn’t misunderstand. Currently the charger IS disconnected by the isolator.

 

[Refueler]

No I didn’t misunderstand. Currently the charger IS disconnected by the isolator.

Which I suggest - change so that charger is not disconnected by isolator. I understood your original post saying you had isolator disconnecting charger ...

 

[JOHNPEET]

I have always fed charger direct to batterys or their connectors .... so that even with isolators OFF - the batterys are still charged ...

I do not like idea of having isolator ON to charge - as that means the whole boat is then open to power ... and if a fault develops - even if charger shuts off - the boat still has all that energyu from batterys available. May sound a bit paranoid ... but I've seen boats after electricla faults !
With isolator off - but charger still able to charge batterys - if a fault develops - the charger should shut down ... .... boat then safe.

Obviously all the supplies and final circuits on the boat are protected by fuses which under fault conditions, limit the fault current drawn from the batteries prior to automatic disconnection. Also circuits are only live up to the controlling device/switch.

There are no loads left on when the boat is left unoccupied, so the sort of fault (loose connection) that can exist which doesn’t draw excess current but can produce heat will be a low risk.

 

[PaulRainbow]

Interesting one this for me also! I have a similar Victron charger except that it is 3 channel and 60amp. The three outputs of which I’ve connected to the load side of the three battery isolators that I have (engine start, house and windlass)
I pondered over this issue for a long time regarding which side of the isolators the charger should be connected to and in the end did the above. I took that approach on the basis that I thought it safer to have the battery isolators do exactly that - isolate the batteries from everything! It does mean that when I’m on shore power, the battery isolators have to be left on so that the batteries are being charged though.
Interested to hear the arguments either way or is there a right/wrong way or just personal preference?

In terms of safety i don't think it matters one way or another*, as long as the boat is wired correctly with appropriate circuit protection (which i know yours is).

* One possible issue, if the charging is left on when the boat is unattended and a LA battery shorts two cells the battery will get very hot and gas, a lot. It's very rare though and because of that we don't normally take any measures to prevent it.

My preference, and that of every manufacturer i have come across, is to have the chargers connected to the battery side of the isolators, or directly to the batteries. But the choice is, of course, yours, it's your boat.

 

[JOHNPEET]

In terms of safety i don't think it matters one way or another*, as long as the boat is wired correctly with appropriate circuit protection (which i know yours is).

* One possible issue, if the charging is left on when the boat is unattended and a LA battery shorts two cells the battery will get very hot and gas, a lot. It's very rare though and because of that we don't normally take any measures to prevent it.

My preference, and that of every manufacturer i have come across, is to have the chargers connected to the battery side of the isolators, or directly to the batteries. But the choice is, of course, yours, it's your boat.

Thanks Paul.

My batteries are all AGM - not sure if that makes any difference in this instance.

When some of these issues raise their heads on the forum, sometimes it just makes you question why you’ve made a particular choice on the matter and whether that choice was sound.

 

[Mr Googler]

Thanks Paul.

My batteries are all AGM - not sure if that makes any difference in this instance.

When some of these issues raise their heads on the forum, sometimes it just makes you question why you’ve made a particular choice on the matter and whether that choice was sound.

Dont question anything John…..you know more than most of us combined here having constructed youre own boat! What you should do is a new thread on how its all been going!