New Victron Inverter (Multiplus 3000) not charging batteries

[nottheone]

Yes fully recharge the batteries if you can. But even if you can just them back to 12v you will get a better idea of whats going on.

[nottheone]

3 hours ago, Alan de Enfield said:

2/0 AWG is not big enough.

 

2/0 AWG is rated at 225 amps at 60 degrees - your victron will be using 300+ amps if it is working towards in maximum 3Kw

 

The length from battery to Inverter will also affect the cable size needed - is it more than 1 metre ?

Hi Alan unless you know for sure his cable run is over 3 meters this is incorrect.

 

Most suppliers rate there 70mm2 welding cable at well over 400a continuous at the low voltages we are talking about.

 

3m of 70mm will have a lower volt drop than the 5m of 100mm that Victron class as acceptable.

[Tony Brooks]

10 hours ago, billso said:

Hi Alan unless you know for sure his cable run is over 3 meters this is incorrect.

 

Most suppliers rate there 70mm2 welding cable at well over 400a continuous at the low voltages we are talking about.

 

3m of 70mm will have a lower volt drop than the 5m of 100mm that Victron class as acceptable.

 

I would be wary of that advice unless I had converted AWG to CCSA and done the calculations. The higher current rating you quote could well be related to insulation type and thickness, and nothing to do with voltdrop at all. As those cables, as I understand it, were the original ones they may well be rated at less current than the same CCSA cables with modern insulation.

 

In my view, one should always ignore makers and catalogue data as to maximum current and do the voltdrop calculation.

[Alan de Enfield]

11 hours ago, billso said:

Hi Alan unless you know for sure his cable run is over 3 meters this is incorrect.

 

Most suppliers rate there 70mm2 welding cable at well over 400a continuous at the low voltages we are talking about.

 

3m of 70mm will have a lower volt drop than the 5m of 100mm that Victron class as acceptable.

 

Cable operating temperature makes a huge difference to the current rating (hence me quoting the normal 60 degrees).

 

Welding cable, when used as designed, will be simply used in 'short bursts' but whilst conneceted to a 3KW inverter it could be 'in use' for hours contiuously - we do not know what the OP is planning to run from it - it may be that much smaller cabling will be more than adequate for the appliances he wants to run - but - when he sells the boat and someone wants to use the full capability of the inverter ............................................. Hmmmm.

 

You could use "550 Paracord" to moor your boat, it would hold it safely moored on a canal and be just as good as your "19mm 3-strand", but if you use the Paracord for mooring up on a tidal river, or, on a canal when a speeding boat comes past, you will then find that using incorrect 'stuff' results in much unhappiness.

 

I think 15 years working as a cable designer for a major cable manufacturer, writing some of the British Standards cable specifications, NCB specifications etc etc had given me a basic understanding of cable and wiring.

 

A 3 metre run of 70mm2  based on 12v and 300 amps will have a volt drop of ~4.5% which is considerable above the industry acceptable norms.

3% is the maximum acceptable and the target is to achieve below 2%

[GUMPY]

The size of the cable is irrelevant to the OP problem since the cable fitted should be enough for the charger to function.

However one thing has just occurred to me and that is has the megafuse in the combi blown as this would prevent charging.

[pearley]

46 minutes ago, Loddon said:

The size of the cable is irrelevant to the OP problem since the cable fitted should be enough for the charger to function.

However one thing has just occurred to me and that is has the megafuse in the combi blown as this would prevent charging.

Don't think current Multiples has an internal megafuse. Haven't looked inside my new one but one on old boat didn't. Whereas the one that replaced did.

[MtB]

52 minutes ago, Loddon said:

The size of the cable is irrelevant to the OP problem since the cable fitted should be enough for the charger to function.

However one thing has just occurred to me and that is has the megafuse in the combi blown as this would prevent charging.

 

It might be helpful if the OP could tell us if this new Victron ever worked, or if it was duff straight from the box. 

[David Mack]

On 10/09/2021 at 10:17, canalboat77 said:

 

I assume that the top battery is your starter and the bottom 3 are the domestic bank. 

Just wondering why you have wires connected to both ends of the domestic bank. Best practice is that all connections to the battery bank should be taken from the same point, ideally at the diagonally opposite corners. And if you have a ammeter shunt, this should be connected to the battery bank negative, with all other connections made to the other end of the shunt.

[canalboat77]

On 11/09/2021 at 10:37, MtB said:

 

It might be helpful if the OP could tell us if this new Victron ever worked, or if it was duff straight from the box. 

Ive only just had this connected and as soon as we did, we had the two lights. 

[GUMPY]

2 minutes ago, canalboat77 said:

Ive only just had this connected and as soon as we did, we had the two lights. 

Have you done the moves I suggested earlier re disconnection and reconnection?

It's very easy to discombobulate an inverter/charger😎

[canalboat77]

Just now, Loddon said:

Have you done the moves I suggested earlier re disconnection and reconnection?

It's very easy to discombobulate an inverter/charger😎

Yes, and no luck. ☹️

[GUMPY]

3 minutes ago, canalboat77 said:

Yes, and no luck. ☹️

In which case it's serious.

I would return it to the supplier telling them it's NFG 😱

[canalboat77]

11 minutes ago, Loddon said:

In which case it's serious.

I would return it to the supplier telling them it's NFG 😱

Yeah, I’ve done the first step and opened up a support ticket with Midland Chandlers - where I purchased it from. 

[canalboat77]

Just remembered I didn’t provide closure for this topic, and figured maybe one day someone else might have this issue. The culprit was……temperature sensor out of the box was faulty. I guess I just assumed as it was new it worked. 😒 That will teach me. Switched it out for a magical Bluetooth dongle and it’s all good. Thanks everyone above for all your help. Much appreciated.