What size cable for 50 amp B2B charger

[Martynovo]

Several months ago you sorted my B to B wiring with some excellent replies but only now am I having the courage to start. Immediately some questions.

The fuse at the starter battery wire is 50 amp, so why does a new wire have to be put through to a 50 amp B2B if there is no other load on the wire? I have bought a new 6 AWG wire, if I have to use it threading through the Hymer double floor and insulation seems almost impossible is there another permissible route? If I have to use the new wire then do I have to increase to a larger ANL type fuse?

I was hoping to do my change over in stages and fit a Lithium 100AH later. The existing AGM is Varta A 95 amp hour but 6 years old. But if I first install the 50 amp hour B2B will that be too much for the AGM battery and therefore I have to do it all at once?

And finally my manual says EBL29 installed, I have EBL30 and initially only the mains AC connection seems different, is there anything else you know of?

Many Thanks

 

[Lenny HB]

50 amp will be too high for a single lead battery.
Cable size depends on the length of run link to cable calculate below aim for less than 3% volt drop.

Normal Hymer wiring is 16mm2 so should be OK.
Disconnect the starter battery feed to the EBL and feed that to the input of the B2B.

 

[Martynovo]

50 amp will be too high for a single lead battery.
Cable size depends on the length of run link to cable calculate below aim for less than 3% volt drop.

Normal Hymer wiring is 16mm2 so should be OK.
Disconnect the starter battery feed to the EBL and feed that to the input of the B2B.

Thanks Lenny,
Ok, so its be brave, spend the money and do it all at once, .

 

[nicholsong]

50 amp will be too high for a single lead battery.
Cable size depends on the length of run link to cable calculate below aim for less than 3% volt drop.

Normal Hymer wiring is 16mm2 so should be OK.
Disconnect the starter battery feed to the EBL and feed that to the input of the B2B.

When you knowledgeable guys quote in one breath square mm and then in another Amp loading I cannot connect the two.

Is there a chart which converts the load to the cable size?

 

[Lenny HB]

I forgot to put the link in.

Voltage Drop Calculator | 12 Volt Planet Cable Calculator

Use our Voltage Drop Calculator to select the correct Cable for your campervan, motorhome or boat wiring application. Cable Calculator for Auto and Marine Electrical Components from 12 Volt Planet - Cable Size Calculator

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[Lenny HB]

When you knowledgeable guys quote in one breath square mm and then in another Amp loading I cannot connect the two.

Is there a chart which converts the load to the cable size?

It's not that simple as you have to allow for volt drop across the cable, see link above.
So length of cable has a bearing on the size of cable to use.