Electrical Battery cabling
- Thread starter Kirstyandyjb
- Start date
Thats the way, I use 8 B&S cable since the distance isn't great and at 85amps more than capable as the van wiring wouldn't handle half that anyway, 6 B&S is just too bulky, keep the lengths the same and use proper terminals not the light weight jobs ........... I would also fit a maxi fuse or breakers on the POS and NEG leads going to your BM, 35/40amp is plenty big enough in most cases, this will safeguard the battery and make for easy disconnect. The only leads I would have hanging off the batteries other than the ones for the BM is if you have an Inverter.
This link is a great read on the subject, informative without the inane chatter of some... https://caravanchronicles.com/guides/how-to-connect-two-batteries-in-parallel/
,,,,,,,,,,,,,, these terminals will carry the load....
This link is a great read on the subject, informative without the inane chatter of some... https://caravanchronicles.com/guides/how-to-connect-two-batteries-in-parallel/
,,,,,,,,,,,,,, these terminals will carry the load....
So am I correct in thinking that the 230AH combine battery would never actually flow at that current as the draw/ input current from the J35BM is 35A? At present the cable from battery to J35BM is 10mm2
AH is a measure of battery capacity not current. For example a 230AH battery could (in theory) supply 23 amps for 10 hours or 230amps for 1 hour which is why Drover said to use a master fuse - ideally as close to the battery terminals as possible. The j35 manual (page 14) specifies a 40A fuse.
And no surprise, the J35 number has nothing to do with what it can actually do. The specs say "The J35 can simultaneously deliver up to 20A (J35A) or 35A (J35B-L, J35D) to the caravan battery and loads from the mains input source, with a maximum charging current of 15A (J35A) or 30A (J35B-L, J35D)"
teambmpro.com
And no surprise, the J35 number has nothing to do with what it can actually do. The specs say "The J35 can simultaneously deliver up to 20A (J35A) or 35A (J35B-L, J35D) to the caravan battery and loads from the mains input source, with a maximum charging current of 15A (J35A) or 30A (J35B-L, J35D)"
J35A - 12V Power Management System For Jayco AUS | BMPRO
J35 Model A is a 12V Power Management System with a multi-stage battery charger, with total current of 20 Amp. A maximum DC charging current is 15 Amp.
teambmpro.com
10m2 is usually 8 B&S/8 AWG and from the BMS it usually gets smaller..................... If you want to burn some grey cells again one of my favourite sites ; https://caravanchronicles.com/guides/understanding-cable-and-cable-sizes/
With 230ah of storage that means you technically only have 115ah, being 50% of storage for AGMs is usable if you want your batteries to have a long life, in reality I would say you should have 100ah to use, stated capacities of batteries and solar panels are always on the wishful side ........... ideally do a audit of power draw to see how much in an average day you need, noting that not everything is being used for hours on end ............. with everything turned off, turn one unit on at a time, take the reading then switch it off and go to the next, work out how long you would use it each day, do the math and add them all up. My rig I work on 40amp a day as a general figure for a busy winters day, using diesel heater, HWS, pump and with my Foxbox on, thats with a 3 way fridge fitted not a compressor fridge , compressor fridge would want that much at least. .......
With 230ah of storage that means you technically only have 115ah, being 50% of storage for AGMs is usable if you want your batteries to have a long life, in reality I would say you should have 100ah to use, stated capacities of batteries and solar panels are always on the wishful side ........... ideally do a audit of power draw to see how much in an average day you need, noting that not everything is being used for hours on end ............. with everything turned off, turn one unit on at a time, take the reading then switch it off and go to the next, work out how long you would use it each day, do the math and add them all up. My rig I work on 40amp a day as a general figure for a busy winters day, using diesel heater, HWS, pump and with my Foxbox on, thats with a 3 way fridge fitted not a compressor fridge , compressor fridge would want that much at least. .......