Leisure Battery, capacity of secondary terminals.

[rustic]

Sort of caravan related, Just that ours floats.. :augie
We have two Lucas 100Ah Leisure batteries on the boat.
I prefer to use the two sets of 8mm studs, in place of the tapered battery posts.

I raised this question on a boating forum, and I was informed there was a maximum current limit.
I can find no information on either the batteries, or any battery supplier web site.

Has anybody got any idea about this?

Logic implies it should be the same as the terminal posts, ie unlimited, dependant on the battery capacity, otherwise it would be declared.:nenau

I have emailed Lucas, but I don't expect a reply till next week.

Best regards,

Rustic.

 

[makeitfit]

I guess it's down to the size of the terminal fitting you can attach to an 8mm bolt ? Search that way not the battery end, as the post or bolt out put will be the same .

 

[rustic]

I guess it's down to the size of the terminal fitting you can attach to an 8mm bolt ? Search that way not the battery end, as the post or bolt out put will be the same .

Thanks, I have already made up the cables to crimps, the cable is 25mm2 good for over 130 amps. Which is more than enough for my 800 W inverter and electric start Honda 15 Outboard.

The first suggestion from the forum was, limited to 60 amps, and there might be internal heating in the battery....:nenau

Now the boating forum are not that great with electrics, but neither are some of the Boat Safety Standards Inspectors.:doh

My next BSS inspection is in September, and they even insist on a minimum 25 mm2 cables to the batteries, so in preparation, I am replacing 16mm2 which have been adequate before, but then I only had one battery, and no inverter.

Rustic

 

[makeitfit]

What crimp method are you using, as a certain loss may be accounted there. Although small I'd have thought. On our boat we soldered the wire in the crimp after the mechanical squeezing bit was done :thumb2
I just cant see any difference at the battery end from bolt to post as they're both on the same molded connection in the battery .

 

[solarman216]

the only limit is what the battery can supply, as a leisure battery is a start battery with a different label on it, a good reference will be the cold starting amps, so if these two batteries are in parallel you can expect over 900 amps, but what could you be using to draw that amount of power, and of course only for a very short period, it is really down to the maximum power you are likely to need rather than what the battery can supply, Rick

 

[solarman216]

just read post 3 (came on while I was typing) the reason 25 mm sq cable is spec is purely on boat safety grounds, the cable should be able to sustain a dead short long enough to blow the fuse (probably a 300 amp mega fuse) it has nothing to do with your load, Rick

 

[rustic]

Hi Rick, that's what. thought, The terminals are soldered, and are a close fit into the tinned lug.

I assumed that there was enough material linking the 8mm stud to the tapered terminal post, I personally don't think it's a problem, as we will only draw 70 amps max on the inverter, and if we happen to start the engine, 80 amps for 4 seconds, max.

We can use either battery, or both together.

Rustic

 

[rustic]

just read post 3 (came on while I was typing) the reason 25 mm sq cable is spec is purely on boat safety grounds, the cable should be able to sustain a dead short long enough to blow the fuse (probably a 300 amp mega fuse) it has nothing to do with your load, Rick

No mega fuses required, although I have fitted a100 Amp Mega Fuse to the inverter, with separate isolator, none on the outboard though.

The boat safety spec relies on the battery isolators on the 25mm2 side. after that, smaller fuses for distribution,.

 

[solarman216]

No mega fuses required, although I have fitted a100 Amp Mega Fuse to the inverter, with separate isolator, none on the outboard though.

The boat safety spec relies on the battery isolators on the 25mm2 side. after that, smaller fuses for distribution,.

Have things changed? when I had my narrow boat had to put batteries in S/S tray to contain all the acid and a 300 amp fuse as close to the battery as practical except the starter, but that was a separate battery anyway, also as we had permanently connected bilge pumps these had to be fused commensurate with the pump current draw, batteries by the way were 800 AH full traction, able to discharge to 80% of rated capacity so we had over 600 Ah available bearing in mind the fridge was the most power hungry item on board at 100 Ah in 24 hours we could just about survive a week end mored in a place where engine running was a no no, Rick

 

[exosteve]

I will just put this on favorites and read when ive been college for 12 months:lol