Idiot's guide to a self build battery

[Joeboy]

Even just working out how to load the fuses left me feeling like a daftie!!

I guess you've probably worked it out by now. For others this guy has done a diy install of an offgrid Victron setup using Pylontech batteries. He has loads of videos of all the steps. This one is for the battery fuses which look similar to yours -> LINK

That's very kind of you to think that Andy, in this instance I worked it out. Good man for posting in the link, it all matters, thank you. I continually have to relearn electrical stuff, for some reason it just won't stick longterm. No matter, just one more of those things on the pre job ticklist.. 'learn this stuff'! PS, OGB, oh yes on the positive clunk for make/break airgap.

[sharpener]

This information might be outdated but jump leads bought in Aldi used to be a cheap source of very high-quality high-current cable…

Good tip. I got caught out buying cable some time ago, made the mistake of buying from eBay. When the cable arrived it was suspiciously light for 25mm² and a quick check showed that it wasn't actually copper at all, but copper coated aluminium. No good at all, as the current rating for 25mm² CCA is way lower than that for proper copper wire, around half IIRC.

Hmmmn, possibly bugger.... the last batch I bought for adding the 2kW inverter was heavy welding cable. I will weigh this batch on its arrival. OGB, thanks for that. I have heard the same story on full reels of say 75mm2 multicore coming in from China for vessel refits/mods, fully certified and inspected yet fake. Its a bad one eh?

Sourcing cable from China can be very problematic. I once worked for a mobile radio manufacturer which bought vehicle cableforms through a reputable purchasing agent but even so we had a large batch with no continuity in the screen. Investigation showed there was just green slime under the sheath, the copper braid was not tinned as per spec and the excess HCl in the PVC had dissolved the copper completely.

[AE-NMidlands]

Good tip. I got caught out buying cable some time ago, made the mistake of buying from eBay. When the cable arrived it was suspiciously light for 25mm² and a quick check showed that it wasn't actually copper at all, but copper coated aluminium. No good at all, as the current rating for 25mm² CCA is way lower than that for proper copper wire, around half IIRC.

Hmmmn, possibly bugger.... the last batch I bought for adding the 2kW inverter was heavy welding cable. I will weigh this batch on its arrival. OGB, thanks for that. I have heard the same story on full reels of say 75mm2 multicore coming in from China for vessel refits/mods, fully certified and inspected yet fake. Its a bad one eh?

Sourcing cable from China can be very problematic. I once worked for a mobile radio manufacturer which bought vehicle cableforms through a reputable purchasing agent but even so we had a large batch with no continuity in the screen. Investigation showed there was just green slime under the sheath, the copper braid was not tinned as per spec and the excess HCl in the PVC had dissolved the copper completely.

I once had to do a "holiday analysis!" (Really.)
It was on tin-plated copper wire, and "holidays" was the term for gaps in the plating, can't remember whether it was electro- or hot-dip plated
Anyway it was a nice understandable process... You cut several dozen standard lengths off, then stripped the rubber insulation/ sheathing off very carefully to avoid any scratches. Fold the wire bundle in half and immerse it in a pickle with the cut ends well above the surface for a certain time at a specified temperature. Said pickle designed not to attack tin but to react with copper.
Remove wire, analyse pickle for copper content and look up the area of exposed copper which would give that amount etched off... then divide the area by the surface area of the immersed wire to find how much of the plating was missing.

I think it was done because exposed copper rotted the rubber insulation (whereas tin didn't) and this was in safety-critical application so any which fell off could have caused a serious accident.
Thanks for prompting the memory!
A

[sharpener]

I think it was done because exposed copper rotted the rubber insulation (whereas tin didn't) and this was in safety-critical application so any which fell off could have caused a serious accident.
Thanks for prompting the memory!
A

Or maybe if the insulation really was rubber (those were the days) the sulphur used in vulcanising it attacked the bare copper to form non-conducting (or semi-conducting) copper sulphide.

Glad in a way to know our experience wasn't unique.

Forgot to say our incident resulted in the discovery that owing to a design error the screen had always been used for the mic live connection not ground at all!

[Joeboy]

Only a simple thing yet it is a beginning. SWMBO very kindly donated a section of stored tabletop to be the wall mounting board for the batteries. Only the first two cuts but we are on our way!

I am going to fit the batteries on their side so they are stud out. Easier for access and allows me a good airgap above the hybrid inverter.

[Joeboy]

That's the mounting board up and anchored, 9 fixing points! Also added the first mounting rail for my own reference and perspective. Anyone in Aberdeenshire have a hydraulic crimper for hire before I go to the Bay?

[Joeboy]

Liking this for a tenner AND I get to hit it legitimately with a hammer!!!! How good is that?
https://www.ebay.co.uk/itm/125226085006 ... 04QAvD_BwE

[nowty]

Liking this for a tenner AND I get to hit it legitimately with a hammer!!!! How good is that?
https://www.ebay.co.uk/itm/125226085006 ... 04QAvD_BwE

I've got one of those, but the proper hydraulic ones are only £15 quid more.

[Joeboy]

Liking this for a tenner AND I get to hit it legitimately with a hammer!!!! How good is that?
https://www.ebay.co.uk/itm/125226085006 ... 04QAvD_BwE

I've got one of those, but the proper hydraulic ones are only £15 quid more.

Cheers Nowty, my mind works thus....
Big hammer work, excellent!
The £15 buys the plywood board insets...
Aye, but BIG HAMMER!!!

[Fintray]

That's the mounting board up and anchored, 9 fixing points! Also added the first mounting rail for my own reference and perspective. Anyone in Aberdeenshire have a hydraulic crimper for hire before I go to the Bay?

I have a crimper but not hydraulic, it's German made I think and should be able to do the size of crimps that you require.