Swapping my leisure battery to LiFePO4

[Stay Frosty]

Could always put the battery under the drivers seat too with an isolator fixed to the seat base and a shunt attached to the battery negative post and earthed to the VW ground stud on the floor there then a single red 4 or 0 guage cable to a live busbar or multi way fuse in that existing mains area.
There's umpteen ways of doing this and none of them are particularly right or wrong in fact generally the whole process is ongoing with the electrical demands altering as time goes on.

 

[roadtripper]

I also think if you put battens screwed/glued into the floor not deep enough to go through the floor that will help restrain the battery.

Like seatbelts it really only has destructive energy if it can move and smash into something during heavy braking.

 

[wallport]

Looking at the busbar suggested above (VTE 250a Large 4 point M8), I was shocked at the size of the thing - is it really this big?

• Overall dims (inc. cover): 167.37 (L) x 35.19 (W) x 51.17 (H) mm

(I assume height is how far it sticks out from the wall). Looking at the available space and given the assumption the battery will be hard against the wall, there is no room to mount something as long as this where the positive wires emerge. There will only be 64mm between the mains unit and the battery. Mounting vertically is an option but I'm wondering whether busbars which are not strips exist? A square with 2 on top and 2 below for example. I searched for something like this on voltplanet, ebay and amazon without success. I did find this https://www.amazon.co.uk/STANEW-Heavy-Power-Distribution-BusBar/dp/B0C5LV7ZBW (M10 but says also available for M8) which is plus and minus in that configuration but joined together. This did suggest to me that what I'm looking for should exist? Anybody aware of anything?

 

[roadtripper]

Have you looked at the high power junction boxes @ginkster suggested?

Power Jointing Box 120A - 2 Way

300A, 2-way jointing box for connecting battery cables. Glass-filled nylon material with a hinged lid, M8 connection studs, nyloc nuts & 6mm mounting hole.

www.12voltplanet.co.uk

They may fit better for you - depending on how many connections you need to get on you may need the 3 way - stacked ring terminals need a bit of space to splay out to give room for the cable crimp area

 

[ginkster]

Looking at the busbar suggested above (VTE 250a Large 4 point M8), I was shocked at the size of the thing - is it really this big?

• Overall dims (inc. cover): 167.37 (L) x 35.19 (W) x 51.17 (H) mm

(I assume height is how far it sticks out from the wall). Looking at the available space and given the assumption the battery will be hard against the wall, there is no room to mount something as long as this where the positive wires emerge. There will only be 64mm between the mains unit and the battery. Mounting vertically is an option but I'm wondering whether busbars which are not strips exist? A square with 2 on top and 2 below for example. I searched for something like this on voltplanet, ebay and amazon without success. I did find this https://www.amazon.co.uk/STANEW-Heavy-Power-Distribution-BusBar/dp/B0C5LV7ZBW (M10 but says also available for M8) which is plus and minus in that configuration but joined together. This did suggest to me that what I'm looking for should exist? Anybody aware of anything?

I showed an alternative in post 24 or there are the post mounts mentioned by RT. You don’t need a 250a busbar as the battery is limited to 100a so you could go for a smaller, cheaper 150a busbar which may help with space.

 

[meza]

Jeepers that bus bar set is expensive, nearly £40 on Amazon.

Might want to look at something smaller, like:

HOIIME 12 V - 48 V Bus Bar Power Distribution Block with 4 x M8 Terminal Studs, High Performance Module BUSBAR with Cover for Cars RVs Ships Yachts (Red & Black, 2 pieces) : Amazon.co.uk: DIY & Tools
(I've got these, the quality is good. Using them with a 200ah batt and 2000w inverter. Although saying that the inverter is straight to the battery so not even using the bus bar.)

or

HOIIME 150A 48V Bus Bar Power Distribution Block with 4 x M5 Terminal Studs, High Performance Module Heavy-duty BusBars with Transparent Cover for Cars RVs Ships Yachts (Black & Red, 2 Pack) : Amazon.co.uk: DIY & Tools

 

[TallPaul_S]

Tbh M6 studs would be fine too, that should open up some more options.

 

[meza]

I also think if you put battens screwed/glued into the floor not deep enough to go through the floor that will help restrain the battery.

I agree with this. Don't over think it, make your life simpler; screw into the existing wooden floor. It's held down by the bed and cupboards.
If you're in a situation where they're flying around the van you'll already have a lot on your plate!

 

[roadtripper]

The only place I really worry about battery security is on yachts - 45 degrees over on the heel and regularly dropping a couple of tons off one wave into the next very rapidly finds anything loose in the electrics or indeed anywhere on board!

If your T6 is doing that then... ouch.

 

[wallport]

Thanks all. Decided to kick this off before the new battery arrives and have bought a couple of 2 way jointing boxes similar but slightly smaller than the one suggested and 2 pre made leads. I intend to mount the boxes close to the holes but outside the profile of the new battery and migrate the wiring over and connect with the new wires to the existing battery.

When the new battery arrives it will then be simpler to plug it in. I do intend to add a fuse and am still looking at the possibility of an isolation switch. I don't suppose anyone sells a combined switch and fuse in the same unit?

Boxing - well I'm still thinking, perhaps overthinking, on the options but I do appreciate all of the suggestions.

 

[TallPaul_S]

What are the 2 way boxes you've gone for?

Just be aware some look like 2 way bus bars, but are in fact just 2 bolts in a plastic housing - ie the 2 studs aren't connected so you can't use it like a busbar.

For example:

https://amzn.eu/d/0zKFhop

I speak from experience.

 

[wallport]

It was this:

2 Way M8 8mm Battery Cable Power Distribution / Connector Jointing Box 120 AMP | eBay

Power jointing boxes suitable for joining together several cables. M8 Bolts (13mm Locking Nuts included). Sturdy PVC box with clip off lid.

www.ebay.co.uk

I realise I could have trouble due to the number of cables splayed on top of each other but gotta try it and see or spend forever wondering and never make progress.

 

[ginkster]

It was this:

2 Way M8 8mm Battery Cable Power Distribution / Connector Jointing Box 120 AMP | eBay

Power jointing boxes suitable for joining together several cables. M8 Bolts (13mm Locking Nuts included). Sturdy PVC box with clip off lid.

www.ebay.co.uk

I realise I could have trouble due to the number of cables splayed on top of each other but gotta try it and see or spend forever wondering and never make progress.

You can cut extra slots out of the back or remove the post between the 2 holes on the front if you need more space. Don’t over think it!

 

[wallport]

I quite fancy the fuse solution which Meza suggested as this could just sit off the battery connector on top of the battery without other mounting:

A way to save some space with main battery fuse is a terminal mounted fuse holder:

https://www.amazon.co.uk/Battery-Terminal-Block-Voltage-Marine/dp/B0CCV6ZHQF

This one comes with a 250a fuse ie rated maybe too high. Does this matter and if so what size do I need? 150a?
(AFACIT these are MRBF Terminal fuses)

 

[TallPaul_S]

Plenty of choice on Amazon if you search for terminal fuse block.

https://amzn.eu/d/2zRf5Be

150a would be plenty for your needs, 100a even. You can always swap out the fuse.

You could probably just attach your existing positive terminals to this, so long as they reach.

 

[ginkster]

I quite fancy the fuse solution which Meza suggested as this could just sit off the battery connector on top of the battery without other mounting:


This one comes with a 250a fuse ie rated maybe too high. Does this matter and if so what size do I need? 150a?
(AFACIT these are MRBF Terminal fuses)

They are a good solution but personally I’d go for the Blue Sea one rather than a nameless one from eBay/Amazon. I’d fit a 100a fuse as the absolute highest. As you don’t have an inverter you will get nowhere near the BMS limit of 100a so go for the maximum protection of the cables.

 

[wallport]

They are a good solution but personally I’d go for the Blue Sea one rather than a nameless one from eBay/Amazon

I saw this and thought maybe wise to pay a few pennies more for quality. However, they seem to cost £34! Are you sure this cost is justified or can you suggest a cheaper source?

 

[meza]

I’m happy enough with the cheap one

 

[wallport]

Think I'm gonna go with this one on amazon:
X AUTOHAUX 1 Set 100A Battery Fuse Terminal Fuse Block Fuse 58V for Car Boat https://amzn.eu/d/fqVvnSu
Not sure if this make is good but at least it's not unbranded and has option to come with the 100a fuse.

 

[wallport]

Got a shipment notice today - battery originally expected end of month looks like it's arriving any day! I'm looking to speed things up now with that news.

Got the battery out and managed to get decent access behind the panel by getting the victron out of the way. Also found another screw low down at the back. This has allowed me to trace that battery select cable from the d250se. Guess what... it does go to the battery negative terminal despite the battery not being an AGM. Don't know what this will have done to my old battery but at least the good news is that I just need to reroute it to the positive terminal.