Battery in boot.

[runas74]

Hi, relocating battery into the boot of my Datsun, sharing the space of the OEM fuel tank location eg the fuel tank is in the boot too.
Currently I've mounted the battery in a commercial plastic battery box (similar to which you would fine a boat) it has been bolted to the boot floor and the box lid has had clips fitted to hold the lid.
The battery itself is secured from under the battery box with a stainless strap with the standard j-bolts and saddle over the battery, it's extremely secure and 100% covered.
However it's security is not my question.
Basically is this acceptable or does the battery need to vented outside and the box 100% sealed too?
I did mention what and how I was doing to my certifier and he seemed ok with it however in reading some Q&As here I feel there was a few of the finer points he may of not of mentioned I needed to address.
Thanks in advance

This may be clearer

Also, in one of the previous posts there was a questions regarding fuel tanks in a Toyota KE30 specifically drains in case of cell rupture, being that this tank is 100% OM in placement etc and will remain OM with the exception of fuel lines going to a lift pump from there to a surge tank under the car,there are no drain holes in the floor for fuel to drain from in case of a rupture? as this is how it came from the factory and the tank is unmodified is this something I need to address ?

[Leon]

Right, so I will have to do that awful thing where I answer your question with another question. Because there's a little bit more that I need to know.

Is the boot of the car sealed away from the cabin (that being the part of the car with human beings inside it), or do the boot and the cabin share the same airspace?

Electrical systems
2.3(13) A battery fitted to a low volume vehicle must:
(a) be secured by, or enclosed in, a device or structure, appropriate for the
weight and load of the battery being used, to prevent it from shifting
during braking, cornering, acceleration, or impact; and
(b) incorporate some method of preventing acid spills from entering the
passenger compartment of the vehicle; and
(c) be sealed from the passenger compartment and ventilated to the vehicle
exterior, where charging and subsequent gas emission may occur while
the vehicle is operating; and
(d) be safely wired and protected from short circuits.

If your cabin isn't sealed between the cabin and the boot, then yes, you should vent the battery box outside the car. MotorSport NZ has that same requirement too (if you're intending to race the car). Also note, if you're intending to race the car, head over to their regs and familiarise yourself with those too. Battery tie down points are some of the most common scrutineering failures.

If your fuel system is OE to your car, then our rules about fuel drains do not apply. You can if you wish comply with it, but it isn't mandatory.

[runas74]

Thanks Leon,
Short answer No the boot and cabin are not sealed for each other, and No the car wont be raced.
I have since asking the question figured out that the box in the car will not be adequate, so Im in the process of making another one.
Which raises a another question, "(c) be sealed from the passenger compartment and ventilated to the vehicle
exterior"
Can you please shed some light on what will be deemed adequate "ventilation" for the purpose?
I'm guessing a tube out side of the car from box but what size ?

Thanks Runas

[Leon]

Hi Runas,

So, where we're talking about ventilation, it's just so that if you end up with an over charging battery, that when the battery vents, it isn't doing so into the same air space as you. So something as simple as a rubber tube or hose that runs through the bottom of your battery box through the floor of the car (you could even be cunning and route it through a boot bung if you wanted). We don't require a specific size.

Alternatively, maybe price up a gel (or similar) type battery that can't emit gas. That might do two things, reduce the weight you're carrying around, and also means that you don't need to box up and externally ventilate your battery.

I know if I was doing the mods you're looking at, for the sake of simplicity, I'd be going to a non venting style of battery.

While I know that you've said you're not intending to race the car, this fitment of a non venting battery would also comply with MotorSport NZ rules. So this comment is probably more for the benefit of other people who might read this thread, more so than yourself.

[joshua]

Hi
Just to clarify for wiring. I read (d) above to run wiring safely as to not short circuit. Can the main cable run external under the vehicle or does it need to run through the cabin area? I was told it can’t run external.
But would like to know for sure.
Thanks

[Chris]

You can run the cable externally, but it needs to be protected from damage. Think of a battery cable as you would a brake line or fuel line (you would not run on of those under the chassis - for example)
If it passes through any holes in the body or chassis then the holes must have appropriate rubber grommets etc.

Cheers

Chris

[andyg75]

Would a sealed Lead acid battery be “non venting”?
In regards to the mounting of the battery in the boot what would be preferable,
- a metal battery tray welded in place with hold down clamp securing battery?

-Boat type battery box secured by bolts & rivnuts?
lid & hold down strap.

[Chris]

Aug 9, 2021 19:57:35 GMT 12 andyg75 said:

Would a sealed Lead acid battery be “non venting”?
In regards to the mounting of the battery in the boot what would be preferable,
- a metal battery tray welded in place with hold down clamp securing battery?

-Boat type battery box secured by bolts & rivnuts?
lid & hold down strap.

Hi Andy

There are no lead acid batteries that are non-venting. Without a vent, the gas produced through the normal charge/discharge cycle can cause the battery to swell and rupture. 

By non-venting it would mean something like an AGM (Absorbed Glass Mat) or Gel Cell batteries (like an Optima/Odyssey etc) but even these batteries do vent albeit at a much lower level.

The mounting must be suitable for the weight of the battery so probably a couple of 10mm bolts securing to the boot floor with a flat plate top of the box and bottom of the floor to help spread the load (similar to a seatbelt doubler plate) The battery must also be secured down inside the box.

The battery box must contain any acid spill in case of an accident and also gas emissions when a venting battery shares the same air as vehicle occupants. (noting a boot area is consider to share the same air when it is not appropriately sealed from the passenger compartment)

A marine style "boat type" box will contain acid spills, but it does not contain the gas emissions. The best solution I have seen is the "Moroso" style battery box as per the picture below. You do not need to get a Moroso brand box, but a similar design would work well. 



Hopefully that helps

Cheers

Chris