openinverter forum

Spurred by the latest Lab Update #59: Installing a Nissan 24 kWh battery in an Audi A2 video from the handsome and well spoken Jan and his side kick Johannes (who rumor has it doesn't even own a sweater vest) the Newb asks:

Does your DIY battery pack need to be rubber mounted in your EV Conversion vehicle?

Assumptions: we are using batteries from donor hybrid vehicles such as a Chevy Volt or a BMW 530e or electric vehicles such as the Nissan Leaf or a Tesla, most likely extracted from their original battery encasings.

Never seen these rubber mounted. Batteries don't create any vibration as opposed to the drive train, so no need to decouple them for that reason. They also don't mind vibration, no need for decoupling from that side either.

I'm terrible at mechanics, so I hope for more comments

johu wrote: ↑Fri Apr 22, 2022 1:13 pmI'm terrible at mechanics, ...

that's what I love about your work

Surely a battery doesn't CREATE vibrations, but could be affected by them. would only be road inputs on an EV.

Veh OEMs don't use any isolation for battery mounting so that likely means you don't need to either. They've been designed to withstand the vehicle's life of road input accelerations. Pretty much every EV conversion has rigid mounted battery packs.

vwbrady wrote: ↑Fri Apr 22, 2022 3:18 pm Surely a battery doesn't CREATE vibrations, but could be affected by them. would only be road inputs on an EV.

Veh OEMs don't use any isolation for battery mounting so that likely means you don't need to either. They've been designed to withstand the vehicle's life of road input accelerations. Pretty much every EV conversion has rigid mounted battery packs.

thank you I appreciate that, seems like it's sprung weight as is most of the rest of the vehicle so we should be good, it's not like we are rolling down the street without any suspension at all

I suspect hard mounting will probably improve NVH (more mass directly attached to the chassis, instead of a lot of weight flopping about on rubber mounts)

Vehicle shock mounts should be fully capable of withstanding vibrations because of battery mass. If not, replace them.
However that does mean all modules need to be securely fastened. If any of them would be loose it could rub against the others and cause wear, fretting and untold damage...

Most of the donor vehicles are monocoque/unibody construction. The only instance I would be concerned about the battery case would be if fitting to a ladder rail chassis. The extra flexibility particularly when twisting might stress the battery case which it was not designed for. In that case I might consider rubber mounting.