Re: making lights
I searched but can't find my old thread regarding SLA batteries and mounting them.
I've always used SLAs and on my first bike I was having premature battery failures. There is a battery manufacturer/distributor here in Denver and I spoke to one of their engineers about my problem. He told me that mounting an SLA on its side and subjecting them to shock or vibration can loosen the plates and allow them to touch, shorting the battery internally.
He explained that the plates are set into grooves in the top and bottom of the case. If mounted vertically shock and vibration usually doesn't hurt but with the battery laying on its side you stand a chance of having battery problems. Your plan to carry the battery in a bag will probably take care of the potential problem.
I remounted my battery so it sat vertically and have never had another problem.
Just some input based on my experience.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"