Electric Bikes - replacement ElecTrec battery?

Anybody know what kind of SLA batteries are inside the battery pack that came with my ElecTrec? It'll cost me $200+ to buy a new pack after shipping if I go to Electrik Motion. Can I get it any cheaper if I figure out how to just change the batteries inside the pack (possibly get some higher quality ones at the same time....)?

Has anyone tried replacing batteries in an electrec (formerly LashOut, now Rayos)
-Keith

Edit-
Having taken another look at my battery pack, I'm not sure if it can be done - the holes that I thought had screws and nuts actually have pop-rivet looking things in them. I could probably drill them out, but then I'd have to come up with a way to hold the thing closed afterwards. Any suggestions?

What about something after market?
-Keith

There only a few standard size SLA. It is either 12V 7-8AH or 12V 12AH. Both are standard and very available. They are used in computer UPSs, so if you have an electronics supplier they may carry them.
Otherwise, I see both on ebay all the time.
Open the box and do some measurements. They are either ~7x2.5x4 or 7x4x4 inches that is.

I called Electrik Motion today.
The batteries ARE replaceable - those aren't pop rivets, they're 3mm hex, just deep in.
They say they use a pair of 12v 14Ah deep cycle SLAs that are basically marine grade.

Electrik Motion is also working on a new battery based on one of the various lithium chemistries that will have twice the range, but only weigh about 9lbs, and will be back compatible. (Its not due out till the spring, still in R&D, no word on cost.)
-Keith

I hope they can come up with a battery with better range. The last I tested, I got 11 miles on a charge

http://www.pingbattery.com

This guy is reported to be the most honest/reliable/inexpensive of the LiFe Chinese sellers. A lot of folks seem to use YESA as well, but I'm gonna buy from Ping just as soon as my sla's die, which won't be too long at the rate I'm going. So, if you need 24v 12 - 20ah, he has them on his website store. He also has auctions going on e-bay, where his feedback, last time I looked, was 100%. Sure, LiFe costs are higher, initially, but most seem to think it is worth it, energy, cost and weight wise.

when i upgraded to lithium ion, my pack went from 19lbs to 6 3/4 lbs. it feels like a bike again