I have a source for a few aux batteries that are better than Optima yellow tops But, I need to know if there is IMMEDIATE interest before I empty my bank account to pick them up. I can sell them at about $200 each. Perhaps as low as $175 but expect $200. I don't know for sure how many yet but there will be somewhere between 5 and 15. I'll sell on a first come-first serve based on email post times. Reply ASAP as I'll need to pick these up this coming week. If you need them shipped be prepared for extra sticker shock. They are HEAVY (about 60 lbs.) but small for their ratings. If you can pay me for them and wait for them to be delivered by TCB hand-off that will work as well, but I have to be paid for them ASAP. 15.5" long 4.25" wide 10.25" high In a bus with cabinets you could put 2 side-by-side in a westy cabinet. I'm not absolutely certain about the height and length but two may fit in the driver-side battery tray area. These batteries are rated at 92 AH at the C/10 rating (at C/20 it would be about 100 AH) Optima yellow top batteries are rated at 55 AH at the C/20 rating (at C/10 it would be about 50 AH) http://www.windsun.com/Batteries/Battery_FAQ.htm#Amp-Hour%20Capacity These are PowerSafe SBS C11 batteries. Retail is normally $300+ (http://www.gotbatteries.com/items.asp?params=batteries/SLA/1/Hawker/Enersys/SBSC11/SL215/36L215S1). Specs are at http://www.enersysreservepower.com/documents/US-SBS-PS-001_1206.pdf They can be mounted any way except fully upside down. They are "AGM" batteries like the Optima so there's no liquid acid to spill and they can be charged with a regular car battery charger and your alternator without a special regulator (which is required by gel-cell batteries). These are new, unused batteries but they are a surplus lot so no warranty. But the ones I've seen so far have construction dates in 2005/2006 and were factory maintained. They have stickers indicating topping charges were done in 2006. If you're setting up a dual battery system these are the way to go. They should run an inverter or a big stereo for DAYS. Gerald