Replacement Battery

**Norm** · July 21, 2011, 04:09 PM

I doubt 0.5 rise in compression is going to make that big of a difference. I thought you were more stratospheric ...

**McFred** · July 21, 2011, 04:52 PM

I live at about 5500' elevation and my 11:1 static compression ratio commuter reads 180psi with my compression tester. For grins, I took my tester along for a roadtrip a while back and at 500' elevation my engine read 240psi cylinder pressure. That's an additional 60psi. The car's pistons each have ~10.75 square inches of area. That's a little more than 600 pounds more force the starter had to work on approaching top dead center. I think a high CR engine at sea level would be a good test for a battery like my commuter car has.

People like Payne are building their NA engines and will probably see much higher than 240psi cranking pressure. The newer Atoms have 11.5:1 CR and I don't know what additional friction a low CR LSJ with a few additional rotors, pullies and belts have over my engine at altitude. I don't think it'd be a problem, but If I end up making a dozen of these things I'd rather not have a dozen marginal batteries I can't recover my costs from.

As a liberal SWAG I think I can source materials for about $250-$275 per oversized battery at the prototype rates. It might end up being less.

Right now, I have 1 extra battery that I can loan to someone around sealevel to test on an LSJ and/or a SC K20/AA300. If it behaves positively I'll go ahead and see about a preliminary price quote for supplies for a slighty larger battery.

**silver** · July 24, 2011, 06:20 PM

I'm at 500 feet elevation if that's close enough for your test. I have a battery tender, would you want that to be used on this battery?

If you want me to test it for you I can, as long as it won't kill my existing battery by having to shelve it during the testing time....which I'm sure I can share the battery tender to keep them both charged, or whatever your directions would be.

**McFred** · July 26, 2011, 10:27 AM

If you want to try it that's cool. PM me your address or call (I think I gave you my PH#)

I measured about 7 milliamps average current draw from my Atom's RFID system. At 7 milliamps the battery should easily last about 3-4 weeks before the voltage starts dropping significantly. I intend to make 2 of these batteries as it sits, one for me and another for a friend.

A basic battery tender won't work that well since they're usually set for lead/acid batteries. The LiFePO4s have a slightly higher voltage so a tender will typically shut off before the battery's full. A basic 3-10 amp battery charger would work better to recharge a battery. Otherwise just drive the car and it'll stay charged.

**Steve** · June 13, 2013, 03:51 PM

I'm reviving this two-year old thread to report that there was a funny smell in the garage today, accompanied by a strange sound coming from the Atom. I investigated, and found that the Odyssey PC680 battery in the Atom (which I keep connected to a CTEK Multi US 7002 charger) was bubbling. Not sure whether to blame the battery or the charger, but I found a 2005 thread over on FerrariChat that also reported one of these batteries oozing when connected to a charger, so I'm leaning toward the battery.

Any updated recommendations on a good Atom replacement battery? I'm unwilling to put another Odyssey in.

**silver** · June 13, 2013, 03:54 PM

Originally Posted by Steve

I'm reviving this two-year old thread to report that there was a funny smell in the garage today, accompanied by a strange sound coming from the Atom. I investigated, and found that the Odyssey PC680 battery in the Atom (which I keep connected to a CTEK Multi US 7002 charger) was bubbling. Not sure whether to blame the battery or the charger, but I found a 2005 thread over on FerrariChat that also reported one of these batteries oozing when connected to a charger, so I'm leaning toward the battery.

Any updated recommendations on a good Atom replacement battery? I'm unwilling to put another Odyssey in.

I think I've had an Odyssey for 2 years at least, and it's always been on the charger, no issues....and Texas summers usually have 90-110 days over 100F

I'll go double check the battery brand in a little bit and let you know for sure if that's what I have, if it's not,then you'll have an option.

I got it from batteries plus

**Steve** · June 13, 2013, 04:14 PM

Originally Posted by silver

I think I've had an Odyssey for 2 years at least, and it's always been on the charger, no issues....and Texas summers usually have 90-110 days over 100F

I'll go double check the battery brand in a little bit and let you know for sure if that's what I have, if it's not,then you'll have an option.

I got it from batteries plus

Got mine from Batteries Plus, too! I bet it's the same one.

**MadMaxAtom** · June 13, 2013, 04:55 PM

I swear by the Braille AGM batteries. Have been using them for dozens of years in many applications and they never let me down. The 2015 can be had off the 'Bay for $170 including shipping,worldwide. Brand New Braille No Weight B2015 Battery 15 lbs 1067 Cranking Amp Free Shipping | eBay

I get at least one vehicle towed in every few months with an Odyssey battery under the hood,which the owner swears is good...cause it's almost "new"..and is junk. Just saying...

**sector: 4** · January 6, 2019, 01:01 PM

Originally Posted by Steve

I'm reviving this two-year old thread to report that there was a funny smell in the garage today, accompanied by a strange sound coming from the Atom. I investigated, and found that the Odyssey PC680 battery in the Atom (which I keep connected to a CTEK Multi US 7002 charger) was bubbling. Not sure whether to blame the battery or the charger, but I found a 2005 thread over on FerrariChat that also reported one of these batteries oozing when connected to a charger, so I'm leaning toward the battery.

Any updated recommendations on a good Atom replacement battery? I'm unwilling to put another Odyssey in.

My fully-charged Odyssey PC680 can no longer turn the engine over in 45 deg. F weather and it's only the second winter! The Atom is small and light but it still uses a car engine. Really, it should use a car battery, not a motorcycle battery. If it had a car battery, I would expect it to last a few more years than this Odyssey battery has. I may as well try a $40 off brand rather than spending $130 for an Odyssey if isn't going to last 2 winters.

**timcking** · September 5, 2019, 07:35 PM

Here's my experience with my 2009 Atom 3. In my second year of ownership (new), I had to replace the OEM Braille B20145 battery (14.5 lbs, 20 Ah, 250 CCA) after keeping it on a battery maintainer. Replacing it inkind was $150. I decided to try an Odyssey PC680 (15.4 lbs, 16 Ah, 220 CCA) for $120 and this lasted another year. Frustrated, I did some research and found a Shorai lithium-iron LFX18L1-BS12 slightly smaller drop-in replacement (2.12 lbs, 18 Ah, 270 CCA) and I'm still using it six years later. I no longer need to put it on a maintainer, since I installed a battery cut-off switch and it holds a charge all winter. This cost $180, which I think was money well-spent. I've never had any issues with it.

Now, before anyone "goes off" with concerns over fire danger, etc, etc, etc; realize you have to use a simple charger for lithium batteries, and this is an FYI, not a recommendation. It's entirely up to your discretion.

Still using the Shorai replacement. No problems. Always starts after winter w/o charging.