Low Profile Batteries

[ranger58sb]

Originally Posted by OldManMirage

I may have to re-think the AGM's on their side. I have researched a bit more and it "seems" they are designed to orient that way if needed ?

I think they're often mounted sideways in military aircraft and armor and so forth. (And in aircraft, up isn't always up, anyway.) Both Odyssey and Concorde/Lifeline support those markets a lot, I think.

A real form-factor oddity is the Odyssey ODS-AGM470FTT (was PC-1800-FT). I noticed this one while looking at how to improve an existing 24VDC bank of two 8Ds for inverter use. It looks like these are almost 8Ds in capacity, and it also looks like I could maybe mount four of them upright in the same horizontal footprint as two 8Ds, assuming I can deal with the extra height. We'll see...

But my point is only that these, on their side, might be worth a look too, if you can also deal with the weight issues.

-Chris

[PaulCrawhorn]

Yes AGM is just fine sideways

really the most compelling reason for using AGM at all.

Northstar, Lifeline and Odyssey.

Can call up or email their support engineers, ask which lines they recommend.

[OldManMirage]

Thanks for the replies, I welcome them all.

I do believe AGM's are in my future now.

Can someone comment on the difference between them and Gel batteries ?

[PaulCrawhorn]

GEL can last longer if coddled, but more susceptible to damage and less energy dense.

Fussier on getting the charge profile right, easy to overcharge, bit longer getting to 100% Full.

Sonnenschein did a tech transfer deal to EPM / Deka, who OEMs for Trojans

[CarlF]

AGM’s are not a great choice for a cruising boat if you anchor out. They have to be charged to 100% almost every day or they lose capacity rapidly due to PSOC (partial state of charge) sulfation. I went through two sets of Lifelines with them each lasting less than 3 years despite never discharging more than 50%. They make great starting batteries as those are almost always at 100% charge. Also fine if you plug into a slip most nights.

Google PSOC AGM.

I’d take a look at lithium. It’s an expensive but prices have come down a lot. No need to “roll your own” the prices of “drop-in’s” are very attractive . You only need half as many AH since the batteries can be run way down without damage. If you go this route get advice from someone with substantial experience with MARINE lithium installation. There’s a LOT of outdated and misinformation on the internet. The four big areas of concern are 1) not overcharging 2) protecting your alternator from overheating or being damaged by a BMS cutoff, 3) cabling to equally charge and discharge multiple batteries 4) fusing

[OldManMirage]

I have read about AGM's and the problems with PSOC. I hope to deal with that by having plenty of solar and upgrading my alternator. If I find I need more I'll figure out a way to get it. I can add more solar to my current setup of 2 150 watt panels fairly easily. I could do a wind generator if I had to, although not my preference.

I'm not ready to make the move to lithium, the cost being the main reason. That and I am much more comfortable with "conventional" batteries. Knowing that I can use AGM's on their side really is deciding factor for me.

I'm reading more on the difference between the gel and AGM, just for my own knowledge. I'm still planning for AGM's at this point.

[Pete7]

If they are going on their side, how about the spiral wrapped ones like Optima?

Soz, that's another evening you are now going to be googling

[sailorboy1]

Dont get the gels, they have no practical advantage.

It is pretty doubtful that 2-150w solar panels are going to get your batteries truly fully charged if you have refrigeration. It takes pretty much 4-5 hours at absorption to recharge an AGM. So a couple hours to get to absorption and then 4-5 hours of good sun.

Dosnt mean that AGMs are a bad choice for you. It just means you need to realize that batteries are a cruising consumable. You have to decide whether YOU are there to serve them so they last 6 years, or if they are there to serve you and last 3 years.

[Cheechako]

I think you are going to spend a lot on large cabling and the resultant E losses for very little gain. Find a better spot near your existing batteries!

[donradcliffe]

Gel batteries tolerate PSOC better, but can be quickly wrecked by charging at too high a voltage, and can't be used with dumb regulators. They are just as energy dense, but a bit more expensive. I replaced them twice in 17 years of full time cruising. I would go with LiFe today, but they also require smart regulators. Lithiums charge faster and have much less voltage sag under load.

[jordanbigel]

Originally Posted by OldManMirage

I'm reading more on the difference between the gel and AGM, just for my own knowledge. I'm still planning for AGM's at this point.

In my experience AGMs are less tolerant of high temperatures compared to Gel cells.

[Bycrick]

See the above posts. Don’t let the AGM lovers convince you that they’re a perfect solution. Most of the manufacturers will tell you that gels last longer than AGMs, but only if you treat them right. As for the odyssey spiral batteries, they’re built to trade off high peak-current for lower overall capacity. Hence, I don’t use them for house batteries. But they’re great for starters, windlass, or winches.

[akopac]

You can replace what you have with firefly’s. You will need 1/2 the anphrs because the usable capacity is like 90%

[PaulCrawhorn]

Odyssey sold off their spiral line to Johnson Controls, Optima label, like a decade ago

Great Starters and dual-use for say a short winching, but since the transfer sub par for true deep cycling. Same happened to Diehard in previous decades.

FLA will also shorten lifespan from PSOC abuse, but in this use case AGM is best.

To avoid PSOC abuse use FF source at high amps early in the morning for the first Bulk stage, then keep loads down so your solar can get them to 100% over the next 7 hours, Absorb stage accepts lower and lower current.

The FF run may need to be 2 hours, calibrate from experience. every other cycle can be to 98% rather than 100% every time.

Or just accept a 3-4 year replacement cycle, rather than 7-8.

[bcboomer]

Get a set of Firefly G31s and put them on their sides.

They don't have any of the drawbacks of regular AGMs and can be safely discharged to 50% or not completely charged without loosing capacity.

Not cheap but cheaper than all the upgrades needed with LiPO