Charger Reccomendation for AGM Battery

[nixid]

Bought a used AGM battery, 215AH 12v
http://www.fullriverbattery.com/product/batteries/DC215-12
Primary purpose is to power refrigerator while camping.
1-What is a good charger for this type/size battery? Will be stored 90% of time.
2-What is a good way to see what condition the battery is in currently? Shows 12.8v on cheap volt meter.

 

[john61ct]

Sterling ProCharge Ultra and ProMariner Pronautic P, good for any type, set to mfg specs.

Go for at least 80A, or as high as you can afford.

The only reliable test for current battery AH capacity is a 20-hour load test. Can do yourself, easier to pay a pro.

 

[teotwaki]

Start with what they recommend for charging specs resources.fullriverbattery.com/fullriver-battery/charging-instructions/batteries.pdf

If I read it correctly they want a max of 15.3 volts which might be hard to find in most chargers.

They do suggest to give them a call "please contact your local Fullriver Battery distributor for assistance." 800-522-8191

 

[nixid]

John61ct chargers look to cost 4x what I paid for battery, any cheaper alternatives?

Max 15.3 volts is at 32 degrees, lucky for me I live in Phoenix so 77 degrees 14.7 volts.

And I did send Fullriver an email asking for a recomendation too.

Is Centech's load tester at harbor freidght worth the $20 to get an idea of the condition of the battery?
http://www.harborfreight.com/100-amp-612v-battery-load-tester-61747.html

 

[dwh]

Props to Fullriver for publishing such extensive data on their specs.

14.7 bulk, 14.7 absorb. Same specs as Odyssey (same as the 2 x 200ah Chinese AGMs I picked up used as well).

For shore charging, anything recommended by Odyssey will work.

Could also get by with an Iota with IQ/4 brain - 14.8 bulk, 14.2 absorb. The lower absorb voltage will take a bit longer to get there, but that doesn't really matter on shore power.


As for testing a house battery, I prefer a slow discharge test over a heavy load test. Put a 10a load on the battery and see how long it takes to get down to 10.5v.

Heavy load test can push a marginal battery over the edge into failure. Seen quite a few batteries, that maybe had another year of useful life, ruined by auto parts dorks using a carbon pile tester (next best thing to a dead short).

Of course, battery sellers don't mind when the battery fails the "load test" and they get to sell you a new one. I won't let the counter guys do a carbon pile test unless I want a replacement under warranty. In that case, by all means, go right ahead and short that sucker out.

 

[nixid]

DWH
Normally not reccomended that deep cycle taken below 50% 12.06, are you saying take it to 10.5 to see what the total AH are just this one time?
Amazon has many iotas, any rec on model and or what Amp to choose?

 

[DaveInDenver]

Yes, 10.5V is considered a 100% discharge. You don't want to routinely deep discharge like that but for the purposes of measuring capacity that's the test, to take a fully charged battery from resting (usually about 12.8V) to 10.5V and measure the amp-hours it delivers.

As an aside, this is an important point when detailing a power system. You don't get all the capacity from a battery unless you fully discharge it. So if you're basing times on, say 100 A-hr, and need to get it most of the time you will probably shorten the life of your battery. You'll get quite a bit less capacity if you follow the cycle recommendations for longevity.

I have an IOTA DLS-45/IQ4 that has met all my needs for many years. I'd buy another without reservation.

 

[dwh]

One measure of battery life is "cycles".

The "50% rule" is based on off-grid, fixed base solar system design. It's a trade off between long battery life and battery cost.

Take a lead-acid battery down 20% every day and fully recharge it the next day and you might do that 3,000 times (10 years daily use) before you have to spend the money to replace the battery. Down 50% every day, and full recharge the next day and on average you'll get 1,000 cycles (3 years daily use).

So 50% is the sweet spot that solar designers shoot for so as to not have to spend more on batteries than they have to. Take the batteries below 50% ON A DAILY BASIS and they have to replace more often. Higher cost over time. Limiting discharge to 20% ON A DAILY BASIS means they have to buy more battery at the beginning, and at replacement time. Again, more money over time.

So for a FBO (fixed base operation) the 50% rule is the "internet solar guru" default recommendation.


But let's say you use the battery only for weekend camping. You take it down 100%. You can do that around 300 times before it's due for replacement. How many weekends is that?

For a weekender, most of the time the battery will die of old age (average 4-6 years) before they ever even have to think about the number of times they went below 50%.


Draining the battery 100% to see what the capacity is, is an occasional thing. Annually, quarterly, whatever. It isn't going to shorten battery life in any way you'll ever notice.

No worries.


With Iota definately get the IQ/4 brain for charging flooded or AGM lead-acid batteries. No IQ/4 for gelled electrolyte lead-acid or lithium iron phosphate - 14.8v is too high for those.

My Chinese 200ah AGMs say to "limit initial current" (translation: bulk charge) to 54a. Which is basically C/4 (capacity in amp hous divided by 4). C/4 used to be what all battery manufacturers recommended as max - before AGMs.

Thrse days most top AGM makers say, "no current limit as long as you keep an eye on temps".

Certain Odysseys get flaky if not regularly topped up to 14.7v. Odyssey's recommended recovery procedure is drain 100% and then recharge bulk to 14.7v and absorb at 14.7v using a MINIMUM of C*.4 (40a charge current per 100ah of battery capacity).


So...for your 200ah AGM battery, you should probably go for C/4 as a MINIMUM. So a 45a or 55a minimum.

For my pair of 200ah (parallel 12v for 400ah total), I'll probably stay around 25a (C/8) on the shore charger. That way I can run it off a dinky generator if need be. And I'll probably never need it anyway with 300w of solar...damn things were already in float mode by 7am this morning (heh...no loads hooked up yet ).

 

[nixid]

Fullriver emailed me back with a reccomendation of the NOCO G15000 amazon link http://a.co/djoTEJC
Noco page https://no.co/g15000

Anyone familar have an opinion on this product?

 

[DaveInDenver]

A 15 amp charger seems awful light for 215 A-hr. I believe Noco makes a fine charger but I'd go for their 26A at least. I use a 45A charger for a pair that combine for 100 A-hr personally.

 

[dwh]

For shore power I'd certainly go bigger. The only reason I'll be staying down around 25a is that I carry the smallest generator I can find - just for battery charging.

If I was planning on charging these big batteries from shore power at home, I'd go with a 90a Iota. If from a power pole at a campsite, probably stay around 45a so as not to overload the possibly dodgy campsite shore power.

45a would be just about right running from a Honda eu2000 inverter generator as well.

I have to go smaller or buy a bigger generator, which I don't want to do for this camper. So I'm stuck with a smaller charger.

But like I said, I've got way too much solar, and that's going to get the batteries fully topped up anyway, so having an undersized charger is no big deal for me.

 

[The Artisan]

DWH how large is your battery bank? I went with this :
PM3-45-12 Power Supply 45 Amp 12 volt and
Power Pulse 12 volt
Honda 2000
3 33 agm lifelines.
Kevin

 

[dwh]

DWH how large is your battery bank?

Buddy of mine bought this:

http://forum.expeditionportal.com/threads/168638-300W-Astronergy-Solar-Panel

And this:

http://forum.expeditionportal.com/threads/168637-Two-4D-AGM-Batteries

Then he didn't use them and I bought them from him a couple weeks ago when he was moving.

2 x 12v 200ah 4D size Chinese AGMs. Paralleled for a 400ah @ 12v bank. Very low use and after months of resting, both still dead-on at 12.8v. Hundred and twenty frickin' pounds. Each. Bloody hell.

I paid $300 for the PV and the batteries. Added a Victron 100/30 ($220 Amazon) and hooked everything up the other day. Working fine so far. Haven't wired up any loads or the alternaor or shore chargers to it yet. Just watching to see how the solar works in isolation first. This weekend I'll use an inverter and some loads to take the bank down a ways and see how it goes the next day with recharge off solar only.

I went with this :
PM3-45-12 Power Supply 45 Amp 12 volt

Bad news. The marketing says it's basically the same as Iota, but it isn't. It's basically the same as a Progressive Dynamics.

The Iota with IQ/4 brain bulks to 14.8v, then absorbs at 14.2v for 8 hours, then drops to float.

True 3-stage.

The Progressive Dynamics and the Powermax bulk to 14.4v, then drop straight to float at 13.6v. Their marketing BS calls that an absorb stage, but the voltage is too low - 13.6 is a float voltage. Then, after a set time at float, they drop to 13.2v - which is just a very low float voltage.

Not true 3-stage. Just a 2-stage (bulk/float) with a second, lower float voltage after a while.

Honestly, the bulk to 14.4v is a bit too low to properly pump up AGMs (flooded too). But it would be acceptable if it was followed by a good long absorb at 14v+. But it isn't. No real absorb stage at all.

Those things are designed for RVs that spend all their time hooked up to shore power where you want to make damned sure the batteries never get overcharged.

They aren't designed to keep batteries properly recharged and topped off.

and
Power Pulse 12 volt

Not familiar with it. They call it a charger, but it just looks like a desulfator to me. Desulfators are good. Only caveat, there are reports that some desulfators interfere with some solar MPPT units. Apparently the pulsing throws off the tracking. Not common though - very few reports of problems.

Honda 2000
3 33 agm lifelines.
Kevin

Sorry to be the bearer of bad news Brother Kevin, but you need a better charger to keep those Lifelines healthy.

 

[The Artisan]

Thanks I have 10 1 watt lights (4 sections not all on at the same time) and batteries are used for this only and charge phones puter. The rest would be genset or mostly shore power. Do you think the charger is enough for that small of use?
Kevin

 

[dwh]

Thanks I have 10 1 watt lights (4 sections not all on at the same time) and batteries are used for this only and charge phones puter. The rest would be genset or mostly shore power. Do you think the charger is enough for that small of use?
Kevin

Well, it'll work. It's just an overly conservative (safe) design, which is a tradeoff that doesn't make for great battery charging. But, "mostly genset or shore power" is what they are made for.

And if you're charging off the vehicle AND the voltage is high enough, that'll pump up the batteries and provide some absorb time if you drive for a few hours.

Still...lead-acid batteries need to be kept topped off to 100% as much as possible for long life, so you are probably shaving a bit of life off the batteries. Which you might never notice unless you're full-timing.


On the plus side, that overly conservative charge profile looks to just about perfect for lithium iron phosphate batteries, so when replacement time comes, if you go with LiFePo, you'll already have the perfect charger.