Community Forums

acheron800 · 12-10-2022, 05:14 PM

I'm about to cram 3 AGMs under my step. 4 is not gonna happen for sure.

I have a Xantrex 458 with controller and it asks to set the battery bank amp hours. I will have 300AH but the only settings are for 200 then 400 then up from there.

Anybody familiar with this? Which should I choose? 200 or 400? Or does it not make a difference? Also, any input on the charging profile? These are renogy AGMs. Would the standard AGM charging profile be ideal?

Any help is greatly appreciated. Just don't want to fry my new batteries by doing something wrong.

twinboat · 12-10-2022, 06:08 PM

The AH setting is for absorb time. Best to be conservative and use the lower setting.

You need to compare the inverter AGM profile with the battery charging specs.

Iceclimber · 12-10-2022, 07:06 PM

Kinda doubt that it matters. The 458 (no offense) is not exactly cutting edge tech and a modified sine at that. Maybe time to upgrade with the savings on that 4th battery

KD4UPL · 12-11-2022, 06:50 PM

The bank size is likely used to determine how low the charge amps have to drop before it switches to float. This is usually 2% of capacity. If you set to 400 it will transition a little sooner. Set to 200 it will stay in absorb a little longer.
Have you looked up the recommended charge voltages for your batteries and what the actual voltages are on the AGM setting? I'd start with that. Might be dead on, might be way off.

acheron800 · 12-11-2022, 10:45 PM

Quote:

Originally Posted by twinboat

The AH setting is for absorb time. Best to be conservative and use the lower setting.

You need to compare the inverter AGM profile with the battery charging specs.

Honestly I don't know how to read the table.

Here are the specs.

https://www.renogy.com/content/RNG-B...-Datasheet.pdf

acheron800 · 12-11-2022, 10:48 PM

Quote:

Originally Posted by Iceclimber

Kinda doubt that it matters. The 458 (no offense) is not exactly cutting edge tech and a modified sine at that. Maybe time to upgrade with the savings on that 4th battery

458 has been great to me since 2018. Powered everything just fine. Only blew a gfi once when the wife was running a hair dryer.

And I got it for like $800 new. When it goes ill get a newer one.

acheron800 · 12-11-2022, 10:49 PM

Quote:

Originally Posted by KD4UPL

The bank size is likely used to determine how low the charge amps have to drop before it switches to float. This is usually 2% of capacity. If you set to 400 it will transition a little sooner. Set to 200 it will stay in absorb a little longer.
Have you looked up the recommended charge voltages for your batteries and what the actual voltages are on the AGM setting? I'd start with that. Might be dead on, might be way off.

Here are the specs but I don't really know how to translate it.

https://www.renogy.com/content/RNG-BATT-AGM12-100/AGM100-Datasheet.pdf

twinboat · 12-12-2022, 06:09 AM

You'll need to look up the charging specs of the inverter/charger.
It will list absorb and float voltages for the battery types, FL, AGM, ......

That's what you need to compare the battery specs with.

acheron800 · 12-12-2022, 11:53 AM

Quote:

Originally Posted by twinboat

You'll need to look up the charging specs of the inverter/charger.
It will list absorb and float voltages for the battery types, FL, AGM, ......

That's what you need to compare the battery specs with.

Here are the specs, any thoughts?

twinboat · 12-12-2022, 12:14 PM

I would use the Flooded setting.

Also set the charger to 90 amp max output.
Your batteries say 30 amps max but you have 3.

200 AH bank capacity.

acheron800 · 12-12-2022, 12:30 PM

Quote:

Originally Posted by twinboat

I would use the Flooded setting.

Also set the charger to 90 amp max output.
Your batteries say 30 amps max but you have 3.

200 AH bank capacity.

Thanks for the info. What do you make of this? Is this saying the charger is always putting out 100A?

twinboat · 12-12-2022, 12:56 PM

There should be a setting to drop max bulk charging down to 90 amps or 90% charge rate.
It's only putting out 100 amps until the voltage comes up to absorb voltage. They all work that way.

acheron800 · 12-13-2022, 06:42 PM

Well good thing I got only 3 and not 4 batteries.

Barely fit.

Ray,IN · 12-13-2022, 10:29 PM

Without knowing how your wiring is arranged, my Xantrex charges the starting batteries as well as house batteries. I have 3 house and 2 start batteries and leave it set to 100A, which is max for the charger.
That is 20A max. per battery for bulk phase, but since it is a "smart" charger I never do see 100A output on the display.