Community Forums

CountryB · 11-20-2020, 09:25 AM

My Coach has the Xantrex-Trace 2512RV Inverter-Charger with the RC7 remote display.

In the configuration settings there is an option to select the "max charge rate".

What is the purpose of this setting - why would anyone want to choose less than a 100% Charge Rate?

RichardE · 11-20-2020, 12:12 PM

In the rare circumstance that you may wish to reduce the current output because you have a small battery bank and don't want to charge above the recommended rate, OR you wish to impart a slow tricke charge in an attempt to revive dead batteries, OR the 110V power supply is limited and you wish to limit the drain going to the charger.

The latter could also be handled by setting the maximum AC power input.

CountryB · 11-20-2020, 12:31 PM

Thanks Richard.

757driver · 11-20-2020, 12:55 PM

Practical example. Typical motorhome has four 6v GC2 flooded batteries with a total of 440AH capacity. Recommended charge rate for most flooded batteries is between 10-15% of the C rating. A typical inverter/charger has a 100 amp charger. For the above example to be within the recommended charge rate of 44-66 amps need to set the charger to between 50-70% of its total output.

shootist · 11-21-2020, 09:24 PM

Has to do with how much ac power you have available. If you're on the gennie and running ac's , micro etc.. Or plugged into 30 amp the charger can easily draw enough power to start popping breakers from low voltage .

96 Wideglide · 11-21-2020, 10:37 PM

Quote:

Originally Posted by 757driver

Practical example. Typical motorhome has four 6v GC2 flooded batteries with a total of 440AH capacity. Recommended charge rate for most flooded batteries is between 10-15% of the C rating. A typical inverter/charger has a 100 amp charger. For the above example to be within the recommended charge rate of 44-66 amps need to set the charger to between 50-70% of its total output.

This ^^

It's adjustable for use on different size battery banks.
I have my 100A Magnum charger set at 60% to charge the 4 6V batteries (460 AH total). If I were to add another pair, I would turn it up to 80%.

twinboat · 11-22-2020, 12:25 AM

Quote:

Originally Posted by shootist

Has to do with how much ac power you have available. If you're on the gennie and running ac's , micro etc.. Or plugged into 30 amp the charger can easily draw enough power to start popping breakers from low voltage .

It's the " Shore Max " setting, that you change when on limited shore or generator power, to prevent breaker tripping.

Charge rate is a configuration setting depending on battery bank size, while Shore Max is a temporary setting.

CountryB · 11-22-2020, 06:17 AM

My Xantrex has a setting for "Battery Capacity in Ah" that sets the length of Time for absorption charging before it switches to Float mode.
According to the manual, in Auto, it charges in this mode for 1.8 hrs. If set to 500Ah this charge time would be 2.5 hrs. I left the setting in Auto. My House batteries are 450 Ah (four 225Ah GC2).

Then there is the "Max Charge Rate" setting that I'm asking about here.

And there is a setting for "Shore Power" - which I have set to 20A since I'm plugged into a 20A outlet while in storage.

Thanks for your help understanding this.

CountryB · 11-22-2020, 06:28 AM

Quote:

Originally Posted by 757driver

Practical example. Typical motorhome has four 6v GC2 flooded batteries with a total of 440AH capacity. Recommended charge rate for most flooded batteries is between 10-15% of the C rating. A typical inverter/charger has a 100 amp charger. For the above example to be within the recommended charge rate of 44-66 amps need to set the charger to between 50-70% of its total output.

The specs on my Xantrex 2512RV unit says the maximum charge rate is 120A.

My batteries are four deep cycle GC2 (225Ah each) - so 450Ah for the House bank. And for the Chassis batteries there are two Group 31 (950CCA). At some point (when the House batteries are fully charged) the "Big Boy - BIRD" setup will combine the House and Chassis to keep both sets charged.

What should the Max Charge rate be on my setup? 50% (which would be 60A charge rate)? I left it in default mode for now.

The shore Power setting drops the charging amperage - so I think the Shore Power setting overrides the Max Charge rate setting (i.e. In Shore Power 20A, the charge amperage is limited to 20A), but when plugged into 50A Shore Power (with the Shore Power setting at "30A or More" - then the Max Charge Rate setting is used. Does this sound correct?

757driver · 11-22-2020, 01:39 PM

Quote:

Originally Posted by CountryB

The specs on my Xantrex 2512RV unit says the maximum charge rate is 120A.

My batteries are four deep cycle GC2 (225Ah each) - so 450Ah for the House bank. And for the Chassis batteries there are two Group 31 (950CCA). At some point (when the House batteries are fully charged) the "Big Boy - BIRD" setup will combine the House and Chassis to keep both sets charged.

What should the Max Charge rate be on my setup? 50% (which would be 60A charge rate)? I left it in default mode for now.

The shore Power setting drops the charging amperage - so I think the Shore Power setting overrides the Max Charge rate setting (i.e. In Shore Power 20A, the charge amperage is limited to 20A), but when plugged into 50A Shore Power (with the Shore Power setting at "30A or More" - then the Max Charge Rate setting is used. Does this sound correct?

Yes, I would set the max. charge rate to 50% (assuming you have flooded batteries). It will be better for the batteries in the long run and you will get less off gassing and less corrosion around your battery posts and battery compartment.

If your charge amps is indeed limited to 20A when shore power is dialed back to 20A keep in mind that this is 20A AC power which is roughly 180 amps of DC charge (something your charger is not capable of). If you are seeing a reduction in your charge amps while on 20A shore power it could be one of two things either your batteries are getting full and the amps are reducing or other AC loads are being run and it is reducing what the charger gets to stay within the 20A shore power setting.

757driver · 11-22-2020, 01:42 PM

I see in your previous post that you circled AGM batteries. Do you have AGM batteries? If so what brand are they? You may be able to have a slightly higher charge rate setting.

CountryB · 11-22-2020, 03:00 PM

I have new AGM batteries. Just installed last week.
They are made by Crown Batteries. 220Ah @ 20Hr. "GC2 6V Deep Cycle Sealed".

Thanks for your reply. I'm just looking for the best charge rate - whatever will provide the best battery longevity.

These batteries are expensive. I want them to last.

https://www.crownbattery.com/hubfs/D...Deep-Cycle.pdf

757driver · 11-22-2020, 08:16 PM

Quote:

Originally Posted by CountryB

I have new AGM batteries. Just installed last week.
They are made by Crown Batteries. 220Ah @ 20Hr. "GC2 6V Deep Cycle Sealed".

Thanks for your reply. I'm just looking for the best charge rate - whatever will provide the best battery longevity.

These batteries are expensive. I want them to last.

https://www.crownbattery.com/hubfs/D...Deep-Cycle.pdf

Crown recommends 10% of the C rating up to a maximum of 25% of C. I would set it at 50-60% charge rate. For battery capacity I would set it to 500 amp (just slightly over what you have) which will give a 2.5 hour Absorb phase. Battery type set to AGM will give the closest to what Crown recommends for Bulk/Absorb/Float.