Ok, going the ‘AGM route’ now…charging ?

[Danjuan]

Hi, I’m a 2020 Navion with 1.5 year old NAPA Lead Acid house batteries that have gone basically flat several times while boondocking around trees because of the excessive load, from fridge with no propane mode, even ‘night mode’.
I know this issue has been kicked around a lot, especially where Lithium comes in… will the Sprinter engine alternator and regulator know the proper charging algorithm for charging these two New Renogy 100Ah batteries? I/we know the settings on Zamp solar charger and Xantrex inverter/charger/controller are simply changed to AGM, but driving down the road, will Mr. Sprinter want to overcharge and too quickly ?
Also, I’ve been told these AGMs won’t let themselves go low enough to where they damage themselves, tru ? I know the fridge has a 10 volt shutoff mode but by that time, the damage is done.

All Ears, Dan in the rainy PNW.

[BobC]

There are many online resources that say yes, go ahead and do it. However, if you want to be safe, install a DC-to-DC charger. This is what I did. I installed a 40A Renogy charger. They are available in several different amp ratings:

https://www.amazon.com/renogy-dc-cha...+to+dc+charger

[Danjuan]

Thanx Bob,
Yes, I’m torn on the various opinions out there. I appreciate your personal experience and referral ,will look into it especially because new batts are same brand.
Simplish’ to install?
Do yours have a safe low Ah cutoff built in ?
Dan

[BobC]

Installation was pretty easy. The only complicated part was finding out where to connect the alternator sensing circuit wire (DC+ ignition in manual). I'm not sure what you mean about low Ah cutoff. I suggest you check out the manual:

https://www.renogy.com/content/RNG-D...060-Manual.pdf

[Danjuan]

Thanks again for the manual info.
In low Ah cutoff, I was trying to ask if there is a failsafe ‘smart feature’ within these batts to stop them from over discharge.
Dan

[BobC]

The DC-to-DC charger is an input device so I'm pretty sure it's not going to monitor and manage the output side. I'm sure someone will have a suggestion.

[creativepart]

Yes, the lead acid chemistry is what regulates the charging and is the reason that LFP is so different.

See, when you charge LA batteries as they get ever closer to a full charge the internal electrical resistance increases. So as this resistance increases it makes it more difficult for any Charger (including the vehicle alternator) to continue to add current to the battery. This happens naturally, no external regulator is needed. This applies to AGM batteries just as it does to Flooded Lead Acid batteries.

This is where LiFePO4 batteries completely differ from LA and where conventional Converters and Alternators have difficulty charging correctly. LFP batteries will take all the current a charging device can supply. During this process electrical resistance does not increase so there is nothing to prevent a LFP battery from demanding more and more current… to the point of overloading the alternator. Burning it up in the process.

This is one of the reasons people that replace LA/AGM batteries with LFP batteries change out their converter and make provisions for vehicle alternator charging. Well, that and the higher resting voltage of LFP batteries.

AGMs are still Lead Acid batteries so, converters and alternators are well equipped to charge them. AGMs do have slightly different charging profiles than FLA batteries but it’s not such a huge difference that your alternator will have any problems charging them.

[V29]

creativepart, I am pleasurably surprised to see such a 100% accurate explanation regarding Batteries, charging, Lead acid, AGM, Lithium, ... that I have never seen in the RV or Marine communities! I no longer attempt to explain/educate/convince, it can only go in a bad direction. Batteries and electricity is so straight forward, but long held misbeliefs are nearly impossible to change. Thanks!

FYI, I am an OEM in the marine industry. The systems are nearly the same. Re Lead Acid or AGM, the charging profiles are nearly identical - only 0.1Vdc different so the same chargers/programming may be used without any harm to chargers or batteries. Lithium, in my professional opinion, should be avoided for a multitude of reasons (not going there now).

[bigb]

Not to mention the Sprinter chassis already has an AGM starting battery which gets charged by the same alternator that charges the house bank. From my understanding the thing you need to know with AGM is that an old school plug in battery charger could exceed the safe voltage for the AGM but the vehicle charging system will work fine with AGM.

[Danjuan]

Thank-Q all for the input.
I ordered a Renogy 40 DC-DC charger and temp sensor to safe up, but after reading the info booklet about charging profiles, I realized how similar AGM-Gel are to LA.
Vast diff for if & when I go Lithium.
So, for now, I’m sending them back to the Amazon Cloud.

[Ontario Don]

Hi - Congrats on your new coach.

Regarding your original question about alternator charging rates - if you plan on upgrading your coach batteries, you are currently safe with the factory configuration for your 2020 Navion,

When Winnebago did the model upgrades on the Navion / View back in '20, they removed the classic booster solenoid under the passenger's seat, and replaced it with a current limited electronic charge relay. This current limiter was added specifically to address the concern from Mercedes that the new Lithium coach battery option was going to tax the Sprinter's alternator.

If you lift up the Styrofoam dust cover under the passenger seat, you will see the Mastervolt Charge Mate Pro 40 current limited charge relay sitting there.

https://www.mastervolt.com/products/...e-mate-pro-40/

This current limiter is set for a max of 40 amps, but in our '21 View we have never seen the battery get charged from the alternator with anything greater than about 35 amps, and that is at high RPM while hill climbing. In cruise, it likes to sit at about 25 - 30 amps.

Now, if you are looking for more than the advertised 40 amps out of the alternator, that is a whole different issue - but if you are concerned about taxing your alternator due to the addition of AGM or LifePO4 coach batteries, Winnebago has looked after that with their factory electrical configuration.

We installed LifePO4 coach batteries as our first mod in our '21 View, and after changing the battery chemistry options on the Zamp solar controller and the Xantrex charger / inverter, we have never looked back.

Anyone who installs a DC - DC charger in a 2020 and newer View / Navion must be doing it for a different reason than to protect the alternator. I'm not sure what that reason would be, maybe to bypass the factory installed current limiter, for some reason...

Looking back on the 3 1/2 years we have had our '21 View, the addition of LifePO4 batteries has been a game changer for our dry camping operations - even in the winter. The upgrade was pretty simple, thanks to the addition of the new Charge Mate Pro 40 charge relay.

Cheers,

[Danjuan]

Originally Posted by Ontario Don

Hi - Congrats on your new coach.

Regarding your original question about alternator charging rates - if you plan on upgrading your coach batteries, you are currently safe with the factory configuration for your 2020 Navion,

When Winnebago did the model upgrades on the Navion / View back in '20, they removed the classic booster solenoid under the passenger's seat, and replaced it with a current limited electronic charge relay. This current limiter was added specifically to address the concern from Mercedes that the new Lithium coach battery option was going to tax the Sprinter's alternator.

If you lift up the Styrofoam dust cover under the passenger seat, you will see the Mastervolt Charge Mate Pro 40 current limited charge relay sitting there.

https://www.mastervolt.com/products/...e-mate-pro-40/

This current limiter is set for a max of 40 amps, but in our '21 View we have never seen the battery get charged from the alternator with anything greater than about 35 amps, and that is at high RPM while hill climbing. In cruise, it likes to sit at about 25 - 30 amps.

Now, if you are looking for more than the advertised 40 amps out of the alternator, that is a whole different issue - but if you are concerned about taxing your alternator due to the addition of AGM or LifePO4 coach batteries, Winnebago has looked after that with their factory electrical configuration.

We installed LifePO4 coach batteries as our first mod in our '21 View, and after changing the battery chemistry options on the Zamp solar controller and the Xantrex charger / inverter, we have never looked back.

Anyone who installs a DC - DC charger in a 2020 and newer View / Navion must be doing it for a different reason than to protect the alternator. I'm not sure what that reason would be, maybe to bypass the factory installed current limiter, for some reason...

Looking back on the 3 1/2 years we have had our '21 View, the addition of LifePO4 batteries has been a game changer for our dry camping operations - even in the winter. The upgrade was pretty simple, thanks to the addition of the new Charge Mate Pro 40 charge relay.

Cheers,

Don, I appreciate your intelligent input on this battery thing.
It comes as great news for if’n when we go the lithium route.
I acquired these very little used and apparently never flattened Renogy AGM 100s for a ‘sweet deal’ from out daughter who just completed a Schoolie Shortbus buildout after she upgraded to Lithium. We shall see how they compare to our feeble LA house batts.
In the meantime, I continue to weed out the ongoing quirks, such IS life, folks !
Cheers Indeeed ~~~~~>

[Ray,IN]

Lead-acid, AGM, GEL-cell are the same battery chemistry in different forms. They charge the same way, just install the Renogy AGM batteries and continue as normal.
Renogy AGM 100A electrical specifications: https://www.renogy.com/deep-cycle-ag...12-volt-100ah/
I have 3 for house battery bank and they are Grrrreat!

[Danjuan]

… the news I like to hear !
Jean
Tanx agin!