Upgrading Battery on 2800BH

[SkolCamper]

I'm upgrading the batteries on my 2020 Imagine 2800bh. Going from the factory deep cycle battery to 2 - Renogy 100ah AGM batteries. My question is this: will the factory converter (WFCO 9855?) charge the AGM batteries?

 

[Riverbug]

I won't try to talk you into LiFePO4 but hope you have at least considered the option. The 9855 does not specifically state it is compatible with AGM. The charge profile is a little low for that type of battery. You could likely get by with it though. Or, you could go with LiFePO4, keeping that charger for now and still get longer life, and more usable capacity at 1/3 the weight. And, if you don't really need that extra capacity, you could buy one and get the equivalent capacity of two AGMs given voltage curves. Just saying...

 

[NB Canada]

I'm upgrading the batteries on my 2020 Imagine 2800bh. Going from the factory deep cycle battery to 2 - Renogy 100ah AGM batteries. My question is this: will the factory converter (WFCO 9855?) charge the AGM batteries?

What is the exact purpose of upgrading your batteries btw?

Are you planning for extended off grid stays because that still isn’t much power

 

[Chipworkz]

If you have the 9855-AD, it does talk about AGM batteries.

"For standard Lead Acid and AGM batteries, WFCO power converters still use the Three-Stage Smart Charging to efectively maximize battery life by monitoring through the diferent phases of the charge cycle."

and

"LEAD ACID & AGM THREE-STAGE SMART CHARGING To maximize battery life for lead acid and AGM batteries, it is best to charge batteries slowly, keep them topped of with a trickle-charge when the RV is not being used. The 3-Stage “smart” charger continuously measures the battery voltage output and regulates the amount of charge using three modes of operation: Power, Charge and Storage modes. All WFCO power converters have automatic three-stage switching power supplies. The converter senses which mode it needs to be in by checking the RV system voltage"

I just put in my Lithium batteries and like others have said, it did not correctly "Auto Detect" them so I upgraded to another converter. Just in case you go that route.

 

[SkolCamper]

I won't try to talk you into LiFePO4 but hope you have at least considered the option. The 9855 does not specifically state it is compatible with AGM. The charge profile is a little low for that type of battery. You could likely get by with it though. Or, you could go with LiFePO4, keeping that charger for now and still get longer life, and more usable capacity at 1/3 the weight. And, if you don't really need that extra capacity, you could buy one and get the equivalent capacity of two AGMs given voltage curves. Just saying...

I was trying to shy away from lithium batteries because I didn't think my converter would charge them.

 

[SkolCamper]

What is the exact purpose of upgrading your batteries btw?

Are you planning for extended off grid stays because that still isn’t much power

I have installed the 3000 watt Renogy inverter. I wanted to upgrade the batteries to make sure I could push enough to the inverter to power the camper while off grid. I also have the 200 watt Renogy solar panels.

I did a test run this past weekend and everything worked fairly well. There wasn't enough sun to fully charge the batteries on the second day, but otherwise it worked well.

The reason for my post was to make sure I could charge the batteries, prior to a trip, through the converter, while plugged into my home outlet.

 

[Riverbug]

I was trying to shy away from lithium batteries because I didn't think my converter would charge them.

I assumed from your original post that you have the 9855 and not 9855AD (which is lithium compatible). If you just have the 9855, it will still charge LiFePO4 batteries. It will not charge them to 100% (more like 80ish%), and it will not charge them quickly. I ran my first 206AH SOK battery off the basic WFCO charger for 1.5 years. I still have that battery and it still works great.

Some will say the issue is that they don't get topped off and the cells do not get balanced. True enough. But many people only charge LFP (LiFePO4) batteries in off grid systems to 13.8V - 14.2V for years to avoid stressing them and they still perform excellently. The truth is, a battery with good cells do not drift far enough quickly enough cause a noticeable issue. In fact, if you have enough capacity it would only show up when you run the battery down so low that the cell with the lowest voltage hits the cutoff while others still have power to give. But we're not talking hours of capacity left on the table, we're talking minutes. Not sure what you decided to do, but maybe this will help for future reference.

 

[coglesby]

I have used a non-lithium converter/charger with a lithium battery and monitored with a victron shunt. The battery does in fact get to 100% charge (if it does so within 4 hours with a WFCO 9800 series converter/charger) because the converter/charger starts in bulk mode at 14.6V, but when the converter/charger goes into float mode at 13.2V (after 4 hours with a WFCO 9800 series converter/charger), the battery slowly depletes down to 13.2V which is ~80% charge.

 

[coglesby]

If you have the 9855-AD, it does talk about AGM batteries.

"For standard Lead Acid and AGM batteries, WFCO power converters still use the Three-Stage Smart Charging to efectively maximize battery life by monitoring through the diferent phases of the charge cycle."

and

"LEAD ACID & AGM THREE-STAGE SMART CHARGING To maximize battery life for lead acid and AGM batteries, it is best to charge batteries slowly, keep them topped of with a trickle-charge when the RV is not being used. The 3-Stage “smart” charger continuously measures the battery voltage output and regulates the amount of charge using three modes of operation: Power, Charge and Storage modes. All WFCO power converters have automatic three-stage switching power supplies. The converter senses which mode it needs to be in by checking the RV system voltage"

I just put in my Lithium batteries and like others have said, it did not correctly "Auto Detect" them so I upgraded to another converter. Just in case you go that route.

Under warranty, I sent my WFCO-9875-AD to WFCO and they put in a jumper to lock it into lithium mode at their cost for the shipping because it would not remain in Lithium mode.

 

[Riverbug]

I have used a non-lithium converter/charger with a lithium battery and monitored with a victron shunt. The battery does in fact get to 100% charge (if it does so within 4 hours with a WFCO 9800 series converter/charger) because the converter/charger starts in bulk mode at 14.6V, but when the converter/charger goes into float mode at 13.2V (after 4 hours with a WFCO 9800 series converter/charger), the battery slowly depletes down to 13.2V which is ~80% charge.

Okay. You left off AD in your first post. Makes sense now.

 

[SkolCamper]

Not really sure which version I have. Probably should look just to be certain.

 

[coglesby]

Okay. You left off AD in your first post. Makes sense now.

First comment and one you quoted was non-AD and that’s what happens. I watched it with the charts from my shunt. It was 9855. Fully charges lifepo4 battery while in stage 1 & 2 and then the battery slowly discharges back to 13.2V after the non-AD goes in stage 3 float mode which is 13.2V.

Second comment was after I switched it out for the AD.

 

[Riverbug]

First comment and one you quoted was non-AD and that’s what happens. I watched it with the charts from my shunt. It was 9855. Fully charges lifepo4 battery while in stage 1 & 2 and then the battery slowly discharges back to 13.2V after the non-AD goes in stage 3 float mode which is 13.2V.

Second comment was after I switched it out for the AD.

Yeah sorry. I just realized I was not responding to the OP. All good now.

Just for anyone else trying to decipher all of this. A 9855 states it will charge at 14.4V, but most find that is optimistic and often never see 14.4V, likely due to the wire gauge and length between the battery up front and power center in middle or rear of the RV. The 9855 is not lithium compatible due to the charge voltage.

A 9855AD (AD=Auto Detect for liFePO4) is lithium compatible and stated charge at 14.6V. I've not had one so cannot attest to whether or not it reaches full 14.6V as stated. I just haven't seen much feedback one way or the other. It seems many people that upgrade, end up going to a third-party charger for LFP.

 

[coglesby]

Yeah sorry. I just realized I was not responding to the OP. All good now.

Just for anyone else trying to decipher all of this. A 9855 states it will charge at 14.4V, but most find that is optimistic and often never see 14.4V, likely due to the wire gauge and length between the battery up front and power center in middle or rear of the RV. The 9855 is not lithium compatible due to the charge voltage.

A 9855AD (AD=Auto Detect for liFePO4) is lithium compatible and stated charge at 14.6V. I've not had one so cannot attest to whether or not it reaches full 14.6V as stated. I just haven't seen much feedback one way or the other. It seems many people that upgrade, end up going to a third-party charger for LFP.

most folks don't understand how the 3 stage converter/chargers work. They are right that you won't see 14.4V but that is by design. For example, if you have a 55A converter/charger, when it hits 55A it will not provide any more current. If the battery voltage will only reach 13.5V with 55A forced into it, that's all you will get because the converter/charger will only supply a maximum of 55A. Once the battery voltage rises to 14.4V with 55A or less the converter charger will stop at 14.4V and the converter/charger will realize the battery is nearly charged and drop to 13.6V forced which is known as absorption mode.

The 9855 non-AD is not lithuim compatable due to the float mode being 13.2V. Float mode needs to be 13.8V for Lithium.