Community Forums

ADiamond · 08-11-2022, 02:03 PM

I have a 2016 Ventana 4369, we spend time in campsites most of the time, sometimes we will do 1 or 2 nights without hookups. I wouldn't expect to use the air, microwave or cooktop, just the residential fridge. We have a Magnum 2812 inverter with the ME-RC Control. We bought the rig used with 8 6v flooded batteries. I'd like to get away from the maintenance and go to AGM or LiFePo.

I like the Lithium for the weight difference, reduced charging time, more usable power, bluetooth interface, don't like to price. Will LiFePo work with the charger and inverter? I think I can use a custom charge profile for the ME-RC. I've seen questions about charging while driving and that it's a problem.

AGMs aren't that cheap but less than Lithium (not as much as I thought). I think the ME-RC has canned profiles for charging. If I buy 12v/100Ah can I get away with 4?

Do I need to do anything special because the existing battery bank is setup in series/parallel because of the 6v?
Any help is appreciated, this is a pain in the neck.

bentjm · 08-11-2022, 04:50 PM

There are lots of threads about this.

AGMs will be simplest.

Lithium will require some rewiring of the charging connection between the house and chassis batteries.

Good discussion here:

https://www.irv2.com/forums/f103/con...um-588250.html

truk4u · 08-11-2022, 06:33 PM

If you go with Lifeline 4CT’s, your Magnum will have a Lifeline AGM charge setting. Whatever you decide, go with AGM and not cheap wet batteries with all the corrosion and watering.

99dart · 08-11-2022, 07:17 PM

I agree with truk4U. AGM will be easiest and less money. AGM's recharge faster than flooded cell and don't off gas (if mounted where fumes might enter cabin). Also, little to no corrosion on battery posts. I have Interstate AGM's installed new when we purchased our MH 2 1/2 yrs ago. They hold quite well when overnighting with the residential fridge.

richpatty · 08-12-2022, 06:23 AM

Of course my vote is for lithiums. :-)

I guess it would matter if you are going to keep this Rv a long time…then lithium’s may be worth it. Also, while you have the batteries our (no matter what type you go with), I would replace the ME-RC with the ME-ARC and add the BMK (battery monitoring kit) as it will REALLY help you know what the state of your batteries are.

I just upgraded my batteries (mentioned in the link above) and I have the same magnum inverter. It really was not that bad. And wiring 12v batteries is actually easier than 6v (in my opinion).

PM me if you have any questions.

DavidEM · 08-12-2022, 07:11 AM

If you are considering matching your existing 440 Ah usable with lithiums then that will likely put too much load on your chassis alternator. A dc2dc charger is a typical solution but that will also require changes to your battery isolation and control system.

So unless you want to increase your usable Ahs, then switch to AGMs.

David

wolfe10 · 08-12-2022, 07:17 AM

Without knowing how you use your coach, we really can't offer sage advice.

If not too much boondocking, AGM's such as Lifeline are an excellent choice.

If extensive boondocking, then indeed consider Li batteries. But be aware that that is NOT just a battery swap out. You will need to control your alternator output (smart regulator with temperature sensor) or DC to DC charger. And, your current charger or inverter/charger may or may not properly charge Li batteries. Yes, more homework is needed to see which of your equipment would need to be updated/replaced to accommodate the Li's.

richpatty · 08-12-2022, 07:22 AM

To address the alternator question, I chose the LI-Bim option. Was an easy swap out…

**pasdad1** · 08-12-2022, 07:28 AM

Go with the Lifeline 6volt AGM. They are a direct replacement for what you have and will be maintenance free for a lifetime use of 6-10 years….

Persistent · 08-12-2022, 07:45 AM

I have a 2016 Ventana 4369, we spend time in campsites most of the time, sometimes we will do 1 or 2 nights without hookups. I wouldn't expect to use the air, microwave or cooktop, just the residential fridge. We have a Magnum 2812 inverter with the ME-RC Control. We bought the rig used with 8 6v flooded batteries. I'd like to get away from the maintenance and go to AGM or LiFePo.

I like the Lithium for the weight difference, reduced charging time, more usable power, bluetooth interface, don't like to price. Will LiFePo work with the charger and inverter? I think I can use a custom charge profile for the ME-RC.

Some Li "drop in" batteries will work with the Magnum 2812. Of course it requires a custom program to do so. Some Li battery companies provide expert system design help to advise how to do it. Battle Born provides online and phone help for good advice.

Eight 6 volt gulf cart batteries may be 4 X 220 a/h = 880 amp hours at 12 volts.

You may get away with 500 amp hours of Li batteries. How you use your existing set would suggest how big the Li set should be. If you recharge at 50%, 500 amp hours would probably be enough.

I've seen questions about charging while driving and that it's a problem.

Depending on the design of the Li battery BMS, a 500 amp hour Li bank can draw huge charging current from the RV alternator. The Li battery bank can also generate load dumps when the BMS suddenly disconnects.

To prevent heat damage and high voltage spikes, install a B2B charger and alternator high voltage suppressor designed to match your RV system capability. A good installer or a good Li battery manufacturer can provide expert design assistance and review your planned installation. One US manufacturer even requires a design review before they will sell their batteries to you.

AGMs aren't that cheap but less than Lithium (not as much as I thought). I think the ME-RC has canned profiles for charging. If I buy 12v/100Ah can I get away with 4?

Lead acid batteries come in many different size and capacity configurations. Counting batteries is only a rough estimation of what you need. Replacing the eight batteries you have with eight 12 volt batteries of the same physical size will probably provide the same capacity.

Get the amp hour specification from your current flooded cell battery bank. Each pair of 6 volt batteries is equal to one 12 volt battery. Example: A pair of 220 amp hour 6 volt batteries makes one 220 amp hour 12 volt battery.

You may need 880 amp hours of AGM 12 volt batteries to equal your current configuration. That may be nine 100 amp hour 12 volt AGM batteries = 900 amp hours. It all depends on physical size of the batteries and the space available to install them.

Do I need to do anything special because the existing battery bank is setup in series/parallel because of the 6v?

There probably are 6 volt AGM batteries equivalent to your existing 6 volt flooded cell batteries. It this case, hook up the new batteries the same as the old.

Depending on price and availability you may wish to switch to 12 volt AGM batteries. In this case, the length of the cables used to connect the multiple 12 volt batteries together in parallel configuration will be different.

757driver · 08-12-2022, 08:17 AM

Quote:

Originally Posted by truk4u

If you go with Lifeline 4CT’s, your Magnum will have a Lifeline AGM charge setting. Whatever you decide, go with AGM and not cheap wet batteries with all the corrosion and watering.

In the 2016 version of the Magnum ME-RC (and some later ones as well) the Lifeline AGM1 setting is incorrect and will only give a float voltage of 13.1v instead of Lifeline’s recommended float voltage of 13.3v.

It does not sound like much of a difference but in many cases it may be the difference in getting a charge to the chassis batteries while on shore power through the factory installed BIM.

truk4u · 08-12-2022, 09:15 AM

If your Magnum doesn’t have the proper charge voltage for Lifeline, just use the custom setting for bulk/absorption/float. If you want to go to 12v you would need 4D’s at 210 amp or 8D’s at 255 amp assuming there is room in the bay. Finding 12v batteries with the same footprint as 8 of the 6v will be tough not to mention the lower amp hrs as the case size gets smaller.

If your a serious dry camper, the Lifeline 6CT’s is a good way to increase your amp hour capacity, 300 amp hr vs 220 amp hour, so 6 of the 6CT’s would give you 1200 amp hours or 600 usable at 50%.

Glad to help if I can.