Battery Upgrade and Solar Question

[eyemgh]

I have a 2018 Raven Shell. It has a heater, one powered fan, three strips of LEDs, and the standard back porch light. It came with a single 12V AGM, but it's getting weak. The load is relatively low, but we do winter camp, and I might add a Dometic refrigerator/freezer.

I'm thinking about replacing it with 2 6V in series. Do I need anything extra if I do (other than adding a monitor at that time)?

Also, any primers on adding solar? I looked at some of the links in the ultimate battery post, but they take me back to the home page.

Thanks!

 

[rando]

Switching to two 6V batteries in series will not buy you anything but a lot of weight. Without the fridge, you should be OK with a single 70 - 100 Ah 12V battery. If you are adding a fridge, you will probably want to add solar as well. If you camp in warm shady place you may possibly want to upgrade to a 100Ah LiFePO4 battery, or 2 70 Ah lead acid in parallel.

 

[eyemgh]

Switching to two 6V batteries in series will not buy you anything but a lot of weight. Without the fridge, you should be OK with a single 70 - 100 Ah 12V battery. If you are adding a fridge, you will probably want to add solar as well. If you camp in warm shady place you may possibly want to upgrade to a 100Ah LiFePO4 battery, or 2 70 Ah lead acid in parallel.

According to FWC (I clearly don’t remember the physics of why this is), one 12V AGM is 75ah, two is 150ah, and 2 6v is 225ah.

https://fourwheelcampers.com/video/camper-battery-power-options-agm-lithium/

EDIT: The spiderwebs are clearing. Two 6V in series = 12V with same capacity. Capacity is higher due to three cells in same footprint as 6 cells would be in a 12V.

As intrigued as I am about LiPO, the cost is probably going to be prohibitive.

 

[rando]

With lead acid more capacity = more weight, and there is not much difference if you use 12V in parallel or 6V in series.

So yes you can get 225Ah (at 12V) with 2x6V batteries, but with what you are describing that is almost certainly more capacity than you need, and each battery will be about 70lbs. If you want to stick with lead acid, then 2x75ah in parallel will likely be plenty of capacity. Most 6V 225Ah batteries are also wet cell (aka flooded) batteries, meaning you will need to access them somewhat regularly to check and fill the electrolyte. The 12v in parallel option has the slight advantage that each battery is redundant, so if you have a battery failure, you can still use the other one and you can easily get sealed AGM batteries which don't need any maintenance.

Also don't rule out LiFePO4, the prices of these are dropping very rapidly, and you can get a 100Ah battery (which would be plenty) for around $500 - $600, which includes bluetooth monitoring.

 

[eyemgh]

Also don't rule out LiFePO4, the prices of these are dropping very rapidly, and you can get a 100Ah battery (which would be plenty) for around $500 - $600, which includes bluetooth monitoring.

I'd prefer to go this route as they'll last longer and I can discharge them more deeply. I assumed though that I'd have to add a bunch of other hardware. Is there a plug and play option? What if we decide to add solar later? Thanks!

 

[eyemgh]

I'd prefer to go this route as they'll last longer and I can discharge them more deeply. I assumed though that I'd have to add a bunch of other hardware. Is there a plug and play option? Thanks!

Bump to try to get an answer to this. I'll have the Blue Sea isolator and a 30a IOTA charger. Thanks!

BTW, not going to do solar or a refrigerator on this rig. Total power needs are heater fan, roof fan, 3 LED strips of indoor lights. entry level porch light, phone recharging and soon to be added ARB awning light strip.

 

[Beach]

Not certain but I don't think you can set the Iota up to the required charging profile of the lifpo4 battery. Maybe Vic or Rando can advise.

 

[eyemgh]

Not certain but I don't think you can set the Iota up to the required charging profile of the lifpo4 battery. Maybe Vic or Rando can advise.

That's the advice I'm looking for!

I'm not really even sure if the move to LiFePO makes sense, given the fact that we'll likely upgrade in 1-2 years. Maybe another AGM is fine. Not sure.

 

[ntsqd]

A Li-anything conversion was a very new thing when we last needed batteries, so we have a pair of AGM 2GC's. A lot of weight for the capacity, but such batteries are built for this sort of use where few 12V batteries are. Even those claiming to be "deep cycle". The next batteries we buy will be Li chemistry unless something better comes along AND such conversions have been well sorted out by then.

If you're thinking to upgrade in a year or two I'd go with an AGM this time around. Doubt that you'd get your money out of a Li conversion. All the while be looking and learning about the conversion for the next camper.

 

[eyemgh]

A Li-anything conversion was a very new thing when we last needed batteries, so we have a pair of AGM 2GC's. A lot of weight for the capacity, but such batteries are built for this sort of use where few 12V batteries are. Even those claiming to be "deep cycle". The next batteries we buy will be Li chemistry unless something better comes along AND such conversions have been well sorted out by then.

If you're thinking to upgrade in a year or two I'd go with an AGM this time around. Doubt that you'd get your money out of a Li conversion. All the while be looking and learning about the conversion for the next camper.

I think I'm leaning that way, but staying with a single. Space is tight in my build and we don't use much power. Which AGM are you using?

 

[Beach]

I replaced my optima(really a dual purpose) with a true deep cycle from Renogy(100 ah) AGM (Found it on amazon for less than $200). I run my fridge on propane so my elect. needs are fairly minimal; fans, led lights, phone charging, etc. My 60 watt panel keeps up fine and with the 100 ah capacity, I usually see 12.4v to 12.5v after 2-3 days when we are off grid. Get a good deep cycle battery(not a dual purpose) and you'll likely be fine.

 

[heinphoto]

Not certain but I don't think you can set the Iota up to the required charging profile of the lifpo4 battery. Maybe Vic or Rando can advise.

It depends on which version of the Iota you have installed. A 2018 FWC probably has the DLS-30/IQ4, which is the version with the integrated IQ4 charge controller that is set up for lead acid battery chemistry. That version unfortunately doesn't allow the charge profile to be be changed. There is a different version of the DLS-30 that allows IQ4 "dongles" with charge profiles for different battery chemistries to be plugged in. If you do most of your charging with a solar controller set up for LiFePO4 batteries, then using the Iota with the integrated IQ4 from time to time probably won't hurt anything. However, I wouldn't use it as the only charging source.

 

[eyemgh]

I replaced my optima(really a dual purpose) with a true deep cycle from Renogy(100 ah) AGM (Found it on amazon for less than $200). I run my fridge on propane so my elect. needs are fairly minimal; fans, led lights, phone charging, etc. My 60 watt panel keeps up fine and with the 100 ah capacity, I usually see 12.4v to 12.5v after 2-3 days when we are off grid. Get a good deep cycle battery(not a dual purpose) and you'll likely be fine.

Thanks! I’ll look at the Renology.

It depends on which version of the Iota you have installed. A 2018 FWC probably has the DLS-30/IQ4, which is the version with the integrated IQ4 charge controller that is set up for lead acid battery chemistry. That version unfortunately doesn't allow the charge profile to be be changed. There is a different version of the DLS-30 that allows IQ4 "dongles" with charge profiles for different battery chemistries to be plugged in. If you do most of your charging with a solar controller set up for LiFePO4 batteries, then using the Iota with the integrated IQ4 from time to time probably won't hurt anything. However, I wouldn't use it as the only charging source.

Mine didn’t actually come with the IOTA. A friend had one and is installing it for me. He lost the dongle, so I bought a new one. They’re only $20. I’ll have to look at the specs. I don’t have solar and don’t plan to add it, so alternator and shore are the only options. It’s sounding like another AGM might be the way to go.

 

[heinphoto]

Mine didn’t actually come with the IOTA. A friend had one and is installing it for me. He lost the dongle, so I bought a new one. They’re only $20. I’ll have to look at the specs. I don’t have solar and don’t plan to add it, so alternator and shore are the only options. It’s sounding like another AGM might be the way to go.

That's great. You can just get a different dongle if you decide to change from AGM to LiFePO4 at some point. We are stuck unless we replace the Iota when we upgrade to LiFePO4. Fortunately, we don't use shore power much.

FWIW, if you are planning to rely on the alternator for charging, you might consider upgrading the wiring from the truck to the battery (if you haven't already). FWC typically installs 10 AWG from the truck to the camper. That's a long run and small gauge to supply much charging current. We recently had ours upgraded to 4 AWG and it made a huge difference. We also had a DC-DC charger installed in anticipation of upgrading when our current AGMs need to be replaced. It probably isn't necessary right now, but it does provide multi-stage charging that is separate from whatever charge profile the alternator uses.

 

[eyemgh]

That's great. You can just get a different dongle if you decide to change from AGM to LiFePO4 at some point. We are stuck unless we replace the Iota when we upgrade to LiFePO4. Fortunately, we don't use shore power much.

FWIW, if you are planning to rely on the alternator for charging, you might consider upgrading the wiring from the truck to the battery (if you haven't already). FWC typically installs 10 AWG from the truck to the camper. That's a long run and small gauge to supply much charging current. We recently had ours upgraded to 4 AWG and it made a huge difference. We also had a DC-DC charger installed in anticipation of upgrading when our current AGMs need to be replaced. It probably isn't necessary right now, but it does provide multi-stage charging that is separate from whatever charge profile the alternator uses.

Good call. We never shore power either. the only reason we're setting this up with the IOTA is that the alternator was the only charging we had. It's probably been chronically under charged. We'll plug at home to get the battery topped off.

 

[ntsqd]

As to what AGM's we're using, I'd have to look. I'm sure that they're nothing special as I wasn't willing to put a bunch of money into batteries for a camper that I wasn't sure if we'd have it much longer. Turned out that the replacement camper also used 2GC's and had a fairly new pair of wet batteries in it. So we still have those AGM's now in the newer camper.

In the old camper I put a single 100W panel on the roof with a PWM type controller and it kept up with all of our needs. But we're in the desert SW where we get lots of sun year round. So much so that at the time I wished that I'd done the solar first and then the truck connection may never have happened.
The new camper has a single 160W panel and it doesn't do quite as well. I suspect that most of the problem is in the no-name controller.

If you have power available where ever the camper is parked between trips and uses you might consider a maintainer. I set up both campers so that their maintainer is live whenever we do plug into shore power. I've also put a dual sensing ACR in both campers so when the shore power or solar has topped off the camper batteries it then goes to work on topping off the AGM truck batteries. I see that as a big downside to a DC-DC charger, as best as I can tell they only work in one direction. If forced to use a DC-DC charger I would seriously consider setting up a maintainer for the truck batteries that is plugged into the camper's shore power circuit as late model trucks have lots of little draws that when parked for a while can pull the starting batteries flat.

 

[eyemgh]

As to what AGM's we're using, I'd have to look. I'm sure that they're nothing special as I wasn't willing to put a bunch of money into batteries for a camper that I wasn't sure if we'd have it much longer. Turned out that the replacement camper also used 2GC's and had a fairly new pair of wet batteries in it. So we still have those AGM's now in the newer camper.

In the old camper I put a single 100W panel on the roof with a PWM type controller and it kept up with all of our needs. But we're in the desert SW where we get lots of sun year round. So much so that at the time I wished that I'd done the solar first and then the truck connection may never have happened.
The new camper has a single 160W panel and it doesn't do quite as well. I suspect that most of the problem is in the no-name controller.

If you have power available where ever the camper is parked between trips and uses you might consider a maintainer. I set up both campers so that their maintainer is live whenever we do plug into shore power. I've also put a dual sensing ACR in both campers so when the shore power or solar has topped off the camper batteries it then goes to work on topping off the AGM truck batteries. I see that as a big downside to a DC-DC charger, as best as I can tell they only work in one direction. If forced to use a DC-DC charger I would seriously consider setting up a maintainer for the truck batteries that is plugged into the camper's shore power circuit as late model trucks have lots of little draws that when parked for a while can pull the starting batteries flat.

The IOTA with IQ4 is a multi stage charger. It will charge at up to 14.8v, initially, eventually slowing, and finally shifting into float mode. Pretty slick.