Replacing 2 AGMs with 1 100Ah LiFePO4?

[Alaska]

I've got a 2017 Fleet. My original batts have reached the end and I'm planning to replace them with a single 100Ah LiFePO4.

Things electrical are not my forte, so I've come here for some expertise.

I've got a Zamp Solar ZS-30A.

If I pull my old batteries and replace them with the LifePO4 and set the controller to the LifePO4 setting what else do I need to know and do?

To quote the FWC Electrical basics and upgrading to lithium manifesto:

What do I need to do to use a lithium battery in my FWC? Well, really, nothing. You CAN just chuck one in there. If you have the newer MPPT (overland solar) controller, you’ll probably even be able to fully charge it a lot of the time.
If you really want to get the most out of your investment though, you should definitely install at the very least, a battery monitor.
After that, a DCDC charger. While you’re at it with the DCDC though, please upgrade that tiny wiring from the alternator back to the camper. Otherwise you’ll never get the full use of the DCDC. You’ll be limited to about 15-20% of it’s capacity.

I'll look into the rest of the suggestions later this winter, but for now I'd like to just get the battery in there and hit the road.

Basic question: Since I'm going from two batteries to one, what do I do with the other two battery cables?

Thanks!

​

 

[Wandering Sagebrush]

I've got a 2017 Fleet. My original batts have reached the end and I'm planning to replace them with a single 100Ah LiFePO4.
<snip>
Basic question: Since I'm going from two batteries to one, what do I do with the other two battery cables?

The jumpers? Save them in case you decide on paralleling two LiFePO4s.

 

[kmcintyre]

I'm not sure what the amp rating is on your 2 AGM's but you may lose a bit of storage but depending on your electrical usage, you might be ok. I'm assuming the LifePO's you are purchasing will come with a BMS too and if that's the case, make sure you set that up correctly and you should be fine (again assuming the wiring us upgraded to something other than the 10ga FWC uses).

 

[veryactivelife]

If you’re not ready to install a DCDC charger with wiring upgraded to 6AWG then you should disconnect your alternator charging or you run the risk of frying your alternator.

Dean

 

[Vic Harder]

you can just chuck the LiFePo4 battery in there, but given what they cost, why would you?

Getting 5-6 years out of your original batter(ies) is good. Better would be knowing why. To do that, you need that SOC battery monitor. I and others here are liking Victron products. Check out their BMV712 or the Smart Shunt. Both are good.

Then consider getting a different solar charge controller. Yours is uses PWM, which is going to waste a lot of solar power vs an MPPT controller. Again, Victron products come to mind. I use the MPPT 100/30 for my setup.

And then look at that wiring and DCDC controller add on.

 

[Alaska]

I'd like to thank each of you for the responses. My old batteries were 75ah AGM. I'm going to go ahead with the swap to lithium with appropriate upgrades, done by someone with more knowledge than myself. The information provided here was very valuable in explaining what I wanted him to do.

Thanks again!

 

[Wallowa]

you can just chuck the LiFePo4 battery in there, but given what they cost, why would you?

Getting 5-6 years out of your original batter(ies) is good. Better would be knowing why. To do that, you need that SOC battery monitor. I and others here are liking Victron products. Check out their BMV712 or the Smart Shunt. Both are good.

Then consider getting a different solar charge controller. Yours is uses PWM, which is going to waste a lot of solar power vs an MPPT controller. Again, Victron products come to mind. I use the MPPT 100/30 for my setup.

And then look at that wiring and DCDC controller add on.

Alaska...Vic nails all the points...would suggest the BB100ah internally heated LiPO4....you will never regret it....along with upgrades Vic mentioned...I did this and can use '16 Hawk in subzero conditions...DC/DC and my 330 w of solar along with the BMS/heater keeps everything online...BB has 10year warranty...

 

[Jsoboti]

Ive seen a couple forum posts where people are plugging their IOTA DLS-30/IQ4 into their DCDC charger, as a workaround for the DLS-30/IQ4 not having a LiPO4 charging profile.

Thoughts on this? First thoughts is it feels wrong but I have no idea why.

 

[Jon R]

Ive seen a couple forum posts where people are plugging their IOTA DLS-30/IQ4 into their DCDC charger, as a workaround for the DLS-30/IQ4 not having a LiPO4 charging profile.

Thoughts on this? First thoughts is it feels wrong but I have no idea why.

It will work. Assuming you disconnect the DC to DC charger input from the truck battery, the DLS-30 will operate in power supply mode delivering up to 30 amps at roughly 13.4 volts. If you have a DC to DC charger with an output of 30 amps, it will draw maximum output from the DLS during bulk charging. The DLS is supposedly rated for that and is fan cooled, but you might have cooling issues. I haven’t tried it myself.

 

[FAW3]

I have a '18 Hawk and replaced my 2 old AGM's with one 100AH Renology Lithium battery a year ago.

I have the FWC 160 watt roof solar panel, 30 amp Zamp controller and the IOTA charger/converter. Isotherm 12vt. 130 qt refrigerator, propane furnace, 2 powered roof fans.

I've found that the existing charging system with the Zamp set to LI-ion works great. I made no changes to other components and have had excellent results. I almost never use shore power, the solar panel setup works fine in most cases to be fully charged after a long night by noon. My plan was to try it and if needed make other changes if needed. They have not been needed.

I have noticed that the voltage profile of the LI-ion is much better than AGM or lead acid...the voltage drop is much flatter and as a result you don't get the low voltage issues like poorly running furnace or refrigerator.

I do see in winter the need for more solar due to clouds and low sun angle. I as needed augment the roof solar panel with a Bluetti PV120 portable solar panel. The flexibility of placement is ideal...better than having another fixed flat solar panel on the roof.

 

[Durango1]

I have a '18 Hawk and replaced my 2 old AGM's with one 100AH Renology Lithium battery a year ago.

I have the FWC 160 watt roof solar panel, 30 amp Zamp controller and the IOTA charger/converter. Isotherm 12vt. 130 qt refrigerator, propane furnace, 2 powered roof fans.

I've found that the existing charging system with the Zamp set to LI-ion works great. I made no changes to other components and have had excellent results. I almost never use shore power, the solar panel setup works fine in most cases to be fully charged after a long night by noon. My plan was to try it and if needed make other changes if needed. They have not been needed.

I have noticed that the voltage profile of the LI-ion is much better than AGM or lead acid...the voltage drop is much flatter and as a result you don't get the low voltage issues like poorly running furnace or refrigerator.

I do see in winter the need for more solar due to clouds and low sun angle. I as needed augment the roof solar panel with a Bluetti PV120 portable solar panel. The flexibility of placement is ideal...better than having another fixed flat solar panel on the roof.

Your experience is super useful to me, Frank, because it mirrors my setup AND I am a total idiot electrically! I have a 2018 Grandby flatbed equipped the same as your Hawk with the two original AGM's from FWC. (I can't get them to die!)

QUESTION: What year is your Ram 3500? I have a 2018 Ram 3500 chassis cab with the 6.4 liter gas engine, aisin tranny and a 4.30 rear end. This combo has worked great but I'm concerned about any smart alternator charging issues with the lithium swap.

NOTE: When Denny Saunder's team installed my camper I had them run (I believe) stranded 4 gauge cable from the alternator back to the camper. Any thoughts on charging problems? TIA

 

[Vic Harder]

with 4AWG wire and a DCDC charger, you will be fine with your high IQ (aka smart) alternator.

 

[FAW3]

Your experience is super useful to me, Frank, because it mirrors my setup AND I am a total idiot electrically! I have a 2018 Grandby flatbed equipped the same as your Hawk with the two original AGM's from FWC. (I can't get them to die!)

QUESTION: What year is your Ram 3500? I have a 2018 Ram 3500 chassis cab with the 6.4 liter gas engine, aisin tranny and a 4.30 rear end. This combo has worked great but I'm concerned about any smart alternator charging issues with the lithium swap.

NOTE: When Denny Saunder's team installed my camper I had them run (I believe) stranded 4 gauge cable from the alternator back to the camper. Any thoughts on charging problems? TIA

2005 RAM Crew Cab 3500 with the Cummins.