Replace SLA batteries with LiFeP04 batteries

One Old Guy

New Member
Joined
Aug 16, 2021
Messages
9
The following is installed on my 5th wheel and has been working for over 6 years.

DC Power
The solar system is 12 volt and consists of:
450 (4x100 + 1x 50)watts of Renogy solar panels
Controlled by a Bogart SC2030 & TM2030
2 Trojan T145s in series (260ah & 145lbs)
The on board shore power converter is a Progressive Dynamics Intelipower PD9260C
We have a Tripp-Lite PV2000FC which is a 2000 watt inverter with a dedicated outlet but we have never used it.

AC power:
The AC side is protected against voltage fluctuations, power surges & incorrectly wired shore power by a Progressive Industries EMS-HW50C
We have an Onan 5500 generator (HGJAA) that is connected to the AC side through a IOTA ITS-50R transfer switch.

We do spend some time off grid but a week is the maximum then we will usually be attached to shore power for a few days. The TV hasn’t been on in years & the microwave is used sparingly for a few minutes a day. There is no intention to run the air conditioner when not connected to shore power.

I would like to change out the Trojan batteries for LiFeP04 batteries (In the range of 200 to 400ah) using as much of my existing equipment and as simply as possible. The LiFeP04 batteries will need to start the generator occasionally which I understand might be a challenge. I’m looking at ReBel batteries, SOK and Ampere Time. Are there any others I should consider? What batteries do you recommend?

One other change is to replace the absorption RV fridge for a 12V DC compressor fridge in the 10 cu ft range – preferably with a Danfoss compressor. Any recommendations?

Finally it appears as if my power converter is not up to the task of charging LiFeP04 batteries. I’m looking at AIMS but leaning to one of the Progressive Dynamics as I’ve had good luck with my existing charger. What converter charger would you recommend?

TIA
 

smoothJoey

Hoop Dee Doo!
Joined
Nov 30, 2019
Messages
9,802
Go with the aims its actually a charger and quite capable to charge lifepo4 batteries.
Just turn off the breaker and leave the legacy converter where it is.
You might use it in an emergency in the unlikely event that something happened to your aims charger.
You lead acid batteries are probably not inside the living space because they off-gas.
You will want to put your lifepo4 batteries in the living space to keep them at a more reasonable temperature.
Its important to the have the charger close to the batteries and connected with wire of ample thickness to ensure a proper and timely charge.
If far less important to be close to the ac/dc distribution panel(where the converter will be languishing in pergatory).

Other than the batteries you may need a new shunt for the Bogart battery monitor.
You'll want some quality fuses, wire and some busbars just to make the wiring safe, orderly and maintainable.

How is your generator started now?

Just to confirm, you are not interested in running the ac part of the distribution panel off of your inverter?
 

One Old Guy

New Member
Joined
Aug 16, 2021
Messages
9
“Go with the aims its actually a charger and quite capable to charge lifepo4 batteries.”
So while plugged into shore power & leaving the Aims plugged in for days at a time is OK?

Just turn off the breaker and leave the legacy converter where it is.
👍🏻You might use it in an emergency in the unlikely event that something happened to your aims charger.

“You lead acid batteries are probably not inside the living space because they off-gas. “
Correct they’re in the basement.
“You will want to put your lifepo4 batteries in the living space to keep them at a more reasonable temperature.”
Living space is at a premium which is why I was leaning towards the SOK & ReBel for their low temp control.

👍🏻Its important to the have the charger close to the batteries and connected with wire of ample thickness to ensure a proper and timely charge.
If far less important to be close to the ac/dc distribution panel(where the converter will be languishing in pergatory).

“Other than the batteries you may need a new shunt for the Bogart battery monitor.”
I have Bogart 500a shunt installed. Do I need a new one?
“You'll want some quality fuses, wire and some busbars just to make the wiring safe, orderly and maintainable.”
It probably wouldn’t hurt to get new fuses. I used busbars & 4 & 6 gauge wire except for the 2 ought wiring to the inverter.

“How is your generator started now?”
From the trojan house batteries ~ which I‘m looking to upgrade to LiFePO4 which is ❓❓❓

“Just to confirm, you are not interested in running the ac part of the distribution panel off of your inverter?”
That is correct.

thanks
 

smoothJoey

Hoop Dee Doo!
Joined
Nov 30, 2019
Messages
9,802
“You will want to put your lifepo4 batteries in the living space to keep them at a more reasonable temperature.”
Living space is at a premium which is why I was leaning towards the SOK & ReBel for their low temp control.
lfp are not crazy about heat either.
Its not sudden death like charging them below 32F but it takes it toll over time.

👍🏻Its important to the have the charger close to the batteries and connected with wire of ample thickness to ensure a proper and timely charge.
If far less important to be close to the ac/dc distribution panel(where the converter will be languishing in pergatory).

“Other than the batteries you may need a new shunt for the Bogart battery monitor.”
I have Bogart 500a shunt installed. Do I need a new one?
Should be fine.

“How is your generator started now?”
From the trojan house batteries ~ which I‘m looking to upgrade to LiFePO4 which is ❓❓❓
Maybe you mean they provide the juice, I meant are they started manually or automatically.
If automatic what component is driving the process?
 

One Old Guy

New Member
Joined
Aug 16, 2021
Messages
9
“lfp are not crazy about heat either.”
Some of the areas we travel through reach 100+ & ac isn’t started until we arrive and are hooked up to shore power. When we stop, if there’s no shore power fans and vents are used.
So that’s a concern.

“Its not sudden death like charging them below 32F but it takes it toll over time.”
When we camp in the cold (freezing ~ infrequently but it has happened) we add extra clothing and extra blankets.

Our 5th wheel is good size for us (not compared to current models) but was built making use of most of the space. I can’t think of any unused space. The area used by the bottom drawer of a built in cabinet might be repurposed.

Trojans provide the juice but the generator is started manually.
 
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