ELB 99 + LiFePo4 + DC-DC charger / MPPT

[LukasDC]

I purchased a Dethleffs Globebus FIAT (year 2005).
It has following set-up

• ELB 99, 12v - 16A (wiesheu elektronik), battery switch set to GEL connected to an AMG battery
• Solar panel -> Alden Sunpower System 75 (fuse 5amp) -> connected directly to the battery

1) I want to insert a LiFePO4 battery (Renogy Core Basic 200Ah)
Do I need to change something on the set-up?

2) I got a Renogy 12V 50A DC-DC battery charger with MPPT
Do I need this component (or would it be beneficial) and if so, how would I add this in the set-up?

Any information is more than welcome.

 

[autorouter]

ELB 99, 12v - 16A (wiesheu elektronik), battery switch set to GEL connected to an AMG battery

Not ideal, an AGM needs a slightly higher absorption charging voltage, so the long-term battery life would be reduced.

1) I want to insert a LiFePO4 battery (Renogy Core Basic 200Ah)
Do I need to change something on the set-up?

For occasional use, the gel setting should be OK. (AGM setting is a bit too high for lithium). If you are always charging the lithium from mains hookup then it's a good idea to get a charger with a lithium setting. Disabling the inbuilt charger on an EBL99 is very easy.

2) I got a Renogy 12V 50A DC-DC battery charger with MPPT
Do I need this component (or would it be beneficial) and if so, how would I add this in the set-up?

A DC-DC battery charger (also called a Battery-to-Battery, B2B or Booster) is a very good idea with a lithium battery. You need to disable the existing leisure battery charging arrangement, which is a 'split charge relay' located inside the EBL.

It's easy to do this with an EBL. Near the starter battery there should be a big 50A fuse, a standard 20A fuse and maybe a 2A or 5A fuse. Simply remove the big 50A fuse. All the other functions from the starter battery (fridge while driving, battery voltage reading, battery trickle-charging on hookup etc.) go through the other wire with the 20A fuse.

The Renogy DC-DC Charger is 50A, which is too high to route it through the EBL as some people have done with 30A chargers. You need to wire it directly from the starter battery to the leisure battery, not through the EBL. With big fuses, 70A or 80A, near the battery ends of both wires.

 

[LukasDC]

Not ideal, an AGM needs a slightly higher absorption charging voltage, so the long-term battery life would be reduced.

For occasional use, the gel setting should be OK. (AGM setting is a bit too high for lithium). If you are always charging the lithium from mains hookup then it's a good idea to get a charger with a lithium setting. Disabling the inbuilt charger on an EBL99 is very easy.

A DC-DC battery charger (also called a Battery-to-Battery, B2B or Booster) is a very good idea with a lithium battery. You need to disable the existing leisure battery charging arrangement, which is a 'split charge relay' located inside the EBL.

It's easy to do this with an EBL. Near the starter battery there should be a big 50A fuse, a standard 20A fuse and maybe a 2A or 5A fuse. Simply remove the big 50A fuse. All the other functions from the starter battery (fridge while driving, battery voltage reading, battery trickle-charging on hookup etc.) go through the other wire with the 20A fuse.

The Renogy DC-DC Charger is 50A, which is too high to route it through the EBL as some people have done with 30A chargers. You need to wire it directly from the starter battery to the leisure battery, not through the EBL. With big fuses, 70A or 80A, near the battery ends of both wires.

Super, thanks for the practical advice
One clarification regarding [With big fuses, 70A or 80A, near the battery ends of both wires.] You mean between the starter battery and Renogy DC-DC charger and/or between de Renogy DC-DC charger en the lithium battery? Red wire (positive) only?

Regards
//Lukas

 

[autorouter]

The original system has a wire from the starter battery, with a 50A fuse near the starter battery, and a wire from the leisure battery,with a 50A fuse near the leisure battery.

You are wiring up something similar, with larger fuses. The fuses are supposed to be very near the batteries, to protect the wire in case anything goes wrong. So, two fuses, one on each of the two wires, as near to the batteries as you can.