My enquirey is from New Zealand we have a 2018 Benimar Mileo 243, UK spec and wondered if anyone has experience on changing to lithium sulphate house batteries it is fitted with one 250watt solar panel has a CBE CB522 charger and a CBE PRS 300 solar regulator. The original batteries fitted are two 100amp lead acids. The controller has a setting for lithium but charger only has an option of pb or agm. I am a great believer in learning from other peoples experience.
Swapping to Lithium Sulphate house batteries
- Thread starter kiwicampa
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- Apr 27, 2008
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I didn't think lithium sulphur batteries were commercially available yet. They have very high energy density which is good but can only take a limited number of recharge cycles before degrading.
Did you mean ordinary lithium batteries as used in some motorhomes, if so there are quite a few on here use them.
Did you mean ordinary lithium batteries as used in some motorhomes, if so there are quite a few on here use them.
I do not have a Benimar but I do have a CBE charger and a LiFePO4 battery. On the Pb setting it under charges the the Li battery but this is fine for me because I never need a full battery when on electric hook up and the 85-90% charge is better for the battery. The Gel setting (not AGM) keeps the battery at 100% but I think this is best avoided. When I am off grid I want a full battery so I have fitted a B2B which makes sure I always have a full battery when I arrive.
If you fit a B2B directly to the battery you will need to disable your existing split charge arrangement. If the B2B is of a low enough output you could feed it into the system via the existing split charge relay. What you must avoid is having both systems (B2B and split charge) running in parallel, this creates an electrical loop.
If you fit a B2B directly to the battery you will need to disable your existing split charge arrangement. If the B2B is of a low enough output you could feed it into the system via the existing split charge relay. What you must avoid is having both systems (B2B and split charge) running in parallel, this creates an electrical loop.
Thank you for that I did not mention in my original post my system also has CBE CSB -2 fitted is this what you mean by a B2B or will I have to replace it
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I think Lithium Sulfur batteries are still really in the experimental stage, even though they were successfully used on a solar-powered aircraft to keep it going during the night. The usual technology used in motorhomes is Lithium Iron Phosphate, LiFePO4, which has a bit less energy storage for the same weight as other Lithium Ion technologies, but it a lot safer. It doesn't burst into flames if damaged like the others do.
The CSB-2 is different from a B2B. It does the opposite, trickle-charging the starter battery from the leisure battery. It is useful if for example the MH has solar to keep the leisure batteries full, and you are parked for a week or more without running the engine. It stops the starter battery from gradually going flat.
A B2B only works when the engine is running, and takes power from the alternator/starter battery to feed a battery charger that charges the leisure battery. It is better than a split charge relay, which just connects both batteries together so that the alternator can charge them both. A B2B can ensure the correct charging profile for whatever type of leisure battery you choose. A B2B is usually fitted if a lithium leisure battery is fitted.
The CSB-2 has a different function to the B2B, so it can be left in place to keep the starter battery charged from the leisure battery.
A B2B is a more substantial charger than the CSB-2 trickle-charger, and requires some planning to make sure it is installed correctly. First, because it is a high-power charger, it needs thick wires, correctly fused. Maybe the existing wiring is thick enough, but the chances are it isn't. A low-power B2B (20A to 30A) could perhaps be wired through the Sargent PSU, but anything bigger will need to go direct to the leisure battery. And if you are thinking of LiFePO4 batteries, it's a good idea to fit a bigger B2B to take advantage of the faster charging rate of lithium.
The other thing you need to do, as Pausim says, is disable the existing split charge arrangement. There are various ways of doing this, depending on the details of the PSU. The trick is to disable the split charging without disabling other functions like the fridge or the voltage readings.
A B2B is a more substantial charger than the CSB-2 trickle-charger, and requires some planning to make sure it is installed correctly. First, because it is a high-power charger, it needs thick wires, correctly fused. Maybe the existing wiring is thick enough, but the chances are it isn't. A low-power B2B (20A to 30A) could perhaps be wired through the Sargent PSU, but anything bigger will need to go direct to the leisure battery. And if you are thinking of LiFePO4 batteries, it's a good idea to fit a bigger B2B to take advantage of the faster charging rate of lithium.
The other thing you need to do, as Pausim says, is disable the existing split charge arrangement. There are various ways of doing this, depending on the details of the PSU. The trick is to disable the split charging without disabling other functions like the fridge or the voltage readings.
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