Short version:
Is there any reason I shouldn't run a B2B charger between our existing leisure battery, and a new, budget LiFePO4 battery, at least as a short-term measure whilst we upgrade the other chargers/etc to something with a suitable lithium charging profile?
Long version:
We've a 2013 Autocruise Alto with the standard Sargeant EC4xx control panel, PX300 charger, an 'effectively' unbranded PWM solar charger (fitted prior to us buying the van) and a Varta 90ah leisure battery. I'm unsure of the output of the solar panel at this point, but the van is a PVC so I assume 100-150W.
In order to tempt my OH away from sites with hookup, I want to fit an inverter. We'll need ~1000W for around 15mins per day. Factoring in inverter (in)efficiency, I'm planning for around 1200W, or 100A at 12v.
This amount of current draw is generally best spread across multiple batteries, so we're weighing up 2-3 larger lesisure batteries vs 1-2 LiFePO4 batteries. Some manufacturers do say they support 100A draw on a 100Ah battery (C1) though I realise this is not considered a good idea for longevity.
However, other than this need for the inverter, our power usage appears to be minimal! We've only had the van 6-7 months, but even in the winter we seem to be served well by our solar panel - I added a Victron SmartShunt last summer and even on a few nights away this winter, running fridge and heater, I've not seen the capacity on the leisure battery drop to less than 85%, and by the time we're up and about it tends to be on the rise again. .We don't run a TV/etc in the van, so it's 12v lights, device chargers, heating etc only, and we tend to drive the van most days.
I tend to try to buy something 'good' which will last, but seeing the costs add up here, I am tempted to try a cheaper/most basic approach first and then, if we're getting value from it, upgrade later.
Doing Lithium properly, means that aside from the battery cost, we'll need a new mains charger and a B2B, as the Sargent panel doesn't support a lithium charge profile so far as I can see.
I have found a very good price (sub-£320) for a 100ah 'Ultramax' LiFePO4 leisure battery, I realise they are low-end, but I see a couple of members on here have used them. In order to spread out the cost, rather than replacing all the chargers now, is there any reason I couldnt' fit this as effectively an independent system in the short term- with only the inverter load connected to it, and then charge it with a B2B (with lithium profile) from the exisitng leisure battery?
My thinking being, if this is possible, then we only need to buy the battery, a B2B, and the inverter initially (plus connections, fuses/etc) - once we've proven that it works, and have some idea of the 'real world' usage, we can then gradually start upgrading the rest of the components, and switch the lithium battery in in place of the existing one. We could even add a second lithium at that point.
Is this something others have done? Any reason anyone can see why it wouldn't be a good idea? I imagine we'd need to keep the rate of charge from the existing system fairly low, and perhaps ensure that the B2B is only 'active' when the other system is being charged - either from EHU, solar or the existing split charge setup? We'd have all day to get as much charge into the battery as possible, before the inverter was used again - and once the concept is proven, I'm likely to get more enthusiasm about spending the rest of the money to 'finish' the system properly!
Is there any reason I shouldn't run a B2B charger between our existing leisure battery, and a new, budget LiFePO4 battery, at least as a short-term measure whilst we upgrade the other chargers/etc to something with a suitable lithium charging profile?
Long version:
We've a 2013 Autocruise Alto with the standard Sargeant EC4xx control panel, PX300 charger, an 'effectively' unbranded PWM solar charger (fitted prior to us buying the van) and a Varta 90ah leisure battery. I'm unsure of the output of the solar panel at this point, but the van is a PVC so I assume 100-150W.
In order to tempt my OH away from sites with hookup, I want to fit an inverter. We'll need ~1000W for around 15mins per day. Factoring in inverter (in)efficiency, I'm planning for around 1200W, or 100A at 12v.
This amount of current draw is generally best spread across multiple batteries, so we're weighing up 2-3 larger lesisure batteries vs 1-2 LiFePO4 batteries. Some manufacturers do say they support 100A draw on a 100Ah battery (C1) though I realise this is not considered a good idea for longevity.
However, other than this need for the inverter, our power usage appears to be minimal! We've only had the van 6-7 months, but even in the winter we seem to be served well by our solar panel - I added a Victron SmartShunt last summer and even on a few nights away this winter, running fridge and heater, I've not seen the capacity on the leisure battery drop to less than 85%, and by the time we're up and about it tends to be on the rise again. .We don't run a TV/etc in the van, so it's 12v lights, device chargers, heating etc only, and we tend to drive the van most days.
I tend to try to buy something 'good' which will last, but seeing the costs add up here, I am tempted to try a cheaper/most basic approach first and then, if we're getting value from it, upgrade later.
Doing Lithium properly, means that aside from the battery cost, we'll need a new mains charger and a B2B, as the Sargent panel doesn't support a lithium charge profile so far as I can see.
I have found a very good price (sub-£320) for a 100ah 'Ultramax' LiFePO4 leisure battery, I realise they are low-end, but I see a couple of members on here have used them. In order to spread out the cost, rather than replacing all the chargers now, is there any reason I couldnt' fit this as effectively an independent system in the short term- with only the inverter load connected to it, and then charge it with a B2B (with lithium profile) from the exisitng leisure battery?
My thinking being, if this is possible, then we only need to buy the battery, a B2B, and the inverter initially (plus connections, fuses/etc) - once we've proven that it works, and have some idea of the 'real world' usage, we can then gradually start upgrading the rest of the components, and switch the lithium battery in in place of the existing one. We could even add a second lithium at that point.
Is this something others have done? Any reason anyone can see why it wouldn't be a good idea? I imagine we'd need to keep the rate of charge from the existing system fairly low, and perhaps ensure that the B2B is only 'active' when the other system is being charged - either from EHU, solar or the existing split charge setup? We'd have all day to get as much charge into the battery as possible, before the inverter was used again - and once the concept is proven, I'm likely to get more enthusiasm about spending the rest of the money to 'finish' the system properly!
) unless there was a significant price difference.
