AMcQ46
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The leisure battery (LB) on my 2 yr old Ford Transit based van has given up, as I unwittingly had been discharging it way below 50%, so based on some good advise on another thread, I have fitted a shunt type state of charge monitor so I can better manage the battery charge, and its the addition of the SOC device that has sparked my latest questions.
A new LB has been fitted, and for now I have replaced like for like with a 100Ah Banner Bull lead acid battery.
so with my new battery monitor, I was now looking at the current flowing into and out of the LB under various conditions, but is the charging side that has got me confused.
When I fitted the battery I had already charged it up to 100% off the van, and when running off EHU, it keeps it topped up to that level … all good.
BUT,
When I drive the van, I was assuming it would also continue to maintain the leisure Battery at 100% off the alternator, but it doesn’t, most of the journey, there is a significant current (between 6 and 10 Amps) flowing out of my fully charged Leisure bat, back to the Starter battery.
From what I have read, my van will have a “Smart Alternator” as its Euro6 spec, and it looks to be keeping the starter battery at 12.3V during the journey (a basic volt meter in the cigarette lighter socket), and with my fully charged leisure battery being closer to 13V, the current is flowing OUT rather than holding it at fully charged.
In a test that I videoed, I had the van habitation side switched off, so there was no power draw on the leisure battery (LB) and it was sitting at 96% charged, 12.6V, and 0 amps flowing through the shunt (on the -ve cable between LB and chassis earth point).
When I crank the engine there is initially an -11A draw out of the LB for a couple of seconds, then it swings sinusoidally to +18A charge into LB for a couple of seconds before decaying and turning into -9A draw OUT again and then decaying slowly, but staying -ve for most of the journey….Resulting with the LB being slightly lower charge capacity at the end of the trip compared to when I set off.
As soon as I turn the engine off, the current flow goes to 0A.
I am chasing the team that did my van conversion to establish if I have B2B charger or a split charge relay, as I believe for the smart alternator it should be a B2B
So my questions here are:
1) With a smart alternator is the starter battery supposed to be charging higher than the 12.3V that I was measuring at the cigarette lighter? do I need to tap in closer to the actual battery? . Note that I have no problems with the van starting or flattening the main battery.
2) is it normal to have a current flow OUT of the LB when the engine is running, I thought it was supposed to be a one way device.
3) if it is normal, how do I stop the LB being dragged back down from its full state of charge?
4) if it is not normal, what other checks do I need to do to find the problem,? I dont want to kill another LB, and I also want to make sure I have 100% charge when I arrive at my destination for the weekend.
other info:
van has 100W solar on the roof and a basic solar controller which looks to be connected to both starter & Leisure battery.
A new LB has been fitted, and for now I have replaced like for like with a 100Ah Banner Bull lead acid battery.
so with my new battery monitor, I was now looking at the current flowing into and out of the LB under various conditions, but is the charging side that has got me confused.
When I fitted the battery I had already charged it up to 100% off the van, and when running off EHU, it keeps it topped up to that level … all good.
BUT,
When I drive the van, I was assuming it would also continue to maintain the leisure Battery at 100% off the alternator, but it doesn’t, most of the journey, there is a significant current (between 6 and 10 Amps) flowing out of my fully charged Leisure bat, back to the Starter battery.
From what I have read, my van will have a “Smart Alternator” as its Euro6 spec, and it looks to be keeping the starter battery at 12.3V during the journey (a basic volt meter in the cigarette lighter socket), and with my fully charged leisure battery being closer to 13V, the current is flowing OUT rather than holding it at fully charged.
In a test that I videoed, I had the van habitation side switched off, so there was no power draw on the leisure battery (LB) and it was sitting at 96% charged, 12.6V, and 0 amps flowing through the shunt (on the -ve cable between LB and chassis earth point).
When I crank the engine there is initially an -11A draw out of the LB for a couple of seconds, then it swings sinusoidally to +18A charge into LB for a couple of seconds before decaying and turning into -9A draw OUT again and then decaying slowly, but staying -ve for most of the journey….Resulting with the LB being slightly lower charge capacity at the end of the trip compared to when I set off.
As soon as I turn the engine off, the current flow goes to 0A.
I am chasing the team that did my van conversion to establish if I have B2B charger or a split charge relay, as I believe for the smart alternator it should be a B2B
So my questions here are:
1) With a smart alternator is the starter battery supposed to be charging higher than the 12.3V that I was measuring at the cigarette lighter? do I need to tap in closer to the actual battery? . Note that I have no problems with the van starting or flattening the main battery.
2) is it normal to have a current flow OUT of the LB when the engine is running, I thought it was supposed to be a one way device.
3) if it is normal, how do I stop the LB being dragged back down from its full state of charge?
4) if it is not normal, what other checks do I need to do to find the problem,? I dont want to kill another LB, and I also want to make sure I have 100% charge when I arrive at my destination for the weekend.
other info:
van has 100W solar on the roof and a basic solar controller which looks to be connected to both starter & Leisure battery.
