Confused again

Folkranger

Folkranger

Joined
May 2, 2014
Posts
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Location
Washington
Funster No
31,281
MH
Hymer B 584DL
Exp
17 years + 35 tugging
Never know whether I should keep the van with lithium battery on hook up all the time when standing over winter.
 
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It is also covered in the appendix at the end of the manual. In your last photo, if you follow the arrow from auxiliary battery, it guides you in the place I described above. The spade is level with positive stud, a bit to the left.
 
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Raul said:
It is also covered in the appendix at the end of the manual. In your last photo, if you follow the arrow from auxiliary battery, it guides you in the place I described above. The spade is level with positive stud, a bit to the left.
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Yes, got it thanks. it says TR Charge. I'm surprised there's nothing connected to it.
Now I just need to find where to connect this to without running cables to the starter battery.
 
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Anything +ve that comes from the starter battery and is near the inverter.

It’s not connected as many ppl don’t know about this feature, despite being documented in the manual.
 
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Raul In looking for a positive from the starter battery I came across this diagram of my Victron BMS 12/200. It seems to show the positives linked between the leisure and starter batteries. I don't understand this. Could it be because the BMS 12/200 switches the negatives.

If I connected the 4v auxilliary charging point to the starter positive, would it not also be charging the Lithium battery?

That's why this thread is called confused again. I'm trying to do things that I don't understand.

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Never seen a bms linking the two +ve. The only place those two come close to each other is at B2B.
 
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Raul said:
Never seen a bms linking the two +ve. The only place those two come close to each other is at B2B.
Click to expand...
Screenshot_20221104_150043_eBay~2.jpg
 
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Folkranger said:
In looking for a positive from the starter battery I came across this diagram of my Victron BMS 12/200. It seems to show the positives linked between the leisure and starter batteries. I don't understand this. Could it be because the BMS 12/200 switches the negatives.
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Are you sure this is the exact BMS? In the overview datasheet, it compares all similar battery management and protection devices. It says the 'BMS 12/200' is for systems with an alternator but no inverter/charger. And the 'Smart BMS 12/200' is for systems with an alternator and an inverter/charger.

You are right that the BMS 12/200 switches the negatives. But the Smart BMS 12/200 switches the positives.
 
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autorouter said:
Are you sure this is the exact BMS? In the overview datasheet, it compares all similar battery management and protection devices. It says the 'BMS 12/200' is for systems with an alternator but no inverter/charger. And the 'Smart BMS 12/200' is for systems with an alternator and an inverter/charger.

You are right that the BMS 12/200 switches the negatives. But the Smart BMS 12/200 switches the positives.
Click to expand...
Mine has the BMS 12/200 (not smart)
20221103_145040.jpg

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I think you need to be very careful if fitting extra gizmos to your setup. This BMS is very unusual in that it is on the battery negatives.

The starter battery negative is connected to the chassis earth, But the leisure battery negative is definitely not connected to the chassis earth. All the loads, through the EBL, are not connected to the chassis earth.

If you want to have loads which are connected to the chassis earth, you need something like one of those fully isolated Orion DC-DC converters, which keep the input and output positives and negatives isolated. I'm not sure I fully understand your system without further information, but that's what I can see so far.

For anyone else reading this, note that the Smart BMS 12/200 isn't like this, it doesn't have isolated negatives.

I think the BatteryMaster might only work if the negatives of the two batteries are connected to the chassis, so it might not work in this setup.
 
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autorouter said:
I think you need to be very careful if fitting extra gizmos to your setup. This BMS is very unusual in that it is on the battery negatives.

The starter battery negative is connected to the chassis earth, But the leisure battery negative is definitely not connected to the chassis earth. All the loads, through the EBL, are not connected to the chassis earth.

If you want to have loads which are connected to the chassis earth, you need something like one of those fully isolated Orion DC-DC converters, which keep the input and output positives and negatives isolated. I'm not sure I fully understand your system without further information, but that's what I can see so far.

For anyone else reading this, note that the Smart BMS 12/200 isn't like this, it doesn't have isolated negatives.

I think the BatteryMaster might only work if the negatives of the two batteries are connected to the chassis, so it might not work in this setup.
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I don't understand much of this but I also noted the negative switching when reading the manual. Leaves me wondering how to best maintain these batteries over winter or whether there's some magic setup which taakes care of this. I'll just continue manual monitoring to be safe.
 
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I've always assumed that the owner before me who kitted this out for his own use knew exactly what he was doing as he owned a marina and built and refitted boats. Marine work tends to be much more advanced than motorhome work.
 
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Folkranger said:
I've always assumed that the owner before me who kitted this out for his own use knew exactly what he was doing as he owned a marina and built and refitted boats. Marine work tends to be much more advanced than motorhome work.
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Perhaps marine works are different because most boats don’t have a metal chassis (steel canal boats excepted). I guess it means the negatives are more likely to be separate.

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Folkranger said:
I don't understand much of this but I also noted the negative switching when reading the manual. Leaves me wondering how to best maintain these batteries over winter or whether there's some magic setup which taakes care of this. I'll just continue manual monitoring to be safe.
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If you have access to EHU, I would think that a mains-powered battery maintainer like a CTEK or Optimate would do the job. This kind of thing is used by classic car owners and fair weather bikers to maintain batteries in storage. The output is isolated from the input.

There's no big problem designing a DC-DC battery maintainer with isolated outputs, it's just that the market is small so you're unlikely to find one. Victron do the Orion DC-DC converter and DC-DC-charger in isolated and non-isolated versions, but they sell to the marine market too. The Orion charger is for charging the leisure battery from the alternator/starter battery while driving, not for maintaining the starter battery when stopped. They do a 1.1A version of the BlueSmart IP65 mains charger that looks about right for maintaining a starter battery.

I use a CTEK MXS5.0, but that's because it has a motorbike battery charge mode as well as a vehicle battery charge mode. At the moment, one of them is trickle-charging the battery of the car on the drive while I am away, so it starts first time when I get back. However for just maintaining the starter battery you could use a CTEK XS 0.8.
 
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I have one of these
ijopower.com

Victron Energy Orion-Tr 12/12-9A (110W) Isolated DC-DC Converter - Retail - Ijo Power

Victron Energy Orion-Tr 12/12-9A (110W) Isolated DC-DC Converter - Retail. Victron Energy Orion-Tr 12/12-9A (110W) Isolated DC-DC Converter - Retail Remote on/off The remote on/off eliminates the need for a high current switch in the input wiring. The remote on/off can be operated with a low...
ijopower.com ijopower.com
connected to a cheap 12v time clock to keep my engine battery topped up when in storage. I didn’t need the isolated negatives but got it cheap. I set it to run for a short period each day powered by the leisure battery to give a little charge to the engine battery, just a top up.
 
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I'd always assumed the ehu trickle charged the starter battery and fully charged the leisure battery. Am I wrong?
 
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Folkranger said:
I'd always assumed the ehu trickle charged the starter battery and fully charged the leisure battery. Am I wrong?
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Some do, some don't, some have a switch to select which one to charge, so it's not automatic.

It's easy to tell if you have a multimeter. If the voltage at the battery terminals is 13.0V or higher, then something is charging it (EHU, solar etc)
 
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So if the charger charges the starter battery and the battery management system protects the Lithium battery by reducing charge when not used for 24 hours then I don't need anything else and I've been chasing shadows?

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Both batteries rise to 13.5v with the ehu so I assume that this charges both.
I'll set a timer to give a bit of charge each day.
Interestingly, the multimeter at the starter battery gave 12.57V, The panel said 12.7V and the tracker report said 13V. Who do you believe?
 
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Pausim said:
I can check my engine battery using my tracker app and get texts about my leisure battery from my Truma iNet box.
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Maybe check the accuracy of the tracker. Mine tells me 13V but my panel says 12.7V and a multimeter at the battery says 12.57V
 
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Move on to May 2023 and the starter battery has dropped to 12.2V. EHU was not charging, found the Victron multi control was somehow set to OFF. Probably to exposed a position and gets knoked off.
 
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