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Orion-Tr DC-DC Converter (12v/12v, 20A) as charger?

Yeah saving 54 dollars to spend >32 dollars plus time and risk of failure is a bad gamble in my book.

I'd try to find a different spot for it. Under a seat perhaps? The whole selling point of victron is reliability and adding a bunch of stuff hurts that.

That said, you can still just set the thing to 13.6v and call it a day, and keep your $54.
 
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Setting the non-smart charger to a lower voltage such as 13.6 volts at pack -> 3.4 volts per cell would pretty much eliminate the need for charge termination logic and all the associated smart components.

Holding the cells at 3.4V will not stress them nearly as much as holding them at 3.6 or 3.65V which most people avoid since three factors in rate aging seems to be (time) * (temperature) * (voltage).

Good luck and may your skiing trips be cozy.
 
, which needs to contain my H8 AGM, 105AH LiFePo4, 2KW diesel heater, and DC/DC charger!
Victron DC to DC chargers are passive cooled and need mounting vertically with good airflow.
Also your lithium battery will age faster at high temperatures.

To detect a particular voltage level and take action there are low cost analogue circuits that can be put together at very low cost.
Or use something like this from ebay,
Mike
 
Yeah saving 54 dollars to spend >32 dollars plus time and risk of failure is a bad gamble in my book.

I'd try to find a different spot for it. Under a seat perhaps? The whole selling point of victron is reliability and adding a bunch of stuff hurts that.

That said, you can still just set the thing to 13.6v and call it a day, and keep your $54.
I just realized I could get these at discount from my local marine supply chain (we have a corporate account) so the smart charger is only $155 (as opposed to $165) before tax. That makes it kind of a no-brainer. The spread becomes literally $40.

I'll likely place the charger inside one of my other compartments which actually has a vent to the outside. Should get adequate airflow there and it is a non-insulated compartment. XC90s are weird...so many little storage holes in the back! The LiFePo4 will be "upstream" of the heater so it will only have cool intake air passing over it. I don't anticipate it getting THAT hot, but I will move things if it does. My JBD BMS has two temp leads so I will have plenty of monitoring capability. I'll primarily be running the heater in sub-freezing temperatures, so it will have a very cool ambient environment. If anything, I'm worried about freezing the battery...may have to build a small battery heater or position the battery closer to the heater itself!
 
I just realized I could get these at discount from my local marine supply chain (we have a corporate account) so the smart charger is only $155 (as opposed to $165) before tax. That makes it kind of a no-brainer. The spread becomes literally $40.

I'll likely place the charger inside one of my other compartments which actually has a vent to the outside. Should get adequate airflow there and it is a non-insulated compartment. XC90s are weird...so many little storage holes in the back! The LiFePo4 will be "upstream" of the heater so it will only have cool intake air passing over it. I don't anticipate it getting THAT hot, but I will move things if it does. My JBD BMS has two temp leads so I will have plenty of monitoring capability. I'll primarily be running the heater in sub-freezing temperatures, so it will have a very cool ambient environment. If anything, I'm worried about freezing the battery...may have to build a small battery heater or position the battery closer to the heater itself!
So fun fact. I actually did build a heater into mine.

And many others. You have a few options to get it up to operating temp as well. Run the heater from the vehicle until it's up to temp then start your diesel heater.

OR just start the diesel right away off the vehicle power and use some of the heat to warm the lithium.

I'm trying to come up with a temperature controlled solution that will let me bleed some of the heated air into my battery box. Difficult since the battery and heater are outside in my tongue box and valves to do that sort of thing are pricey.
 
So fun fact. I actually did build a heater into mine.

And many others. You have a few options to get it up to operating temp as well. Run the heater from the vehicle until it's up to temp then start your diesel heater.

OR just start the diesel right away off the vehicle power and use some of the heat to warm the lithium.

I'm trying to come up with a temperature controlled solution that will let me bleed some of the heated air into my battery box. Difficult since the battery and heater are outside in my tongue box and valves to do that sort of thing are pricey.
You have a diesel heater in your install? Does that generally keep the battery ambient temp warm enough? Or do you also have a heater specifically for the battery?

I was thinking I might have to add a heating pad and thermostat. I can get both of those very cheap off Amazon — something like $30 for the whole lot. I’ll test and see if I can get by without it once the temps start to drop…if not, I’ll rig something up. I like how you mentioned siphoning heat from the interior to keep it warm. The diesel heater will be pulling air from inside, so I assume that the air in the battery compartment will gradually warm!

One weird thing: inside my BMS config file it mentions “total capacity” and “total cycle capacity.” I have the former set at 105000 mAh (for my 105AH cells) but the BMS default is “80,000 mAh” for “total cycle capacity.” Should that be left that way?

I set my high voltage cutoff for each cell at 3.65 (that’s what the data from the manufacturer said was the max charge voltage) and the low at 2.5 (again manufacturer spec). Any reason to change any of those numbers to something else? When I changed capacity to 105 AH (UP from 100) and raised the cell max charge from 3.4V (default) to 3.65, somehow the BMS jumped from 47% SOC to estimating 95% SOC! That’s confusing me a lot. Pack voltage is only 13.35V and VictronConnect reports charge voltage is only 13.66V. Ideas?

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You have a diesel heater in your install? Does that generally keep the battery ambient temp warm enough? Or do you also have a heater specifically for the battery?

I was thinking I might have to add a heating pad and thermostat. I can get both of those very cheap off Amazon — something like $30 for the whole lot. I’ll test and see if I can get by without it once the temps start to drop…if not, I’ll rig something up. I like how you mentioned siphoning heat from the interior to keep it warm. The diesel heater will be pulling air from inside, so I assume that the air in the battery compartment will gradually warm!

One weird thing: inside my BMS config file it mentions “total capacity” and “total cycle capacity.” I have the former set at 105000 mAh (for my 105AH cells) but the BMS default is “80,000 mAh” for “total cycle capacity.” Should that be left that way?

I set my high voltage cutoff for each cell at 3.65 (that’s what the data from the manufacturer said was the max charge voltage) and the low at 2.5 (again manufacturer spec). Any reason to change any of those numbers to something else? When I changed capacity to 105 AH (UP from 100) and raised the cell max charge from 3.4V (default) to 3.65, somehow the BMS jumped from 47% SOC to estimating 95% SOC! That’s confusing me a lot. Pack voltage is only 13.35V and VictronConnect reports charge voltage is only 13.66V. Ideas?

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I have both because the tongue box itself is not insulated and the heater actually pulls cold outside air past the battery from outside. This is necessary due to the extreme small volume of the camper. The lowest possible output of the thing would vastly overheat the camper otherwise. Less efficient, sure, but it also stays nice and dry as a result.

If I had to do it all over again I wouldn't have done it this way and I'd have the hot duct near the battery box.


I think just bleeding some of the heat into the lid of the battery box would do the job but I presently have no good way to do so. Perhaps a 12v fan can provide some heat exchange from the outside of the heat duct without itself overheating.

Will be wasted energy but then my heater is grossly oversized anyways.

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The heater output goes up away from the battery.

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Setting the non-smart charger to a lower voltage such as 13.6 volts at pack -> 3.4 volts per cell would pretty much eliminate the need for charge termination logic and all the associated smart components.

Holding the cells at 3.4V will not stress them nearly as much as holding them at 3.6 or 3.65V which most people avoid since three factors in rate aging seems to be (time) * (temperature) * (voltage).

Good luck and may your skiing trips be cozy.

13.6v works great for mine.

My issue is my converter drops to 13.2v and the battery starts discharging lmao

Gotta sort that one out.
 
have had decent experience with this simple dc blower; decent static pressure, decent noise

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attached CPAP tubing to the outlet for one air move experiment. perhaps there’s some other more appropriate tubing for heat context

could put blower in warm space, apply 6-12VDC and it could blow through a tube that exits near the terminals of the battery or something like that.

just throwin more hacky ideas out there
 
Hah…so did my balance, threw my cells into a pack, hooked up the BMS…and realized that one of my cells is def not grade A. Hit high voltage disconnect WAY before the others. It’s at 3.5V while my other cells are at 3.45. Wonderful. The supplier agreed to air freight me a new cell though, so I guess it’s okay (assuming he follows through).
 
13.6v works great for mine.

My issue is my converter drops to 13.2v and the battery starts discharging lmao

Gotta sort that one out.
Is your converter bidirectional? The smart chargers aren’t but that’s interesting if the converters are.
 
Is your converter bidirectional? The smart chargers aren’t but that’s interesting if the converters are.
No.

It's just 120vac to 12vdc charging. The battery discharges because it's higher voltage than the 13.2v and there are a few parasitic loads if I don't shut it all down and pull fuses.
 
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