Recent content by Bzzzt

That is plenty to maintain a temperature. My four pads at 10W each warm the batteries 30F in a couple of hours. This is for 8 120A cells in a 2" foam enclosure.

I used silicone heating pads that adhere directly to the cells (AliExpress etc...). They had built in thermistors so you could track the temperature of the pads themselves in order to keep the outsides of the cells from getting crispy. However, I ended up wiring 4 pads in series which resulted...

I thought I'd throw this out there since if it happened to us it will probably happen to someone else. We noticed a low charge rate of 20 amps to the 240Ah LiFePO4 house batteries in our Ram Promaster (100A is more typical). This coincided with a check engine light. A multimeter showed around...

The Mr. Heater isn't vented, but we do run an air exchanger 24-7. Two adults easily put out 6 pounds of moisture per day from respiration. Add cooking (with gasoline) and drying out wet clothing and you get a LOT of moisture in a small space! The 1.6 pounds of water vapour from running a pound...

Sounds like you have it covered! Some sort of way to heat them up in place if things go sideways would be nice but you might be just fine for a 'normal' winter.

It is not so good if you aren't around, but we've used a Mr Heater as both emergency heat and as a very pleasant source of radiant heat when we manage to get a chill.

We found that when it was plenty cold outside we would still freeze parts of the van with the thermostat set to 40F. We bumped the base temperature to 50F which largely solved it but when it goes to -30F the edges of the van still freeze (2" rigid foam insulation all around). If the batteries...

This is the way I do it and it has handily kept the current around 70-80 amps into a 240Ah battery. It's trial and error as far as the wiring goes. I think one thing to keep in mind is that if you draw the batteries right down, say to 12 volts, the initial charging current could be quite high (I...

The more I look at the AliExpress picture the more confused I am. If this is actually an N-channel IPT015N10N5 MOSFET why is it shown here as a high side switch? The Drain is labelled Out(+) and the Source is labelled In(+)! In that case wouldn't it simply conduct via the MOSFET body diode? What...

Yup, I hear you. If you need to protect against reverse currents this will fail, similar to the melting Victron BPs I imagine. In my case I had to use some additional circuitry to get a solid 0 (on) to 13V (off) signal to control the PNP MOSFETs. If you have a BMS that can pull this off for you...

Sorry, this isn't a proper reply to your question but how about 'just' using MOSFETs and skipping their control circuitry? If you have a control signal to drive the gates you should be able to make up a simple PCB containing a MOSFET and possibly a protection diode. The great thing is that they...

Whoops! Made irrelevant comments. Deleted to save confusion.

2) Amps in is almost equal to amps out (for LiFePO4) but watts in does NOT equal watts out. I have made this mistake before!

I have the Promaster with the 220 Amp alternator. I currently charge at around 100-120 Amps in winter and 50-60 Amps in summer. 30 Amps seems awfully low! I think it is acceptable to put the alternator under more stress. Similarly, driving the van puts the van under more stress than not driving...

I like the idea of having a resistor reserved for worse case scenarios. If there actually is a danger of overloading the alternators (endlessly debatable) it only exists between 0 and maybe 10% state-of-charge. After this the rising battery voltage should limit the amps to a reasonable level. If...