sounds so easy you could design this thing in your sleep pickup everything you need at ace hardware and build it on your lunch break You might eat into some of that space saved by the lithiums with the growing list of lithium battery accouterments such as B2B chargers, voltage isolators, insulated boxes, temperature controllers, etc, etc

At the end of the week of building this out wouldn't it have been easier to just plop AGMS under the front seats with a cheap stinger solenoid charge controller connected to the alternator via house battery? And then you could start charging instantly when you start the PM, wouldnt have to wait for the batteries to warm.

Read into teslas system, its interesting. Each 18650 cell is in direct contact with a cooling/heating fluid which circulates around the individual cells in clear plastic trays. Its pretty neat because of the way the cells are spread out (this makes them easier to heat or cool) and the plastic trays are clear so you see the liquid running thru the battery pack. It might take a while to warm a hunk of mass as such with a 100ah battleborn without overheating the edges of it.

 

Read into teslas system, its interesting. Each 18650 cell is in direct contact with a cooling/heating fluid which circulates around the individual cells in clear plastic trays. Its pretty neat because of the way the cells are spread out (this makes them easier to heat or cool) and the plastic trays are clear so you see the liquid running thru the battery pack. It might take a while to warm a hunk of mass as such with a 100ah battleborn without overheating the edges of it.

Super interesting. I’d seen the Tesla system but looked at it mostly from a cooling perspective.

I’ve just emailed enerdrive to ask if their dC2DC charger would protect the batteries from a current from the alternator on start up if it was cold enough to be a problem.

I plan to use our van a lot in the winter at ski fields. Popping a battery would be a bad thing ?

 

I'm just going to link to my comment about keeping batteries warm in the other thread:
https://www.promasterforum.com/forum/showthread.php?t=86479

 

No its not hard and you arent missing anything. The AGM people just have a strange obsession. Its mostly purchase justification like with anything else.

Ill add that for anyone looking into lithiums, you are better off not even talking about it here unfortunately. This forum is fantastic for a lot of reasons. Talking about the latest in tech stuff isnt one of them.

 

Well, if this is so easy, lets see someone's thermostatically controlled heated lithium battery box? Of course its not impossible but I think the devil is in the details. The EVs use small cells with a large surface area and gradually warm the batteries with heating/cooling fluid running along their surface. If they could have just heated or cooled the air around the batteries or used resistive "heat tape" you would think they would have.

For this DIY heated battery box how long does it take for the heat to reach the center of one those large battle born drop in replacements? Would applying heat tape to the outside of these cells overheat the cells/material at the outside of the battery case? Seems you would want to heat gradually if the heating surface is touching them. Warming the batteries by heating the surrounding air seems like it will take a while, how long I dont know? How many AH does it take to raise their temperature? By the time they are warm, have you lost your charging (driving) opportunity? To me it all seems like a PITA and un-necessarily complicated and expensive compared to the alternatives. Also, forget about the cost for a moment, when you start adding B2B chargers, heated battery boxes, thermo-controllers, etc. and add up the weight and size of all of this stuff would you actually have saved space and weight vs the alternatives?

 

Don't take this the wrong way, but I think you are over thinking this

ref: Wowbagger
"...cut...I have my batteries in a box under the van, so they aren't even in the conditioned space. I have a section of heat tape wrapped around them in the box. I have been in VERY cold conditions - 10F and lower - and had no problems keeping the batteries at 55F. The heat tape draw very little current; even if I am boondocking I can just leave the inverter on and run the tape all night with no problem.
I have also found that just running down the road at highway speeds, even in the afore-mentioned 10F weather, the batteries stay at 55F due to the heat from the engine blowing out under the van."

 

Simple, don't charge them below freezing. Turn off your alternator charing with a simple switch (I leave mine off 99.9% of the time), don't plug into shore power and turn off your solar with a switch or an automatic method like I have here:

I have sinced moved to Nevada and don't really worry about it anymore as it only gets below freezing at night. I still have this setup, but I will be removing it in favor of a simpler setup that is lower consumption.

 

You know I don’t think this is a deal breaker either, although I wouldn’t recommend Lithium yet for storage in a big van. Not because the disadvantages are the issue but because the advantages are not important in our use for almost all of us.

1. High discharge ability? Really not an issue as we mostly don’t do anything a few FLA or AGM can’t easily do.
2. High charging rate? Really? it’s a van and if you have a source that has to put out so much power add FLA’s or AGMs
3 Lighter? The van will carry 2 tons! Come on now.
4. Space savings? Wait until you add the other desired add ons!
5. SOC advantage. Again add a couple more FLA’s or AGM’s to equalize it.
6. Lifetime? Yet to be proven, the van is good for about 10 years if used and FLA’s probably will do that. Mine always have.

If the lithium’s with their ad-ons were near the same price (and they may be in the future) then that one disadvantage about freezing would be easily solved. Technology is great and I have a lot of stuff with lithium of some sort. I tried my darnedest to get my sister to buy a Tesla3. I am not against it. But if you bought or are thinking about lithium for your van you are deluded to push it as a better thing because for our use it is a prestige issue not really a better option..... YET. Flame me I can use the heat, AZ is cold this week!

 

Just been reading about this.

https://relionbattery.com/blog/lithium-battery-cold-weather

Interesting how long it takes to warm up.

For me the problem would be starting a van that has been parked empty somewhere cold. If it takes an hour for the batteries to warm through that’s a problem as the van would be trying to charge the battery from the alternator straight away

I haven’t seen a BMS (yet) with cold protection, many have temp sensors for heat protection only. If heat protection is possible surely cold protection is too

 

I haven’t seen a BMS (yet) with cold protection, many have temp sensors for heat protection only.

My Elite Power Systems BMS has low temperature cut-out on charging.

 

One hour to warmup is just too long, for me at least the opportunity to charge via alternator has come and gone after an hour of driving.

Im sure they're just overthinking this too. Maybe wowbagger could sell them his system or start selling his undermount heated battery box.

also, holy smokes, that battery is $1,350: https://relionbattery.com/products/lithium/rb100-lt

 

That RELion plug is a piece of work.

"RELiON has developed a new series of lithium iron phosphate batteries that can charge at temperatures down to -20°C (-4°F)."

Then, "For example, with the low-temperature RELiON RB100-LT 100Ah battery, it takes about an hour to warm from -20°C to +5°C before charging begins."

"RELiON’s low-temperature series look and operate exactly like our other batteries, with the same power and performance. They have the same charge time at above-freezing temperatures."

The key is that when "charging" starts, the charging source warms the batteries before starting to charge them. I’m so excited.

 

We are using Zeravolt (www.zeravolt.com) LiFePO4 batteries in all future builds. Has a bluetooth app and can charge below freezing (BMS activates heating element inside the battery). We helped in the development and I tested them over the past 15 months.

 

Currently available only to OEM installers. Please fill out questionnaire to be set up as a Zeravolt OEM installer.

Not practicable for a DIY install.

 

The BMS on the Renogy & Battleborn 12v Lithiums have low temp charging cutouts now.

 

Battleborn batteries now have heating elements.

 

This just solved my battery concerns for Canadian winters!

 

We just mounted our LiFePo4 in the conditioned (heated) space inside the van. If the inside of the van is below freezing I have water problems anyway.

Granted, it would be great to sling the batteries under the floor for space reasons, but having them inside the van is not a huge issue for our build.