LiFePO4 battery sizes that fit in 200 drawer wings (1 Viewer)

Hants

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1. ARB drawers

2. Have to check with Slee. They made it custom - may be willing to make more. I worked with Ben on it. I pressed for the installation this way - LiFePo in the engine bay would be significantly compromised by distance and heat. The mount is immovable - even in a severe accident, the battery won’t be a projectile.

Now that I have it and have tested some, I’m very pleased. With the BCDC40, charge time is very low... probably need to run the engine an hour or two every couple days for “reasonable” loads. Not enough battery to run a 3000W inverter, but for “normal” loads like lights, fridges, radios, etc. it is perfect.

Note that due to discharge rate limitations, you’d need 2 100AH LiFePo batteries to run a 2000 or 3000W inverter well.

I have run 2+ days on the battery without running the rig and voltage is still > 12. Will better exercise in the spring/summer. Pretty sure I won’t see a need for solar. If I do, will address it then.

Even 1/2” longer, and width will stop you. You could do 1/2” narrower, then get longer by an inch or two. Relion doesn’t make a footprint like that, but someone may.
 
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Charge and discharge down to -4F. That’s painfully cold. Note the heater/ac vent right next to the battery - If you’re relying on the alternator or BCDC to charge, shouldn’t be a problem.
I think they way Relion list this is a bit misleading. Here is the way I understand it. Basically if the temp drops below 32F you can still charge, but it’s have to be at a much lower current. If it then dropped below 14F you’d have to drop that current in half again, all the way down to the -4F they list as the coldest you can charge. So basically 32F is the coldest you can charge it unless you have a way to drop the charging current. So technically it can be charged as low as -4F........but not really. There is nothing I know of in the RedArc BCDC that cares what temp the battery is so it’s just going to send it’s full charge regardless. If you do charge at that higher current, even once it could completey ruin that battery.

Relion did just recently come out with a LT range of batteries. The LT stands for low temperature. Now those batteries work different. If it drops below 32F and the BMS is sent a charge, the battery will use energy in the battery to actually heat the cells first, before it actually starts charging. So that line, actually can be charged in temps as low as -4F, but that’s because of the charger. Only problem I have with those is the battery size of 13” long. They only make a LT version in 50 and 100 Ah, no 75Ah like you have.

So all that being said, what appeals to me about BattleBorn is they actually have a low temperature shut off built into the BMS. So with that I believe when the battery temp drops to 25F it automatically shuts off so it won’t accept a charge no matter what you throw at it. It won’t kick back on til the cells are back to 32F, and then It’ll turn itself back on and take a charge again automatically. So, dummy proof if you will , which is what I like.

So who knows, maybe it’s just a situation you could avoid mostly. I’d just ask myself how often during daylight hours am I just hanging out at camp below 32F? Can’t say I’ve had that situation happen yet. But.....I have woke up in a camp where it dropped well below 32 overnight, and the sun came out. If I had solar and the sun kicked on the charger while it was still below 32F suddenly could have a $900 doh :censor:on my hands.

Battery experts feel free to tell me I’m completely misunderstanding this situation. I’m am no battery expert by any means, just googled a bunch of stuff and watched too much TouTube.

Attached see the way Relion answers this in their FAQ

D7483035-2A80-4CBA-93FD-30DF9C6D588C.jpeg
 
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1. ARB drawers

2. Have to check with Slee. They made it custom - may be willing to make more. I worked with Ben on it. I pressed for the installation this way - LiFePo in the engine bay would be significantly compromised by distance and heat. The mount is immovable - even in a severe accident, the battery won’t be a projectile.

Now that I have it and have tested some, I’m very pleased. With the BCDC40, charge time is very low... probably need to run the engine an hour or two every couple days for “reasonable” loads. Not enough battery to run a 3000W inverter, but for “normal” loads like lights, fridges, radios, etc. it is perfect.

Note that due to discharge rate limitations, you’d need 2 100AH LiFePo batteries to run a 2000 or 3000W inverter well.

I have run 2+ days on the battery without running the rig and voltage is still > 12. Will better exercise in the spring/summer. Pretty sure I won’t see a need for solar. If I do, will address it then.

Even 1/2” longer, and width will stop you. You could do 1/2” narrower, then get longer by an inch or two. Relion doesn’t make a footprint like that, but someone may.
Thanks for all the details. FYI that is a REALLY clean way they mounted that. I’m a Bit envious . If I end up going with the same Relion as you I’ll reach out to Slee about that Group 24 tray. Definitely not a standard size tray. If I go with a different battery I’ll for sure show those pics to the shop that’s doing my install to model their mounting configuration based off that. Really like where they put the BCDC also, as close as you can get to the battery in an otherwise unused spot. I like the safety angle having it secured like that, and doesn’t hurt how pretty and factory it looks. Well done.
 

sdnative

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32F / 0C is about where lithium plating side reactions start to occur, but it's not a hard cutoff. You can safely charge below freezing but at much lower rates, down to some lower temp limit. Relion mentions <0.1C from 32F-14F and <0.05C from 14C to -4C.

RE heated batteries: my understanding is the battleborn uses the energy inside the battery to heat, while the relion uses the power from the charger itself to warm up the battery before the BMS diverts power to actually charge.

You seem to be correct, the Redarc doesn't appear to have a low temp cutoff. You could sell the Redarc and get yourself a Victron that has low temp cutoff and bluetooth (actually really neat interface). The Victrons aren't nearly as compact as the Redarc though.

EDIT: the Victron Orion DC-DC chargers do not have a low temp cutoff, but the MPPT chargers can be configured for low temp cutoff with an extra sensing module.
 
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radman

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ou could sell the Redarc and get yourself a Victron that has low temp cutoff and bluetooth (actually really neat interface). The Victrons aren't nearly as compact as the Redarc though.
I’ve been wondering why there’s been so much redarc love on here... in spite of having to get 2 victron units (dc to dc and mppt), cost should be close, but more control and Bluetooth!
 

radman

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Looking at the Victron product line - see the 712 battery monitor. Not seeing a DCDC charger that has temp limiting. @sdnative can you point me to the options?

Victron Energy Orion-Tr Smart 12/12-Volt 30 amp 360-Watt DC-DC Charger, Isolated (Bluetooth) Amazon product
Here’s the monitor I use.
AiLi Battery Monitor Voltmeter Ammeter Voltage Current Meter 8-80V 0-100A Auto Car Motor Boat Caravan RV Motorhome Amazon product
 

sdnative

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Looking at the Victron product line - see the 712 battery monitor. Not seeing a DCDC charger that has temp limiting. @sdnative can you point me to the options?

I thought I remembered seeing a temperature setting in one of the configuration pages, but never payed much attention to it. I just double checked and the particular charger I am using (Orion-Tr smart isolated) does not have a temperature cutoff. I have looked at a couple different Victron products so it could have been one of the others. The BMS I am using does have a low temp cutoff. I have 3 different devices configured via bluetooth and was mixing them up.

I stand corrected, thanks for pointing that out.


EDIT: the Victron MPPT charger does support low temp cutoff.
 
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So would the Victron 712 with temp sensor solve the issue? Am I understanding it correctly that it’d basically block any charge from going to the battery is the temp sensor says it’s under 32F?

it’s an additional $226 I wasn’t planning to spend, but if it made the whole cold temp charging worry a non issue I think that’s be money well spent.

This would also open up the battery selection because I wouldn’t need something like BattleBorn that has the low temp shut off built in. I read several heated solar threads on this quite a few people concerned that BattleBorn doesn’t shut off til it is 25F. Concern being you could still ruin the battery if you sent a charge between 25-32 degrees. Why wouldn’t they have just set the battery to turn off below 32?

F6560856-19A3-4D1C-A2D7-977C6FEB8C4D.jpeg
 

DesmoPilot

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So would the Victron 712 with temp sensor solve the issue? Am I understanding it correctly that it’d basically block any charge from going to the battery is the temp sensor says it’s under 32F?

it’s an additional $226 I wasn’t planning to spend, but if it made the whole cold temp charging worry a non issue I think that’s be money well spent.

This would also open up the battery selection because I wouldn’t need something like BattleBorn that has the low temp shut off built in. I read several heated solar threads on this quite a few people concerned that BattleBorn doesn’t shut off til it is 25F. Concern being you could still ruin the battery if you sent a charge between 25-32 degrees. Why wouldn’t they have just set the battery to turn off below 32?

View attachment 2549973
You are correct. The Victron BMS opens at cold temperatures and therefore cuts off charging. I ran this and other Victron components in a couple of rigs. Absolutely love their products.
 
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Maybe a heating pad is the path of least resistance?
Yeah Considered the heating pad route, problem I saw is pretty much all the drop in options are maxed out width wise to fit in the wing, so I doubt there’s any extra room to wrap in a warming blanket. If I had the battery on top of the drawers, heating pad would definitely be an easy option. My ideal would be the LT line by Relion that the BMS just automatically uses battery power to heat when it needs it. Now that’s the dummy proof solution. The 100Ah they have is 13” long though so no way it’d fit in that spot. The next size down in the LT line is only 50Ah. As of today that Victron monitor with the temp sensor is my leading contender. Also considering that Lion Energy now as a battery option, has a smaller footprint than the others
 

sdnative

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Seems like there would be a simple temperature relay / contactor that you could use to disconnect the charging sources? Depending on the charger, it would need to be rated at 50A or so (for DC-DC, much less for PV).

The Victron BMV monitor does have a relay on the back of the display but it's not rated for much current. You may be able to switch a charger's remote input terminals, but you would need another larger contactor in series to switch the main charger input.

Also if you do use some form of a relay (or BMS) to disconnect the battery, make sure the charger(s) can handle the sudden disconnect of the output while under load without being damaged. There could be a significant voltage spike induced on the output terminals of the charger. Safest way would be to disconnect the charging sources (charger inputs) first.


I am sure you have already been here, but if not spend some time over on DIY Solar Power Forum - https://diysolarforum.com/. Lots of good info on this type of stuff.
 
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Seems like there would be a simple temperature relay / contactor that you could use to disconnect the charging sources? Depending on the charger, it would need to be rated at 50A or so (for DC-DC, much less for PV).

The Victron BMV monitor does have a relay on the back of the display but it's not rated for much current. You may be able to switch a charger's remote input terminals, but you would need another larger contactor in series to switch the main charger input.

Also if you do use some form of a relay (or BMS) to disconnect the battery, make sure the charger(s) can handle the sudden disconnect of the output while under load without being damaged. There could be a significant voltage spike induced on the output terminals of the charger. Safest way would be to disconnect the charging sources (charger inputs) first.


I am sure you have already been here, but if not spend some time over on DIY Solar Power Forum - https://diysolarforum.com/. Lots of good info on this type of stuff.
Thanks for the tip. I had spent a bit of time over on that Solar forum. A lot of it starts to go over my head real quick. hmmmm. The particular charger I ordered is the ReArc BCDC 1225D. At 25A you think that's still potentially an issue if the Victron disconnected under load?
 

sdnative

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Thanks for the tip. I had spent a bit of time over on that Solar forum. A lot of it starts to go over my head real quick. hmmmm. The particular charger I ordered is the ReArc BCDC 1225D. At 25A you think that's still potentially an issue if the Victron disconnected under load?

Not sure. That would be a question for Redarc support.

If you are able, draw up your schematic and post it somewhere for review before you spend money on parts.
 

Hants

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Seems like there would be a simple temperature relay / contactor that you could use to disconnect the charging sources? Depending on the charger, it would need to be rated at 50A or so (for DC-DC, much less for PV).

The Victron BMV monitor does have a relay on the back of the display but it's not rated for much current. You may be able to switch a charger's remote input terminals, but you would need another larger contactor in series to switch the main charger input.

Also if you do use some form of a relay (or BMS) to disconnect the battery, make sure the charger(s) can handle the sudden disconnect of the output while under load without being damaged. There could be a significant voltage spike induced on the output terminals of the charger. Safest way would be to disconnect the charging sources (charger inputs) first.


I am sure you have already been here, but if not spend some time over on DIY Solar Power Forum - https://diysolarforum.com/. Lots of good info on this type of stuff.

If the DCDC charger is ignition switched, you should be able to put the temp relay in ignition input rather than to the charging output.

If it is voltage sensing (I only know of this with paralleling relays, not DCDC chargers), you’d need high current.
 

sdnative

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The Redarc BCDC doesn't have a dedicated input for ignition (or remote) like some other chargers have, else that would be easy. The ignition detection is done by a voltage measurement threshold on the main input. It does have the "blue wire" which is used to identify the type of alternator being used (standard/temp compensating vs low voltage). Apparently the function of this blue wire has changed over the years with different versions of the BCDC. I have seen some wiring schematics showing the blue wire being used as an ignition enable, but officially it is used to configure the alternator type. You may be able to design a circuit using the blue wire to disable charging, but I don't know if that would disable all charging inputs, or just the DC-DC (and force the input to PV which wouldn't solve the problem).
 

radman

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The Redarc BCDC doesn't have a dedicated input for ignition (or remote) like some other chargers have, else that would be easy. The ignition detection is done by a voltage measurement threshold on the main input. It does have the "blue wire" which is used to identify the type of alternator being used (standard/temp compensating vs low voltage). Apparently the function of this blue wire has changed over the years with different versions of the BCDC. I have seen some wiring schematics showing the blue wire being used as an ignition enable, but officially it is used to configure the alternator type. You may be able to design a circuit using the blue wire to disable charging, but I don't know if that would disable all charging inputs, or just the DC-DC (and force the input to PV which wouldn't solve the problem).
My SOK battery order just got cancelled so now it’s back to the drawing board. Any particular reason to get the 18amp victron vs the 30amp?
Less load on the alternator?
 

sdnative

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I got the 18A because it was considerably less expensive, I didn't want to put too much of a load on my alternator, and I could get away with running 8 gauge wire. It does take a long time to charge though. A 30A would have been better but would have required at least 6ga, preferably 4ga wire which would have been a hassle to run through the firewall, under the dash, etc. In hindsight, I should have gotten the 30A as it is a better fit for my large battery.

For 100Ah battery, either the 18A or 30A would be fine, just depends on how fast you need to charge.

Plan on mounting the charger as close to the battery as reasonably possible and run larger cable to minimize the voltage drop. Reason is the charger senses battery charge state by the measured output voltage and the current flow will cause a larger voltage drop in smaller wire. On the input side, the charger senses engine running condition by the measured input voltage, so don't skimp on the wire size from the engine to the charger.
 

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