Redarc BMS 30, not for use in Cold temps

[john61ct]

If you go to the trouble of building insulated & heated boxen for your House bank,

Or build the bank in modules easy to take with you from one heated space to the next

that is the key to using (especially charging) LFP in cold climates anyway.

Then the original version will act as a failsafe to prevent you inadvertantly destroying the cells.

Which you would otherwise need to devise.

 

[Red90]

Seem crazy that they have a cold limit. The worst that could happen if it is colder out is the battery is a bit undercharged. It would really suck to have your charger die on you at -40.

 

[john61ct]

This is a design feature, not a bug in the context of where the unit comes from.

In Australia people that can afford Redarc gear use LFP

Quality deep cycle lead banks are **much** more expensive than NA

LFP relatively much cheaper, for many years now, plenty of local makers sell quality turnkey packs

therefore market penetration is much more advanced.

An LFP bank worth 10grand can be permanently rendered instant scrap if you try to charge at any decent current rate when the cells are cold enough.

Which barely ever happens down under, few camp in cold weather, at all.

 

[Chadx]

Seem crazy that they have a cold limit. The worst that could happen if it is colder out is the battery is a bit undercharged. It would really suck to have your charger die on you at -40.

As mentioned, it was an issue with early units. They have remedied as of 2019 and the units will charge each battery chemistry as appropriate. My unit was simply an older unit. REDARC replaced the shunt/battery sensor under warranty, I installed it, and all is good now. Those that buy the latest REDARC battery manager 30 will not have an issue charging in the cold.

 

[Chadx]

This is a design feature, not a bug in the context of where the unit comes from.

By REDARCS admission, that isn't correct. The battery sensor was not working per spec. The unit's performance did not match their own literature and users manual. Only the Lithium battery setting should have been cold-temperature limited. No reason to limit all battery chemistry charging do to the limits of one chemistry. The battery sensor on my unit has been replaced under warranty and at no cost to me (except a little elbow grease) with a different part number that performs to the original REDARC spec. All REDARV battery management systems now will charge non-lithium battery types well below freezing as REDARC intended.

 

[Red90]

As mentioned, it was an issue with early units. They have remedied as of 2019 and the units will charge each battery chemistry as appropriate. My unit was simply an older unit. REDARC replaced the shunt/battery sensor under warranty, I installed it, and all is good now. Those that buy the latest REDARC battery manager 30 will not have an issue charging in the cold.

I thought you said above it won’t charge below -13F. Did I misunderstand?

 

[Chadx]

Correct in that the AGM/lead acid lower charge limit is -13F (-25C) per the manual. That one I've not tested. And I just unhooked my battery so will not get to check the REDARC lower limit this winter when it drops below that.
When I answered you above, I had misunderstood your post and thought that you thought the current units were limited to 32F (0C) for AGM/Lead acid, but now I understand that you meant that -13F (-25C) should not be a limit for AGM/Lead Acid. A -13F limit will definitely impact far fewer users than a 32F limit, but see your point questioning why there is a cutoff at all (Well, as long as the battery is above 10.5v because below 10.5v, a battery will freeze solid and charging that would be big trouble). But as long as the charger compensates due to temp, I agree there really isn't a reason for it not to charge when below -13F (-25C).

 

[82SC]

I had a similar issue recently with my Patriot X3 in Yosemite.

I have emailed Redarc and referenced your experience.

Before I found your post I was looking at these RV tank heaters you stick on to the tank and are thermostat regulated to trigger when temps drop too low. Looks like you could just wire them to the battery itself and it should heat themselves when needed. I know many modern Li come with their own BMS with heating elements. But my X3 still has the stock Gel batteries. Which I do plan to upgrade to Li once they crap out.

But hopefully my problem is solved with the upgrade you did

 

[Gravity]

Changed my BMS 30 over to AGM mode to help with cold weather charging of my Relion 300-LT lithium battery. Works awesome and will still get the battery to 90-95% vs 100% which is totally fine for the occasional cold snap. Super easy with the Redvision monitor....

 

[Christian P.]

Changed my BMS 30 over to AGM mode to help with cold weather charging of my Relion 300-LT lithium battery. Works awesome and will still get the battery to 90-95% vs 100% which is totally fine for the occasional cold snap. Super easy with the Redvision monitor....

Thanks - I may need to do the same.

 

[Chadx]

Changed my BMS 30 over to AGM mode to help with cold weather charging of my Relion 300-LT lithium battery. Works awesome and will still get the battery to 90-95% vs 100% which is totally fine for the occasional cold snap. Super easy with the Redvision monitor....

For readers unaware, the Relion 300-LT is a purpose built, low temperature (LT) lithium battery with internal heating element. When charge is applied, it first warms the battery core temp to above freezing and only then starts to allow current to recharge the battery. This is why @Gravity can get away with changing the REDARC 30 to AGM mode and charge below freezing. If your lithium battery does not have internal (or external) heating to keep the battery core temp a bit above freezing, do not run your REDARC30 in AGM mode when temps are below freezing. True that most lithium have a BMS that will prevent charging when below freezing, but that is meant as a failsafe and there is no reason to attempt to charge a non-heated, lithium battery when its core temp is below freezing. If you battery is not heated, leave the REDARC30 on Lithium setting.

A note on the Relion heated batteries. Relion states the 300-LT should only be charged down to -4F. The AGM setting on the REDARC30 will keep pushing charge all the way down to -14F. Those core battery temps are unlikely, but possible. Not sure an extra 10F makes a difference, but mentioning it for awareness. I assume they say -4F is about the coldest that the internal heating pad can compensate/overcome. Micro environment (battery box) could influence that considerably so Relion is likely be conservative and accounting for a battery in an outside, non insulated battery box.

 

[RAM5500 CAMPERTHING]

Still pretty dumbfounded on why folks continue to buy the RedArc stuff other than the "Overland Marketing Machine" pumped by gear vendors that have nice profit margin on it.

Victron is far superior in every way, 100% adjustable for every single parameter, and even costs less.

Do more research folks!

 

[john61ct]

Aussies like supporting Aussie made goods

 

[Chadx]

Also, many have REDARC manager 30 as original equipment from the camper manufacturer. While it may not be top shelf, it's a significant step up from a lot of the units these camper manufacturers used to install. And the issue outlined early in this post has been taken care of. True that the REDARC is not fully programable like a lot of the other manufacturers chargers/controllers (Victron comes to mind), but it gets the job done quite well in a compact all-in-one so no plans to rip out something that is working well and spend time or money on replacing.

 

[mep1811]

So just heard back from the engineering department at REDARC.

Apparently they are aware of this issue and have been selling all BMS 30 systems with the sensor 3 since Dec 2019. They will ship this sensor to replace my current sensor for the battery once they have them back in stock apparently which there currently are non in North America at the moment. No idea when they will restock, I've asked for them to just switch my entire unit out for a new one instead of just the sensor. Waiting to hear back, shouldn't be an issue with them, they have been great to deal with and work with as soon as they are made aware of the issue.

This sensor will allow charging of lead acid batteries down to -25degrees C. PDF attached.

Is the sensor marked with the number 2 or 3? ⁷