AGM CHARGING TEMPERATURE

[haycord]

The Renogy 12V 200AH Battery data sheet states Operating Temp is 32-122F. The Ambient Temp extremes here are 15 Deg (rarely) to 105 DegF. The batteries are outside but protected from the weather in a ventilated enclosure. Can someone help me understand the result of charging below 32F?

I'm also considering using a HEATTRAK Sidewalk heating mat (3.2 Amps) under the batteries with a Greenhouse Thermostat - and connected to Utility power. If there's no Utility thats a lot of power to put on the Array...

Thanks

 

[pollenface]

Higher voltage is needed for lower temps, temp coefficient should be stated on the spec sheet.

 

[chrisski]

The Renogy 12V 200AH Battery data sheet states Operating Temp is 32-122F. The Ambient Temp extremes here are 15 Deg (rarely) to 105 DegF. The batteries are outside but protected from the weather in a ventilated enclosure. Can someone help me understand the result of charging below 32F?

I'm also considering using a HEATTRAK Sidewalk heating mat (3.2 Amps) under the batteries with a Greenhouse Thermostat - and connected to Utility power. If there's no Utility thats a lot of power to put on the Array...

Thanks

That sounds like a Lithium Battey not AGM.

What is the model#?

@HRTKD has a thread on heating pads. Unfortunately, I can’t find the thread. He used an insulated box with on off switches and this worked for a Colorado winter and did not require a lot of power.

 

[haycord]

There is no Model number as such. It is listed as Renogy 12V 200AH AGM GEL Deep Cycle. I can post the link to the datasheet if its okay?

 

[chrisski]

There is no Model number as such. It is listed as Renogy 12V 200AH AGM GEL Deep Cycle. I can post the link to the datasheet if its okay?

View attachment 194841

I wonder why Renogy has this 32 f limit on their AGMs.

I see your operating temperature nearly matches the Trojan AGM battery. I could not find a “do not charge below temperature” other than the operating temp in any of the Trojan guides.

 

[seneysolar]

Nothing bad will happen if you charge when colder than 32, it just won't take a full charge right away, but as they charge they self heat and come up eventually.

 

[OzSolar]

I wonder why Renogy has this 32 f limit on their AGMs.

Most likely it's a misprint.

 

[Hogheavenfarm]

Mine are out in the barn and its been down to 12 degrees, no issues at all.

 

[pollenface]

only bad thing is capacity is reduced slightly in cold weather

 

[haycord]

Great information. Thank yall

 

[chrisski]

Most likely it's a misprint.

I have found other Renogy documentation that was incorrect. For me, it was which MC4 connector was the positive on their panel. Two different Renogy Documents said different. In that case the voltage from a DMM does not lie.

Nothing bad will happen if you charge when colder than 32, it just won't take a full charge right away, but as they charge they self heat and come up eventually.

Mine are out in the barn and its been down to 12 degrees, no issues at all.

For the OP, I'd still recommend contacting Renogy and seeing their response. I have a dozen Renogy Panels, and at least their sales dept responded to questions before I purchased.

With these guys saying they do it with that AGM, I'm pretty confident, but no offense to them, I'd still want to hear it from he who gets the money.

 

[haycord]

Renogy confirmed the 32F lower operating limit. They also said attempting to charge below 32 could result in it not accepting a charge and/or damage. They suggested I purchase battery heating pads. I didn't think about it at the time but now - 'Operating Range' obviously means do not charge or discharge below 32. Wow! I'm impressed...

 

[chrisski]

Renogy confirmed the 32F lower operating limit. They also said attempting to charge below 32 could result in it not accepting a charge and/or damage. They suggested I purchase battery heating pads. I didn't think about it at the time but now - 'Operating Range' obviously means do not charge or discharge below 32. Wow! I'm impressed...

IMO the Renogy support that answered your question based this off the spec sheet, so at least he’s reading that.

For liability, I would not go against what he says, but no reason an AGM battery can’t operate to below freezing.

I can only think they increased the charging temp to 32 f based off number of warranty claims.

 

[seneysolar]

Operating temperature i assume plans for worst case scenario. Coincidentally theirs lines up with freezing ------dead batteries will freeze, even agm ----- dont charge a frozen battery.

I dont see any issues charging/discharging/using a perfectly good agm below 32, just dont let it freeze. (Sit below 60% soc)

Will it meet "book specs" at extreme low temperatures- no.
Will it still work - yes.

 

[haycord]

I agree, that is likely a backdoor way to get out of a warranty claim. That spec is ridiculous considering they want off-grid mountain cabin customers... buyer beware.