Renogy batteries and charging

[Groover]

I am thinking about putting Renogy lithium-iron batteries in by RV but Renogy sales tells me that I need a charger made specifically for that type of battery. I currently have a Magnum ME2012 charger/inverter that has lots of adjustments but nothing that specifically says lithium. I tried every way that I can think of to contact Magnum about an upgrade with no success. So I am asking here. Does anyone here use a Magnum charger with lithium-iron batteries and how is it working out for you?

[Itinerant1]

Something else to think about the ability to view individual cell voltage incase one was starting to drift, even with cell balancing. Bluetooth app or hardwired.

Any programmable charger will work with lfp batteries.

[Groover]

I just came across this recent comparison of lithium batteries on youtube. I have seen Renogy batteries on sale for $800 each direct from Renogy but have never seen Battleborn batteries for less than the asking price of $949. Before I purchase I will compare prices at the time. Based on what I would know now I would pay $50 more for the Battleborn but probably not $150.

Lithium battery comparison

Battleborn seems to have put together some better charging information:

Battleborn charging

They even have specific instructions for my charger:

Magnum charger settings

[Groover]

Almot wrote:

Groover wrote:

This is what is in the manual on-line: "• Standard Charge shall consist of charging at 0.2C constant current rate until the battery reaches 14.6V.
The battery shall then be charged at a constant voltage of 14.6V while tapering the charge current.
Charging will terminate when the charging current has tapered to a 0.02CA."

Make sure this is a manual for your particular battery. Since Renogy is in batteries business now, God knows what other batteries they might sell.

Applying charging current after full charge is not very common with Li. In fact, applying any current after 90-95% of full charge is not a good idea with Li, the detail that manufacturers prefer not to mention. Get a charging graph V vs SOC% for your battery and stay within 30-90%. 40-50% while in prolonged storage.

That came from their online manual for the battery. It seems to call for limiting amperage until full voltage is reached then limiting voltage from that point on. I called Renogy a few days after posting that and the tech guy I talked with acted like he had never heard of the .2C limit and thought that the 50amp charging limit was more realistic.

My next question if I do this is how to handle the battery isolator that charges the house batteries when the main engine is running. My alternator produces 14.1V. It appears that I am going to have see what the lithium battery voltage does when the Magnum charger is turned off. If it drops rapidly to or below 14.1 there won't be an issue. If the batteries try to stay above 14.1 they could run themselves down backfeeding into the chassis circuit. That shouldn't be too hard to figure out. The worst case would be that I disable the house battery charging from the alternator until the voltage drops.

[Almot]

Groover wrote:

This is what is in the manual on-line: "• Standard Charge shall consist of charging at 0.2C constant current rate until the battery reaches 14.6V.
The battery shall then be charged at a constant voltage of 14.6V while tapering the charge current.
Charging will terminate when the charging current has tapered to a 0.02CA."

Make sure this is a manual for your particular battery. Since Renogy is in batteries business now, God knows what other batteries they might sell.

Applying charging current after full charge is not very common with Li. In fact, applying any current after 90-95% of full charge is not a good idea with Li, the detail that manufacturers prefer not to mention. Get a charging graph V vs SOC% for your battery and stay within 30-90%. 40-50% while in prolonged storage.

[allen8106]

Groover wrote:

drsteve wrote:
Ask Renogy for the specific requirements for charging their batteries.

Also the desulferizing routine would need to be disabled. With those batteries setting me back about $3,300 I don't want to do too much trial and error.

With the Magnum inverter and the ME-RC50 the de-sulfication routine is a manual operation by holding the charge button down for like 3 seconds while in float mode.

[allen8106]

When used with the Magnum ME-RC50 you can use custom charge settings that will charge the lithium batteries correctly.

[pianotuna]

Hi Groover,

Thanks for letting us know.

[Groover]

The Magnum charger has a custom setting and it looks like all that I need to do is put it on the custom setting, set it 14.6V and disable the desulferizing routine. Just in case anybody is wondering.

[2oldman]

Groover wrote:
"• Standard Charge shall consist of charging at 0.2C constant current rate until the battery reaches 14.6V.

Other specs I find on Renogy site say you can charge at up to .50 C (50amps), so I don't understand the .2 thing. With 4 at 80 that's probably all you can throw at them anyway. I can charge my pack at equivalent 136 amps.

Lwiddis wrote:
But 2oldman won’t that void the battery warranty?

I don't know.. haven't read it.

[Groover]

drsteve wrote:
Ask Renogy for the specific requirements for charging their batteries.

This is what is in the manual on-line: "• Standard Charge shall consist of charging at 0.2C constant current rate until the battery reaches 14.6V.
The battery shall then be charged at a constant voltage of 14.6V while tapering the charge current.
Charging will terminate when the charging current has tapered to a 0.02CA. Charge Time is approximately
7 hours. Safe Charging consists of temperatures between 32 ºF and 113 ºF."

It sounds like with four 100ahr batteries I could charge at 80amps up to 14.6V then try to hold 14.6V until fully charged. I will have to play with the Magnum unit to see if it will let me do that. Also the desulferizing routine would need to be disabled. With those batteries setting me back about $3,300 I don't want to do too much trial and error.

[Groover]

pianotuna wrote:
LI in general, do not prefer a float charge.

I see Renogy is offering a 170 amp-hour 12 volt battery.

Interestingly the cost per kwh is less for the 100ahr battery than it is for the 170ahr. However, the maximum current is about the same. I guess that is due to the cell protection circuits. I figured that 4 100ahr batteries would be better than 2 or 3 of the bigger ones so that I would be less likely to exceed the rated discharge rate plus my coach is set up for 4 medium size batteries already.

[Groover]

pianotuna wrote:
https://www.magnum-dimensions.com/mobile-power-products

and to email or phone them:

https://www.magnum-dimensions.com/contact-power-conversion-solutions-team

Groover wrote:
I am thinking about putting Renogy lithium-iron batteries in by RV but Renogy sales tells me that I need a charger made specifically for that type of battery. I currently have a Magnum ME2012 charger/inverter that has lots of adjustments but nothing that specifically says lithium. I tried every way that I can think of to contact Magnum about an upgrade with no success. So I am asking here. Does anyone here use a Magnum charger with lithium-iron batteries and how is it working out for you?

I have used the email on the Magnum page 2 weeks ago and called every number on the page with no response yet. A couple of days ago I spent an hour on hold and advanced from #3 in line to #2.

[pianotuna]

https://www.magnum-dimensions.com/mobile-power-products

and to email or phone them:

https://www.magnum-dimensions.com/contact-power-conversion-solutions-team

Groover wrote:
I am thinking about putting Renogy lithium-iron batteries in by RV but Renogy sales tells me that I need a charger made specifically for that type of battery. I currently have a Magnum ME2012 charger/inverter that has lots of adjustments but nothing that specifically says lithium. I tried every way that I can think of to contact Magnum about an upgrade with no success. So I am asking here. Does anyone here use a Magnum charger with lithium-iron batteries and how is it working out for you?

[pianotuna]

LI in general, do not prefer a float charge.

I see Renogy is offering a 170 amp-hour 12 volt battery.