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littlewiggler avatar image
littlewiggler asked

Renogy battery charging parameters once again...

There have been several posts here about the right settings for Victron products with Renogy batteries. Most of the answers have been estimates and there has been very little documented from Renogy.

Renogy recently introduced a new MPPT/Isolator charger (DCC50S). What is interesting is that in the manual they give the following charge parameters:

Based on this chart would it be safe to say that setting the following would be the best course of action for these Renogy LIoN batteries?

Absorption voltage: 14.4V

Maximum absorption time: 1 hour

Float voltage: 9V (since that is the lowest it can be set. I've been using 13.6V)

Equalization voltage: 14:4 (just in case it gets set to equalize - that button is easy to hit on the mobile app)

Automatic equalization: Disabled.

Thoughts?

battery charging
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dlello2 avatar image dlello2 commented ·

Hey there! Found this post as I'm in a similar situation here in 2020 (two 100ah Renogy LiFePo4 batteries, DCC50S DC-DC Charger, Victron 702 BMS).


Can you tell me if you ever resolved what the best/most optimal settings were?


Thanks a lot!

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5 Answers
dereck avatar image
dereck answered ·

Interesting detective work. But when I asked Renogy they said,

”With our Li batteries, we would recommend setting the charging voltage to 14.4 ± 0.2V, the float voltage must be set to the same voltage as our batteries do not require a floating stage. ”

But at the same time I have been told that that float voltage will kill the batteries.


In summary, given that we are talking about guesses and workarounds for very expensive batteries from one of the main suppliers of PV gear for mobile uses in the US, it would be real nice if Victron gave us the option to not have a float voltage and to completely disable equalization, since that is the correct way to work with these batteries.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

There are two ways to interpret the "no floating stage" advice:

1 - it HOLDS the absorption voltage indefinitely. Setting the float voltage to be the same as the absorption voltage would be the equivalent of this.

2 - once the target absorption voltage has been reached, and the absorption phase is over, no additional power is provided to the batteries, and the battery either holds the voltage itself, or falls back to a lower voltage, until it falls below the re-bulk threshold. Setting the float voltage to the minimum allowable value would be the equivalent of this.

Generally speaking from what I do know about lithium batteries is that once the target voltage is reached, that's it, and the battery should not be charged any further (ie #2)

In these cases where Victron has not tested the batteries, and has not been given specific instructions that have been confirmed with the battery manufacturers, the best case is to get the battery supplier or manufacturer to provide the required settings for their batteries.

Otherwise we are all just giving it our best guess.

Ultimately if there is an issue, which leads to a warranty claim on the battery, the best case is that you have followed the battery manufacturers or suppliers directions for how the batteries are to be charged. Or at the very least have a history of correspondence with them where you are seeking their advice for how their batteries are to be used, and following that to the best of your ability with the info they do provide.

It isn't Victron's place to give advice on specific batteries that are not yet on the supported list.

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Justin Cook avatar image
Justin Cook answered ·

Given that Renogy doesn't actually make anything they sell (they're a branding company, not a manufacturer), it doesn't surprise me that people are getting differing/conflicting information from them about their branded products. At the Victron/Sterling/Blue Sea/Battle Born distributor that I work for, we always strongly advise against purchasing Renogy products, not necessarily because they're bad products, but because they're shot-in-the-dark products... whether or not you get a good device depends entirely upon which Chinese warehouse overstock they recently bought up and slapped their name on. And as for support... well, neither we, nor Renogy, nor especially Victron are going to be able to offer support or advice for Renogy products because they didn't make or design them, so no one actually really knows what their specs are.

Bottom line: If you want real support, you need to pay a little more to buy products that are designed by the companies whose name the product bears, like Victron, Battle Born, ReLion, Blue Sea, Sterling, etc... and it works out better in the long run because those companies also offer real warranties on their products.

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dereck avatar image dereck commented ·

I’ve got two grand sunk into Renogy batteries. I realize you don’t handle their products but just their competitors’ but buying different gear is not an option for me.

Their specs, and design, and BMS have been consistent for a few years for their batteries so I’m surprised that is still considered a moving target.

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Justin Cook avatar image Justin Cook ♦♦ dereck commented ·

I think anything by them will continue to be considered a moving target until they start designing/making their own devices. I'm glad to hear that you've had a positive experience with their batteries and BMS, but I have a very long list of customers who have had to swap theirs out from between 6 months to 3 years, roughly, due to cell failure/BMS failure/erratic BMS behaviour.

Again, whether you get a good batch or a bad batch really just depends on which warehouse's overstock they bought and put their name on... sounds like you got a good batch, and that's great to hear. The people who've gotten bad batches come back to Victron or Battle Born batteries after usually having very little success trying to initiate warranty claims from Renogy.

Then again, the good batches truly are good... but without proven consistency in quality, performance, and materials, I'd be surprised if Renogy ever makes it onto Victron's supported list.

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cozzie avatar image
cozzie answered ·

So, now 4 years on, I'm now in the same boat with the new Victron MultiPlus-II and 4 Renogy 170Ah batteries. I also have a Renogy 60A MPPT CC and it has the following "Battery Charging Parameters" listed for LFP batteries:

High Voltage Disconnect 16 V

Equalization Voltage -----

Boost Voltage 14.4V

Float Voltage -----

Boost Return Voltage 13.2 V

Low Voltage Reconnect 12.6 V

Under Voltage Warning 12 V

Low Voltage Disconnect 11V

Over-Discharge Delay Time 5s

Boost Duration -----

Equalization Interval -----

Equalization Duration -----

Now, being 4 years since the original tread, how did your parameter settings go with the MultiPlus? Any issues/problems with the batteries or inverter?


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evn avatar image
evn answered ·

I talked to support about this so thought I'd post here. I shared this link to AMSolar https://amsolar.com/rv-solar/support when they said "no float voltage" and they shared this article on Battle Born https://battlebornbatteries.com/charging-battleborn-lifepo4-batteries/ (good to read)

I went over this with support and we came up with the following for my Renogy Smart 100ah LiFePo4 Batteries and a Victron Solar MPPT (support agreed w/the following)

Boost Voltage: 14.4V

Float Voltage: 13.5V

Charged Voltage: 13.9V (I may set this lower - Battery University Link)

Which more or less matches the OP

Hope this helps someone

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evn avatar image evn commented ·

https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteries

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goose-f16 avatar image
goose-f16 answered ·

yes.. I have discovered the same.. the Renogy products hold the voltage at the boost and unnecessarily will age your batteries.. I have the DC to DC.. I built a user setup that has the boost at 14.3, float at 13.5, and EQ at 14.3, and time off, with absorption at boost charge 1 hour.. this way it will always cut off just before my Balmar house alternator does, or the Inverter charger does.. it will be the first unit to float.. this is really important!! This will by my last renogy product and I have almost everything else victron, When the smart Orion comes out that has .Can or VE.direct, sign me up for 60 amps of isolated units.. I figured this out using a smart shunt on the unit just monitoring voltage.. b/c the smart shunt wont really work on a non isolated unit as a dc meter.. so either way, I will need insulated units for DC meter/shunts.. I know this was about renogy batteries, but its important to note that their products hold charging levels elevated too long.. so they are saying their batteries can handle it.. I totally disagree.. have had this tech for years.. you hold a LIFE battery at bulk voltage, you will ruin it eventually.. it has to be able to relax to float range


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