Lithium charging not great

[WDPatterson]

Originally Posted by jasin1

I thought keystone changed/upgraded the converter when they started offering factory solar?

question …if you have two sources for charging the battery ..solar and converter…does it trick the converter into thinking it doesn’t need to charge 100% if the solar is charging at the moment?

What kind of lithium batteries do you have? Do they have a battery management system, a BMS, on them?

[WDPatterson]

Originally Posted by JRTJH

Danny,

I agree with your post... That said, I still have not been able to nail down Keystone as to which WFCO converter they install with each "SolarFlex system"...

What I mean by that is this:

The SolarFlex 200 is "configured for lead acid batteries" and the factory does not install any batteries. It's up to the dealership to install what they carry. Some of us get a single Gp 24 hybrid. Some get two Gp 27's and others might even get a "remanufactured no name battery".... It's my understanding (and Keystone won't confirm or deny) that all SolarFlex 200 systems are equipped with a WFCO "lead acid only" converter/charger.

Then, moving to the SolarFlex 400i, there are still NO batteries from the factory as standard equipment, but you can order it with either 1 or 2 Dragonfly batteries. Also, you can upgrade that system if you special order it, with additional rooftop panels, a second inverter and a "inverter friendly air conditioner"... That said, Keystone has not confirmed whether "ALL" of the 400i systems ship with a Li compatible converter/charger or if only those that have the special order Li batteries as part of the order come equipped with the correct charger. And, if not ordered with Li batteries, it's going to be equipped with what the dealer puts in all their other trailers (probably a single Gp 24)...

Then there's the 600i system that does come with a 270 AH Dragonfly battery, but the cost of that system makes it restrictive for all but the most expensive Keystone trailers... I don't know of very many "Keystone entry level or mid level buyers" that would be willing to up the price by roughly $12,000 for the 600i system.... As far as I know, since the Li battery is standard with the package, I'd suspect that the converter/charger is properly equipped to charge the battery the factory installs....

That said, if the dealership is installing batteries, I'd suspect that Keystone would not spend the extra money for a Li specific charger knowing that most people wouldn't install Li batteries "at the dealership" but would just learn from their mistakes, that a single Gp 24 "provided by the dealer" simply is not enough battery for their trailer.....

All that said, looking at the SolarFlex 400i battery option, it states, "Factory installation & system prep"... I wonder if the "system prep" is the changeout of the converter/charger to one that supports Li charging ??????

$12,000 for only 600 watts of solar panels? Man, they sure know how to take people for a ride.

[WDPatterson]

Originally Posted by colby

Did you also check out the profile of the Victron converter? If that came from Keystone as part of he package, it may be set for SLA rather than Lithium. If the solar panels are working properly and the controller is configured for Lithium, you should be getting some higher voltage from the Victron to the batteries.

You are absolutely 100% correct. It doesn't really matter what the converter inside the trailer does. The charge controller should be an MPPT controller, and it should be set to charge to about 13.65 volts. The 200 watt panel is a little undernourished. Going to need more wattage from your panels. I suggest, if you have the real estate on your roof, buy some residential or commercial PERC72 solar panels, as many as you can fit on the roof.

Also, keep in mind that almost any battery is going to "settle", meaning that charge voltage is actually going to drop a little bit to its actual operational voltage. So, even if you charge it 14.4 volts, you're going to get a little bit of drop to the operational voltage. As long as you're well above 12.2 to 12.8 volts, you're doing pretty well. With lithium iron phosphate batteries, you're going to see more like 13 volts and above.

[WDPatterson]

Originally Posted by firestation12

Hopefully I’m not repeating something that has been covered in this thread. A few comments about lithium batteries may help to explain the observations the OP is having. Inside the case of a typical lithium is a BMS (battery monitoring system) that performs several functions. In no particular order are the following: monitor each of the 4 individual cells and stop charging input when the first cell reaches about 13.3, conversely stop battery output when the first cell reaches a predetermined target voltage, not allowing input of a charging voltage should the battery temperature fall below 32 degrees, regulate amperage ingress and amperage egress (this figure be as high as a ridiculous 250 amps). Each cell of a lithium battery typically Under goes a top balancing process during manufacture where basically each of the cells are put in a parallel chain and are charged at 3.3 volts (+/-) @ perhaps 10 amps for a period of 1-2 days. This process causes all the cells to reach the full charge cutoff and discharge cutout voltage when the BMS sees the first cell to reach the target figure. A fully charged battery voltage is roughly 13.3 volts after a brief post charging rest. A hallmark of lithium batteries is the voltage remains fairly flat throughout the discharge period, ability to rapidly charge (unlike lead acid). Several methods are acceptable to charge lithiums. For example, It’s ok to use a standard voltage converter then use a lithium type solar controller to top off the batteries to 100%. Lithium settings on solar controllers send usually 14.4 volts in bulk charging mode to the batteries. It’s ok to charge to say 90% with no harm. Regardless of whatever charging system is in play, the internal BMS get the final say on virtually every aspect of the battery’s operation. The OP’s 13.2-13.3V is likely a normally operating lithium battery.

Everything you said is correct, except for the fact that the BMS will actually operate on cells in a series. Depends on how many cells are in series. If you have four cells operating at 3.65 volts, you'll get a total of 14.6 volts from the charger. The BMS will shut everything off when it gets to that point. Charger will be taken out of line. Battery will settle, balance, and then go back into operating mode when there is a load on it..

[firestation12]

[QUOTE=WDPatterson;531036]Everything you said is correct, except for the fact that the BMS will actually operate on cells in a series. Depends on how many cells are in series. If you have four cells operating at 3.65 volts, you'll get a total of 14.6 volts from the charger. The BMS will shut everything off when it gets to that point. Charger will be taken out of line. Battery will settle, balance, and then go back into operating mode when there is a load on it..

The BMS does indeed monitor the cells in a series configuration. However, the parallel comment referred only to top balancing the cells to assure all reach the same peak voltage at inception. The idea is to create a battery wherein all cells reach the high point and low point cutoff voltages at the same time. Personally, I’ve not seen resting voltages above 13.3 at full charge for a 4 cell “12 volt” lithium iron phosphate battery. 14.4 is the typical bulk charge voltage preprogrammed by Renogy and Victron on their solar controllers. Some allow a custom charge profile to be user programmed.

[WDPatterson]

[QUOTE=firestation12;531100]

Originally Posted by WDPatterson

Everything you said is correct, except for the fact that the BMS will actually operate on cells in a series. Depends on how many cells are in series. If you have four cells operating at 3.65 volts, you'll get a total of 14.6 volts from the charger. The BMS will shut everything off when it gets to that point. Charger will be taken out of line. Battery will settle, balance, and then go back into operating mode when there is a load on it..

The BMS does indeed monitor the cells in a series configuration. However, the parallel comment referred only to top balancing the cells to assure all reach the same peak voltage at inception. The idea is to create a battery wherein all cells reach the high point and low point cutoff voltages at the same time. Personally, I’ve not seen resting voltages above 13.3 at full charge for a 4 cell “12 volt” lithium iron phosphate battery. 14.4 is the typical bulk charge voltage preprogrammed by Renogy and Victron on their solar controllers. Some allow a custom charge profile to be user programmed.

Sorry. I had a typo, and didn't check my work until this morning. Thanks for the reply. Each cell gets charged at 3.65 volts, for a total of 14.6 volts at the charge controller. That's the top charge, where they all balance. That's what you do with Lithium Iron Phosphate Batteries.
The charge controllers will keep pushing that, the BMS will regulate. The BMS will stop charge, and shut off the CMOS at 14.6.
Once you take the charge off, the battery will hover at 14.6, and slowly settle to its operating voltage. That's how it works. And, if you do it that way everyday, using the Sun as your power source, those batteries will maintain and balance correctly. Otherwise, any lower voltage, and you simply don't get your batteries topped off.