Generator charging batteries 2021 Isata 5 30FW

[msusslin]

We just spend 3 days boon-docking and found that the generator still takes a long time to top off the batteries. About 7 hours to go from 55%SOC to 99%SOC.
Right way we found that the battery setup was incorrect, set to flooded versus custom, as mentioned in prior forums to be a Firefly software bug. Apparently, we need to check that setting very time we had the RV in storage. The charge rate, after the firefly 4.6 update, was correct at 100%, versus 20% with ver 4.5.
Vlmgat, Question, the charger is set to Float, is that correct as you mentioned Bulk charge in a prior forum threat, about 1 1/2 years ago? The watts rate was about 500W and about 28 to 40A while the generator was running. The residential fridge and other items draw about 15A up to 22A at times.

It appears that the generator is insufficient to charge the batteries in less than 4 hours, as in some parks (that's the allowed generator run times) to keep peace and quiet. Solar charging is not an option with all of them beautiful trees.
As mentioned in other forums running the RV engine for up to 2 hours charges the batteries much faster.
We also turned off the fridge overnight to save the batteries from drawing down too much. Works good with minimal temperature loss.

Am I missing something? We have 400AH of LI batteries and 800W of solar on board for our adventures.

[sdelam]

If your looking to charge quicker it needs to be in bulk charge mode. Absorption and float are a lower charge mode

[TitanMike]

With 400 ah of LiFePo4 batteries it will take a lot of time to charge with a somewhat standard sized converter/charger.

Ideally the charger is no smaller than 25% of the total capacity of the battery bank and can be up to 50% of total. A 400 ah battery bank is ideally "fed" by a charger capable of delivering at least 100 amps and even up to 200 amps total. The latter will often require two chargers operating in parallel. For example, Victron offers chargers that can be synchronized to provide optimum charging current for rapid chargers of batteries (as long as adequate 120V power is available).

Being set to the wrong mode will certainly limit but just remember that too small a charger will be a lot like trying to fill a large gas tank from a pump with a small nozzle. If's going to take a long time.

On top of charger size, one needs to make sure there isn't a lot of loss in the wires between charger and batteries.

[toshu]

Originally Posted by msusslin

We just spend 3 days boon-docking and found that the generator still takes a long time to top off the batteries. About 7 hours to go from 55%SOC to 99%SOC.
Right way we found that the battery setup was incorrect, set to flooded versus custom, as mentioned in prior forums to be a Firefly software bug. Apparently, we need to check that setting very time we had the RV in storage. The charge rate, after the firefly 4.6 update, was correct at 100%, versus 20% with ver 4.5.
Vlmgat, Question, the charger is set to Float, is that correct as you mentioned Bulk charge in a prior forum threat, about 1 1/2 years ago? The watts rate was about 500W and about 28 to 40A while the generator was running. The residential fridge and other items draw about 15A up to 22A at times.

It appears that the generator is insufficient to charge the batteries in less than 4 hours, as in some parks (that's the allowed generator run times) to keep peace and quiet. Solar charging is not an option with all of them beautiful trees.
As mentioned in other forums running the RV engine for up to 2 hours charges the batteries much faster.
We also turned off the fridge overnight to save the batteries from drawing down too much. Works good with minimal temperature loss.

Am I missing something? We have 400AH of LI batteries and 800W of solar on board for our adventures.

Attachment 280616

Attachment 280617

Attachment 280618

I have had my Xplorer firefly settings at 14.6 for absorption and 13.8 for float.
When I need to get high voltage for proper slide operation I set float to 14.2-14.3 then immediately return float to 13.8 after slide operation.

Last boondocking trip I also shut off inverter while going to sleep and my domestic refer was fine..and my batteries didn't drop down as far.

[vlamgat]

I had used Bulk as a substitute for Absorb out of habit as that is a term used in aerospace which has been my day job for eons.

My experience has been the same as Toshu commented with some nuances. I typically see the SoC decline from 100% at the boon dock arrival to about 60% over 3 hours depending on ambient while running the fridge off the inverter, some MV and the TV plugged into my lap top. The generator will bring it back to 100% in another 3 hours if I switch to Fridge/Propane, do not use the AC but do use the fans in the AC or the overheads. And that charge will after 7 hours with some TV use, coffee, a burst of MV and be in the mid 60s% wise. No AC of course.

I use a 14.4 Absorb charge and a 13.8 Float and yes, after coming out of storage you do have to reset the battery type to custom which remembers these settings. I also raise the Absorb setting to 14.4 and wait for it to show on the monitor before moving the slide in or out. I usually remember to put it back as soon as the slide game is completed but occasionally have left it in the higher voltage without a noticeable effect...yet.

I have seen the charge rate over 130 amps occasionally. Not something I monitor closely but I do check it when the batteries are low and I either go to shore power or switch on the generator. This rate will decline to 40/60 amp rate if an AC is running or the SoC is above 80%. I have also noticed that the generator will get from say 85% to 100% SoC very much quicker than getting from 60% to 80%.

[Aussieguy]

Originally Posted by TitanMike

Ideally the charger is no smaller than 25% of the total capacity of the battery bank and can be up to 50% of total. A 400 ah battery bank is ideally "fed" by a charger capable of delivering at least 100 amps and even up to 200 amps total. The latter will often require two chargers operating in parallel. For example, Victron offers chargers that can be synchronized to provide optimum charging current for rapid chargers of batteries (as long as adequate 120V power is available).

Yep... what Titan said

The bottleneck is a single or too small .... converter.

The generator should provide enough power to recharge BUT if you are trying to use only one small converter then it has to divide up it's output 12v to:
A) maintain whatever you have turn ON.
B) send enough amps to the battery bank to charge

DO you intend to do a lot more boondocking or visiting parks with generator restrictions?

You could look at your usage and find ways to lessen the demand on the batteries

Have a knowledgeable person look at your present system.
then design up a balanced charging setup that will work for your requirements. (maybe using multiple chargers)


work out your actual usage...

if you mostly use less than 200amps per day could you benefit from splitting your 400ah Bank ..... into 2 separate 200ah banks ?
use one 200ah bank while....... the other 200ah bank is resting / charging

are you running the generator only when the bank is getting low
OR topping up the batteries every day ?

[msusslin]

Originally Posted by Aussieguy

Yep... what Titan said

are you running the generator only when the bank is getting low
OR topping up the batteries every day ?

We start running the generator in the morning after the night use. We would like to keep the generator running during the day to keep the fridge going if we have no solar. However, certain parks have generator run time restrictions.

[msusslin]

Originally Posted by toshu

I have had my Xplorer firefly settings at 14.6 for absorption and 13.8 for float.
When I need to get high voltage for proper slide operation I set float to 14.2-14.3 then immediately return float to 13.8 after slide operation.

Last boondocking trip I also shut off inverter while going to sleep and my domestic refer was fine..and my batteries didn't drop down as far.

We do that too, however, if during the day we have no solar we will have to run the generator longer than 2 hours to keep up with demand and have the batteries ready for the night. Running the RV engine is the only solution so far, hence my concern is that the Onan8K generator might be insufficient to charge the batteries in the time allotment. Some have mentioned the converter to be too small for the job. Heck, I don't know.

Would you know what the absorption time setting is and what it should be set at? Currently set at .1 hours.
Toshu and Vlmagat what is yours set at?

[TitanMike]

Originally Posted by msusslin

We do that too, however, if during the day we have no solar we will have to run the generator longer than 2 hours to keep up with demand and have the batteries ready for the night. Running the RV engine is the only solution so far, hence my concern is that the Onan8K generator might be insufficient to charge the batteries in the time allotment. Some have mentioned the converter to be too small for the job. Heck, I don't know.



Would you know what the absorption time setting is and what it should be set at? Currently set at .1 hours.

Toshu and Vlmagat what is yours set at?

Attachment 280642

Why would an 8K(w) generator be insufficient?

What size is your converter/charger. A 60 amp converter (common size) only draws 900 watts (.9 Kw). That's all the charge you are going to get out of the generator unless you have a larger converter or multiple converters in parallel.


It looks like the max converter output is 41 amps. Whatever part of that that isn't being used in RV is going into the batteries. If at 50% SOC it's going to take a minimum of 5 hours to even get close to 100% SOC.

If you want faster charging you can run generator along with solar power when sun is up--- or more converter/charger capacity. No way around it.

BTW absorption time recommended setting will vary by battery mfr. I have two Battleborns and they recommend .5 hr per 100ah battery. I have my charger set for one hour. If bulk rate time can be set that will depend on total ah capacity and charger output. 400 ah with a 40-50 amp charger should be set for a max of 8-10 hours. An amount of time one would expect a good battery bank to be fully charged.

Sent from my SM-N950U1 using Forest River Forums mobile app

[Aussieguy]

I would think that while using the RV , generator and batteries it is not that critical to get the battery level to exactly 100% every day , just replace what you used getting them to a level as high as possible ... deep cycle batteries are designed for this type of work.



then at end of trip or when you finally get a campground with hookup

you can take as much time as needed to get them topped off to 100% and equalized

[CHICKDOE]

Originally Posted by TitanMike

Why would an 8K(w) generator be insufficient?

What size is your converter/charger. A 60 amp converter (common size) only draws 900 watts (.9 Kw). That's all the charge you are going to get out of the generator unless you have a larger converter or multiple converters in parallel.


It looks like the max converter output is 41 amps. Whatever part of that that isn't being used in RV is going into the batteries. If at 50% SOC it's going to take a minimum of 5 hours to even get close to 100% SOC.

If you want faster charging you can run generator along with solar power when sun is up--- or more converter/charger capacity. No way around it.

BTW absorption time recommended setting will vary by battery mfr. I have two Battleborns and they recommend .5 hr per 100ah battery. I have my charger set for one hour. If bulk rate time can be set that will depend on total ah capacity and charger output. 400 ah with a 40-50 amp charger should be set for a max of 8-10 hours. An amount of time one would expect a good battery bank to be fully charged.

Sent from my SM-N950U1 using Forest River Forums mobile app

what converter do you have that allows you to vary the bulk rate times? it sounds your converter has this and probably other user programable settings.

[TitanMike]

Originally Posted by CHICKDOE

what converter do you have that allows you to vary the bulk rate times? it sounds your converter has this and probably other user programable settings.

I recently upgraded to a Victron Phoenix IP-43 Smart Charger 12/50. It networks with my Victron BMV 712 battery monitor and Victron Smart Solar Charger.

The charger has numerous programmable settings to tailor the charging profiles for what you feel best for your batteries, Lead-Acid or LiFePo4.

It also has a feature that boosts charging voltage from the charger until it reaches the desired voltage at the batteries in order to overcome voltage loss in the wires. Senses voltage from the batteries via the BMV so the charger isn't fooled by voltage drop over connecting wires.

Was designed for boats that use large battery banks and it can be used in parallel with another IP43. They will synchronize and each deliver up it's max output into a thirsty battery bank.

Here's a datasheet on the unit.

https://www.victronenergy.com/upload...0-240V-EN-.pdf

Word of warning, it is pricey. However I was about to upgrade my old PD converter to one of their new ones and this was only a "couple of tanks of gas" more expensive Well worth it however.


It has 5 stages for Lead Acid batteries and three for "Lithium".

Lithium has a bulk charge voltage, an absorption voltage, and a Storage voltage, each easily programmable via bluetooth and a free app.

Also allows the 120 volt input current to be limited should one have a limited power source (small extension, small generator, etc).

[TitanMike]

Originally Posted by Aussieguy

I would think that while using the RV , generator and batteries it is not that critical to get the battery level to exactly 100% every day , just replace what you used getting them to a level as high as possible ... deep cycle batteries are designed for this type of work.



then at end of trip or when you finally get a campground with hookup

you can take as much time as needed to get them topped off to 100% and equalized

The OP has LIFePo4 batteries and they really need to be charge fully on a regular basis. If you don't you start running into unbalanced cells and partial charging can lead to a "charge deficit". If each day you only replace a percentage of the power used, eventually you end up with a well undercharged battery that may let you down on a cold night.

When your "boondocking" is more than just a night in a rest area or a couple nights of dry camping, it's best to fully charge when you can, solar or generator,

[Phreak480]

For all the folks commenting based on small converters in their trailers please realize that info isn't really relevant here. This is a much more capable and controllable setup than a simple multi stage converter charger.

first of all this rig has a sizeable inverter charger capable of at least 100amps of charging power (my 2017 can charge that high and the new ones might be higher) and as long as it's fed proper input and set properly it should be able to easily charge these batteries in a few hours.


To the OP, I'd suggest trying to force bulk mode, not exactly sure how in your setup as my 2017 has different controls.

[Chuck_S]

It's helpful to think of the battery sucking power from the charge source and the strength of the sucking is based on voltage differential. An 11 volt battery will suck hard but since surface voltage increases rapidly this tapers off quickly. (Voltmeters only sense surface charged so a reading of 12.7vDC does NOT always indicate a full battery.) A charger voltage of 13.8v only results in a trickle charge. Smart chargers (and even my converter) boost their voltage to keep the differential high.

I read (somewhere) that taking a battery from 80% to 100% takes just as long as going from 20% to 80% which makes trying for a 100% battery a long process. WW2 diesel electric submarines had to run on the surface to charge their batteries and I also read it was common for them to run in the 20%-60% charge level. Batteries at this level absorb power very quickly.

-- Chuck

[Aussieguy]

Originally Posted by msusslin

We start running the generator in the morning after the night use. We would like to keep the generator running during the day to keep the fridge going if we have no solar. However, certain parks have generator run time restrictions.

I would find a knowledgeable person ... solar / off-grid
in person that can look at your:

ACTUAL USAGE then battery / charging system + daily charge times + charge rates + how often you can charge

He/she can then advise you...
you spent the $$ on quality batteries and now need advice that is probably beyond 90% of us.


Much more information is required to give good advise!
number of batteries , how the batteries are joined , 4 x 100ah , 2 x200ah , usage each day ,
solar panels type, size and number
room to stow a solar suitcase or 2 for better positioning


ideal solution would be more solar,
but that depends on your intended visit locations how often you change location.
winter in FL or TX or staying in that cold frozen stuff?

certainly looks like to me you need a better charging system that suites your needs. May be worth your time and a few $$ to seek professional help
(NOT the Local RV center)


my 2c

[Aussieguy]

Originally Posted by TitanMike

The OP has LIFePo4 batteries and they really need to be charge fully on a regular basis. If you don't you start running into unbalanced cells and partial charging can lead to a "charge deficit". If each day you only replace a percentage of the power used, eventually you end up with a well undercharged battery that may let you down on a cold night.

When your "boondocking" is more than just a night in a rest area or a couple nights of dry camping, it's best to fully charge when you can, solar or generator,

Isn't that what I said....
then at end of trip or when you finally get a campground with hookup

you can take as much time as needed to get them topped off to 100% and equalized

I class lifepo4 as deep cycle ........ and they are designed to be deeply discharged
won't kill the battery if they boondock once in a while and then fully charges the battery when he/she can

Camping suppose to be fun and not have to worry about every single ounce of battery life battery all the time.

[Captain Insaino]

X2 What Aussieguy suggested about solar. You dismissed it due to shady conditions. A few panels in series can provide decent additional charging amperage even in full shade.

[msusslin]

Originally Posted by Phreak480

For all the folks commenting based on small converters in their trailers please realize that info isn't really relevant here. This is a much more capable and controllable setup than a simple multi stage converter charger.

first of all this rig has a sizeable inverter charger capable of at least 100amps of charging power (my 2017 can charge that high and the new ones might be higher) and as long as it's fed proper input and set properly it should be able to easily charge these batteries in a few hours.


To the OP, I'd suggest trying to force bulk mode, not exactly sure how in your setup as my 2017 has different controls.

Thank you for your feedback. As far as I'm concerned, the converter is not the issue, it's the proper settings I might need to finetune.
I don't see a setup on our firefly to set the charger to Bulk mode, as the charger is set to Float.

[msusslin]

Originally Posted by Captain Insaino

X2 What Aussieguy suggested about solar. You dismissed it due to shady conditions. A few panels in series can provide decent additional charging amperage even in full shade.

We do get some solar charging during the day which will reduce the Amp usage during the day slightly, just not enough to recharge the batteries as they would under full sun. 800W in series panels on the roof.