Convert to LiFePo4 battery video

[F350guy]

Originally Posted by craigav

It doesn't appear that Progressive Dynamics states the charge profile for your converter outside of the LI setting. It is common though for many non-li converters to charge at 14.4 until the current is below 5a or timed out (often 4 hours) and then drop to 13.6 and then if no load (or little load) down to 13.2 until a higher current load is placed on the converter (or the voltage drops further), such a profile is not a concern even for a LifePo4 setup. Just that if you had a lot of LifePo4 capacity then it would take longer to reach 100% charge. I have a PM3 that is not two stage (the model prior to the LI model) and has either constant voltage (adjustable) or 3 stage. With it set at 3 stage, then it behaves as I described above and what I prefer. Keeping a LifePo4 at 14.4~14.6 forever will decrease the overall life of it.

I wouldn't make any changes to the new truck until after you determined what the current flow (amps) is to the trailer. If you don't have a clamp style dc digital ammeter, then that is what I would order first and then determine if installing a dc2dc charger is needed. Having even a small (say 20a) dc2dc charger in the trailer at the battery location is likely what I would install as having it would keep the charge current to the trailer low enough to not to have to worry about overloading anything. Keep in mind that if you pull over at a non-shore power location for an overnight, that you need to unplug the trailer connecter otherwise your truck battery itself could run down if you used too much power in the RV overnight or if the DC2DC charger kept charging off of the truck's battery. If you installed a 20a renogy (likely victron as well) and installed that in the truck itself instead of in the trailer (under the hood somewhere perhaps) then the dc2dc charger does have the ability to turn itself off based on whether or not the key is turned on, so in that case, once you turn off the truck, you wouldn't have to worry about unplugging the trailer connector. Point being, I likely would install a DC2DC charger, although I would check the current flow first to see if I really needed one, but for the key off disconnect, that could be of value in of itself otherwise you will need to unplug the trailer each time. ~CA

btw, I suggest a 20a dc2dc charger more to protect the truck's existing wiring, not necessarily for the alternator. A 20a output dc2dc charger will likely pull ~25a on the input side and I wouldn't be surprised to find the existing charge circuit in the truck to the trailer connecter to be rated\fused at 30 amps. Anything larger would likely require running new and heavier cables all the way from the trucks battery/alternator to the RV's battery.

I ordered a Victron 12 12/18 dc to dc isolated charger and a clamp style meter. I will probably wait until I get the new truck to install the charger but thought I might as well get it now. If I'm understanding you correctly it's best not mount the charger using the trailer side of the truck charging line to power it. I found it connected to a bus bar above the battery compartment along with the solar charge wire. I don't have solar, just the prep. The truck wire is 10 ga. I will check the voltage once I get the clamp meter. The truck on order will have 410 amp dual alternator so not sure that makes any difference. I also think my current truck does also. Thanks.

[craigav]

Originally Posted by F350guy

I ordered a Victron 12 12/18 dc to dc isolated charger and a clamp style meter. I will probably wait until I get the new truck to install the charger but thought I might as well get it now. If I'm understanding you correctly it's best not mount the charger using the trailer side of the truck charging line to power it. I found it connected to a bus bar above the battery compartment along with the solar charge wire. I don't have solar, just the prep. The truck wire is 10 ga. I will check the voltage once I get the clamp meter. The truck on order will have 410 amp dual alternator so not sure that makes any difference. I also think my current truck does also. Thanks.

In line with some of my earlier ramblings Every setup is a bit different and if you are going to be using an 18 amp DC2DC charger (I suspect that is the output) then the input would be likely around 20% higher so ~22a and that wouldn't concern me if installed in the RV and using the existing setup. The concern would be more when using a larger DC2DC charger, say in the 40a~60a+ output range which would likely exceed most trucks charge line and the trailer connector. I haven't looked at new trucks lately, but I suspect most are wired and protected at around 30a for the 12v power line going from the truck to the RV. The other concern (that I don't think applies to the Victron... maybe and something to check) is that many DC2DC chargers need an ignition trigger connection to turn on and off, and if the DC2DC charger doesn't have that or sense the higher voltage, it could continue to operate (stay turned on and charging) even with the Truck turned off which would drain the truck's batteries if you don't disconnect the trailer connector. ~CA

[F350guy]

Craig, hope you will see this. I don't know if I have an issue or not. Hopefully not.

I got everything hooked up and it is working. I haven't tested the jacks yet but will some time today. My concern is with my new PowerMax PM3-55LKL converter. The on line literature and specs say in the lithium setting it will fast charge at 14.6 volts and then float at 13.6. I'm not sure why but the manual that came with mine says it will float at 13.2, not 13.6. I checked the battery before I installed it and it showed it was 13.18. I have a shunt based monitor and when I hooked everything up it showed 13.2. The converter made a humming noise for a few minutes when I turned it on and the voltage at the battery was above 13.3 but then dropped to 13.24 when it shut off. My assumption is the converter thinks the battery is where it should be at 13.2 The Renogy 200ah battery shows full charge is 13.6 volts. The 13.2 I'm getting is 90% according to the chart.

From what I can deduce the converter will always keep my battery at 90% charge. I don't know if that's a good thing or not. I know it will operate everything so that's not a concern. My concern is for the long term health of the battery.

The PowerMax has a switch for 3 charge settings. One is the lithium. Another is a constant charge rate which can be adjusted. The other is for LA and AGM. It is a 3 stage setting. (1) A fast charge of 14.6V, (2) a standard charge (absorption 13.6) to bring the battery up to a full charge at a safe rate and (3) a trickle charge (float 13.2) to keep the battery fresh during times of load inactivity. Would this be a better setting for my lithium? Thanks.

[craigav]

Hi Jim, I will likely be checking the forums only in the evenings for a while so hopefully that doesn't delay you.

The first thing I would suggest doing is to make sure the converter is working correctly. Also, what I suspect is that they provided the older LK manual, check out the link and at the bottom of my comment here and at the bottom of that link (web page) is link to the correct manual for the LKL and has the 2 stage details in it. In the manual is a reference that you need to switch the mode with the unit powered off. Likely it only determines the mode upon startup and even if you did switch it to 2-stage when it was powered off, I would do it again, power off the converter, slide the switch left and right and then back to 2 stage then power it back on. I suspect it is in the 3 stage mode if your voltage was 13.2 which it should go to 13.2 only in the 3-stage mode, otherwise 13.6 should be the lowest in the 2-stage mode.

Which Shunt monitor do you have? I ask because knowing the charge level can help you determine what the best settings are for you. Also, which Renogy battery do you have? Some have bluetooth and I believe those with BT can give you a state of charge like your shunt based monitor will.

At a high level, I would likely use the 2 stage setting of the converter as the most common setting as that likely would be best overall for most scenarios. However, if the mode switch is relatively handy, I would use the 14.6 fixed voltage during times you plan to need battery power when you will have extended periods of time between charging availability such as if you plan to be boondocking as well as when you want to charge it back to 100% in the shortest time possible (such as when charging via a generator), and I likely would use the 3 stage during times you plan to store the RV for a week or more so the charge level will come down some. I will add that just going by voltage isn't really a good way to determine the charge level, but the shunt if setup to count the input and output current should be able to do that, in any case, the 3-stage mode can help you get to ~60% easier, or you could just turn off the converter via the breaker or unplug it. It may be hard to get to ~60% battery in any of the modes as the 2 and 3-stage mode will likely kick the converter back to the 14.6 before the battery ever gets that low but I would suspect you could get a bit lower with the 3-stage mode. I will add that for a LifePo4, for the most longevity you don't want to keep it at 100% charge level always, unless of course you need that, and the battery will still last a long time but not as long as if you stay around 85% and store it around 60%.

Check out this link and look at the bottom for a link to your converter. ~CA

https://powermaxconverters.com/produ...ithium-series/

this is a direct link to the manual

https://powermaxconverters.com/wp-co...KL-Manual.docx

[F350guy]

Thanks, Craig. Love your expert responses. I have a Renogy 200ah Core battery. It does not have Bluetooth nor is it heated. I saw they are coming out with one sometime soon but I need a battery now. For $20 more they included their shunt based monitor. I don't know how accurate it is.

I do have the PowerMax 55LKL. Yesterday it would hum for a little bit then go off. My voltage as shown by my meter and by the monitor was 13.1 this morning. The converter was doing nothing. I called PowerMax and they had me remove it and check the voltage coming out. It showed 13.52 in float mode which should have been good enough. I hooked it back up an maybe for 30 minutes or so the fan would cycle on and off and the voltage at the battery increased to 13.4. Then it just quit. I cycled the jacks to see if I could get it to start again but no luck. I did smell something like hot electronics. I called PM again and they are sending me a new one as they think it is defective.

I hope to have it in a few days and maybe have better luck.

[craigav]

I suspect the converter may be bad as well based on the voltages you stated when in the 2-stage mode.

Is this the shunt monitor you have?

https://www.renogy.com/500a-battery-monitor-with-shunt/

[F350guy]

Yes it is.

Everything is on hold now waiting on the new converter. It's got to make its way from Florida to Oklahoma. We were hoping to take the grandkids somewhere on spring break next week. We'll see.

[Kevin Cooper]

Originally Posted by F350guy

Yes it is.

Everything is on hold now waiting on the new converter. It's got to make its way from Florida to Oklahoma. We were hoping to take the grandkids somewhere on spring break next week. We'll see.

The grandkids are very very important! Your converter is working somewhat, right? So what if it doesn’t charge to 100%.
Or you can take it with you, and change it while you ate out. Grands love to help!
Life’s to short to waste!

[F350guy]

Got the new converter in today. It's working exactly like it is supposed to. Thanks to Craig for the help and Kevin for starting this thread. It's been very helpful. The only thing left to do is hook up to the truck and see if the dc to dc charger works. Don't really need it for now but it's gravy if it does. The trip with the grandkids is on.