Going LiPoFe4 - Renogy Sale - Page 3

**creativepart** · 04-13-2022, 06:48 AM

Thanks for that diagram. I think it is the same as mine. It gives me lots of ideas. I’m going to head out to the storage yard and check out a few things in the next day or two.

**creativepart** · 04-13-2022, 10:26 AM

Here is some current thinking about this:

DavidM · 04-13-2022, 11:11 AM

Looks like a slick way to use the DC2DC charger or the BIM with a flick of the switch.

David

**creativepart** · 04-13-2022, 11:24 AM

The issue still is the generator. I'm going to do some testing this week. I'm going to remove the cable from the BIM to the Batteries and see if the Generator will start. I'm expecting that it will not.

The other question is... If the cable from the BIM is removed but the RV's engine is running will the generator start? Looking at the drawing it "might."

We stop for lunch and run the gen to make lunch. Will I have to go out to the battery bay and switch over from off or D2D charging to connect the BIM to start the genset? PLUS many times we run the generator while we drive to run the A/C in the west texas heat. Will we be able to do that with the connection from the house batteries to the BIM in the OFF position.

Shedboy · 04-14-2022, 08:30 AM

Thanks for the Renogy info, it worked! Although converting to LiFePO4 wasn't on my priority list, I don't think the cost of upgrade is going to diminish in the future so I committed. Now have to collect parts to complete. Next on the list is upgrade from 300w inverter to 1000w unit w integrated T/R and solar controller. Xantrex seems to have a comprehensive offering.

**creativepart** · 04-14-2022, 12:20 PM

Great Shedboy. Let us know how you proceed.

**creativepart** · 04-14-2022, 12:37 PM

I went out to the RV in storage today. I found that my plan in post #12 above will not work.

I easily located the cable from the House side of the BIM on the battery bank. And removing that cable stopped all charging from the alternator. BUT it also removed all power to the Coach Disconnect solenoid. This not only made it impossible to start the generator but when I tried to start the gen it kicked off the solenoid and all power from the house was out and the solenoid wouldn't reset - because it had no power to it.

I also learned that the alternator puts out 65 amps at first start up of the engine. This number dropped pretty quickly to 55 amps. Also, when revving the engine it changed the amps a little but not tons.

So, plan would be to put a disconnect on the wiring from the Alternator to the BIM (chassis disconnect). But if I did that the Chassis battery would lose charging from the alternator when driving. Not good.

Lastly, it "might" be OK to do nothing. My RV has been in storage for almost a month and I have covered storage so my solar doesn't trickle charge my house battery bank. Today, my house batteries were at 12.39volts which is about 80% state of charge. Starting the engine produced 65 amps of charging.

I have had others with similar systems to mine tell me they didn't do anything but monitor the alternator's output via the Victron smartshunt app as they drove and that they have had no issues over a fairly long period of time.

That doesn't seem all that comforting.

Still thinking and digesting all of this info right now. We leave for a 4 week trip in two weeks. So, I very well may NOT install the new batteries before we leave.

DavidM · 04-14-2022, 12:54 PM

I have been following this issue for over a year on three RV forums and one boating forum and several people have reported their alternator current while charging into depleted lithium batteries. No one has reported bad effects on the alternator.

Here is a very, very broad summary of what has been reported and heck maybe I made some of it up, can't remember everything

:

Two moderately depleted 100 Ah lithium batteries will pull 40-50 amps when the chassis engine is started. It is believed that this is ok for the alternator.

With four such batteries the current jumps to 80 amps. One thought it was ok, another didn't.

And FWIW Mercedes recommends limiting external (to the chassis) current from their Sprinter alternator to 40 amps. Some have said you can go as high as 60 with no harm.

Sooooooo, I would hook the lithiums up after letting them discharge to at least 50% and measure the current from the alternator. Also check the case temp with an IR gun. Anything below 50 amps and 200 F is probably ok.

David

**creativepart** · 04-14-2022, 01:07 PM

Easier said than done David. When my batteries arrived they were 30% SOC and I charged them up to 99%. They lose a little siting in my garage but not all that much. I don't have a inverter at home that I could connect and bring the batteries down to 50%.

The four AGM batteries I have in my RV now weigh 65 lbs each. Removing them, installing the new batteries for a "test." is a major operation.

Even then, if the test turns out "good" will I ever feel safe - as in, sure that my alternator is safe and next that my batteries are safe. And, knowing that I won't break down 1000 miles from home.

More study is needed. That's for sure.

uthurricaner · 04-14-2022, 01:44 PM

Creativepart, I would not wait too long to run some capacity tests on the batteries or find out how long Renogy return policy is. AS far as using the alternator directly on yours and my motorhome, that is a no go. The alternator charging amps may be fine on certain motorhomes as it is a function of the wire size from the alternator to the house batteries. In are case, Winnebago to there credit uses some very large wire. I did a test with one 100 amp battery 75% discharged and had 80 amps of charge current. As I recall we hove 175 amp alternators so I would not go much over 60 amps charge rate.

Sam

DavidM · 04-14-2022, 03:40 PM

Quote:

Originally Posted by uthurricaner

Creativepart, I would not wait too long to run some capacity tests on the batteries or find out how long Renogy return policy is. AS far as using the alternator directly on yours and my motorhome, that is a no go. The alternator charging amps may be fine on certain motorhomes as it is a function of the wire size from the alternator to the house batteries. In are case, Winnebago to there credit uses some very large wire. I did a test with one 100 amp battery 75% discharged and had 80 amps of charge current. As I recall we hove 175 amp alternators so I would not go much over 60 amps charge rate.

Sam

Yes, wire size will have a lot to do with charging current. If you are seeing 80 amps into a 50% charged single 100 Ah battery, I agree that is too much.

I will add you to my mental database of those reporting alternator charging current.

David

**creativepart** · 04-14-2022, 05:42 PM

OK, here's my new Plan B Remove the Precision Circuits BIM.

With the addition of the D2D charger every function is maintained EXCEPT Automatic Charging of the Chassis Battery on Shore Power AND AUX Emergency linking of both house and chassis batteries.

What do you folks think of this idea?

uthurricaner · 04-15-2022, 07:54 AM

I don't see any way around eliminating that BIM. What I'm going to do is install a switch in the ground wire to the BIM. This way I can use the bim when it is needed to charge the chassis battery and for emergency start. There is no problem with the alternator charging unless the house batteries are discharged from boondocking so I will always disengage the switch for the bim when dry camping. Still it is a work in progress and this is not a perfect solution. Creativepart, I'm sure your aware of this but your drawing did not show it, make sure you fuse the input and output lines on the dc to dc charger.
Sam

**creativepart** · 04-15-2022, 08:07 AM

Sam, how do you find the ground wire on the BIM. Can it be seen in the photo below?

I guess the BIM is mounted horizontally and the ground wire is behind it in this photo???

uthurricaner · 04-15-2022, 11:07 AM

Yes it is about 3" behind the large wire with the yellow heat shrink. It is a #14 white wire. Trace that wire and cut it at least 6" from the conn point so you can splice onto it. Check out the pic of the bim I posted.

Sam

**creativepart** · 04-15-2022, 01:54 PM

I spent some time going over the BIM and Disconnect Relay wiring today. I've pretty much got a plan to physically remove the BIM. I'll label all the wiring so I can reconnect it if I need to.

I've ordered the 30 amp Victron D2D charger, fuses, 8ga wire etc. All arrives on Monday.

I plan to bring the RV home tomorrow, get the BIM removed, uninstall the old batteries and install the new batteries over the weekend. Then next week when all the stuff arrives I'll wire up the D2D charger.

I did some extensive testing to determine what cables to remove to disable all the power to the BIM and how to get it out of the RV. I thought it was going to be a tangle of wires but honestly, it doesn't seem that bad.

The photo I've been posting of this area is not my RV. Here's the photo on my RV. I'm psyched, looking forward to this.

**creativepart** · 04-15-2022, 03:44 PM

Getting ready for my battery changeover from 4-100ah AGM to 2-200ah LiFePo4 Batteries this weekend I downloaded the battery wiring PDF from the Winnie Owner's Resources website.

I have color coded all the cables and identified where they connect so I can be prepared to accommodate the various connections. Having worked with photoshop for decades made this a fairly easy process.

Of course, I've taken a LOT of photos of the batteries and their cables. So, it shouldn't be too difficult to get this all sorted (he says confidently).

Here's the batteries in OEM configuration:

**creativepart** · 04-16-2022, 04:01 PM

Day One:

I removed the BIM today. I decided to not remove it from the RV. After disconnecting the two main chassis/house battery cables and unscrewing the metal base from it's mount I could pull it completely out into the compartment and I decided to wrap it in foam to protect it I was able to slide it back behind the two power solenoids but kept the smaller cables the go to the ignition, the AUX start wiring, etc connected in their places in case I ever need to go back to stock on this.

It's not a difficult job. If you did it more than once it would take an hour. If you need to pickup a few parts, find lost tools and eat lunch it takes about 3 to 4 hours.

I've tested I believe everything and all indications are that everything works as expected.

Here's a photo of my BIM removed but before going back into the power cabinet in the RV.

**creativepart** · 04-17-2022, 02:51 PM

Day Two

Four 100ah AGMs removed and 2-200ah LiFePo4 batteries installed. All is well and working normally. The combined pair of new batteries are 130lbs lighter than the four AGMs that were removed.

Only one surprise - the new batteries was enough wider than the old ones that I have to get a longer piece of metal strapping to tie down the batteries.

Victron DC to DC charger due to arrive tomorrow and be installed probably on Tuesday. Then the project will be complete.

Here's the empty battery bay... and the full battery bay with new LiPo batteries.

**creativepart** · 04-20-2022, 05:14 PM

Day 4
All done... well, one little thing still to do.

I installed the Victron Orion-TR Smart DC to DC charger today. So now my house batteries will receive a charge when I'm driving the RV.

I power the D2D charger off of the Chassis (starter) battery and this Victron charger automatically senses when the engine is running. So, there is no need to run an ignition trigger cable to turn the charger on or off when driving/not driving.

The one little project still to do is to install an Amp-L-Start device. This device senses the voltage of the Chassis battery and the voltage of the House battery and when the Chassis battery discharges while sitting in a campground for weeks and weeks, this device keeps a trickle charge on the starter battery by taking power from the House batteries.

After all this is completed I should have replaced all but one of the functions of the BIM I removed on the first day. Whew!