Converting to Lithium house Batteries

[BobC]

You can get a pretty good education here on LiPo batteries, although it's not RV-specific:

https://www.youtube.com/channel/UCoj...q8kmJme-5dnN0Q

[19view]

Thanks creativepart. I did confirm that the charging profile of the converter is compatible with these batteries. I'll read more from the link you sent me.

[19view]

I believe my rig is very similar to yours (2019 View, Sprinter chassis, 220 amp alternator). I was told by Battle Born that the alternator may create TOO much charging current to their 110Ah LiFe batteries (2) and that a DC to DC charger may be necessary. I could see nowhere in the posts I have read that this was an issue. Did you check the charging amperage from the alternator into your lithium battery bank? That was a suggestion from a different person at Battle Born when I called back for more clarification. He also brought up isolation as an issue, in that there could be a power drain from the house to the chassis battery. Have you had any problems with these issues?

Thanks for your input.

[creativepart]

Originally Posted by 19view

I believe my rig is very similar to yours (2019 View, Sprinter chassis, 220 amp alternator). I was told by Battle Born that the alternator may create TOO much charging current to their 110Ah LiFe batteries (2) and that a DC to DC charger may be necessary. I could see nowhere in the posts I have read that this was an issue. Did you check the charging amperage from the alternator into your lithium battery bank?

Back on page 2 of this thread and in other batteries posts I have been saying

This is a common discussion point. Not unusual at all. Some folks chose to ignore the issue, some remove the alternator from the house battery bank entirely, some use an isolator and some use other methods to accommodate the charging of LiPo batteries with their vehicle’s alternator.

Rather than be a problem for charging Lithium batteries, I have been advised that the biggest issue is with the Alternator. That the Lithium batteries are able to withdraw so many amps from the alternator that it can overheat and fail.

I see many battery companies and installers suggesting Dc to Dc chargers. Taking a set amount of amps from the alternator and then providing the best charging profile for the Lithium battery chemistry. This approach protects both the batteries and the alternator.

[19view]

Thanks. My rig is in a shop now to swap the lead acid with the lithiums. I've asked them to check the amperage from the alternator and will go from there. They don't want to take on the installation of the DC-DC charger, like many other shops I have called.

[gurroz]

Originally Posted by creativepart

Back on page 2 of this thread and in other batteries posts I have been saying

Rather than be a problem for charging Lithium batteries, I have been advised that the biggest issue is with the Alternator. That the Lithium batteries are able to withdraw so many amps from the alternator that it can overheat and fail.

My understanding is if the lithium battery has a low state of charge your alternator can overheat and fail if you are charging for an extended period of time. It does not seem to be a problem if the batteries are charged at a high level. I intend to turn my coach batteries off during transit or possibly run them for 15-20 minutes going down the road charging off the alternator and then turning them off for an extended period of time. I use solar and a Bluetti 500W battery pack for TV and device charging so my coach batteries are rarely discharged to 50%.

[Phil G.]

I'd have thought that modern alternators were well controlled by electronics so as to be impossible to burn up in any way.

Our motorhome's 130 amp Ford alternator is able to deliver at up to an 80 amp rate with the engine idling when our 230AH AGM coach battery bank has been 50% discharged from camping. The performance curve for the alternator shows 80 amps to be at it's limit with the engine spinning at only idle RPM ... and it has been performing this way for around 14 years. The Ford alternator is of course over-driven by it's pulley so as to spin faster than actual engine RPM.

I'd be really surprised if a 220 amp Sprinter alternator could be damaged by any external load presented to it - due to protection circuits that must be, or had better be, either built into it or contained in a separate box mounted close by.

Isn't there a Sprinter document available somewhere for owners specifying what the 220 amp alternator is capable of - and how well it's protected from load damage?

[AJMike]

Originally Posted by Phil G.

I'd have thought that modern alternators were well controlled by electronics so as to be impossible to burn up in any way.

Our motorhome's 130 amp Ford alternator is able to deliver at up to an 80 amp rate with the engine idling when our 230AH AGM coach battery bank has been 50% discharged from camping. The performance curve for the alternator shows 80 amps to be at it's limit with the engine spinning at only idle RPM ... and it has been performing this way for around 14 years. The Ford alternator is of course over-driven by it's pulley so as to spin faster than actual engine RPM.

I'd be really surprised if a 220 amp Sprinter alternator could be damaged by any external load presented to it - due to protection circuits that must be, or had better be, either built into it or contained in a separate box mounted close by.

Isn't there a Sprinter document available somewhere for owners specifying what the 220 amp alternator is capable of - and how well it's protected from load damage?

We just had 2 BB Lithium batteries installed in our 2018 Fuse (on a Ford Transit 350 HD chassis) along with a Renogy 40 amp DC-DC charger. I am only mentioning this because it might have some bearing on your comments.

I also have a Victron battery monitor and have installed the Victron app on my smartphone and I was monitoring the charger output while we were driving. What I noticed was that the current output, normally about 35-42 amps (the compressor fridge was running eating some of this, and the solar panels were adding some as well) would suddenly drop back to at or near 0 amps. This would last for perhaps 10 seconds and then it would go back up to the 40 amp range. I assumed at the time that the electronic in the alternator was shutting the output down momentarily to keep the alternator healthy. That is a guess, of course, but something was going on and I don't think it was an issue with the charger itself, which seemed to work properly in all other respects.

As for the alternator output, with the charger shut down (I have an ON/OFF switch on the ignition line to the charger) and with the alternator bridge active I noticed well over 100 amps going to the batteries so the alternator is capable of outputting well over 80 amps. It is rated at 210 amps but I would not expect to see that.

[19view]

Thanks for all the comments. It is helpful.

[gurroz]

AjMike, you and I are close to being neighbors, I live in Gilbert. It appears we are on the sale lithium battery conversion journey. I have enjoyed your post. Thanks for the contributions. I learn a great deal from this forum, thanks everyone.

[AJMike]

Originally Posted by gurroz

AjMike, you and I are close to being neighbors, I live in Gilbert. It appears we are on the sale lithium battery conversion journey. I have enjoyed your post. Thanks for the contributions. I learn a great deal from this forum, thanks everyone.

Hello neighbor.

We live in the east Valley, so not so far from Gilbert and, of course, we are often in Gilbert shopping, or at least were until all of this mess.

I have to admit that this has been quite an experience for me.

We moved from the OEM batteries to AGMs because I could not properly service the OEM batteries due to the lack of space in the Fuse's battery compartment and the terrible heat during the summer. I assumed that maintenance-free was the way to go. But the compressor fridge in our RV used up so much power during the night that the AGMs were always down to 12.0 or so volts in the morning - not enough to harm them but low enough for me to know that sooner or later we would use too much power for them to handle, so I began to look for Lithium while the AGMs were still perfectly fine.

Fortunately we found a local installer who was both reasonably priced and recommended by Battle Born so we got the batteries at a decent discount and he did the installation of the DC-DC charger as well. The whole business was about 2/3 the price of one of the other local shops, and the work seemed very well done, so we are happy. And I now find that when we get up in the morning I still have 75-80% of battery power so I now sleep better at night.

I put off some work until later this Fall but am satisfied with our purchase and the install job that was done. Hope this goes well for you as well.

[pinchio]

I'm in the process of sizing up my coach for replacing the coach batteries with BB lithiums. I have the 2008 Siteseer running on a 2007 F53 chassis and the alternator puts out about 130amp. My question is do I need to replace the stock battery solenoid with something like Victron Cyrix-li-ct or LI-BIM?

[creativepart]

This seems to be up to you. Many replace their old house batteries with BBs and do nothing else. Other's add a battery isolator (I don't think they replace a solenoid, just add a new one) that limits the time spent charging from the alternator. Still others take what looks like a safer route and install a special DC to DC charger. This limits the alternator output and charges your house batteries with a custom charging profile.

Read as much as you can. Ask Battleborn. I believe they sell both the Battery Isolator and a DC to DC charger.

I've yet to see definitive statements about what's best from anyone but the DC to DC Charger is talked about most often.

[Winterbagoal]

Originally Posted by jcurtisis

WINTERBAGOAL: After grinding off the lip of the existing battery tray were you at all concerned that the new LI batteries extend about 1.5” beyond the sides? I was thinking of putting a piece of thin sheet metal under the batteries and bend the edges up to form a new lip....perhaps that is overkill (?). Also, how thick was the synthetic mat you put underneath the batteries?

I guess I missed this one. Better late then never?
No, as I mentioned in my "grinder" post, I cut a piece of that thick interlocking floor pad to fit the entire east/west bottom of my battery tray, before I placed the new batteries in it. It helps protect them from the vibration of driving, and also keeps road debris from hitting/sticking to the bottoms of the exposed ends of the batteries, had I just dropped the batteries down into the tray with nothing underneath them. I think the mat was around 1/2" thick maybe? The battery tie downs need to have the bases on the back side of the tray compartment raised up a little, but it all fit after some fiddling and just a hint of profanity.
You'll figure it out, as you go.

[AJMike]

Originally Posted by creativepart

This seems to be up to you. Many replace their old house batteries with BBs and do nothing else. Other's add a battery isolator (I don't think they replace a solenoid, just add a new one) that limits the time spent charging from the alternator. Still others take what looks like a safer route and install a special DC to DC charger. This limits the alternator output and charges your house batteries with a custom charging profile.

Read as much as you can. Ask Battleborn. I believe they sell both the Battery Isolator and a DC to DC charger.

I've yet to see definitive statements about what's best from anyone but the DC to DC Charger is talked about most often.

As a newbie to Lithium batteries I suspect I went for what I thought to be the safest route with the DC-DC charger. BB does sell both a charger (which I assume they are very proud of considering how much they charge for it) and a BIM. However, as I mentioned earlier, I have now seen what appears to be the alternator current to the batteries (in my case to the charger) going on and off in what I assume to be a regulated short time interruption to make sure the alternator does not work too hard. And that has made me wonder if I even needed the charger to protect the alternator.

I did measure the current to the batteries when the engine was running and the charger was off and the "bridge" switch activated and it was well over 100 amps. The alternator in our 2018 Fuse is rated at something like 210 amps so there is plenty of power to apply.

[Winterbagoal]

Originally Posted by AJMike

As a newbie to Lithium batteries I suspect I went for what I thought to be the safest route with the DC-DC charger. BB does sell both a charger (which I assume they are very proud of considering how much they charge for it) and a BIM. However, as I mentioned earlier, I have now seen what appears to be the alternator current to the batteries (in my case to the charger) going on and off in what I assume to be a regulated short time interruption to make sure the alternator does not work too hard. And that has made me wonder if I even needed the charger to protect the alternator.

I did measure the current to the batteries when the engine was running and the charger was off and the "bridge" switch activated and it was well over 100 amps. The alternator in our 2018 Fuse is rated at something like 210 amps so there is plenty of power to apply.

Thinking about your slide/blown fuse issue.
Is the DC to DC charger a timed power on/off? Can you set it to connect for a specific period of time, and then disconnect for another period of time, or is it random. or is it based on alternator output and battery resistance?
I'm wondering if you had a perfect storm of DC/DC charger off/on at the same time as you engaged the slide motor(s) and the resultant power surge from the alternator (which is usually helping thr chassis/coach battery to activate the slide?) surge caused the fuse to get caught in the middle and it blew. I don't recall if your engine was running, as it's supposed to, during slide activation?
Section 10-1 in my OM.
"SLIDEOUT ROOM LOCK
SYSTEM
The ignition key must be placed in the on or
run position to operate the slideout room(s). The
park brake must be applied for the room(s) to run.
Winnebago recommends running the engine
whenever you run the slideout rooms in or out,
the engine alternator should insure the rooms
have adequate 12-volt DC power to operate
correctly."
I'm wondering if adding the DC/DC charger has created another problem for you when you want to run stuff that requires the engine running and the alternator/batteries to be providing the power?
Just spitballin' ....

[AJMike]

Originally Posted by Winterbagoal

Thinking about your slide/blown fuse issue.
Is the DC to DC charger a timed power on/off? Can you set it to connect for a specific period of time, and then disconnect for another period of time, or is it random. or is it based on alternator output and battery resistance?

The only information I have is from the Victron BM and it shows that the current to the batteries drops to 0 for very short periods of time, perhaps 15 seconds, before going back to the normal 40 amp output for a relatively long time, so the timeouts are very short and interspersed with long charging times.

Unfortunately since all I see is the current to the batteries I have no way to know if the dropout is caused by the alternator switching off to protect itself or if it is caused by the DC-DC charger. I have been assuming that it is the alternator because there is nothing in the charger documentation that says that it works that way. I would have called Ford to ask them but I don't have a number to do that.

If it is the alternator switching itself off when it senses that it is over some spec then perhaps the charger is not needed. If it is the charger, then it is almost certainly a problem, but I have no way to know which one is the cause.

Part of me is kicking myself for buying and using the Renogy DC-DC charger instead of ordering the Victron 30 amp one, but we were under a time constraint at the time and the Renogy came from Amazon and was thus only a 2 or 3 day delay while the Victron would have had to come from either Flagstaff or San Diego and I have no idea how long it might have been before it actually arrived. In the Fall I expect to replace the inverter/charger for the Lithium one and I am strongly tempted at that time to also replace the Renogy charger with the Victron one. I will see how things go until then.

Originally Posted by Winterbagoal

I'm wondering if you had a perfect storm of DC/DC charger off/on at the same time as you engaged the slide motor(s) and the resultant power surge from the alternator (which is usually helping thr chassis/coach battery to activate the slide?) surge caused the fuse to get caught in the middle and it blew. I don't recall if your engine was running, as it's supposed to, during slide activation?
Section 10-1 in my OM.
"SLIDEOUT ROOM LOCK
SYSTEM
The ignition key must be placed in the on or
run position to operate the slideout room(s). The
park brake must be applied for the room(s) to run.
Winnebago recommends running the engine
whenever you run the slideout rooms in or out,
the engine alternator should insure the roomcs
have adequate 12-volt DC power to operate
correctly."

Interesting thought, but I just don't know.

As you mentioned, it is not really necessary to have the engine running to extend or retract the slide. It is only necessary for the key to be in the ON position and the parking brake to be on. As a general rule I have not run the engine when I extended or retracted the slide but decided to do so with the new BB batteries. After seeing (and replacing) the blown fuse I stopped running the engine with the slide motor and did not have the same problem so I don't know if the two are directly related or if it was some kind of once-in-a-while problem.

We have a trip scheduled for next week and I will see if I can reproduce this problem now that I have a handful of extra fuses.

Originally Posted by Winterbagoal

I'm wondering if adding the DC/DC charger has created another problem for you when you want to run stuff that requires the engine running and the alternator/batteries to be providing the power?
Just spitballin' ....

I hope not, but I don't think there is anything else that I need to do in RV that requires that the engine run except, of course, driving ...

[pinchio]

@ajmike

What did you do with the onboard battery solenoid. The one that connects the chassis battery to coach battery and is engaged when the engine is running to charge both the batteries? Did you remove this and if so how did you deal with the "battery boost" switch that connects to this solenoid?

[AJMike]

Originally Posted by pinchio

@ajmike

What did you do with the onboard battery solenoid. The one that connects the chassis battery to coach battery and is engaged when the engine is running to charge both the batteries? Did you remove this and if so how did you deal with the "battery boost" switch that connects to this solenoid?

I did not do the install myself. I asked BB for a list of recommended installers in this area and I used one of them. I have never been particularly handy with tools and thought that this was not a good time to try to learn.

However the "battery boost", what I call the "bridge" switch, is working properly in the RV. I mentioned to the installer that I wanted it to work and he demo-ed to me that it does work properly. I also asked for an ON/OFF switch in the DC-DC charger line and he installed one of those as well. The Victron BM also monitors the chassis battery and it has been fully charged as well so it appears that both charging circuits are operating properly.