Help with lithium conversion 2000 Pleasure-Way

[Nobadays]

My 2000 Pleasure-Way Excel TD currently has 2 x grp24 lead acid batteries. I want to convert to lithium - LiTime makes a grp24/100ah with cold temp cut-off that should be ideal. I know I will need to change the current converter as it cannot be switched to charge lithium when on shower power or generator. I will also have to replace the battery isolator and herein lies my quandary.

The current battery isolator is a Sure Power 1202. It only has 3 terminals; Alternator, Chassis Battery and House Battery. I plan to replace it with the Li-BIM 225 designed for charging lithium, but in addition to the House/Chassis it includes; Ignition, ground and Sig(nal?).

Obviously House, Chassis, Ground are straightforward. My question is ignition and sig... Am I correct that the sig is indeed "Signal" and would this be the wire currently coming from the alternator? "Wiring diagrams I've found show this to a momentary switch?" Doesn't the alternator wire connect somewhere?

Ignition, I am at a loss unless they just want a hot that is energized when the ignition is on. "Looking at wiring diagrams I think this is the case. .... Or is this where the wire off the alternator connects? "

I have scoured YouTube and forums but every can come up with are newer vans or RV's with no resemblance to what I have. Hoping someone here can steer me in the proper direction!

Thanks!

[booster]

Originally Posted by Nobadays

My 2000 Pleasure-Way Excel TD currently has 2 x grp24 lead acid batteries. I want to convert to lithium - LiTime makes a grp24/100ah with cold temp cut-off that should be ideal. I know I will need to change the current converter as it cannot be switched to charge lithium when on shower power or generator. I will also have to replace the battery isolator and herein lies my quandary.

The current battery isolator is a Sure Power 1202. It only has 3 terminals; Alternator, Chassis Battery and House Battery. I plan to replace it with the Li-BIM 225 designed for charging lithium, but in addition to the House/Chassis it includes; Ignition, ground and Sig(nal?).

Obviously House, Chassis, Ground are straightforward. My question is ignition and sig... Am I correct that the sig is indeed "Signal" and would this be the wire currently coming from the alternator? "Wiring diagrams I've found show this to a momentary switch?" Doesn't the alternator wire connect somewhere?

Ignition, I am at a loss unless they just want a hot that is energized when the ignition is on. "Looking at wiring diagrams I think this is the case. .... Or is this where the wire off the alternator connects? "

I have scoured YouTube and forums but every can come up with are newer vans or RV's with no resemblance to what I have. Hoping someone here can steer me in the proper direction!

Thanks!

Don't worry about the isolator as you really don't want it anyway, or a separator.


The lithium will overload your alternator and wiring do to it's high acceptance rate, so you need to limit current, which is normally done with a battery to battery charger of about 40 amps.



Lots of information on this forum about the conversion you are contemplating, so a search or two would probably help you out.

[Nobadays]

Originally Posted by booster

Don't worry about the isolator as you really don't want it anyway, or

The lithium will overload your alternator and wiring do to it's high acceptance rate, so you need to limit current, which is normally done with a battery to battery charger of about 40 amps.

Lots of information on this forum about the conversion you are contemplating, so a search or two would probably help you out.

My understanding is the BIM is necessary as I will have lead acid Chassis Battery and lithium House batteries. The Li-BIM 225 manages charging to these 2 different chemistries from the alternator.

Yes I have read where a DC to DC charger can be a good option. That said the BIM eliminates the need for this.

I tried searching this forum with no luck. Any specific threads you can point me to? Specifically for older Campervans with the Sure Power Isolator?

I have been reading wiring diagrams for both the Li-BIM 225 and the Sure Power and the BIM lacks an input for the Alternator Output that is present on the Sure Power. Where to put the alternator output wire? Even more confused now!

Thanks!

[booster]

Originally Posted by Nobadays

My understanding is the BIM is necessary as I will have lead acid Chassis Battery and lithium House batteries. The Li-BIM 225 manages charging to these 2 different chemistries from the alternator.

Yes I have read where a DC to DC charger can be a good option. That said the BIM eliminates the need for this.

I tried searching this forum with no luck. Any specific threads you can point me to? Specifically for older Campervans with the Sure Power Isolator?

I have been reading wiring diagrams for both the Li-BIM 225 and the Sure Power and the BIM lacks an input for the Alternator Output that is present on the Sure Power. Where to put the alternator output wire? Even more confused now!

Thanks!

IMO, the B to B eliminates the isolator as that is what it does while converting the "whatever comes out of the alternator" voltage to a real charging profile for the lithium, plus it limits current and keeps the two battery systems isolated. Some B to B chargers have a second output for the starting battery, some don't, but when using the factory alternator only, compared to a separate standalone alternator, you starting battery will see what it is always had for the most part.


All you do is wire the B to B per instructions which will include an activate wire from the ignition most times and a big cable capable of the output rating of the B to B plus about 20%.


Here is a forum specific search. Put "lithium conversion with single alternator" no quotes in the search box.


https://cse.google.com/cse/publicurl...95:k1dvq8an7ly

[Nobadays]

Thanks for the explanation. So if I'm getting this right the DC to DC (B to B?) Charger then would go between my current battery isolator and the lithium batteries. Or put another way, the output from the current isolator would go to the DC to DC then the output from that unit to the house batteries. This leaves the Chassis Battery to continue to get it's feed from the other side of the isolator as it does now.

Thanks for the link... I'm headed there now!

[Nobadays]

Link doesn't work....

[booster]

Originally Posted by Nobadays

Link doesn't work....

I think it is fixed, but it will take you to the search but not the specific search. See the above post for the link and entry needed.

[Nobadays]

Thanks for trying to help but I went through several threads and am still unsure as to how to proceed.

I am not new to electrical components or electrical circuits. We live off-grid and I have designed and installed several solar electric systems for ourselves and neighbors. Unfortunately this RV conversion to lithium has me stumped! For some reason I can't wrap my head around this and as yet can't find an guide that makes it clear to me... feeling frustrated. It can't be this hard!

I will keep searching....

[hbn7hj]

How do you intend to handle freezing temperatures both in storage and in use?

[booster]

Originally Posted by Nobadays

Thanks for trying to help but I went through several threads and am still unsure as to how to proceed.

I am not new to electrical components or electrical circuits. We live off-grid and I have designed and installed several solar electric systems for ourselves and neighbors. Unfortunately this RV conversion to lithium has me stumped! For some reason I can't wrap my head around this and as yet can't find an guide that makes it clear to me... feeling frustrated. It can't be this hard!

I will keep searching....

It really isn't that hard with a single alternator like you are planning to use. Do you get perfect charging, not in my opinion, but almost no systems that are affordable can do that and some shortening of lithium life isn't all that critical now that prices are way down.


Did you happen to read this discussion?


https://www.classbforum.com/forums/f...rade-9752.html


Very similar to what you want to do.


I think that getting away from the BIM will make it a lot more clear to you. AFAIK, the BIM is just a fancy on/off relay to each battery so does essentially nothing to improve the charge profile to lithium batteries. The only real good it would do would be the shutting off the charging when full. It's off time to check voltage (which isn't long enough to be accurate, I think) is just going to slow down your coach battery charging most of the time.


A minimalist system would be a B to B charger for the engine charging, a lithium specific shore charger for when plugged in or on generator, a good shunt based battery monitor like a Victron, and batteries. Of course proper fusing and disconnects needed. All wire sizes need to be checked and make sure they have the right capacity.



It is a good idea to have either the B to B charger or shore charger have a "lithium recovery" mode so you can reactivate the lithium batteries if they have a BMS shutdown happen.


You might also need to heat the batteries depending on where you live and store the van, and where you travel. This is especially true if the batteries are outside the van, like yours probably will be if you just replace, rather than inside.

[RT-NY]

Originally Posted by Nobadays

For some reason I can't wrap my head around this and as yet can't find an guide that makes it clear to me... feeling frustrated. It can't be this hard!

It does not have to be hard at all, depending on your setup and requirements. A lot of the information on this forum is for sophisticated, high-performance, and expensive systems.

I did a very simple lithium upgrade in my 1999 RT 170 - basically a drop-in with with no B2B charger at all. I just installed a hard switch from the existing AGM battery and installed the lithium battery with a quick disconnect so the two systems exist in parallel. I already had upgraded the original converter to a power dynamics, which allows sufficient manual control to successfully charge the lithium or AGM from shore power or generator (I use the manual control when charging the lithium). When charging from the alternator, it never seems to put more than 40amps into the lithium even without a B2B charger (perhaps because my isolator causes a voltage drop that limits the current? I did put in a 45 amp fuse to be safe but it never trips). If I plan to be driving for a long time I just switch over to the AGM to avoid over-charging the lithium. Because the lithium is inside the heated space of the van, I do not need to worry much about cold weather when camping, and for storage I can just switch to the AGM and easily take the lithium out with the quick disconnect. I use a simple (and cheap!) monitor that just measures voltage and total amps in/amps out, so I can tell when the lithium is full because the amps going in drop to a few amps while the voltage increases to full charging voltage.

This might not work for you if you want 200AH of lithium because that might draw too much out of your alternator, but it works great for me and it was only a few hundred dollars and a few hours of work to install. I can now boondock indefinitely by just running the generator every few days.

There are a few characteristics specific to lithium that need to be addressed in any install: 1.having the correct charging voltage; 2. avoiding over-charging (so. knowing when it is fully charged and having a way to stop charging when it is); 3. not charging at all when it is below freezing; 4. not exposing the battery to very cold temps (way below freezing); and 5. not drawing too much power from the alternator.

My set-up addresses all of these issues cheaply but requires attention and manual intervention. For example, although when I am camping and heating the inside of the RV cold temps are not an issue, if I forget when not camping and leave the hard switch on lithium and then drive when it is below freezing I could destroy the battery. The complicated and expensive systems that you see described on this forum are all designed to just address these same issues in more efficient ways (and to wrangle with the specifics, like what is the "correct charging voltage" and how cold is too cold for storage) but there is a cost for that as well.

[RT-NY]

Originally Posted by booster

A minimalist system would be a B to B charger for the engine charging, a lithium specific shore charger for when plugged in or on generator, a good shunt based battery monitor like a Victron, and batteries. Of course proper fusing and disconnects needed. All wire sizes need to be checked and make sure they have the right capacity.

booster - a minimalist system can be even less than that as I described above. You can do without the B2B in some cases (though a auto-reset fuse is a good idea), and you can use a cheap shunt based monitor like the AiLi for $40.00 (all you need is something that shows voltage, amps, and total amps in/amps out). The lithium specific shore charger need be no more than something that delivers a constant 14.4 volts as long as you can manually monitor charging (by keeping on eye on the amps/volts using the AiLi in my case) and stop it when full. And, of course, have some way to not charge the lithium when below freezing and to remove the battery for storage.

[avanti]

I guess it is worth mentioning that another possibility to consider is a DC-AC-DC setup. In this approach, instead of a separate DC-DC converter, you just add a simple second inverter, powered by the engine. You feed the AC output of the inverter into the main house charger just as if it were shore power. That way, the house battery is always charged using the (presumably optimal) charge profile of the main charger, no matter whether the charge current is coming from shore power or the engine.

I went with such a setup because of its conceptual simplicity. I really like having one fewer charger to think about and program.

There are two things to note:
1) Of course, this system has an extra conversion step, and so is technically less efficient. However, this inefficiency only occurs when charging from the engine, which is an energy-rich situation, so it really doesn't matter much.
2) It is good if the main house charger is able to be easily programmed to limit the current drawn from shore power (and thus the charge rate). That way it is easy to limit the load on the engine to any desired level. This is a common feature of modern inverter/chargers.

I am very pleased with this setup. Worth considering.

[booster]

Originally Posted by RT-NY

booster - a minimalist system can be even less than that as I described above. You can do without the B2B in some cases (though a auto-reset fuse is a good idea), and you can use a cheap shunt based monitor like the AiLi for $40.00 (all you need is something that shows voltage, amps, and total amps in/amps out). The lithium specific shore charger need be no more than something that delivers a constant 14.4 volts as long as you can manually monitor charging (by keeping on eye on the amps/volts using the AiLi in my case) and stop it when full. And, of course, have some way to not charge the lithium when below freezing and to remove the battery for storage.

I think we see minimalist a bit differently, but I hear you on the manual part of saving complexity as that can get very, very complicated expensive quickly. You are probably losing about .7v to the isolator so depending on where your alternator is running at any given point (maybe 13.5 to 14.6) you might be charging the lithium or not. I have found our lithium to charge very slowly if the voltage gets much under 13.6v.


The monitor is interesting in what you gain or lose with lower cost units, which are almost all only AH counter/totalizers. The basic Victron is only $110 these days. The biggest issue with any monitor is the ability to calibrate it regularly for accuracy. If you have batteries that balance at 14.4v+ and go there regularly to get balancing, having an auto calibrating monitor is really useful, especially if you are going to be doing a bunch of short chargers that never get to full while camping. The lithium batteries don't have high self discharge as such, but the BMS and/or Bluetooth will make them lose charge that will not show up on a monitor if the BMS is internal to the batteries like most "drop in" style are. If they sit a while, you can have dead battery but show no amps used on the monitor. However much that is between any given charges will determine how inaccurate you are. Most higher end monitors will also have a charge efficiency setting so that can help offset the inaccuracy but not precisely unless you always have the same time between charges and the same depth of discharge.


One very big feature of the Victron monitor is that it has a set of internal contacts that you can use to turn things on and off based on actual SOC the monitor has calculated, or AH used. You can set the on/off points for the contacts and be either NO or NC. Great for controlling a B to B charger on lithium batteries for full cutoff when full or at any SOC you choose. Just have it switch the Ignition input to the b to b.



You are in good shape with the PD charger as it can be manually controlled, but you have to be watching it. Lithium gets to full very quickly once it gets above about 14v so very easy to miss. The PD can work as a power supply to reactivate shutdown lithium BMS batteries also, but you might have to unplug the charge Wizard to get it to run with an off battery.



As you mention, with 200ah of lithium current is going to be quite high is just turned loose without limiting. They would be capable of using the whole capacity of many of factory alternators and overheat them and the wiring if not fused.

[Nobadays]

Originally Posted by hbn7hj

How do you intend to handle freezing temperatures both in storage and in use?

Thank you for your concern.

The batteries I am going to use are the LiTime 12v/100ah with cold temp cut-off. We winter in AZ (Payson) and do see temps below 32°F but rarely are we out camping in the van... using the 12v system during freezing temps. Our winter camping trips are in Southern AZ to escape freezing weather. Storage cold temperatures don't concern me as I've not seen temperatures below around 12°F in Payson.

I know it isn't considered "ideal" to store lifepo4 batteries in negative Ferenhit conditions. That said, we live off-grid at 9,500' in Southern Colorado where temps dip into the negatives frequently in the winter. Our cabin power system includes 400ah/ ~20kwh @ 48v of lifepo4 batteries. When we leave in the late fall/early winter everything is shut down so the batteries sit with no draw or charging. Though they are in the cabin I'm confident the unheated cabin hits negative temperatures from time to time. In 6 years of using this system in this way we have seen no degredation of the lifepo4 batteries.

[Nobadays]

RT-NY.... thanks for this input! I am though hoping to find a bit more of a dummy proof setup.... if it's on me to flip switches properly it likely won't happen!

[Nobadays]

Booster.... thank you for your help and this new thread link. I've read the initial post and it does sound very similar. I will read the replies and see who it has been refined... the original install didn't seem to be very clean.

[Nobadays]

Avanti... this seems like a simple solution! I know I need to replace the current ac/dc converter with a newer model designed to charge lithium batteries. So if I understand correctly you are feeding this converter from an inverter as if from shore power or generator.

A few questions:

What size of 12v inverter?
Did you just power this inverter from the house side of the battery isolator- disconnecting it from the house batteries?
Most converters for RV's have a shore power input and generator input, how do you input 120v from your inverter into the converter?

Thank you!

[RT-NY]

Originally Posted by booster

You are probably losing about .7v to the isolator so depending on where your alternator is running at any given point (maybe 13.5 to 14.6) you might be charging the lithium or not. I have found our lithium to charge very slowly if the voltage gets much under 13.6v.

I would need to confirm the voltage at the battery from the alternator, but I can tell from the amps-in how the lithium is charging. It might start as high as 35-40amps with a depleted battery and drops down from there, perhaps averaging 20amps, so I can usually charge to full with a few hours of driving.

Originally Posted by booster

The monitor is interesting in what you gain or lose with lower cost units, which are almost all only AH counter/totalizers.

Right - so what I do is just charge to full every few days. I can be sure that the battery is full because the amps-in drop down to a few amps while the voltage goes to full charging voltage. Then I can just use cumulative amps-out over the next few days to know when to charge again.

Originally Posted by Nobadays

RT-NY.... thanks for this input! I am though hoping to find a bit more of a dummy proof setup.... if it's on me to flip switches properly it likely won't happen!

My system is definitely not foolproof in that sense! But for a cost of under $500.00 and just a few hours work, I was amazed at how much an improvement it is over the original Roadtrek power configuration. Just three changes -- the Magnetek to Power Dynamics upgrade (which is an exact replacement unit), a cheap drop in 100AH LifePO4 alongside the original battery, and swapping in LED replacement bulbs -- provides many multiples more of available power than the original setup!

[avanti]

Originally Posted by Nobadays

Avanti... this seems like a simple solution! I know I need to replace the current ac/dc converter with a newer model designed to charge lithium batteries. So if I understand correctly you are feeding this converter from an inverter as if from shore power or generator.

Yes, exactly.

A few questions:

What size of 12v inverter?

Depends entirely on what you want as a maximum charge rate and how much current is available from the chassis.

I use this 2200W unit:
https://www.amazon.com/Inverter-2200.../dp/B07ZNTXN7P
which is popular for this purpose. However, I have a Transit Ecoboost with dual alternators, so I have a lot of current available. I usually set the main inverter/charger to draw a max of 13A (@120VAC) from "shore power", which charges at around 1500 watts. Obviously, one can go smaller.

Did you just power this inverter from the house side of the battery isolator- disconnecting it from the house batteries?

No need for a battery isolator. The inverter is always connected to the engine. You just turn it on and off as needed. Draws no current when off. The Giandel has a remote push button, so this can be made very convenient.

Most converters for RV's have a shore power input and generator input, how do you input 120v from your inverter into the converter?

The AC enters via the shore power input. I have an external automatic transfer switch that selects shore power when available and the inverter otherwise. You could just use a manual switch, though.