Lithium upgrade

[gaolsen]

Hello,

I have a 2023 Thor Windsport 34R and I'm interested in upgrading the batteries to Lithium. It came with two 100aH flooded batteries and has a GoSolar! system pre-installed. The controller is a GP-RVC-10-MPPT and I have a 100watt panel on the roof.

Looking through the menus on my LCD, it has options for lithium and looking through the manual for the controller it seems to support lithium. Can I just add in a pair of 200aH lithium batteries, re-connect the cables the way that I found them, and update the touch screen to 400aH Lithium, or is there more that I need to do?

Thanks!

 

[ducksface]

Yes.
Nothing else is needed.
https://www.amazon.com/dp/B0CNVBL5T...94ZP8U2L&psc=1&ref_=list_c_wl_lv_ov_lig_dp_ii

Size constraints may negate your 400ah plan.
Remember;
A 100ah lithium supplies twice the usability as a 100ah conventional.

 

[Chateau_Nomad]

If you have the room, AND you "off-grid" frequently, DEFINITELY put in as many amp hours of battery as will fit!

Note that you now only have 100 amp hours available from your 200 amp hours of lead acid batteries (the 50% rule).

With lithium you technically have the ENTIRE capacity of the battery available... no worries about completely running down to near zero.

With the price of lithium batteries so cheap now I wouldn't hesitate putting in 400Ah (or even more) if you boondock.

IMO, lithium batteries are like computer RAM and hard drive space... you can never have too much.

 

[DavidEM]

This is a somewhat controversial issue on this forum, but I believe in it so here goes:

Everything should work fine with what you describe, except… 400 Ahs of lithium batteries places a big strain on the chassis alternator and can overheat it and cause premature failure. 400 Ahs is sort of in the middle, less and you probably won’t have to do anything, more and it is very likely to overload the alternator. So do this test:

Once you get the new batteries installed, run the batteries down to about 50% SOC. Start the chassis engine and measure the charging current with a clamp on ammeter or a shunt based battery monitor. You shoul read a lot of current, maybe more than 100 amps. After 15 minutes of charging at this high rate, shoot the alternator case. If you read more than 200 F, wait 15 more minutes and shoot it again. If you read 225 F or greater after 30 minutes you are probably cooking your alternator.

There are a couple of solutions: replacing your BIRD or BIM with a Li-BIM 225 which will cut the current in half which should reduce the case temp to 200 or less. Another solution is to install a DC to DC charger which will limit the charging current to it’s rated value; 50 amps will probably work well.

If anyone is interested I will relate my experience in the boating world with a big LA battery bank and a high output Balmar alternator. This experience made me a believer in alternator overheating.

David

 

[Chateau_Nomad]

This is a somewhat controversial issue on this forum, but I believe in it so here goes:

Everything should work fine with what you describe, except… 400 Ahs of lithium batteries places a big strain on the chassis alternator and can overheat it and cause premature failure. 400 Ahs is sort of in the middle, less and you probably won’t have to do anything, more and it is very likely to overload the alternator. So do this test:

Once you get the new batteries installed, run the batteries down to about 50% SOC. Start the chassis engine and measure the charging current with a clamp on ammeter or a shunt based battery monitor. You shoul read a lot of current, maybe more than 100 amps. After 15 minutes of charging at this high rate, shoot the alternator case. If you read more than 200 F, wait 15 more minutes and shoot it again. If you read 225 F or greater after 30 minutes you are probably cooking your alternator.

There are a couple of solutions: replacing your BIRD or BIM with a Li-BIM 225 which will cut the current in half which should reduce the case temp to 200 or less. Another solution is to install a DC to DC charger which will limit the charging current to it’s rated value; 50 amps will probably work well.

If anyone is interested I will relate my experience in the boating world with a big LA battery bank and a high output Balmar alternator. This experience made me a believer in alternator overheating.

David

Don't forget about supplemental charging via solar, generator and/or occasional shore power. I installed a BIM-225 and have had no issues. If the alternator is the only charging source a large battery bank could present a challenge without supplemental charging sources.

 

[PS89]

The Li-BIM 225 doesn't limit charging current, it limits the time and the conditions under which the coach battery bank can be connected to the chassis electrical system.


Battleborn's website has a good document that fully describes the behavior.

 

[DavidEM]

Don't forget about supplemental charging via solar, generator and/or occasional shore power. I installed a BIM-225 and have had no issues. If the alternator is the only charging source a large battery bank could present a challenge without supplemental charging sources.

Yes, but mostly because those other sources will keep the batteries more charged so when you do start the chassis engine, the heavy load won’t affect the alternator as long or as much.

But that is not why RVers install big Li banks. They want to dry camp for days at a time, sometimes in shade with no solar and they don’t want the noise of a generator. But when they finally start the chassis engine to go home or to the next campsite, the heavy load can last for hours as the alternator recharges a big, depleted Li bank.

David

 

[16ACE27]

Yes, but mostly because those other sources will keep the batteries more charged so when you do start the chassis engine, the heavy load won’t affect the alternator as long or as much.

But that is not why RVers install big Li banks. They want to dry camp for days at a time, sometimes in shade with no solar and they don’t want the noise of a generator. But when they finally start the chassis engine to go home or to the next campsite, the heavy load can last for hours as the alternator recharges a big, depleted Li bank.

David

Unless you install a simple SPST switch in series with the "Trombetta" control wiring to disconnect the battery banks. This is where the DC-to-DC charger can be used to limit charging current. And with a DPDT switch and another continuous duty solenoid, you can have the advantages of a BIRD/Trombetta pair and a DC-to-DC charger in parallel.

 

[Chateau_Nomad]

So we have three basic methods:

Li-BIM 225:
When programming the firmware of the Li-BIM 225 I think they took a "best guess", and averaged the length of time to connect the alternator for charging. It connects/disconnects based on time.

Manual switch:
The SPST switch ACE described gives you 100% manual control of connecting/disconnecting the charging. You're responsible for knowing how much load your alternator can handle.

DC-DC charger:
The DC-DC charger allows you to dial in the exact amount of charge... with the intent of not letting too much current damage the alternator.

So what's missing??
The whole premise is controlling current draw (demand) from the alternator, which produces a tremendous amount of HEAT. Heat is the problem. All of these "fixes" use a round-about way of controlling the destructive heat produced by too much current draw.

Is there a device which uses a heat sensor attached directly to the alternator? It's possible you're getting cheated by limiting charging by just guessing. But having actual temperature data from the alternator could allow adjustment of a temperature cutoff point.

 

[16ACE27]

So we have three basic methods:

Li-BIM 225:
When programming the firmware of the Li-BIM 225 I think they took a "best guess", and averaged the length of time to connect the alternator for charging. It connects/disconnects based on time.

Manual switch:
The SPST switch ACE described gives you 100% manual control of connecting/disconnecting the charging. You're responsible for knowing how much load your alternator can handle.

DC-DC charger:
The DC-DC charger allows you to dial in the exact amount of charge... with the intent of not letting too much current damage the alternator.

So what's missing??
The whole premise is controlling current draw (demand) from the alternator, which produces a tremendous amount of HEAT. Heat is the problem. All of these "fixes" use a round-about way of controlling the destructive heat produced by too much current draw.

Is there a device which uses a heat sensor attached directly to the alternator? It's possible you're getting cheated by limiting charging by just guessing. But having actual temperature data from the alternator could allow adjustment of a temperature cutoff point.

I believe some Balmar alternator regulators use a temperature sensor to limit output current, but I have not taken a deep dive into that.

 

[Mark54]

Hello,

I have a 2023 Thor Windsport 34R and I'm interested in upgrading the batteries to Lithium. It came with two 100aH flooded batteries and has a GoSolar! system pre-installed. The controller is a GP-RVC-10-MPPT and I have a 100watt panel on the roof.

Looking through the menus on my LCD, it has options for lithium and looking through the manual for the controller it seems to support lithium. Can I just add in a pair of 200aH lithium batteries, re-connect the cables the way that I found them, and update the touch screen to 400aH Lithium, or is there more that I need to do?

Thanks!

I put two 300Ah batteries in my 20L Tellaro- and had room for two 400Ah ones, except for finding ones that were not too much money. So as Chateau Nomad said- put as much in there as you can. The wires only need to be upsized IF you plan to use more power.
I actually downsized my amp draw by replacing the roof AC with a 12V unit that uses 400W instead of 1100, and is 20dB more quiet. There's lots of units on the market you can use- from $400-2400.
I used the Mabru and had installed by a local custom van place nearby- that was their recommendation. I could have shopped for lower cost, but decided to not DIY since I am 70 and would rather pay someone else!
It's also about 5-6" tall!!

Just check the specs for each one, and DIY or have a mbile tech install. Many use the same 14x14 opening already on the roof, and wire directly to the buss bar. Most have remotes too, instead of fumbling thru the BMPro, or using the inverter/ having to plug into shoreline, etc.

 

[DavidEM]

I believe some Balmar alternator regulators use a temperature sensor to limit output current, but I have not taken a deep dive into that.

Years ago, almost 25, my wife and I cruised the east coast and Bahamas in a 37’ Island Packet sailboat. We had four GC batteries rated at 440 Ahs wired series/paralllel. I installed a high output 100A alternator made by Balmar and an external three stage regulator that made the alternator act like three stage battery charger. This significantly increased the charging rate and the effect was somewhat like charging a Lithium battery, ie the charging rate stayed higher for a longer period as opposed to what would happen withthe fixed voltage of a typical internally regulated alternator.

As an add on that I didn’t appreciate until later, I had Balmar’s alternator temperature probe which provided a signal to the regulator that would cut back the alternator charging rate if it got too hot. Since the engine room on most sailboats is rather tight as was mine, I installed a muffin fan that would blow cooler (relatively speaking) air on the back of the alternator to keep it somewhat cooler as measured by my calibrated fingers -.

After using this rig for a while I noticed that if we stayed in an anchorage for several days with no sun (I had 200 watts of solar panels, a rarity in those days) the batteries would be down to 50%, the limit for most FLAs.

When I left the anchorage under power, the alternator was charging at almost 100A, the alternator’s rating. But after 20 minutes or so it would drop in half. The temperature probe kicked in. This stayed that way for several hours until I made it to the next anchorage.

On another leg I used my calibrated fingertips (I didn’t have an IR gun) and a drop of water to see if it sizzled on the alternator case to see how the temperature built up. I determined that when it got to the point of just sizzling water, the temp probe would cut back and 15 minutes later, no sizzle.

I later learned that 225F was the maximum for best life from an alternator which was consistent with Balmar’s cut back temp. I don’t know what Balmar does today with their temp probes, but I suspect it is similar to what I experienced.

I have since read of UHGs on MHs failing while charging a big Li bank. My guess is alternator overheating caused the failure.

David

 

[MCP-THOR]

I believe some Balmar alternator regulators use a temperature sensor to limit output current, but I have not taken a deep dive into that.

That’s correct, the Balmar regulator and UHG (second alternator) as on the Tellaro has a heat sensor on the alternator and one on the battery bank. Adjustments are available on the regulator, or more easily made on the app. One can also adjust the alternator output by adjusting the belt load manager.

And as you say one can also simply add a switch to turn the charge system “off”.

Not an expert by any means but I have learned from this forum and from my own tinkering with the Tellaro.

 

[MCP-THOR]

Years ago, almost 25, my wife and I cruised the east coast and Bahamas in a 37’ Island Packet sailboat. We had four GC batteries rated at 440 Ahs wired series/paralllel. I installed a high output 100A alternator made by Balmar and an external three stage regulator that made the alternator act like three stage battery charger. This significantly increased the charging rate and the effect was somewhat like charging a Lithium battery, ie the charging rate stayed higher for a longer period as opposed to what would happen withthe fixed voltage of a typical internally regulated alternator.

As an add on that I didn’t appreciate until later, I had Balmar’s alternator temperature probe which provided a signal to the regulator that would cut back the alternator charging rate if it got too hot. Since the engine room on most sailboats is rather tight as was mine, I installed a muffin fan that would blow cooler (relatively speaking) air on the back of the alternator to keep it somewhat cooler as measured by my calibrated fingers -.

After using this rig for a while I noticed that if we stayed in an anchorage for several days with no sun (I had 200 watts of solar panels, a rarity in those days) the batteries would be down to 50%, the limit for most FLAs.

When I left the anchorage under power, the alternator was charging at almost 100A, the alternator’s rating. But after 20 minutes or so it would drop in half. The temperature probe kicked in. This stayed that way for several hours until I made it to the next anchorage.

On another leg I used my calibrated fingertips (I didn’t have an IR gun) and a drop of water to see if it sizzled on the alternator case to see how the temperature built up. I determined that when it got to the point of just sizzling water, the temp probe would cut back and 15 minutes later, no sizzle.

I later learned that 225F was the maximum for best life from an alternator which was consistent with Balmar’s cut back temp. I don’t know what Balmar does today with their temp probes, but I suspect it is similar to what I experienced.

I have since read of UHGs on MHs failing while charging a big Li bank. My guess is alternator overheating caused the failure.

David

I must have been writing as you were posting!!

I like your info. More in depth, more history, and more entertaining. Thanks.

 

[ducksface]

I haven't read of any alternator failures due to MODERN lithium battery size

Do you have a link or two to this problem happening with batteries having internal bms?

Just trying to quash what might be old and outdated thinking.

 

[First RV 4 me]

Unless you install a simple SPST switch in series with the "Trombetta" control wiring to disconnect the battery banks. This is where the DC-to-DC charger can be used to limit charging current. And with a DPDT switch and another continuous duty solenoid, you can have the advantages of a BIRD/Trombetta pair and a DC-to-DC charger in parallel.

I found an alexa enabled 12v relay to control the trombetta. I do have a wifi network in the MH but the relay is also bluetooth and works great. https://www.amazon.com/gp/product/B0C7QQHMCX/ref=ox_sc_saved_title_4?smid=AS7EX0IBKFJOL&psc=1
I ended up using a lot of these to control all the lights in my RV.

 

[16ACE27]

I haven't read of any alternator failures due to MODERN lithium battery size

Do you have a link or two to this problem happening with batteries having internal bms?

Just trying to quash what might be old and outdated thinking.

A single battery's BMS has nothing to do with the alternator.

A single 100 AH LiFePO4 battery will likely not overload a standard OEM alternator as the BMS will limit the charging rate to between .2C to 1C (20 to 100 amps). Most limit it to .5C (50 amps) so even two batteries in parallel is usually not an issue. But as you add more in parallel, the cumulative max charging rate also increases as the BMSs do not know or care about the other BMSs, so they all suck as much current as they are limited to.

So four 100 AH batteries can put a 200 Amp load (or more) on that alternator for hours without external intervention.

Most MAJOR battery/inverter manufacturers warm about this overload issue. This is from Victron:

https://www.victronenergy.com/blog/2019/10/07/careful-alternator-charging-lithium/

 

[16ACE27]

I found an alexa enabled 12v relay to control the trombetta. I do have a wifi network in the MH but the relay is also bluetooth and works great. https://www.amazon.com/gp/product/B0C7QQHMCX/ref=ox_sc_saved_title_4?smid=AS7EX0IBKFJOL&psc=1
I ended up using a lot of these to control all the lights in my RV.

Well, that madi it into my shopping cart. I also have a MH network and I think you just gave me the impetus to add Alexa to it.

 

[ducksface]

I found an alexa enabled https://www.amazon.com/gp/product/B0C7QQHMCX/ref=ox_sc_saved_title_4?smid=AS7EX0IBKFJOL&psc=1
I ended up using a lot of these to control all the lights in my RV.

That same model controls my gates and garage doors.
I didn't add many alexa devices in the rv.
Bathroom fan and electric blankets are all I've added along with
an alexa show to show the cameras at home and act as the input 'hearer'(alexa, show me north camera. Ok).
I found a usb to 12v adapter that powers the show 5 through usb.
https://www.amazon.com/gp/aw/d/B0B87VQ8HN?psc=1&ref=ppx_pop_mob_b_asin_image

Maybe possibly remotely unlikely;
I'll try one of those relays on the windshield wipers.

 

[Chateau_Nomad]

I haven't read of any alternator failures due to MODERN lithium battery size

Do you have a link or two to this problem happening with batteries having internal bms?

Just trying to quash what might be old and outdated thinking.

Not knowing the charging source, any given LiFePO4 battery will draw the maximum current programmed into it's BMS firmware, which could be anywhere from 50 to 200 amps. This has no bearing or correlation to the charging source - the battery will take as much as it's given.

The burden is on the alternator. Sticking a big amp draw device in and expecting a less than capable alternator to handle the task is asking for a disaster.

It's not that difficult to find the battery specs regarding recommended charging amps and the amp rating of the alternator. I suggest anyone installing LiFePO4 batteries to pay attention to those numbers.