Converting to LiFePO4 batteries and Sailor Man's LiFePO4 Build
- Thread starter RF_Burns
- Start date
If you are switching the frog, I strongly recommend that you look at the Webasco Indel units that I am using, particularly with at the accessory that controls the dc motor speed. The Indel Combi that I bought and it fits, has much more storage and uses only 680w in 24 hours (I think that is right). However, the speed control is supposed to reduce the energy draw by another 35%.
I was sort of shocked when we were at the COOP, when I was shown another coach. Opening the access louver to see the back of the refrigerator, I realized that the massive condensing coil at the rear of the refrigerator took up so much space. It was the size of entire refrigerator and was very thick. That left very little room behind the refrigerator.
The Indel Combi seems to be 4” to 6” more shallow. There are 2 small compressors and coils. Take a look at the drawings and specifications.
Adding the controller takes some work, but I think it is well worth it.
Check out the page where I discuss the Indel products in detail and go to their website.
I bought mine from Defender Industries.
Another GMC'r had replaced his original copper radiator with an aluminum. The core was leaking and in bad shape. It was sitting in a heap waiting to go to scrap. I asked for the tanks and we took a Sawsall to it cutting the tanks loose from the core. I used those tanks and my leaky aluminum tank for dimensions to build a copper radiator.
You might be able to get a used radiator from Jeff Sirum at Sirum GMC in Okeechobee. Jeff is scrapping out "parts" GMCs right now and he might have an original radiator from one of them. Then recore it to 3 inches thick, 4 rows of 5/8 tubes, 7/16 in spacing, with 14-16 fins per inch. This core just barely fits our tanks and can be done by any competent radiator shop. At first I thought I might save some money over another aluminum radiator, but the price of copper has gone up so that recoring is near the same price as an aluminum radiator.
There is nothing wrong with the radiator that is in the coach now. I wonder if I could just buy the dual fan and controller and find a way to match them with the existing radiator.
Can't help you with that, but somebody here probably knows. Maybe talk to Jimmy K at Applied.
I would advise any normal installation against that, but with your bazillion amp alternator, you can afford the DC load. I think the hot (cool) set-up is really the Mercedes fan.
Matt
Matt
Ok. I just spent 2 days working with Cliff and discussing things on the coach. After much discussion, combined with a 10% increase in the 51.2 volt battery bank, I am eliminating the coach's generator.
The tentative Lithionics battery and accessories pick up is March 24th, only 3 weeks from now. We are making the final adjustments in cable lengths, etc.
Both batteries, the battery managen=ment system, the 3 port combiner box and the (2) positive and negative covered minibus bars will be in the generator compartment. The only part of the 51.2 volt system, which is the Victron MultiPlus II, will be inside the coach, under the bed.
This is the updated sketch to make this more compact and neater>
Lithionics is going to fabricate the BMS harness with (2) different lengths of the positive and negative cables to allow for this configuration. I am using the modified busbars instead of custom cables.
I had already made (4) busbars to connect the two pairs of negative and positive BattleBorn GC3 batteieis in series. For that installation, I had already removed the black plastic base and ground off the posts. I had wrapped the positive and negative modified busbars with red and black electrical tape for insulation and identification purposes.
These busbars are rated for 600 amps. Pretty robust.
With the elimination of the BattleBorn batteries, I thought that these (4) modified busbars would just go to waste and then I had a new idea.
What about modifying them again to connect the Lithionics BMS to the new positive and negative busbars. This modification would take cate of the connection od one vertical post to one horizontal post.
Pretty neat, huh?
At least I have been able to use a couple of the components that I thought had become useless. A bonus is that I had already set aside the (4) black plastic bases but I did not throw them away. I am just one of the chronic pack rats that always thinks to never throw something away, because you might find another use for it.
Well it has worked here!
In order to line up the elevation of the covered busbar with the post on the BMS, I was going to fabricate custom Starboard shims. However, I now have (4) unused matching busbar bases To elevate the covered (4) busbars.
Whoops! These busbars were made from (6) post MaxiBus BusBars. The bases can be modified to still function as shims. However, I will have to cut the two unused into (3) equal segments, which can stack at one end to provide the thickness to bore a horizontal hole.
Attachments
This is a better view of how the Indel Drawer 16 will be used as a freezer on the soled maple wire rack to be stained to match the cypress cabinetry. This dc unit will have a dc motor controller added to save energy.
However, this unit will use much more energy, because of limited insulation and will be kept at freezing temperature. It will be mostly used to store ice cubes.
It will be confined in a relatively closed space in the cabinet with a flop down polycarbonate door sealing the air in the wine rack. It will be much cooler than ambient temperature, so it will be used as a wine cooler.
This is how I am altering the Generator Compartment to house the (2) Lithionics 51.2 volt batteries, BMS, 3 Post Combiner Box and distribution positive+negative busbars. If I need more space than the 20", I can move the vertical 1/4" thick alumni plate to the outside of the slider track and then it won't move with the sliding tray and battery.This is the updated sketch to make this more compact and neater>View attachment 7798
Lithionics is going to fabricate the BMS harness with (2) different lengths of the positive and negative cables to allow for this configuration. I am using the modified busbars instead of custom cables.
View attachment 7799
I had already made (4) busbars to connect the two pairs of negative and positive BattleBorn GC3 batteieis in series. For that installation, I had already removed the black plastic base and ground off the posts. I had wrapped the positive and negative modified busbars with red and black electrical tape for insulation and identification purposes.
These busbars are rated for 600 amps. Pretty robust.
With the elimination of the BattleBorn batteries, I thought that these (4) modified busbars would just go to waste and then I had a new idea.
What about modifying them again to connect the Lithionics BMS to the new positive and negative busbars. This modification would take cate of the connection od one vertical post to one horizontal post.
View attachment 7801
Pretty neat, huh?
At least I have been able to use a couple of the components that I thought had become useless. A bonus is that I had already set aside the (4) black plastic bases but I did not throw them away. I am just one of the chronic pack rats that always thinks to never throw something away, because you might find another use for it.
Well it has worked here!
In order to line up the elevation of the covered busbar with the post on the BMS, I was going to fabricate custom Starboard shims. However, I now have (4) unused matching busbar bases To elevate the covered (4) busbars.View attachment 7802View attachment 7804
Whoops! These busbars were made from (6) post MaxiBus BusBars. The bases can be modified to still function as shims. However, I will have to cut the two unused into (3) equal segments, which can stack at one end to provide the thickness to bore a horizontal hole.
I think that this will be petty neat.
I chose to not mount anything on the fiberglass generator compartment enclosure because it is only about 3/16" and not very strong. It is only an enclosure and not considered a structural element by GMC.
The panels are probably going to be riveted to the slide. They are surprisingly heavy and very strong.
Cliff estimated that they would cost between $400 and $500. I called Also in Sarasota and requested to have them cut from remnants. As as result, I paid $88.50 and they we ready in one hour.
with only the batteries and electronics components here, there is very little need for a lot of ventilation and there will be no soot because we are not burning anything here. No annoying rumble, noise or exhaust either.
Everything is electrically plugged in and the batteries require zero maintenance. I don't think that the door will be opened very often even though I installed the gas struts. I was quite tired of being bopped on the head when I was working in there.
It will also not produce any heat like the Onan did.
I don't think that the sliding tray will be pulled out very often.
Hello Sailor Man !!
Thank you so much for the comprehensive posts regarding your switch to LiPo battery systems.
I have read each message with respect and admiration. You are definitely setting the example of how to do things right. I have benefitted and certainly appreciate your efforts and your sharing.
I'm just about to embark on a somewhat similar project - albeit quite a bit lesser scale.
I have a 1973 23 footer. Just my wife, two small dogs, and me. Most of our travels are relatively local - most often to nearby GMC rallies. I just retired so more travelling adventures are in our future. I have long been considering the LiPo upgrades - and now seems to be the time.
With very broad brush data via my Victron BMV 710 (with the bluetooth dongle upgrade) - I estimate a 24 hour period consumes around 50 amp hours of electrical energy. The major consumer is my original compressor (Norcold 726DE) 12/120 refrigerator. Addition use included television (via small inverter), water pump, and lighting.
I'm considering the Victron 3000 watt inverter and 200 - 400 amp hours of LiPo. Will probably include a Cerbo and a GX display system just because.
My current battery of choice is a SOK 206AH battery. Maybe two in parallel. Have you investigated these batteries and might you have an opinion ??
I'm planning to keep my engine battery system completely separate. No LiPo charging from the alternator. Solar maybe. I'm thinking that I can run the 4000 watt generator for an hour or two and recharge sufficiently. Having just typed that - solar is getting more likely
Thank you again for sharing your work. I'm looking forward to any opinion that you may offer - especially if its something like "stay away from those batteries!"
Steve W
Southern California
Thank you so much for the comprehensive posts regarding your switch to LiPo battery systems.
I have read each message with respect and admiration. You are definitely setting the example of how to do things right. I have benefitted and certainly appreciate your efforts and your sharing.
I'm just about to embark on a somewhat similar project - albeit quite a bit lesser scale.
I have a 1973 23 footer. Just my wife, two small dogs, and me. Most of our travels are relatively local - most often to nearby GMC rallies. I just retired so more travelling adventures are in our future. I have long been considering the LiPo upgrades - and now seems to be the time.
With very broad brush data via my Victron BMV 710 (with the bluetooth dongle upgrade) - I estimate a 24 hour period consumes around 50 amp hours of electrical energy. The major consumer is my original compressor (Norcold 726DE) 12/120 refrigerator. Addition use included television (via small inverter), water pump, and lighting.
I'm considering the Victron 3000 watt inverter and 200 - 400 amp hours of LiPo. Will probably include a Cerbo and a GX display system just because.
My current battery of choice is a SOK 206AH battery. Maybe two in parallel. Have you investigated these batteries and might you have an opinion ??
I'm planning to keep my engine battery system completely separate. No LiPo charging from the alternator. Solar maybe. I'm thinking that I can run the 4000 watt generator for an hour or two and recharge sufficiently. Having just typed that - solar is getting more likely
Thank you again for sharing your work. I'm looking forward to any opinion that you may offer - especially if its something like "stay away from those batteries!"
Steve W
Southern California
You might want to check out Will Prowse on YouTube for battery reviews. Also the DIYsolarForum.com for user experiences with different LiFePO4 batteries, inverters and chargers.Hello Sailor Man !!
Thank you so much for the comprehensive posts regarding your switch to LiPo battery systems.
I have read each message with respect and admiration. You are definitely setting the example of how to do things right. I have benefitted and certainly appreciate your efforts and your sharing.
I'm just about to embark on a somewhat similar project - albeit quite a bit lesser scale.
I have a 1973 23 footer. Just my wife, two small dogs, and me. Most of our travels are relatively local - most often to nearby GMC rallies. I just retired so more travelling adventures are in our future. I have long been considering the LiPo upgrades - and now seems to be the time.
With very broad brush data via my Victron BMV 710 (with the bluetooth dongle upgrade) - I estimate a 24 hour period consumes around 50 amp hours of electrical energy. The major consumer is my original compressor (Norcold 726DE) 12/120 refrigerator. Addition use included television (via small inverter), water pump, and lighting.
I'm considering the Victron 3000 watt inverter and 200 - 400 amp hours of LiPo. Will probably include a Cerbo and a GX display system just because.
My current battery of choice is a SOK 206AH battery. Maybe two in parallel. Have you investigated these batteries and might you have an opinion ??
I'm planning to keep my engine battery system completely separate. No LiPo charging from the alternator. Solar maybe. I'm thinking that I can run the 4000 watt generator for an hour or two and recharge sufficiently. Having just typed that - solar is getting more likely
Thank you again for sharing your work. I'm looking forward to any opinion that you may offer - especially if its something like "stay away from those batteries!"
Steve W
Southern California
For charging from the engine alternator I use a DC-DC charger. It takes the varying engine alternator voltage and converts it to a Constant Current/constant Voltage multistage charger that LFP batteries prefer and limits the maximum current so the alternator is not overloaded.
Thanks Bruce !!
I’m completely familiar with Will Prowse’s reviews. Great stuff. And he seems to like these SOK batteries.
Can you provide some details about your LFP conversion ?? Or might it be posted somewhere here already ?? And yea… a DC-DC charger is an option for sure. What flavor DC-DC charger did you choose ??
Steve W
Southern California
Steve,
My system is very simple compared to Sailor Man's.
I have a 175w solar panel mounted on top of the roof pod. This panel matched the size of the pod pretty close. It feeds into a Victron MPPT controller which feeds into the solar inputs of a Samlex EVO-1212F Inverter/charger/transfer switch.
I also have a Renogy 20Amp DC-DC charger feeding into the solar inputs of the Samlex EVO. I have not had any issues with the Renogy DC-DC charger. It appears well built, but I understand their Customer Service is lacking if you have any issues. I have a switch by the driver's seat which allows me to select OFF/10A/20A charging rate. The EVO's solar input is simply in parallel with the battery terminals with a Hall Effect current sensor. The EVO measures the current on the solar input and subtracts it from its internal charger output for a constant current charge. So If I have the charge level set to 40A and the MPPT is sending 5A, the EVO will supply 35A. By having the DC-DC charger also connected there, I can see the rate of charge from both the solar and the DC-DC on the EVO display.
I have a 7.5Cu.Ft. apartment size 120VAC fridge. The EVO synchronizes its power sine wave to the AC input. So switch-over from grid power to inverter and back is seamless to the fridge compressor ,so no motor lockup.
I have two 100A Alberta Lithium Batteries in parallel which have worked well since 2020.
I've had the Samlex EVO since about 2017 and have had no problems with it. Since it is completely programmable, it was a simple change of a few parameters when I changed from lead-acid to LiFePO4 back in 2020. I've used hundreds of Samlex products in 24/7 applications in my business. I've had near zero failures with them.
I have the EVO set to charge at a 40Amp rate to 14.2V. Then constant voltage for 20 minutes. Then float at 13.5V to carry the 12V loads (house lights etc). When I put the coach to bed for the winter, I let the batteries discharge to 13.25V and then disconnect them so there is no parasitic draw. They are still at that voltage come spring. Just hook them back up and let the EVO recharge them and we are good to go again.
I also have a Victron BMS700 to monitor charge levels separate from the EVO.
JWID, hope that helps.
Steve,
I have done little with RV electrics, but am well known locally for upgrading the electrics of racing yachts being repurposed as performance cruisers. Several of these have shown me some areas that can be issues.
I would advise that you retain some means to recover the house bank from the main engine. This way, you will not get caught short on power when you shut down for EOD where ever that happens to be.
Oh, and yes, keep all three of the DC systems separate enough so one cannot kill the other.
Your coach is a 73-23 and I just happen to know about these. So there are some carefully considered suggestions.
Keep the starting battery for the Onan. It may just pull you out of a bad situation. That battery can be the smallest you can buy. I have a garden tractor battery there. Do the Pertronix ignition upgrade as that makes the unit immensely more stable and reliable. Other than that, treat it well and it will take care of you.
If you keep the house bank in the right front corner (starboard bow), be aware that the current location for the converter is not all that good. The cable to the house bank is only a #10 SAE and not all that wonderful. There is no amount of copper you can put in that long run there to fix this. The line loss from there to the bank is a killer.
When you choose a new converter for the new bank, plan to locate it at the passengers left ankle. Run the 120V around to it. When you size this converter, remember that it will only run from the APU or Shore power, so it has substantially no limit for charging rate.
If you still have the buzz-box in the electric space, don't scrap it. They make a terrific 12V bench power supply. I have one of my PD converters there still.
Unfortunately for me, I had acquired a new pair of T105s just before the LFP prices came down so I am kind of stuck for another 8~10 years. That doesn't mean I don't think about it.
Always remember, thinking is the most practical thing to do and do it often.
Matt_C
I have done little with RV electrics, but am well known locally for upgrading the electrics of racing yachts being repurposed as performance cruisers. Several of these have shown me some areas that can be issues.
I would advise that you retain some means to recover the house bank from the main engine. This way, you will not get caught short on power when you shut down for EOD where ever that happens to be.
Oh, and yes, keep all three of the DC systems separate enough so one cannot kill the other.
Your coach is a 73-23 and I just happen to know about these. So there are some carefully considered suggestions.
Keep the starting battery for the Onan. It may just pull you out of a bad situation. That battery can be the smallest you can buy. I have a garden tractor battery there. Do the Pertronix ignition upgrade as that makes the unit immensely more stable and reliable. Other than that, treat it well and it will take care of you.
If you keep the house bank in the right front corner (starboard bow), be aware that the current location for the converter is not all that good. The cable to the house bank is only a #10 SAE and not all that wonderful. There is no amount of copper you can put in that long run there to fix this. The line loss from there to the bank is a killer.
When you choose a new converter for the new bank, plan to locate it at the passengers left ankle. Run the 120V around to it. When you size this converter, remember that it will only run from the APU or Shore power, so it has substantially no limit for charging rate.
If you still have the buzz-box in the electric space, don't scrap it. They make a terrific 12V bench power supply. I have one of my PD converters there still.
Unfortunately for me, I had acquired a new pair of T105s just before the LFP prices came down so I am kind of stuck for another 8~10 years. That doesn't mean I don't think about it.
Always remember, thinking is the most practical thing to do and do it often.
Matt_C
BLIND SIDED AGAIN!!!
Cliff and I have been flummoxed with getting this ProAir II to work. There was little information that I could find as I researched the ProAir information on the net. I did get to Undercount, who uses the compressor in its Sprinter and Mercedes van systems.
Cliff and I came to the conclusion that there was something wrong with the compressor because it would not run when we just tried to power it up. Therefore, I had to but another unit to move ahead.
While trying to located a better source for the compressor than eBay, I finally found the truth.
ProAir, a 46 year old company with 250 to 500 employees applied for Chapter 11 bankruptcy which would allow it to reorganize about two years ago. Then in November, 2022 it filed for Chapter 7, which is liquidation. That means it is totally out of business and no matter how good their products are, I cannot take a chance of them. I found this out about 4;30am this morning.
I have been in a furious research ever since and I have learned a great deal about this country's furious dash into ev vehicles and how that is already impacting the GMC Motorhome.
This is a huge wave and we will either surf it or be wiped out!
The first suitable 12v air conditioning compressor I found was made by Toyota. They were made for the first series of Prius about 2021-2007. What is now currently available are rebuilt compressors from that era. So I continued my search.
12v dc air condition compressors are really no longer being manufactured. The Prius is considered to be a "Light Hybrid" and are passing the "Heavy Hybrid" into the true EV stage. Therefore, the new compressor are now being manufactured in high voltage versions.
In order to catch the wave, I am now searching for the 48v SHS33 version that is listed as being suitable for the Mercedes S Class and E Class Mild Hybrid.
i am early into the search and have not found one yet. The prices I have seen so far are $90 to $1,500.
At least I already have a massive 51.2 volt battery bank arriving on 3/24.
I think that we will all have to get used to high voltage direct current power. We don't see, to be worried about having 120v ac current running around in our motorhomes.
There are units running from 288v to 470 volts. Lithionics is now producing 92.8v, 96v and 102v batteries.
I have been pretty resistant to all of this, but I think that I will have to jump on board!
SteveHello Sailor Man !!
Thank you so much for the comprehensive posts regarding your switch to LiPo battery systems.
I have read each message with respect and admiration. You are definitely setting the example of how to do things right. I have benefitted and certainly appreciate your efforts and your sharing.
I'm just about to embark on a somewhat similar project - albeit quite a bit lesser scale.
I have a 1973 23 footer. Just my wife, two small dogs, and me. Most of our travels are relatively local - most often to nearby GMC rallies. I just retired so more travelling adventures are in our future. I have long been considering the LiPo upgrades - and now seems to be the time.
With very broad brush data via my Victron BMV 710 (with the bluetooth dongle upgrade) - I estimate a 24 hour period consumes around 50 amp hours of electrical energy. The major consumer is my original compressor (Norcold 726DE) 12/120 refrigerator. Addition use included television (via small inverter), water pump, and lighting.
I'm considering the Victron 3000 watt inverter and 200 - 40discussingstartcan0 amp hours of LiPo. Will probably include a Cerbo and a GX display system just because.
My current battery of choice is a SOK 206AH battery. Maybe two in parallel. Have you investigated these batteries and might you have an opinion ??
I'm planning to keep my engine battery system completely separate. No LiPo charging from the alternator. Solar maybe. I'm thinking that I can run the 4000 watt generator for an hour or two and recharge sufficiently. Having just typed that - solar is getting more likely
Thank you again for sharing your work. I'm looking forward to any opinion that you may offer - especially if its something like "stay away from those batteries!"
Steve W
Southern California
Before I will discuss the battery issue, I need to advise you to replace all of the heavy energy users in you coach. If you do this, you will benefit much more by doing this.
ENERGY CONSERVATION FIRST!!!! ------ GET RID OF ALTERNATING CURRENT!
Inverters are not 100% efficient. -----Direct current motors speed can be controlled and are much more efficient.
I would replace you refrigerator with the Indel Combi that I have shown in this tread. Indel says that they estimate a 24 hour draw of 680 watts for the refrigerator and freezer. If you employ their dc motor controller, you will save an additional 30% of dc energy. You will also have more storage capacity and it is much more shallow.
I forgot to mention using an induction range. My wife is locked into seeing an open flame under a pot, so we won't have one. However, an induction range uses only 1/3 of the energy of other means of cooking, so you might want to look into it.
If you look at the two very small, compact expansion coils on the back of the inset, compare them to the massive expansion coil on the rear of your refrigerator.
I was able to locate a tankless lpg hot water heater and a hand held shower head for outside showering for a relatively reasonable cost in the space I saved with the Indel. Pul the electric 5 gal hot water heater and you gain storage space.
I find that most people not longer use the lpg furnace, but they do not remove the furnace or ducts. If you haven’t done that you are missing the opportunity to gain additional storage space.
People do not consider the substantial electrical draw of maintaining 5 gal of hot water in a tank through an inverter when you are not plugged in.
You can also replace your TV with a 12v dc Jensen TV. They are pretty reasonable in price and inverter use is down. DC is much more efficient.
If you are adverse to installing direct current mini-splits, you might be able to replace your roof top ac units with dc powered heat pumps which are far more efficient.
Once you consider using all of these energy conservation improvements you will be amazed at how much less solar collection and battery storage you will require.
I will research the dc roof tops for you. I was disappointed that Dometic did not produce their roof tops using dc power. Indel and Dometic are owned by the same corporation. Why they don’t use the same compressor as the Danfoss in the refrigerator/freezer is just beyond me!
Check all of this out and then take a look at how much smaller a solar panel and battery system you will really need.
Then get back to me,
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Dometic has be selling the 12v Caddy II Marine air conditioner for years. It requires circulating sea water to accept the heat of rejection. They have had the ability to apply this technology to their rooftops. Why they have not is just beyond me.
how large capacity of the A/c compressor you are trying to install as replacement of original ?
