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Looking for complete 12v Lithium/Solar/Generator/Shore Power/Alternator upgrade to my camper

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DaveB

New Member
Joined
Aug 16, 2020
Messages
3
Hey everyone!

I have a truck camper that is currently powered by a pair of 12V AGMs that simply are not cutting it. Just one night of boondocking, including putting down the jacks, minimal use of LED lights and water pump, and watching a couple of hours of TV are taking the batteries down to the point (60-70% per the meter) where we're at risk that there's not enough juice in the morning to work the jacks to put it on the truck to leave.

I'd like to replace these crappy AGMs with a much higher capacity bank of LiFePo4 cells (still at 12v). My system has the following connections that must still work after the upgrade:
  • 120v 30A shore power connection
  • Connection to the carrying truck's alternator thru umbilical
  • 100W solar panel on roof (I think there's a connection for a 2nd panel already there)
  • LP powered generator (that I can't even start if the battery gets too low - electric start only :rolleyes:)
This is all in a 2019 Lance 855S truck camper. The A/C and microwave work only on shore power/generator, but everything else works on either LP or 12V.

I would like to add a second (& maybe a 3rd) solar panel. I also want to stick with 12V for now rather than switch to 24v (the truck has only a 12v alternator).

I've seen lots of plans on your site that have some of these incoming connections, but I have not yet found a comprehensive system diagram that incorporates them all. Can someone please point me to such a layout/plan/blueprint here in the forum or on the DIY website?

Also, I found these: 190Ah 3.2v LiFePo4 cells in a pack of 4 for ~$650 Would that be a good foundation for my upgraded system? With such a small size of 7" x 8-1/4" x 8.5" for the set, it seems like I could use two sets and get 380Ah in the same space as my 2 AGMs with room to spare.

What do you think?

Thanks much!!!
DaveB
 
Welcome to the forums DaveB!

Hope you don't mind, moved this to the vehicle section were hopefully some subject matter experts will see it and respond to your questions.

I'm not sure if $0.285/Wh is a good price on LiFePO4 or not anymore, you might check the battery section to see if anyone is talking about hot deals.

You probably won't find "comprehensive system diagrams" for your specific setup here ... everybody is a little different and it would be hard to find a one-size fits all. However, this is a DIY site so you can hopefully find guidance and help on creating your own diagrams.
 
@DaveB Those are the cells I bought for my camper .... but if I had it to do over again, I would buy the 280 AH that a lot of people are buying now. I'm pretty sure you could get the 280's for less $ than those 190's. 8 of the 280's will give you 560 AH at 12V.
Just do a search for 280 AH and you should find several threads. Xuba is one of the most popular providers. Amy, the sales person has jumped thru hoops for a lot of people and does an excellent job.
 
the 190AH for $630 are rather expensive. For that you can buy 6x 225AH golf cart batteries for a total of 675AH.
The 280Ah are better at $640 ish

The factory AGMs are usually the cheapest available. So meaning no good.

If you don't want to change anything at the charging system,
 
LiFePO4 batteries may not be acceptable for starting the generator. There may be too high of an amp draw. I'm planning to keep a regular deep cycle battery for starting the generator, rather than using the LiFePO4 battery for that. It may be overkill, but I don't want to put too much stress on my BMS and batteries.

The converter you have on-board will use a charge profile that is specific to an AGM battery, or perhaps just a plain flooded lead acid battery. Replacing the converter with one that supports a LiFePO4 charge profile is recommended. Some LiFePO4 manufacturers (Battle Born) say their batteries are direct drop in replacements. Their BMS hopefully has the smarts to handle a non-LiFePO4 charge profile.

There should be an Automatic Transfer Switch (ATS) in your camper. This will send power from either the shore connection or the generator connection, but not both at the same time. This should not have to be changed with the new LiFePO4 batteries.

Your ability to add more solar panels depends on the specifications of the charge controller. If it was a kit like GoPower, then figure out which kit it was and look it up. GoPower has information on their website about upgrading an existing system.
 
i have no trouble starting the generator with 12V 280AH LFP battery

mark
 
4KW, i haven't measured the draw, but i didn't even loose 1% of capacity
 
Mine is 5000 watts and may have a slightly heavier draw. It's the big initial draw that can a problem. I think someone recently reported that their BMS freaked out over the draw the generator tried to put on the LiFePO4 battery.
 
DaveB said:
Hey everyone!

I have a truck camper that is currently powered by a pair of 12V AGMs that simply are not cutting it. Just one night of boondocking, including putting down the jacks, minimal use of LED lights and water pump, and watching a couple of hours of TV are taking the batteries down to the point (60-70% per the meter) where we're at risk that there's not enough juice in the morning to work the jacks to put it on the truck to leave.
...

What do you think?

Thanks much!!!
DaveB
Click to expand...

Based on the info you've given, I think you are getting way ahead of yourself. You can tell that your current setup is coming up short, but you have no way of knowing what part of the equation is out of line. When you say "per the meter", exactly what type of meter are you using? If it's just the simple voltage based capacity gauge, I'd start by getting an inexpensive shunt-based battery monitor such as the AiLi and start quantifying what is going on. It should let you see what effective capacity you are actually getting out of your current batteries, whether they are actually getting fully charged , how much power you are able to generate with your solar and help you to understand what element of your usage is drawing the batteries down. Once you understand a bit more about the current situation in terms of power usage, generation and storage capacity, we should be able to do the math to determine how to improve the deficient portion of your system system, so that it matches your needs. It could be a simple as replacing bad batteries, tracking down vampire loads that are running the batteries down or upgrading the charging capability.
 
cwstnsko said:
Based on the info you've given, I think you are getting way ahead of yourself. You can tell that your current setup is coming up short, but you have no way of knowing what part of the equation is out of line. When you say "per the meter", exactly what type of meter are you using? If it's just the simple voltage based capacity gauge, I'd start by getting an inexpensive shunt-based battery monitor such as the AiLi and start quantifying what is going on. It should let you see what effective capacity you are actually getting out of your current batteries, whether they are actually getting fully charged , how much power you are able to generate with your solar and help you to understand what element of your usage is drawing the batteries down. Once you understand a bit more about the current situation in terms of power usage, generation and storage capacity, we should be able to do the math to determine how to improve the deficient portion of your system system, so that it matches your needs. It could be a simple as replacing bad batteries, tracking down vampire loads that are running the batteries down or upgrading the charging capability.
Click to expand...
Thanks! I agree, and I ordered a shunt meter to enable me to diagnose the problem better. I suspect there may actually be an unexpected drain rather than bad batteries. Even though I would like the additional capacity of LiFePo, swapping the batteries out without removing any drains simply postpones the problem rather than removing it.
 
HRTKD said:
LiFePO4 batteries may not be acceptable for starting the generator. There may be too high of an amp draw. I'm planning to keep a regular deep cycle battery for starting the generator, rather than using the LiFePO4 battery for that. It may be overkill, but I don't want to put too much stress on my BMS and batteries.

The converter you have on-board will use a charge profile that is specific to an AGM battery, or perhaps just a plain flooded lead acid battery. Replacing the converter with one that supports a LiFePO4 charge profile is recommended. Some LiFePO4 manufacturers (Battle Born) say their batteries are direct drop in replacements. Their BMS hopefully has the smarts to handle a non-LiFePO4 charge profile.

There should be an Automatic Transfer Switch (ATS) in your camper. This will send power from either the shore connection or the generator connection, but not both at the same time. This should not have to be changed with the new LiFePO4 batteries.

Your ability to add more solar panels depends on the specifications of the charge controller. If it was a kit like GoPower, then figure out which kit it was and look it up. GoPower has information on their website about upgrading an existing system.
Click to expand...
Jim, thanks much! My real question is about the "charging profiles that include both voltage levels and time at those levels". My camper includes both a GoPower PWM-30 Solar Controller (SC) to charge from the PV, and a Progressive Dynamics PD4000 series Power Control Center (PCC) to charge from 120v shore power. My question is - when BOTH are active: the sun is shining AND I'm hooked up to shore power, how do the two different charging systems charge the batteries without interfering with each other? I don't think they're wired in any way to communicate with each other and cooperate, so what happens if one decides it's time to "bulk charge", while thinks it's time for "absorption"?
 
DaveB said:
Jim, thanks much! My real question is about the "charging profiles that include both voltage levels and time at those levels". My camper includes both a GoPower PWM-30 Solar Controller (SC) to charge from the PV, and a Progressive Dynamics PD4000 series Power Control Center (PCC) to charge from 120v shore power. My question is - when BOTH are active: the sun is shining AND I'm hooked up to shore power, how do the two different charging systems charge the batteries without interfering with each other? I don't think they're wired in any way to communicate with each other and cooperate, so what happens if one decides it's time to "bulk charge", while thinks it's time for "absorption"?
Click to expand...

Will did a video about this. I think he connected 3 solar charge controllers in parallel and all still output the same power as if they were connected alone.
I think it may depend to some degree on the SOC of the battery.

I experimented a little with 2 120Vac chargers .... one was a straight power supply that was set to supply 10A and one was a Victron charger which would supply about 13A when connected alone. When connected in parallel, I was only getting about 14 Amps charge. .... so, your mileage may vary.
 
DaveB said:
Hey everyone!

I have a truck camper that is currently powered by a pair of 12V AGMs that simply are not cutting it. Just one night of boondocking, including putting down the jacks, minimal use of LED lights and water pump, and watching a couple of hours of TV are taking the batteries down to the point (60-70% per the meter) where we're at risk that there's not enough juice in the morning to work the jacks to put it on the truck to leave.

I'd like to replace these crappy AGMs with a much higher capacity bank of LiFePo4 cells (still at 12v). My system has the following connections that must still work after the upgrade:
  • 120v 30A shore power connection
  • Connection to the carrying truck's alternator thru umbilical
  • 100W solar panel on roof (I think there's a connection for a 2nd panel already there)
  • LP powered generator (that I can't even start if the battery gets too low - electric start only :rolleyes:)
This is all in a 2019 Lance 855S truck camper. The A/C and microwave work only on shore power/generator, but everything else works on either LP or 12V.

I would like to add a second (& maybe a 3rd) solar panel. I also want to stick with 12V for now rather than switch to 24v (the truck has only a 12v alternator).

I've seen lots of plans on your site that have some of these incoming connections, but I have not yet found a comprehensive system diagram that incorporates them all. Can someone please point me to such a layout/plan/blueprint here in the forum or on the DIY website?

Also, I found these: 190Ah 3.2v LiFePo4 cells in a pack of 4 for ~$650 Would that be a good foundation for my upgraded system? With such a small size of 7" x 8-1/4" x 8.5" for the set, it seems like I could use two sets and get 380Ah in the same space as my 2 AGMs with room to spare.

What do you think?

Thanks much!!!
DaveB
Click to expand...
Morning Dave from a wet Auckland

To upgrade from lead acid to lithium you are going to need to look at what of your existing system you can and cant use. You've got a relatively new camper so the likelyhood is you will be able to use a lot of it.

Can you provide as much detail as you can on the following items, brand and model number, ideally with links to manufacturers' sites so we can check manuals if we need to

Solar Charge Controller
Solar panel
Inverter
AC to DC charger
and if you have one dc to dc charger, if not do your AGM batteries currently charge while you are driving and if so how are they connected?

Have you done a power audit? Do you know how much power you would like to have available from your batteries? At the moment we only know you want more.
 
DaveB said:
Jim, thanks much! My real question is about the "charging profiles that include both voltage levels and time at those levels". My camper includes both a GoPower PWM-30 Solar Controller (SC) to charge from the PV, and a Progressive Dynamics PD4000 series Power Control Center (PCC) to charge from 120v shore power. My question is - when BOTH are active: the sun is shining AND I'm hooked up to shore power, how do the two different charging systems charge the batteries without interfering with each other? I don't think they're wired in any way to communicate with each other and cooperate, so what happens if one decides it's time to "bulk charge", while thinks it's time for "absorption"?
Click to expand...

My GoPower PWM charge controller seems to defer to the converter. When the converter is active (rarely) the solar charge controller goes to zero amps.
 
HRTKD said:
Mine is 5000 watts and may have a slightly heavier draw. It's the big initial draw that can a problem. I think someone recently reported that their BMS freaked out over the draw the generator tried to put on the LiFePO4 battery.
Click to expand...

A generator like this you can start with a 18ah lead battery easy. Any lithium over 100ah should have no issues to crank that thing.
Different story for a truck engine.

the BMS might be the issue, for the starter you can just bypass the BMS. It's not something which is running all the time and could deep discharge the battery. Many lithium batteries can deliver 10-20C without issue. But most people only build in BMS with 1C or 2C so that shuts your starter off.

Not as crazy as the 50C a lead battery may produce but still enough to get a small generator going.
 
I agree with the sentiments that the 280Ah LiFePO4 cells are a much better deal than what you proposed. I have received quotes for as low as $77.40 per cell.

This thread intrigued me because it sounds like you are considering a full upgrade. I started looking at inverters and I suddenly I was running across these all-in-one controllers on AliExpress. They seem ideal for a small system like an RV. They include the MPPT solar charge controller, the inverter, and even have inputs for generator and shore power.
Has anyone gone with something like this?
Am I being naive thinking that it could be this easy and cheap to set up a 3kW system?
Screenshot_20200827-133431_AliExpress.jpgScreenshot_20200827-133500_AliExpress.jpg
 
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