More Lithium Conversion Questions

[DavePhelps]

My 9 year old AGM batteries are finally at the end of their life and I’ve decided to convert to a LiFePO4 battery system. One Epoch 12v 300ah battery I am looking at will fit nicely in my Legacy1 battery box and will have almost 2x the amp-hr capacity of my 2 6v AGM’s. . I have ordered a new Progressive Dynamics charger/converter module as my old one does not have the lithium switch or the other manual means to charge lithium batteries. So this is all good. My question is about the wiring. I do not have an inverter, nor do I plan to get one in the future. Between propane and 12VDC, I feel pretty comfortable. My current system however is wired with only 6awg wire. This seems way too small (or not??). The crimp connections are also of poor, bordering on dangerous quality. So I want to redo all the wiring from the batteries forward. Distances are short but with the new lithium batteries, I’m wondering what gauge wire is recommended? I have the Blue Sky charge controller and can’t find in the OM the max wire size it can accommodate.

Any other ideas or cautions for this conversion would be appreciated! And thanks to those who have posted a lot of great info in other posts about this conversion.

Cheers.

Dave

[topgun2]

Dave - 

I'll let the electrical experts here on the Forum address the wire size issue .

I'm guessing that your Blue Sky came with a schunt (mine did).  Since you do not have an inverter I assume that your negatives run to the schunt Again this would be like mine except I do have an inverter and for some strange reason Oliver ran the negative for the inverter straight to the inverter thus avoiding the schunt which makes the readings on the Blue Sky remote somewhat suspect).  If any of this is not true for the way you are wired then remember that all negatives should go through the schunt first so that your readout gives you an accurate measure of the electricity that is coming and going in the batteries.  I'd recommend this even if the batteries that you install have bluetooth such that you can read what is going on in the battery(ies) either via an app or on your Blue Sky remote.

Bill

[Snackchaser]

I'm no expert, but If you're not installing an inverter, then minimum wire size would be dictated by your Progressive Dynamics charger output which is probably around 60 to 90 amps depending on the model.  I’d personally go with 4/0 wire.  This will cover large amperage chargers and/or an inverter if you ever wanted to upgrade.   I think Oliver uses 4/0 in their lithium systems.

Is the BlueSky charge controller for solar?  If so, then it's probably around 30 amps for a 340 watt panel.  You can re-use your #6 wire for that.  

Battery shops or Battery Cables USA will custom make different size/length cables with straight or 90 degree lugs.  Plan your run, measure lengths and verify the stud sizes you need, probably all 3/8”.   For cost perspective, I ordered a 24” x 4/0 cable with lugs in January for $30 including shipping.  2/0 was a couple of dollars cheaper per foot.

I also highly recommend that you install a Victron smart shunt on the negative lead so you will know your battery charge percentage level.  Something to think about if your ordering pre-made cables.  They use 3/8 studs too.

Hope this helps, Geoff

[jd1923]

2 hours ago, DavePhelps said:

My question is about the wiring. I do not have an inverter, nor do I plan to get one in the future.

Dave, 6 AWG is all you need. The ONLY reason for anything heavier is when running an inverter. OTT uses 6 AWG to connect the PD charger, the 12VDC fuse panel and everything else.

Make sure all B+ and B- connections are clean and tight. I cut 1/2” off each end to bare new copper in the buses, but if you have good eyelets to the batteries, just steel brush them  

Blue Sky SC in our hull also uses 6 AWG in and out. Check my upgrade link re configuring the Blue Sky for LiFePo4.

Good battery choice, btw! 🤣

[Galway Girl]

Here is the article on upgrading hull 505.

it included new inverter and batteries.

 

https://4-ever-hitched.com/ggs-blog/f/lithium-battery-upgrade?blogcategory=Electrical+Upgrades

[Snackchaser]

Dave, I didn't do a great job at answering your question, so here is some better detail .

#6 is the correct minimum wire size for a 30 amp charger, which would be a small charger for your battery.  Verify which PD model you ordered because the higher amperage models charge faster, but they require larger wire.

There are on-line “dc” calculators to determine minimum wire size based on amps, volts, and length of cable.  I ran the numbers for the PD 30, 45, 60, and 80 amp lithium chargers.  This was based on an guess-estimated one-way cable run of 8’, and a targeted voltage drop of less than 2%, these are the results:

• 30 amps = #6 awg
• 45 amps = #4 awg
• 60 amps = #3 awg
• 80 amps = #2 awg

These numbers might vary slightly depending on the actual wire length and other factors, but if in doubt, go large!

I hope this helps.

Cheers! Geoff

[DavePhelps]

OK, let me try to get through everyone's good advice! 🙏

My new PD converter/charger module is the PD4045CSV, which puts out a max 45 amps.

My solar array is 200 watts (Elite 1 remember). I think the newer models are a bit more.... I hope to add an aux 100 watt panel in the future, so 300 watts of panels.

Yes, my Blue Sky charge controller is for the solar panels, and there is already a schunt installed that communicates with my Blue Sky IPN Remote display.

It sounds like 6awg works for the solar side of my battery charging, but is lacking for the increased amp output of my new converter/charger?
According to Snackchaser"s chart, 4awg wire would be the correct size, for the 45amp output of my converter/charger.

I think I have enough OEM 6awg wire to install new crimp connectors and keep that wire in place from my charge controller . Some of the old ones were not so great. Even have some exposed wire on two connections that were over stripped and then the heat shrink was cut  too short..... For the new converter/charger, I'll run new 4awg to the battery. Sounds like a plan is emerging! Not a lot of room in my trailer's electrical space under rear dinette seat, so glad I don't have to break in to my BS charge controller, it's kind of buried in there.

Thanks again everyone for helping me through this. I'm good with the tools, but with the design side of electrical work I'm a bit lacking.

Best,

Dave

PS.  guess I'll also have to check the fuse from the converter/charger to battery to make sure it's rated for 45 amps.

Edited September 16 by DavePhelps

[jd1923]

38 minutes ago, DavePhelps said:

For the new converter/charger, I'll run new 4awg to the battery. Sounds like a plan is emerging!

Good choice, given the new PD charger is 45A. I believe the original ones were 30A and ours usually read between 20-25A when plugging into shore power. The Blue Sky SC is 25A so 6AWG is just fine.

When I upgraded, I found the ground bus (the one on the floor with many yellow jacketed wires connected) only had one 6 AWG connection to the batteries. Our new inverter/charger is rated at 120A, but i have it set for 50A. Instead of replacing the 6 AWG, I merely added a second 6 AWG wire. Together two 6 AWG cables are equal to one 3 AWG cable. This may be an option for you too.

You need 4 AWG (or 2x 6 AWG) wire size on both sides, the B+ Red and B- Yellow connections from your new charger to your new Epoch battery.

See these links the first one is to calculate wire size, and the second one allows you to calculate the combined AWG of multiple wires: 1) Wire Size Calculator (wirebarn.com) 2) Wire Combination Calculator (wirebarn.com)

Edited September 16 by jd1923

[DavePhelps]

So one final question. The Bussmann circuit breaker between my converter/charger and the hot bus is 40 amp. The next size up is 50amp (Blue Sea)
With my new 45 amp charger, and new 4awg wiring, it seems like the 50 amp breaker would be the way to go. Or is the OEM 40 amp breaker adequate?

Thanks.

Dave

[jd1923]

3 hours ago, DavePhelps said:

So one final question. The Bussmann circuit breaker between my converter/charger and the hot bus is 40 amp. The next size up is 50amp (Blue Sea)
With my new 45 amp charger, and new 4awg wiring, it seems like the 50 amp breaker would be the way to go. Or is the OEM 40 amp breaker adequate?

Thanks.

Dave

I would buy a new 50A Bussman breaker (check PD manual for correct breaker amperage) between the new charger and the batteries on the new 4 AWG B+ Red cable.

You can add a bus or merely connect the current 6 AWG wire to either end of your new 4 AWG cable (at battery or charger) to the current 40A busman which feeds all DC fuses, fuses for stabilizer jacks etc.

This way the 50A breaker governs the charging only and the original 40A breaker governs 12VDC use in the trailer.

If you need more help, post pics. I used our 40A Bussman as described above and I have additional breakers for each solar charger. Note when wiring, the breakers are marked battery and load sides. OTT had some wired backwards in our hull.

Edited September 16 by jd1923

[DavePhelps]

Received this PDF from Progressive Dynamics. Thought I would post it here for anyone's interest.
News to me that when calculating wire length, the combined length of the positive and negative leads must be added together.

Dave

 

Wire-Guage-for-Lithium-Charging.pdf

[Snackchaser]

Thanks, that's a handy chart!  

You really have to be careful using on-line calculators because some specify "one-way," and others leave you guessing.   You can see by their wiring diagram that a one-way measurement may not be accurate, and just 5  feet can make a difference. 

[DavePhelps]

After reading all these posts carefully, and especially the one from JD, I have come up with this wiring plan. I still may consult with an RV solar technician but though I'd post my crude diagram here for any comments. Sorry, my computer graphic skills are non existent. Forgot to write in that all negative leads from charger to battery will also be 4AWG. This is just the Charger/converter side of the system. I left out the solar side for clarity.

Also note the orientation of the fuses to make sure I got that right. I wasn't aware that there was a battery and aux side to them. There are no indications of this on my current Bussmann fuses, but I do see this on newer ones. I may connect the two fuses with a 1/8"x1" copper bar as has been described elsewhere on the forum. Mostly for a clean connection as the distance will be so short between the two. My plan is to mount both fuses to an aluminum plate that is bolted to the existing Starboard panel (?) or whatever it is that Oliver used to mount their components.

Dave

 

 

 

[jd1923]

2 hours ago, DavePhelps said:

My plan is to mount both fuses to an aluminum plate

Good plan in general Dave. It's a good simple solution. I always enjoy hand-drawing plans on good old-fashioned graph paper!

First, do not mount +positive buses, breakers or other connections to a conductor, e.g. aluminum. Simply dropping a tool could touch a hot connection to the grounding conductor. Use some kind or plastic, PVC, or other non-conductive mounting board. 1/4" HDPE, or thicker if preferred, would work well: Amazon.com: HDPE (High Density Polyethylene) Sheet, Opaque White, Standard Tolerance, 1/4" Thickness, 12" Width, 12" Length by Technology Island (12" X 12") : Industrial & Scientific

This may not make sense initially but turn your 50A breaker the other direction. DC breakers are polarized and work on magnetic force and have to be in the direction of current flow. They are marked BAT on one side and AUX (load) on the other side. Normal use is that the battery supplies current through the BAT side of the breaker to the load. In the case of the charger, current is pushed the other direction, from charger to battery, so the directional breaker must be wired in reverse; charger to BAT post and batteries to the AUX side as they are the physical load when charging.

The copper bar is a good idea but will not easily fit given one post needs dual connections. You could easily make a short U-shaped jumper cable with either 4 or 6 AWG wire. 

Lastly, the BAT post of the 40A breaker needs to be connected to the batteries without passing through the 50A breaker as in your drawing. It will still be on the AUX post but after you have switched the direction of the 50A breaker it will be on the right side of the breaker in your drawing so that power to the +tive bus is not going through both breakers.

If you like, post a revised version of your drawing and I'll take a look to see if you if you understood my suggestions. Thanks for doing this, because in advising you, I just reviewed the wiring in my recent upgrade and found I had a directional mistake. Easy to change and I will correct ASAP, thanks again.

 

[Snackchaser]

Oh boy!  Your’e going to get some different opinions here.  But it’s Saul Goodman 😃.  I think your’e drawing is right. . . that's if you are going to use a polarized breaker.  However, a polarized breaker may not be the best choice between the charger and battery.  Here is my logic:

The breaker mainly protects the wire in this application, so you want it close to the power source.  In your case, you have two power sources, the battery and the charger.  The battery has much greater current potential so it should have priority.  Additionally, any short circuit condition will trip the charger’s AC input breaker, but the battery will cook the wire if not properly protected.  Sometimes this is not intuitive, and charger breakers are installed backwards, or at the wrong end of the circuit.  That’s why I’d prefer to use a fuse between the charger and battery, because it protects the wire in both directions and it doesn’t care how far it’s from the power source.

In other applications, such as you’re 40 amp + busbar feed, breakers are great.  But be mindful of how the solar charger is tapped in, so that the smaller gauge wire is properly protected from the battery too.  Consider a fuse or non-polarity breaker if you can find one.

I love this forum, some great discussions.  I wish you guys were my neighbors.

[DavePhelps]

42 minutes ago, jd1923 said:

Lastly, the BAT post of the 40A breaker needs to be connected to the batteries without passing through the 50A breaker as in your drawing. It will still be on the AUX post but after you have switched the direction of the 50A breaker it will be on the right side of the breaker in your drawing so that power to the +tive bus is not going through both breakers.

Thanks so much JD for your help with this. I had a feeling that the aluminum plate was a bad idea so glad to get the confirmation!

Regarding your statement above, do you mean I need to run a second 6AWG positive wire from the LiFePO4 battery to the Battery(line) side of the 40 amp breaker? While still keeping the two fuses connected?

Or a more simple solution might be to eliminate the battery to battery connection between the 50 and 40 amp breakers in my diagram (revised by turning the 50A breaker around as you suggested) and instead connect the aux side of the 50amp breaker to the battery side of the 40 amp breaker. That way power from the LiFePO4 battery would travel down the existing 4AWG wire and then jump over to the 40 amp breaker without traveling through the 50 amp breaker as you suggested. This has my head in a knot. I'll draw it up tomorrow!
 

🙏 Dave

 

[jd1923]

@DavePhelps, I have a new idea after considering what @Snackchaser added. Yeah, it would be great to be neighbors! 🤣

If the charger (AC-DC converter) fails, it would generally blow the 120VAC circuit breaker. If it produces too much DC amperage, the directional wiring I suggested would protect the circuit. If the charger somehow created a dead short on the DC side, without blowing the AC breaker, then you would want it wired as Geoff suggested. Btw, the breaker being close to the battery vs. charger is negligible since it's only 2-4 feet of cable in either direction.

New idea: Keep your original drawing as-is but instead of the 50A breaker, install an ANL fuse. Geoff also mentioned using a fuse. Fuses are NOT directional as DC breakers. BTW, 50A is not enough for the 45A charger (45A x 1.25 = 56A, so go up to 60A). 

Purchase ideas: Amazon.com: Blue Sea Systems 5123 ANL Fuse, 60A : Blue Sea Systems: Automotive

Amazon.com: Blue Sea Systems 5005 ANL Fuse Block with Insulating Cover, 35-300 Amp, 32V DC : Blue Sea Systems: Tools & Home Improvement

Have you removed your original battery cables yet? Check to see if OTT installed an inline ANL fuse. Mine had one, but our hull also has an inverter.

The OEM 12VDC wiring in our hull was reversed from what's shown in your drawing. Switch the bus and breaker in your drawing and that's how ours was installed. OTT also wired both the 40A breaker from (not to) the bus and from the solar breaker in reverse direction. Originally, I thought OTT wired the breaker in the wrong direction, but they did so because the converter is wired directly to the bus (see red 6 AWG cable in wire loom left side of bus in picture).

The picture was taken during my recent upgrade to new batteries, inverter and buses. The two red 6 AWG wires you see loose come from the AUX side of the breakers and were run directly to the batteries. So, OTT reversed the direction as I had suggested and appears to be standard from what I found online.

Anyway, the ANL fuse will provide better overall protection. Be sure to buy an extra fuse!

 

Edited September 20 by jd1923

[DavePhelps]

I somehow missed Snackchaser's post last night. Thanks for that great idea about using a fuse instead of a breaker for the charger to battery connection! It makes good sense to me. So I will amend my proposed diagram above to eliminate the 50 amp breaker, and replace it with a 60amp ANL fuse (per JD's recommendation).

Wondering if now would be a good time to add a battery disconnect switch, or if I even need one. Seems like a lot of folks have added them. I could add one to the negative 4awg wire between the battery and the ground bus. I read (Battleborn Battery website) that putting the switch on the negative lead is potentially safer, so trust their call on that.

I really appreciate all the input I get here. I could hire this all out, but I really want to learn all that I can about the electrical side. And I like doing the work on my own trailer. I've done a lot of my own residential AC work, but the world of 12VDC is quite different in many ways!

JD:

21 hours ago, Snackchaser said:

In other applications, such as you’re 40 amp + busbar feed, breakers are great.  But be mindful of how the solar charger is tapped in, so that the smaller gauge wire is properly protected from the battery too.  Consider a fuse or non-polarity breaker if you can find one.

There is a 30amp breaker between my solar charge controller output and the battery. With the 'aux' connection on the controller side and the' battery' connection on the battery side (seems correct?). The solar panel inputs are not fused, at least not inside the trailer.

I need to now draw out a complete wiring diagram of the entire system. It may take a day or two as I'm pretty swamped right now with other projects. But I'll get it up here as soon as I can. Again, I really appreciate all the help I have received here.👍

Dave

[jd1923]

On 9/19/2024 at 6:07 PM, Snackchaser said:

Oh boy!  You’re going to get some different opinions here...

@DavePhelps thanks for asking the question and I hope your project is going well. And Geoff, you got me thinking of the possibility of a device or wiring failure that could occur either side of a breaker.

I have the direction reversed on the breakers, as I first suggested (see they're upside down in the picture, yellow levers up) protecting charge voltage from two MPPT SCs. Looking at the bigger picture, I added a 75A fuse (far right in picture) safeguarding the batteries and wiring for everything external to the Victron MP2 inverter where they spec'd a 400A fuse to the batteries. The additional 75A fuse will protect our two 30A solar chargers and the 40A breaker that feeds all 12VDC devices/wiring. Another way to word this is if anything fails/shorts to ground in ANY Oliver 12VDC circuit, this fuse will blow, the last stop prior to the 4/0 wiring, the Victron MP2 and the Epoch batteries. 

I used this style fuse but instead of the designed holder, I made my own with 1/4 x 1" copper stock and a 5/16" SAE automotive bolt (torque lightly due to the glass fuse housing). Now that it has tested positive, I should buy a spare: Amazon.com: South Bend Components Fuse only Marine Rated Battery Fuse (MRBF), 58V DC Max, IP66, Ignition Protected (1-Pack) : Automotive

Edited September 24 by jd1923

[routlaw]

I hope @DavePhelps doesn't mind me hijacking his thread but reading through these excellent and informative post has me asking yet more questions which hopefully some of you will provide answers. Like Dave I am also on the verge of upgrading to LifePo batteries after 9 years with my 4 lead acid batteries that are showing weakness. 

1. If never plugging into shore power upgrading to a Power Dynamics charger capable of lithium charging becomes unimportant, correct? 

2. Why the need to upgrade to a more powerful PD charger just for Lithium batteries? If a 30 A charger worked for lead acid or AGM's why would it not provide enough current for LifePO?

3. My direct battery measurement is different than what my Blue Sky IPN Remote indicates, or stated more precisely a direct battery measurement with my multi meter at the terminals indicates 13.89 volts, while the IPN remote is reading 13.4 volts which is almost a half volt difference. Is it possible I have another issue rather than dying batteries?

4. I don't use an inverter, other than occasionally a small unit rated at 400 watts that directly plugs into the 12 volt ports. Probably will not add anything more in the future either. Put another way we tend to be lightweight campers requiring only lights, water pump etc. Am I missing something else worth considering?

Like Dave I am considering the Epoch 300 amp but also looking at the SOK lineup too. Will Prowse and a few others have given high praise for all of the SOK batteries. Great price points too.

Thanks

[mossemi]

@routlaw  I will offer my opinion on your questions and I’m sure others will offer theirs.

1. If never plugging into shore power upgrading to a Power Dynamics charger capable of lithium charging becomes unimportant, correct?  It would only be important if the Oliver batteries were ever in need of a charge and the solar charger was incapable of accomplishing that for you or the next owner.  I believe my lithium compatible battery charging module cost about $150 dollars, a small price to pay for the added benefit it provides to me.

2. Why the need to upgrade to a more powerful PD charger just for Lithium batteries? If a 30 A charger worked for lead acid or AGM's why would it not provide enough current for LifePO?  My original PD charger module was rated at 45A which is the same as replacement the lithium compatible charging module.  And the reason for the replacement is that the original charging module did not have a charging algorithm that supported lithium batteries.

3. My direct battery measurement is different than what my Blue Sky IPN Remote indicates, or stated more precisely a direct battery measurement with my multi meter at the terminals indicates 13.89 volts, while the IPN remote is reading 13.4 volts which is almost a half volt difference. Is it possible I have another issue rather than dying batteries?  When I suspected my original batteries were failing, I removed them from the Oliver, then charged them individually and after a 4 hours resting period, I used a hydrometer to test each cell.  This test method indicated that 2 cells of 1 battery were failing.  Or you could take your batteries to a battery shop for testing.

4. I don't use an inverter, other than occasionally a small unit rated at 400 watts that directly plugs into the 12 volt ports. Probably will not add anything more in the future either. Put another way we tend to be lightweight campers requiring only lights, water pump etc. Am I missing something else worth considering?  Your Oliver already has the ability to charge the house batteries and I think you would be remiss to give up that functionality.

Just my opinion!

Mossey