Lithium Battery

[PeterInNH]

@PeterInNH, here are my thoughts:
1) The WFCO AD probably won't work to charge to full LiFePo4 capacity, mine doesn't. They'll send you a jumper that has worked for others, I haven't installed mine yet. Don't plan on upgrading the charger/converter until you have used your system in the field. My WFCO charges to about 85% and my panels pick up the rest.
2) No, if you have a 2,000-watt inverter, the most you will pull is 2,000 watts. That's also the most your inverter can support at one time. So one AC or the microwave but not both at the same time. If your current cabling is adequate for a 2,000-watt inverter, no change is required.
3) If you don't already have one, you need a fuse adequate to protect the circuit from the largest expected draw. With a 2,000-watt inverter, a 200 Amp fuse would be fine.
4)With the two batteries (could you purchase one of sufficient size, I've seen 540 Ah batteries out there - one battery would eliminate the need for battery bus bars) you'll want cables of sufficient size (the same length) to run from the batteries to the battery bus bars. Then a shorter cable to run to the shunt from the negative bus bar, and a shorter cable to run to a positive bus bar for your draws. These should be heavier cables supporting the anticipated draw of 2,000 watts from the inverter.
5) Assuming no change to the solar panels, then no. But if you're going to use the Victron shunt, then having a Victron solar controller would mean that the two of them could talk to each other.

Hi @Soundsailor

1) Ok, I'll check with WFCO on the jumper and if, as @coglesby says, it voids the warranty will send it to them when have a time window.

2) Well, since the Inverter was installed by GD I have to assume (haha, bad thing I know) that the cabling is sufficient. Will try and get into the compartment and see if I can see what size cables there are.

3) Well, same as #2 ? Should I have expected GD to fuse the existing setup correctly ? However, my question about the fuse was more about going from the 88amps (?) to 400amp and having an inline fuse somewhere just before or after the shunt....
What about a 2nd 'Disconnect' ? It might be useful at some point to easily shut off all battery power to the camper right there at the batteries themselves ?

4) I went into the question of 1 'big' vs more 'smaller' in a thread here somewhere... TEMGOT does have a self heating 460ah, 250amp BMS battery (which, weirdly, costs more than these two combined) but I wanted redundancy so decided to go with 2.
Ok - so if 2000watts is the limiting factor then cables everywhere that will support 200amps is all that is required ? Regardless, I may still go with 4/0 for the short runs between the Bus Bars and Shunt (and Shunt to Bus Bar if I decide to go that route) in case, sometime in the future, I swap out the Inverter and 400amps could be actual usage.

5) Ok, that's interesting - what do I gain since the MPPT Controller that is installed also has an app where I can monitor the Solar activity (other than less apps to watch all the time ? lol) ? If I ever add more solar and need more than the 50amp then I can wait until then ?

Thanks !

 

[Butcher]

Ok, finally starting the actual upgrade to two 300ah LiFePo batteries so picking up the ideas and recommendations from this (and others linked) thread.

I would have the battery grounds attached to the shunt, then the other side of the shunt attached to the buss bar.

I designed/made my own buss bar where the shunt directly attaches to it. I purchased a solid copper bar, drilled holes, and threaded those holes so I can attach cable ends too. I am a German car mechanic by trade, so I used metric fittings.

The reason I did it my was was I figured there will be more work at the buss bar [things connected/disconnected] in the future. Constantly connecting and disconnecting things at the shunt sounds like a potential problem in the future. I also think it looks better.

Other than that, I think you spent a good amount of time understanding your wants/needs and have a well thought out plan.

 

[SolarPoweredRV]

Ok, finally starting the actual upgrade to two 300ah LiFePo batteries so picking up the ideas and recommendations from this (and others linked) thread.

Old: 1 88ah AGM (crappy battery from dealer. lol)

New: 2 300AH Self-Heating LiFePO4 Lithium Battery with Touchable Smart Display & APP Monitoring, Built-in 200A BMS
(Amazon.com).
Ordered and on the way.
New: Some shunt (Most likely - Victron Energy SmartShunt IP65 Battery Monitor (Bluetooth) - Victron Smart Shunt - 6.5V-70V, 500 amp)

Note: the intent with these 2 batteries is to increase Capacity (total AH) not necessarily to handle large amperage draws for a long(er) period of time.

Current Converter: 55AMP WFCO WF-9855-AD
Current Inverter: 2000W WFCO WF-5220
Current Solar Charge Controller: 50AMP Jaboni FS-SF100-50

Am thinking, in an attempt to make it as 'plug and play' as possible, that this could all be just be as simple as:
- directly connecting the individual batteries to two (NEG and POS) Bus Bars
- then connect the Neg Bus Bar to the Shunt
- then connect all the existing Neg connections to the Shunt
(or, as has been suggested, to another Bus Bar and then a single cable back to the Shunt)
- then connect all the existing POS connections to the POS Bus Bar.

Pretty simple wiring/connections all around ... and should provide a combined 400amps of available current while providing redundancy in case of a single battery failure.

My concerns are:
1) Assuming, of course, that the AD actually works (lol) - will I need to immediately upgrade the Converter ? Or, is it something that can be put off until 'Phase 2' ?
If I upgrade how much of the cabling will need to be looked at and possibly upgraded ? Just that between the Converter and the Bus Bar/Battery ?

2) If my math is correct I could be passing (pulling, pushing ?) up to 4800 watts (4800W = 400amps x 12volts) thru the Inverter. Correct ?
Is this a (potential) problem ? Will I need to immediately upgrade the Inverter ? Or, is it something that can also be put off until 'Phase 2' ?
If I upgrade how much of that cabling will need to be looked at and possibly upgraded ?
I don't expect to run both AC's from the battieries so hard to envision going beyond 2000W (but, you never know...). However, what about both 1 AC and the Microwave ?
Is the most important factor the 'draw' from whatever I am running in the camper thru the Inverter ?

3) Is it really necessary to put inline fuses and, possibly, a second disconnect switch somewhere in the new cabling ?
Between the batteries and the Bus Bar ? Between the Bus Bar and the Shunt ? Elsewhere ?

4) New cabling from batteries to Bus Bars and Shunt - what size(s) are necessary (Yes, I know to keep them all the same length...) ?
From batteries to Bus Bar able to support 200amp (ie, 2/0), then from Bus Bar to Shunt able to support 400amps (ie, 4/0 - and the same if I add another Bus Bar between the Shunt and all the other connections) ?
5) Not planning anything regarding the Solar Charge Controller. Is this assumption ok ?

Thanks !

Peter

First, congratulations on starting your upgrade.

1) no, you do not need to immediately upgrade your Converter. You may not even need to upgrade the Converter depending on your final system design, i.e.: if you upgrade to an Inverter/Charger you will eliminate the Converter altogether.

2) Presuming that all your existing wires are adequate for their load, you only need to ensure the cables from the batteries to the buss bars are adequate ( note: you want to size them for your future largest draw, not the current draw)
[I.e.: future proof your system]). You can then connect your current wires to the Buss Bars.

A note regarding the Shunt...

With your Bluetooth battery monitoring capabilities, I don't think a shunt is really necessary. To be honest, I rarely use my shunt for information on my system, I tend to just look up the information from my Victron Solar Controller.

You might try using your system without the shunt and see how you like it.

3) Yes, you should have inline fuses to protect all your wiring. Most systems have a catastrophic fuse at the battery to protect the whole system.

4) size your new cabling to carry your future maximum load, again, future proofing your system.

5) Yes, you don’t need to upgrade everything at once. I don't know if you have read this post yet, but, at the top of the Solar Forum is a posting called "Affordable Solar..." in that post is a link regarding "Installing Solar in Phases..." that explains how you can build your system in wallet friendly Phases.

Good luck, and keep us updated on your progress.

 

[Soundsailor]

The idea to use a copper strip as a bus bar posted by @Butcher is a good one. Just drill holes, you could bolt on the connections. If it were me I'd insulate it with some shrink insulators for cable connections. Something like this should work.

 

[PeterInNH]

I would have the battery grounds attached to the shunt, then the other side of the shunt attached to the buss bar.

I designed/made my own buss bar where the shunt directly attaches to it. I purchased a solid copper bar, drilled holes, and threaded those holes so I can attach cable ends too. I am a German car mechanic by trade, so I used metric fittings.

The reason I did it my was was I figured there will be more work at the buss bar [things connected/disconnected] in the future. Constantly connecting and disconnecting things at the shunt sounds like a potential problem in the future. I also think it looks better.

Other than that, I think you spent a good amount of time understanding your wants/needs and have a well thought out plan.

Hi,

Do you mean battery(ies) to busbar to shunt ? Then the neg connections ? In order to have just a single in-out for the shunt I was planning on:
batteries to busbar to shunt to busbar (and then connecting the neg connections to this last busbar)...

Thanks !

 

[PeterInNH]

First, congratulations on starting your upgrade.

1) no, you do not need to immediately upgrade your Converter. You may not even need to upgrade the Converter depending on your final system design, i.e.: if you upgrade to an Inverter/Charger you will eliminate the Converter altogether.

2) Presuming that all your existing wires are adequate for their load, you only need to ensure the cables from the batteries to the buss bars are adequate ( note: you want to size them for your future largest draw, not the current draw)
[I.e.: future proof your system]). You can then connect your current wires to the Buss Bars.

A note regarding the Shunt...

With your Bluetooth battery monitoring capabilities, I don't think a shunt is really necessary. To be honest, I rarely use my shunt for information on my system, I tend to just look up the information from my Victron Solar Controller.

You might try using your system without the shunt and see how you like it.

3) Yes, you should have inline fuses to protect all your wiring. Most systems have a catastrophic fuse at the battery to protect the whole system.

4) size your new cabling to carry your future maximum load, again, future proofing your system.

5) Yes, you don’t need to upgrade everything at once. I don't know if you have read this post yet, but, at the top of the Solar Forum is a posting called "Affordable Solar..." in that post is a link regarding "Installing Solar in Phases..." that explains how you can build your system in wallet friendly Phases.

Good luck, and keep us updated on your progress.

Hi

re:

1) My primary concern was if a 55amp Converter would be sufficient for charging 600ah of batteries in a resonable amount of time. I'm pretty sure I've run across a thread here/somewhere where the OP had done an upgrade to something in the 100amp range...

2) $ 4) Ok, so the cables I add (after the first busbar and up to the last busbar) with be able to support 400amps (ie, 4/0).

The shunt...: Ok, I'll wait on that until I see what the app interface from TEMGOT looks like. Maybe it makes it easy(ier) to monitor 2 batteries. Good suggestion.

3) Yes, since the batteries could pump 400amps out and most of the rest can't handle that I'll put an additional, upgradeable, fuse inline somewhere.

Thanks for the input !

 

[Butcher]

Do you mean battery(ies) to busbar to shunt ?

No. The battery grounds are attached to shunt, then the other side of the shunt attached to the buss bar.

 

[PeterInNH]

No. The battery grounds are attached to shunt, then the other side of the shunt attached to the buss bar.

Hi,

I remember, I think, reading somewhere that it was not optimal to have multiple (inbound ?) connections to the shunt - hence my thought to 'join' the two batteries via a busbar (getting the 400amp potential) and then feed a single cable both in and out of the shunt.

You're saying that a multiple 200amp connections to the shunt is not a problem (and will, in effect, act just like a busbar) ?

EDIT: found the thread with the single connection reference: Why You Should Use Buss Bars in your Multi Battery Installation

 

[Butcher]

The more connections just means more chances for voltage drops. I guess the only wrong way of doing something is doing it in a way you do not want to do.

The last thing I need is to have multiple buss bars. More things to go wrong. More things to buy. More things to work around.

There are plenty of opinions about things in life. I don't really think there are many wrong opinions. For me, less is better when it comes to electricity flow. Less resistance, less voltage drops, less hassles, etc. That is why I chose to do it my way. I see no advantage of adding more wire and no less than 4 additional contacts for something to go wrong.

I think we can all agree, as long as all the electrons are passing through the shunt, you should get a reliable reading.

 

[Butcher]

You're saying that a multiple 200amp connections to the shunt is not a problem.......

Each of my batteries are capable of discharging at least 1C. That means each battery is capable of discharging +300A. I throttled down each battery to discharge no more than 150A through the BMS. The largest draw on my system would be from the inverter [3kW]. Simple terms, around 250A.

I elected get these large batteries not because what they can deliver, but the storage capacity. I designed the entire system around 400A. I know, it can do more, but if I need that much more, I got a serious problems. In a perfect world, each battery would not deliver less than 75A at full tilt.

I have the absolute bare minimum connections for the inverter. Two at the shunt and 6 at the inverter [2 at each cable and 2 more at the 400A fuse].

 

[PeterInNH]

Hi All,

Given the narrow(ish) space on the tongue (looking at max 13in or so) I couldn't find a (non-metal) battery box that would fit - so I'm building one out of marine grade PT 3/4" ply (pictures coming soon). Unfortunately I believe there's no room for the final busbars (where all the existing Pos and Neg wires would attach) inside the box itself.

So, my question: is there any issue with mounting those busbars to the outside (rear, between box and the front of the trailer) of the box ? Would they require some sort of waterproofing/corrosion protection or is being exposed to the elements just fine (since there are other spots under and along the frame where connected wires are exposed) ?

Thanks !