Another Lithium Battery Upgrade - Check My Work?

[geoffff]

Here's another project upgrading the original Sportsmobile lead acid house electrical system to lithium.

I knew very little about all this electrical stuff until recently, but I've spent the past few weeks watching a ton of Youtube and chatting with Mr GPT. I've learned a lot!

Here is my design so far:

Removing from my old van:

• 4D lead acid battery
• Inteli Power shore power battery charger
• Sure Power Separator

Retaining in my van:

• 12V house fuse box
• wiring to various 12V appliances
• 120 VAC breaker box
• cable to starter battery / engine
• shore power cable

Adding new:

• ACOPower HY200-24M solar panel (200W)
• ACOPower 12V-230AH LiFePO₄ battery (230Ah)
• ACOPOWER SGR-MP30011-2 all-in-one solar charger (MPPT) and inverter (3000W)
• Renogy DCC1212-60 DC-DC charger (60W)
• Switch for emergency engine starting using house battery

I would love to hear any comments and criticism!

 

[1der]

Have you purchased any of this yet?

 

[geoffff]

Yeah, I started with the ACOPower solar/inverter charger and solar and battery, as there was an Indiegogo deal that I went for back in September of last year. Turned out that wasn't the wisest move, as those parts took 5 months to ship!

So, yes, I have those parts.


I've ordered most of the other stuff (Renogy etc.) too, but it's recently from Amazon, so I could return it if needed.

 

[1der]

Got it.

I am personally not a Renogy fan except for their solar panels. I do not like the very limited charging profiles only selectable via dip switches. The Lith profile does not provide for an absorb level below 14.0 from what I have seen in the manual. Personally, it is Victron 50A for me. I have combined a Victron 30A as the first level DC to DC and have Victron 50A combined with that. The 50A has variable output capability so I can match the charging current to my alternator and driving conditions

So, the Renogy 60 would go back if it were my call, replace w a single Victron 50A (or 2) depending the alternator capacity and other engine based draws.

Next - maintaining the starter battery will not be done (I do not think the Renogy 60A has a second battery charging feature). Your solar provides charge to your house battery but it does not pass through to the starter since DC to DC are typically one direction. Bi-directional charging creates challenges as the starter battery voltage exceeds the DC to DC wake up voltage it will think the alternator is putting out. This can be handled by an ignition trigger wire that keeps the DC to DC off until alternator/starter battery voltage is high enough AND the key is in run mode. Still does not get starter battery charging done but solves the DC to DC problem.

Is starter battery maintenance required in your storage situation?

The Emergency start circuit - I can see using that to help charge a weak starter battery but I am concerned about actually starting /cranking the engine through that circuit. Big cables and 400A may be insufficient for the current loads.

3000w of inverter is a lot for our rigs and if one really is needing 3000w then 230A of Lith will be insufficient and 50 or 60 A of charging will require quite a bit of driving to recharge a drawn down bank.

So,that opens up lots of questions about:

What is your use profile? Park for a few days w no engine run? Shading?
What appliances/draws do you have/use?

Need to get those answers, too.

 

[kbeefy]

I know that the Renogy stuff is on the budget end of the scale but I have been using a few of their products for about 3 years and they have all worked flawlessly.


I just ordered that 60A DC-DC for another project.


Some people like to have a switch on the solar input wires, to easilly disconnect them for maintenance.


Ray brings up a good point on the size of that inverter running on a single 230aH battery. The Lipo BMS will have a max current rating and a surge. 100 or 150A is pretty common, with a surge capacity above that. A 3000w inverter could draw over 200A maxed out.



Whats your alternator situation? I found on both my 2004 and 2005 that they could not maintain the 40A draw. I believe both were the original OE alternator which is only rated for 110A. I have upgraded both to 240A alternators and they handle the 40A draw, I will have to wait and see how they handle the 60A but I have no reason to believe they cant.

 

[geoffff]

Thank you for your detailed response!

Renogy...

Yes, I have also generally read about mixed feelings about Renogy. I will give it some thought. I went the Renogy route at the early stages of my charging plan because that is what was pictured in the sample design schematic provided by ACOPower with their all-in-one charger. This was when I hadn't done much learning/research yet.

The ACOPower battery I have doesn't say anything about lower-voltage charging scenarios. It says simply to provide the battery with 14.2 to 14.6 volts for charging.


Bidirectional Charging...

That would be nice. But I haven't had it in the past, so I didn't put too much effort into achieving that. Do you know of a recommended bidirectional DC-DC charger? The Victron 50A DC-DC chargers I see appear to all be unidirectional.

I have been storing the van plugged in to shore power, and using a 120VAC to cigarette-lighter trickle charger to maintain the starter battery. I'm not sure that is a "good idea".


Emergency start...

My old 2004 Sportsmobile had factory-installed a SurePower 1315 bi-directional isolator that would automatically connect the batteries when starting if the starter battery was depleted. That worked great for the occasional situations I used it. So this made me think that the ~10-ft 2 AWG cable Sportsmobile installs between the starter battery and the house battery is sufficient for carrying engine-starting current in my "new" 2005 van as well. That's why I thought to make a bypass switch with 2 AWG cable to the house battery in my new design, too.



> 3000w of inverter is a lot for our rigs

Yes. I don't plan on actually using all 3000W. The ACOPower all-on-one solar charger/inverter does come with 3000W, but I don't see myself actually using anywhere near that - even if I decide to try an induction burner for cooking someday in the future. So, yes, the 3000W capability is likely overkill.


Usage...

• My van sits parked at my house for months at a time. It's out in the sun, but I plug in shore power.
• When traveling, I usually just boondock camp for a single night in each place I visit, and then do a bunch of driving around during the day (sufficient to DC-DC charge my battery).
• However, I do sometimes use my van for week-long events without plug-in, and in that case I do want to be able to rely on my solar.
• My electrical needs are very small. Just the basic Sportsmobile fridge, lights, furnace fan. My old 4D lead acid batteries were sufficient, but I didn't like their short lifespan. There is a chance I will try using an induction cooker someday.

 

[geoffff]

Whats your alternator situation? I found on both my 2004 and 2005 that they could not maintain the 40A draw. I believe both were the original OE alternator which is only rated for 110A. I have upgraded both to 240A alternators and they handle the 40A draw, I will have to wait and see how they handle the 60A but I have no reason to believe they cant.

That's a good question. I very likely have the stock alternator for the 2005 V10 engine, which I read is 130 amps.

How will I know if I over-tax my alternator? Will I notice something while running the engine?

 

[geoffff]

Ray brings up a good point on the size of that inverter running on a single 230aH battery. The Lipo BMS will have a max current rating and a surge. 100 or 150A is pretty common, with a surge capacity above that. A 3000w inverter could draw over 200A maxed out.

While I don't plan on using anywhere near 3000W I should probably design my system it can handle it.

I checked my battery, and the specs say it can provide 200A max. My inverter maxed out would draw roughly 3000W / 12V = 250A -- so it sounds like I would be over-drawing my battery if pull more than 2400W from my inverter.

 

[kbeefy]

That's a good question. I very likely have the stock alternator for the 2005 V10 engine, which I read is 130 amps.

How will I know if I over-tax my alternator? Will I notice something while running the engine?

I check by monitoring the charge voltage of the starting battery. The voltage at the cig lighter or OBDII port are easy to access means of doing this.


All alternators are a bit different, but as long as you maintain 14.4v at the starting battery (cold) your fine. As low as 14.1 is still fine, maybe a bit lower in hot conditions.


With the OE alternators mine would drop below 13v when trying to maintain the 40A charge. If I switched to 20A on the DC-DC charger, that voltage would come back up to 14.1+.


With the high output alternator my starting battery always has 14.4v, regardless of what the DC-DC charger is doing. It's especially critical on the 6.0 diesel, as the injector controller can suffer if it is underpowered.

 

[kbeefy]

While I don't plan on using anywhere near 3000W I should probably design my system it can handle it.

I checked my battery, and the specs say it can provide 200A max. My inverter maxed out would draw roughly 3000W / 12V = 250A -- so it sounds like I would be over-drawing my battery if pull more than 2400W from my inverter.

The max ratings are often not accurate. Mine is rated at 100A continuous but had no problem drawing 130A for a couple minutes. I'm not sure what the surge rating is or how accurate it might be. I added a second battery just to stay on the safe side. As an added bonus, with that configuration I can boondock 10-14 days without worrying about power. I never do, I usually move every day or two like you.


I have an induction hot plate and water kettle (Joule) we use and like very much. The induction usually only draws 40-60A IIRC.

 

[boywonder]

That's a good question. I very likely have the stock alternator for the 2005 V10 engine, which I read is 130 amps.

How will I know if I over-tax my alternator? Will I notice something while running the engine?

You'll notice the smell of burning alternator windings.....lol Seriously, the stock 130A alternator is a max rating.....it puts out lots less at idle. The issue is a lithium battery with a low state-of-charge drawing alternator current at Idle. Lithiums have much lower input and output resistance than lead acids.

It's been a while, but I measured my alternator draw at idle in my 2008 5.4, and it was quite a lot..can't remember exactly how much. My 2008 has DRL....so headlights are drawing all the time. There wasn't lots of headroom left for charging the lithium house battery even when using a 30A Victron Orion.

Here are the alternator output curves from my 2008 service manual

 

[Stormy98]

On a related note, check your alternator wiring too. My Chevy 3500 came with an aftermarket 140A alternator but kept the original wiring and fusible link wire. Nothing was melting, but I suspect that was only because the existing golf cart house batteries didn't draw that much additional current. I'll upgrade the wiring to 2AWG before I connect the Victron Orion XS DC-DC charger in anticipation of getting closer to the 140A limit. Need to do more testing but I was measuring ~90A draw on idle with everything turned on so I likely won't get to utilize the full 50A capability of the Victron without risking overloading the alternator.

 

[geoffff]

I read that Sportsmobiles like mine (2005 with the V10) usually have the 130A alternator installed, but I didn't know for sure. I couldn't make out any label on the old alternator.




So I bought a cheap amp meter and did some experimenting to find out...!

 

[geoffff]

I started the van, and kept adding loads -- and watched what happened.

Starting the van raised the starter battery voltage from 12.6V to about 14V, and I found the alternator was supplying 15A with no accessories turned on.

Then I kept adding loads to the system: headlights, aux lights, air compressor, and even a couple box fans on a 300W inverter.

The battery voltage stayed around 14V until the alternator started putting out 58A. Then the battery voltage started dropping, and I finally it got down to as low as 12.2V with the alternator maxed out at 83A.

 

[geoffff]

Then I used my high-idle throttle controller (I selected a 2x6 model ) to bump the revs up over 2000 RPM. Then the battery voltage increased back to 13.1V and the alternator was putting out 135A.

 

[geoffff]

Overall, here are my results:



So, yes, it looks like I do have the 130A alternator. It supplies only 83A at idle.

 

[geoffff]

So, if were to keep my current alternator, and I wanted to not max out the alternator at idle, I would have about 55A of spare capacity for DC-DC charging (83-28=55) with only my headlights turned on. But what if I also use my aux lights, wipers, or that 65A ARB air compressor?

I think I should look at an alternator upgrade to buy myself a bit more headroom. And also I'll likely go with a smaller DC-DC charger

 

[1der]

re smaller DC to DC - The Orion XS 50 is selectable as to amps input and output. If you want a 30amp Victron, I have one for sale. I had two and replaced one with a 50. From my phone, I can select on/off on the 30, and/ or add a custom output from the 50 to the 30. So, I can use the alternator to charge any amount from 0 to 80 amps from the 220 A alternator capacity. That way if I am on a long drive I can take advantage of charging the batteries at higher rates.

One item that really draws a lot is the dash and/or rear fans.

Anytime I am using my compressor I select high idle (1200+)

Great write up very helpful!

 

[geoffff]

OK, I did a few more tests today with my alternator, and this 60A Renogy DC-DC charger I have - connected to my new LiFePO4 battery.

(I disconnected my old lead acid house battery isolator / charging system for these tests.)



The Renogy 60A charger has an optional reduced-current (30A) mode, which I enabled for some of my tests.

I tested battery charging with: (1) no extra van accessories load, (2) with 95A worth of accessories turned on (various lights along with my air compressor):



As you can see, my engine was pretty happy doing 30A worth of charging with all my van accessories off, but beyond that the charger was maxing out my alternator and pulling current from my starter battery.

(Why in the first test was my alternator putting out 74A when my van only needs about 15A to run, and the Renogy was only pulling 40A? 15+40=55A < 74A I believe this because I had already depleted my starter battery somewhat from repeating the above tests a couple times, and so about 19A of that alternator current was going into the starter battery to recharge it.)

Also, after only 20 minutes of testing, my alternator had heated up to 217°F -- so that's not a good sign.



So all this makes me think that a 30A charger is what I want, but when I go to air up my tires I will still be eating into my starter battery.

Long term I plan to also upgrade my alternator to something slightly larger.

 

[geoffff]

After doing all this, I turned off the charger and measured the recharging of my now slightly depleted starter battery.

Alternator current: 38A
Starter Battery current: 26A

So, it seems like a slightly depleted lead acid starter battery does not pull the full alternator capacity when recharging. I would think a lead acid house battery works the same way -- the charging current is low as the battery approaches a full charge. A DC-DC charger, however, always pulls its full capacity in amps.