Max current

[Marine359]

5amps is a pretty weak cc output. Your new cc must be a pwm not mppt. Most mppt output more than 10 amps if the delta between batt voltage and mppt input voltage is 5v or more. Reminder: if your batt voltage is 13.5 or higher for FLA, and your pv input voltage is below 17v, you’re not gonna see a lot of charge amperage.

[AJMike]

Originally Posted by creativepart

Mike, what new RV do you have???? You traded the Fuse or sold it?

Details Mike, we need them.

We have had some issues lately with high winds when camping. The winds tended to vibrate the slide topper so badly that we ended up retracting the slide to keep the topper safe, but then had no place to sleep since the slide was the bedroom. And where we live in southern Arizona we find ourselves with a lot of high winds lately.

We also had an increasing problem with the bedroom slide itself. Not that it did not work, as it worked properly, but getting around the bed in the middle of the night trying to get to the bathroom. In the end it just got to be too much trouble and we decided we would look for a small C without a slide.

My first pick was the new Winnebago Ekko but when Winnebago dropped the larger model due to design issues we looked elsewhere. I was not prepared to deal with a cartridge toilet and my wife wanted a separate stand-alone shower. We were just driving around doing normal shopping when we passed one of the local dealers and my wife looked at what was parked next to the road and said "I want to see that RV", so we stopped and looked at what turned out to be an LTV clone made by Regency RV (the Ultra Brougham, island bed model). That is an unknown brand for us but we found a slightly used model at a reasonable price and did a deal with the dealer. This RV is on the Sprinter chassis so it is a bit of a learning curve for us, but my wife loves the floor plan. It tends to wallow a bit when the road is not completely flat and I suppose I need to look for stronger springs and perhaps new shocks.

[AJMike]

Originally Posted by Marine359

5amps is a pretty weak cc output. Your new cc must be a pwm not mppt.

Yes. I think most smaller RVs come with PWM controllers, not MPPT ones. This one is a PWM.

Originally Posted by Marine359

Reminder: if your batt voltage is 13.5 or higher for FLA, and your pv input voltage is below 17v, you’re not gonna see a lot of charge amperage.

Our batteries are Lithium, 2 Battle Born 100 AH batteries. The thing is that I don't much trust the SOC shown by the solar controller since it is based on voltage alone and our camping experience in this RV has shown that what is displayed as 100% SOC on the solar controller often means a dead battery in the morning, and the normal overhead of the background stuff is not too high - about 2 amps - so 10 hours of usage should only account for about 20, perhaps 25 AH usage, not 160-180. That is why I wanted to get the SmartShunt installed as quickly as possible. I wanted to know what was really happening.

[creativepart]

Congrats on the new RV. Sounds great.

You probably will want to take a look at www.sprinter-forum.com to pick up info on the Sprinter Chassis. They have tons of info there. I know many Sprinter owners have added Sumo Springs, new shocks and roll-bars to improve handling. I think they put steering stabilizers on them, too.

I would suggest replacing the CC (Solar Charge Controller). You've got $2000 worth of batteries and a $30 solar charge controller.

I know you said you have a Renergy PWM controller, but you might be happier with the Victron 100/30 SmartController. It's a super easy DIY upgrade and then you'd have both the Solar Charger and the Smart Shunt all on one easy to use Victron app. (I have both of these and they even talk to each other over Bluetooth.)

[Marine359]

My experience with The smartshunt is that doesn’t remember SOC if you disconnect battery. Maybe I’m doing something wrong. You can program it to automatically reset SOC to 100%
Also check with BB to find out what the correct reading should be for 100% SOC. It varies by manufacturer. I think most are around 13.6 -13.8v

[Marine359]

Strongly agree with Creative. I have Victron 75/15 and it talks with shunt over Victron connect, and I see both on Bluetooth. And yes, 100/30 is right size for you.

[AJMike]

Originally Posted by creativepart

Mike, make sure you have ALL negative leads running through that shunt on the load side. You should have one for the chassis ground, one for the inverter, one for the solar charge controller and one for the DC/DC charger. I assume you don't have one from the alternator because of the DC/DC charger.

If you see any other wires connected to the batteries they too will need to be relocated to the smartshunt.

Yes. I think that must be the problem.

I installed the SmartShunt in my driveway and we just put the RV back in storage since the HOA does not like having an RV in front of the house, but right before I did that I took a flashlight to look for other wires and found what I believe is an extra wire. The left most battery has 2 connections on its negative post - one to the negative post of the other battery (good) and one to someplace else (bad) so I guess I missed that. Perhaps that is the solar power. I will move it tomorrow morning and see if that solves the problem.

I know I should install a busbar and make connections to it, but there is so little room in the battery box that I will see if I can just add the one connection and if that fixes everything. I will post what I find. When I am better prepared (ie, have the proper tools) I will see about installing a busbar for the connections. I have to learn to do this sometime, and I am getting a bit old to put it off much longer ...

[AJMike]

Yup. That took care of it.

I moved what is probably the solar input wire to the output of the SmartShunt and I now see the solar input to the batteries in the Victron smartphone app, so all seems well. I also replaced the 4 gauge wire with some 2 gauge battery wire that I bought yesterday afternoon, so that issue has also been taken care of.

I do have a question about the Victron MPPT solar controller some of you are recommending. One thing I noticed about the Victron DC-DC Charge controller is that it gets very hot when we are on the road and needs a well ventilated space. In our previous RV I installed a small muffin fan to blow cool air directly over the heat sink to keep it from shutting down due to the heat. Does the MPPT solar controller also get very hot? And does it also need a well ventilated space? The logical place for me to put that is completely enclosed and I would not want to make that kind of mistake.

[Marine359]

Originally Posted by AJMike

Does the MPPT solar controller also get very hot? And does it also need a well ventilated space? The logical place for me to put that is completely enclosed and I would not want to make that kind of mistake.

Mine 75/15 doesn’t get hot at all using a single panel. Might get warm using two panels. IDK yet.

[AJMike]

Originally Posted by Marine359

Mine 75/15 doesn’t get hot at all using a single panel. Might get warm using two panels. IDK yet.

We have 4 100 watt panels on the roof. I guess I should have mentioned that in my post.

[creativepart]

Mike, My Solar Charge Controller doesn't get noticeably hot that I know of. It's in a basement compartment and I don't need to interact with it so, I'd only know if it seemed to be very hot when getting stuff in and out of that compartment - which I do frequently . And, that has not happened.

One other thing - keep in mind that when your batteries are charged... or when some other charger on your RV is in the active process of charging your batteries, you'll see almost zero watts or amps being generated by your solar on the Victron SmartSolar. The CC is directly connected to your batteries. It cuts back on the solar output when they are fully charged. And, as we know, when the onboard converter/charger or inverter/charger or DC/DC charger are actively charging they do so at a higher voltage, ~14v. So, your SmartSolar controller is smart enough to cut back almost all solar charging when it sees that voltage on your batteries.

It's tempting to think that your solar panels are supplying "free" power and your other chargers cut back their charging and let the solar supply all the free power you can get. But that's not how it works.

Turn off all external chargers and have your batteries somewhat depleted and your Solar charge controller will go to town sucking in all the power it can get and delivering it to your batteries. But the minute you plug into shore power, turn on the generator or start your engine and all the solar will be cut back to a bare minimum.

[AJMike]

Originally Posted by creativepart

One other thing - keep in mind that when your batteries are charged... or when some other charger on your RV is in the active process of charging your batteries, you'll see almost zero watts or amps being generated by your solar on the Victron SmartSolar. The CC is directly connected to your batteries. It cuts back on the solar output when they are fully charged. And, as we know, when the onboard converter/charger or inverter/charger or DC/DC charger are actively charging they do so at a higher voltage, ~14v. So, your SmartSolar controller is smart enough to cut back almost all solar charging when it sees that voltage on your batteries.

It's tempting to think that your solar panels are supplying "free" power and your other chargers cut back their charging and let the solar supply all the free power you can get. But that's not how it works.

Turn off all external chargers and have your batteries somewhat depleted and your Solar charge controller will go to town sucking in all the power it can get and delivering it to your batteries. But the minute you plug into shore power, turn on the generator or start your engine and all the solar will be cut back to a bare minimum.

The only experience that I have with the DC-DC Charger, generator and solar was with my previous Fuse. On that I had the same Victron 12/12/30 B2B, a PD9260 converter with the dongle, 400 watts of solar, the Victron 712 Smart and the standard Zamp 30 amp solar controller. And from what I could see the system had no problem combining the B2B output with either the generator output or the solar when the battery was charging.

That is, if we were on the road I might well be getting 30 amps from the B2B but the 712 Smart was showing me that the batteries were charging with perhaps 45 amps, combining the B2B and the solar. Similarly if we were on the road and I ran the generator I would get perhaps 50-55 charging amps from a combination of the B2B and the generator.

I also ran the generator when we were stopped, but since I almost never did that except for very short periods of time to run the microwave I don't know if the generator output would combine with the solar or not. I never bothered to look.

And, of course, the Zamp solar controller shut down the charging current when the battery was fully charged.

This RV was not prepared for Lithium batteries. The current charge controller is not Lithium compatible and there was no BM installed and I am in the process of fixing that. The SmartShunt was the first step and I have an appointment in a couple of weeks to replace the WFCO 9960 with a PD 9260 converter to fix the Lithium compatibility. I have no idea what will happen then with combinations of the two but I will keep an eye on what the input when we travel.

As someone who did not even know that a BM was important when I started all of this a couple of years ago I have become convinced that without one I would have no idea what was really going on. One of the techs asked me why I bothered with the BM as I had the voltage reading from the solar controller and did not seem very convinced when I told him that I did not trust the voltage readings as being representative of the actual battery SOC. Perhaps I am now too convinced of the need for the BM, but I feel more comfortable now that it is installed and working properly.

We are taking another short trip in a day or two and now I think I will have some idea what the actual SOC of the batteries is and if they die again perhaps I will know why.

[bigb]

I am trying to decide on which battery monitor to buy and the Victron Smart Shunt is on my list, I already use their chargers. You guys with the Victron Smart Shunt, how do you like it? Are you happy with your choice?

[Marine359]

Originally Posted by bigb

I am trying to decide on which battery monitor to buy and the Victron Smart Shunt is on my list, I already use their chargers. You guys with the Victron Smart Shunt, how do you like it? Are you happy with your choice?

Very happy with it.

[Wyatt]

I'm guessing Creative part is right when he said, "The system will not work accurately without every single negative battery connection attached to your load side of the shunt."
I did the same thing he did, added a bus bar for all the negative leads that need to now go on the shunt--NOT the battery terminal.

[AJMike]

Originally Posted by bigb

I am trying to decide on which battery monitor to buy and the Victron Smart Shunt is on my list, I already use their chargers. You guys with the Victron Smart Shunt, how do you like it? Are you happy with your choice?

Yes, I am happy with it. The Bluetooth range is shorter than for the 712 Smart, but it is long enough for my needs.

[AJMike]

Originally Posted by Wyatt

I'm guessing Creative part is right when he said, "The system will not work accurately without every single negative battery connection attached to your load side of the shunt."
I did the same thing he did, added a bus bar for all the negative leads that need to now go on the shunt--NOT the battery terminal.

Yes, and that seems to have fixed my problem of not seeing the solar power.

[Tragus52]

https://www.amazon.com/SockitboX-Weatherproof-Electrical-Connection-Enclosure/dp/B009RX5GI2
This will allow you to mount the shunt on the side of your battery box. Hope this helps.