Some Battery Questions

[mlb3820]

We have, on our 2018 LEII:

4-6v AGM batteries

2 Solar Panels (320w)

ZS-30A Charge Controller

2000w Inverter

Composting Toilet with 12v dc fan

We know the solar panels charge the batteries through the controller.  Does anything else help to charge them?

 

On the charging side:

When plugged into 30a 110v, does the AC system charge the batteries?

When plugged into 15a 110v, does the AC system charge the batteries? (Like when running the generator when boondocking or using friends AC when driveway surfiing.)

When plugged into the TV with 7 pin connector, does the TV DC supply help charge the batteries?

In times of bad solar charging weather, how do I charge the batteries? Or is just the solar doing all of the battery charging?

On the consumption side, what draws power from the batteries when plugged into:

30a 110v?

15a 110v?

TV 7 pin with engine running?

Today the tank monitor shows the batteries at 13.5v after a full day of bright sunlight.  What are we supposed to avoid dropping the level below, in volts, to avoid damaging the batteries?

 

Some part of me thinks the batteries should be charged and most demand be met by whatever external power supply you happen to be using (including solar).  Wishful thinking?

 

Cheers,

 

Mark

[KWRJRPE]

Excellent questions!!! and I anxiously look forward to the answers as I am a newbie to travel trailers and battery management. This forum will definitely have the answers to these questions.

[Overland]

The batteries charge when plugged in, regardless of the amps. The tow vehicle will also charge them, albeit slowly. When plugged in, or on generator, the charge current will outweigh anything being drawn from that current so your batteries are still charging.

 

The charge from solar will vary greatly depending on time of day, year, cloudcover, location, etc., so in poor conditions you can easily use power faster than you can charge from solar.  There are a few posts here and there on what you can expect from your solar - I don’t keep track of them though so you’d have to search.

 

Voltage charts vary, but somewhere between 12.1 and 12.5 is generally considered 50% charge.  Others here have much more experience with AGMs than me, though, so I’d defer to them.

[geO]

I think of battery management being a very important aspect especially when camping off the grid. This link explains the importance of a good battery monitoring system. Manyt have ways of getting by with out them, but if you want to understand exactly what is going on a battery monitor is the best way.    http://olivertraveltrailers.com/topic/battery-monitoring/#post-11798

[STEVEnBETTY]

We have, on our 2018 LEII:

4-6v AGM batteries

2 Solar Panels (320w)

ZS-30A Charge Controller

2000w Inverter

Composting Toilet with 12v dc fan

We know the solar panels charge the batteries through the controller. Does anything else help to charge them?

 

On the charging side:

When plugged into 30a 110v, does the AC system charge the batteries?

When plugged into 15a 110v, does the AC system charge the batteries? (Like when running the generator when boondocking or using friends AC when driveway surfiing.)

When plugged into the TV with 7 pin connector, does the TV DC supply help charge the batteries?

In times of bad solar charging weather, how do I charge the batteries? Or is just the solar doing all of the battery charging?

On the consumption side, what draws power from the batteries when plugged into:

30a 110v?

15a 110v?

TV 7 pin with engine running?

Today the tank monitor shows the batteries at 13.5v after a full day of bright sunlight. What are we supposed to avoid dropping the level below, in volts, to avoid damaging the batteries?

 

Some part of me thinks the batteries should be charged and most demand be met by whatever external power supply you happen to be using (including solar). Wishful thinking?

 

Cheers,

 

Mark

 

Mark, first off congratulations on your purchase of an oliver, one of the finest rv's made. I'll try to answer some of your questions. On the charging, yes to all of the above,your converter/charger takes over, and when your solar is insufficient you either need ac current from a plug in or generator. On the consumption side, all of your d.c. appliances draw from your batteries when in use, the solar just replenishes the power used and the converter/charger takes over power management when you're plugged in either with shore power or generator.

 

Try not to go below 12.3 volts when your batteries are at rest, that's the 50% level with agm batteries. When the solar is charging the voltage can go as high as 14% but you have to wait until the batteries are at rest to get a true state of charge with the solar controller we have.

 

geO is correct about the battery monitor, however I've done without so far by just monitoring my voltage early in the morning before the sun comes up and starts charging my batteries. It takes a while to figure your usage out without a separate monitor.

 

This method is crude at best but so far so good, you shouldn't need to monitor your batteries when plugged in your converter takes over that task.

 

I would strongly advise doing some research on battery management and inverter usage, there are multiple posts on this subject throughout this forum.

 

Steve

 

 

[mlb3820]

Thanks to all who posted responses.  Clearly it is battery monitoring that I am after.  I read the linked 2008 article from Chris of Technomadia and saw references to some battery monitors there.  I'll look at some more recent reviews of currently available monitors and report back here.

[geO]

I'm happy with the Tri-Metric and think Oliver should offer a monitoring system as a upgrade.

[RnA]

I’ve been very happy with the Xantrex LinkPro in past RVs.  I’ve purchased another one to put in my E2 this winter.

 

https://www.hodgesmarine.com/Xantrex-Linkpro-Battery-Monitor-p/xan84-2031-00.htm

 

I agree with geO that Oliver should offer a battery monitor as an option.  It takes the guess work out of knowing your  battery state.  For camping off the grid it is my first upgrade.

 

— Randy

[DavidS]

The slightly older Oliver models (mine is a 2016) have the Blue Sky MPPT Solar controller, and this controller has an accurate battery monitor built in to it.

 

If you push the Next button on the Blue Sky remote, the unit wakes up and displays the first screen, the BATTERY VOLT/AMP screen which shows the battery voltage and the net battery current. If you touch the Next button again it switches to the second INPUT CHG OUT screen which displays the input and output currents. Touching the Next button again brings up the BATTERY CAPACITY screen which displays the battery capacity as percent remaining, i.e. 70% or 100% if full.

 

Of course, for the BATTERY CAPACITY screen to be accurate you have to correctly program the remote with info on your batteries. A lot of useful information is available on an earlier thread HERE. I have summarized these programming steps for my AGM batteries in a document which I am happy to send to anyone interested.

 

I used to use an AGM battery chart (HERE) where 100% is 12.84 volts and 50% is 12.24 volts. However, the battery voltage would often not agree with the battery capacity on the Blue Sky remote. For example the battery voltage might say 12.4 volts, but the battery capacity would read 80% full. Additionally, when the batteries are nearly full and charging, the battery voltage often reads well above 13 volts, much higher than the 12.84 volts that represents 100%. I talked to Blue Sky technical support about this apparent discrepancy, and they told me the battery capacity was the much more accurate reading.

[SeaDawg]

I agree that the blue sky monitor is less than perfect, but pretty darn good. It does require input, as do all better battery monitors.

 

We saw a new, and quite nice, battery monitor at the boat show today.. balmar gs200. Includes blue tooth. But... not really set up for solar, yet, so we would have to wait a bit, for  that.

 

It won best of show at ibex  , but, we're finally adding solar to the boat soon. We will likely go with the blue sky we already know  ... their customer service is just amazing,  and product is really durable. Ten years  plus... for us

 

Sherry

[Spike]

We have exactly the same setup in our 2017 Elite II as Mark (mlb3820) and the same kinds of questions.

 

The Zamp solar charge controller has remained a bit of a mystery to me for a while, even though I have reviewed the online manual a few times. I am confused now why folks are recommending a battery monitor in addition to the Zamp solar charge controller, which the company claims on its website will "Monitor, regulate and protect your batteries, panels, and electric system."

 

Our Ollie is parked on our property with no shore power, just the solar. I have been leaving the interior and exterior courtesy lights on all night as a security measure (and sometimes all day when I neglect to turn them off). Now that it is cooler, I have set the thermostat at 45 degrees (which draws some current to move the air around the cabin) and have turned on the water heater (not the Truma type), figuring that those two measures will suffice to keep things from freezing during our mile SE Arizona winters. The Nature's Head fan runs continuously.

 

So far, the batteries seem to be doing well, but these are my questions that I hope someone can answer:

 

1. Why the need for a battery monitor in addition to the Zamp solar charge controller? (And, if I need one, what might be the best choice for us, who would like to be able to boondock--without using the AC or microwave--for a week or so at times.)

 

2. I think that I understand the different readouts when pushing the button on the Zamp--except the one about amp hours ("aH" on the display). Does this number, which seems to vary in my Ollie between the middle teens and low twenties, indicate how much run time I have left at the current load--or something else?

 

3. How many years might I expect my AGM batteries to last if I don't allow them to fall below 12.3 volts?

 

I appreciate Steve's advice: "Try not to go below 12.3 volts when your batteries are at rest, that’s the 50% level with agm batteries." Any other advice for a battery novice like me would be appreciated.

[STEVEnBETTY]

We have exactly the same setup in our 2017 Elite II as Mark (mlb3820) and the same kinds of questions.

 

The Zamp solar charge controller has remained a bit of a mystery to me for a while, even though I have reviewed the online manual a few times. I am confused now why folks are recommending a battery monitor in addition to the Zamp solar charge controller, which the company claims on its website will “Monitor, regulate and protect your batteries, panels, and electric system.”

 

Our Ollie is parked on our property with no shore power, just the solar. I have been leaving the interior and exterior courtesy lights on all night as a security measure (and sometimes all day when I neglect to turn them off). Now that it is cooler, I have set the thermostat at 45 degrees (which draws some current to move the air around the cabin) and have turned on the water heater (not the Truma type), figuring that those two measures will suffice to keep things from freezing during our mile SE Arizona winters. The Nature’s Head fan runs continuously.

 

So far, the batteries seem to be doing well, but these are my questions that I hope someone can answer:

 

1. Why the need for a battery monitor in addition to the Zamp solar charge controller? (And, if I need one, what might be the best choice for us, who would like to be able to boondock–without using the AC or microwave–for a week or so at times.)

 

2. I think that I understand the different readouts when pushing the button on the Zamp–except the one about amp hours (“aH” on the display). Does this number, which seems to vary in my Ollie between the middle teens and low twenties, indicate how much run time I have left at the current load–or something else?

 

3. How many years might I expect my AGM batteries to last if I don’t allow them to fall below 12.3 volts?

 

I appreciate Steve’s advice: “Try not to go below 12.3 volts when your batteries are at rest, that’s the 50% level with agm batteries.” Any other advice for a battery novice like me would be appreciated.

 

Spike, the zamp controller monitors your voltage and amps, but the voltage spikes when the solar is charging your batteries, a separate monitor uses a shunt to divert the current to a separate monitor and it can more accurately track the amps being used and replaced, without a separate monitor, that's why I have to wait until early morning to check the voltage level of my batteries when they are at rest. The trimetric monitor that GeO has is highly recommended, that's the one I was looking at, but I haven't pulled the trigger yet.

 

The amp hour function is how I track the amps being replaced by the solar, if the blue light is displayed on your controller, your panels are charging your batteries, if the green lights are on but the blue light is out your batteries are fully charged and the controller is in "float mode", that's the maintenance stage you ideally want to reach every day. When the sun goes down,and your controller shuts off for the night, if you go to the amp hour function it tells you how many amps the solar has replaced. After a while you can get a pretty good guess on your power usage, a monitor eliminates the guessing. I believe with the agm batteries we have 400 amp hours available, as long as you stay under 200 amps usage that's 50%. When we boondock I try to be conservative with the water and power usage, we generally average between 50 & 75 amp hours a day, with that amount of use our batteries are usually fully recharged by early afternoon and the limiting factor on our stay is water.

 

Batteries are really fickle, I've read that with proper care they should last anywhere between 4 to 7 years, but nothings written in stone, take your vehicles batteries for example, I've had them go as long as 10 years and as short as 1, who knows?

 

Steve

[mlb3820]

A Battery Monitor solution (one of many anyway)

 

I consumed all the feedback above, concluded I need a battery monitor for insight into our battery use that I desire and then set out scouring the web for options. Chris's post (technomadia) from 2008, provided some excellent insight and jumping off point for products to find current versions of and consider.  I concluded I need a standalone monitor, not an add on to an existing system.

 

In all of the above research I narrowed my choices down to two:  the trimetric touted above and the Victron BMV-700 (plus the bluetooth dongle).  Being of a mind to always learn from other people's experiences first, I asked Zamp for their recommendation as well.   They came back today with ...

 

Good morning Mark,

Thank you for your inquiry.

We recommend the product from our premier retailer.

https://backcountrysolar.com/collections/batteries-and-accessories/products/victron-bmv-700-lifepo4-battery-monitor

 

To purchase, please contact our premier online retailers:

Joe with Back Country Solar

https://backcountrysolar.com/

970-245-8046

 

Thank you,

 

Being a bit of  smartphone geek I'll be going with the BMV-700 with the bluetooth interface.

 

 

[mlb3820]

Oh and backcountrysolar is out of stock at the moment.  I ordered from Amazon and included the bluetooth dongle for $193.

[Spike]

the amp hour function it tells you how many amps the solar has replaced. After a while you can get a pretty good guess on your power usage, a monitor eliminates the guessing. I believe with the agm batteries we have 400 amp hours available, as long as you stay under 200 amps usage that’s 50%. When we boondock I try to be conservative with the water and power usage, we generally average between 50 & 75 amp hours a day,

 

Thanks, Steve. That clears up much of the Zamp mystery for me.

[Spike]

Mark,

 

I followed your link to Amazon's IBMV-700 with the bluetooth and put the unit in my shopping cart, but then I read this review from Brett Stone. Here is an excerpt that gets to what he considers is a major issue with the product:

 

"1.0 out of 5 stars***PRODUCT BUGS EXPLAINED. VERY IMPORTANT TO READ THIS REVIEW***

September 17, 2018

 

"First and foremost, I love this device and I love the Bluetooth iPhone App; however there is a HUGE bug in this device which must be known by everyone who is considering purchasing it. Essentially, the purpose of this device is to monitor battery capacity so you are never left on the water with a dead battery and it does a spectacular job measuring load coming off your battery; however it does not measure the power which the gauge consumes on its own and it will consume every last amp left in your battery until it is completely dead and unusable. Unfortunately when it does this, the capacity will still show 99.9% or 100% of your battery remaining but in reality your battery is dead as a doornail and cannot be used."

 

I'm wondering if you read this review and disregarded it for some reason. Perhaps the issue would not be critical if one has solar and is thus not letting the batteries sit without a charge long enough to allow the gauge and dongle to drain them?

 

--Jeff

 

 

[Overland]

I doubt that's true, but even if it were, the BMV 700 draws 4mA, which is only 35 Ah/year.  The 100-hr rate capacity of a Trojan T-105 is 230 Ah, so it would take over 13 years to completely drain your batteries at that rate.  Hopefully, you'll recharge at least once in that time frame.

 

If you get the Victron, then I'd definitely get the newer 712 with built in bluetooth.  I have the 700 in my trailer and the 712 for the house battery in the truck and when I get a chance, I'm going to swap them.  The reason is that if you later go with a Victron solar charge controller, it will want to use the same port that the bluetooth dongle uses, meaning you will no longer have bluetooth.

 

I got mine from Inverter Supply and highly recommend them.  That may be who's selling on Amazon since their prices are identical.

[mlb3820]

Hi Jeff,

 

I was putting more trust in the recommendation from Zamp.

 

But for this user's complaint I'd have suggested an inexpensive solar trickle charger to offset the parasitic load (caused by forgetting to shut the unit off? Twice?).  We used one on our sailboat and had no issues with phantom/parasitic loads draining the house batteries.  For our Airstream (no solar) we added a mechanical shutoff to the negative terminal to eliminate the possibility of unwanted battery drain.

 

In our case today, we have 320 watts of solar panels charging the batteries when the sun shines which is often enough in the CONUS, right?  If it is being stored inside I'd be sure to have the batteries on a smart trickle charger.

 

As an aside, who puts a "gas gauge" a starting battery?

 

Cheers,

 

Mark

[mlb3820]

And at Overland's suggestion I cancelled the order of the BMV-700 and ordered the BMV-712 instead.

[mjrendon]

Great discussion and thank you for posting your results of research.  I believe the battery monitor would be a very useful tool for keeping track of the charge state of the batteries.

 

 

 

The BMV-712 has a current draw of <1ma vs the BMV-700 & 702 <4ma.  They all have pretty small current draw.  The risk is that without any charging they will eventually drain a battery... completely.  With Li batteries, they can be ruined by doing so.  The BMV-712 will take 4 times as long for this to occur vs the BMV-700 & 702.

 

Mike

 

 

[Spike]

And at Overland’s suggestion I cancelled the order of the BMV-700 and ordered the BMV-712 instead.

 

If you can, please let us know how you end up installing it (with photos if possible). I just put the BMV-712 in my Amazon cart, but may go with Inverter Supply, as suggested by Overland, if you report good results with the product and installation. Thanks.

 

--Jeff

[Overland]

Installation difficulty will depend on where you want to install it.  I opted out of the factory stereo, so I had a good spot, though I had too much cabling to try to snake it down between the hulls, so I had to run it through the pantry.  Time consuming, but the cables are zip tied in the front corner and are out of sight enough that I forget they're there.  If you want to install the monitor like I did, you'll need a hole saw, some care, and a fearless disposition.  But it comes with a cover plate if you need to hide a reasonably sized mistake.

 

You might consider installing it somewhere hidden, perhaps right by the shunt or solar charge controller.  In hindsight, I should have done that since mine just repeats info that's easier to read on the Color Control.  But vs. bluetooth, there's a benefit of just being able to glance at it without having to pull out your phone, so consider your choices.

 

Here's where I installed both the shunt and monitor: