When do you recharge?

[Longbeard87]

I am a noob with a new fleet. I am a little confused on how the separator works. At what voltage do you say "time to start the truck" and charge a bit? If I understood my dealer correctly, when it gets too low it will disconnect the batteries and I will have to use "shore power" to charge and then manually reset the separator. Thanks for any help / advice.

 

[kmcintyre]

If it works like my BlueSeas version, you don't really have to do anything. The only issue is if you run the battery too low, it will not allow the camper battery to charge; it thinks there is an issue w/ the camper battery. The separate (as the name implies) only allows charging in one direction so you don't discharge the main battery. It will also turn of the charge when the battery is at some thereshold so it doesn't overcharge.

 

[paulclancy]

When we picked up our fleet at the dealer in April, they advised to keep on eye on the zamp solar charge controller. The separator kicks in when the readout gets down to about 12.4. I've parked for up to a week in the garage (out of the sun) with the kill switch out and have never seen the zamp go below 12.7.
Now my question - how do you (or do you) manually reset the separator ?

 

[DavidO]

To find out how the sure power battery separator works you should look at the manual. FWC has many manuals on their web site here is the one for the battery separator; http://www.fourwh.com/batteryseparator1315.pdf the model is 1314 and the 2 options (8+9) are not used.

 

[Longbeard87]

Thanks DavidO. The manual I was looking at (FWC) didn't really address my questions, maybe it was an old version or something. I will check your link.

Update -

Turns out it was the same manual...... so I guess to better phrase my question, if the battery gets too low as noted in kmcintyre's post, and now it won't allow a charge, do you just put it on a 110v charger to get it back to where it needs to be and then the separator resets itself or is there something manually you have to do to reset the system so it will allow off the truck charging again?

 

[Vic Harder]

if the battery gets too low as noted in kmcintyre's post, and now it won't allow a charge, do you just put it on a 110v charger to get it back to where it needs to be and then the separator resets itself or is there something manually you have to do to reset the system so it will allow off the truck charging again?

Yup, just charge them from shore power until the separator thinks it is safe to reconnect them.

 

[Stalking Light]

Just recharge with shore power or solar until the voltage is high enough for the separator to work. That's why I swapped my separator for a Bluesea ACR, so I have some manual control over things plus it also allows the solar to charge the truck battery if the camper battery is fully charged.

 

[DavidO]

Longbeard, the simple answer is that there is no way to "reset" the system manually. Many owners have switched out the separator with a Blue Sea system. DrJ did a nice write up on that upgrade here http://www.wanderthewest.com/forum/topic/11861-automatic-charge-relay-how-to-improve-your-battery-isolator/
The system he picked did have a simple switch to turn charging on even if the camper batteries were to low for the automatic switching.
If you have a solar system that can provide enough power to get your voltage up. Changing the wire size (larger wire) from the truck battery to the separator can help the separator stay connected as the voltage drop will be less. You can also install a switch to bypass the Separator something like this. https://smile.amazon.com/Blue-Sea-Systems-Circuit-Battery/dp/B000MMH1SK/ref=pd_sim_200_2?_encoding=UTF8&pd_rd_i=B000MMH1SK&pd_rd_r=V70NTZZXVV4M1CTY9TW2&pd_rd_w=g62pr&pd_rd_wg=YD7Of&psc=1&refRID=V70NTZZXVV4M1CTY9TW2
Just be sure to turn it off before you shut down your truck.

 

[Longbeard87]

Ok. Thanks for all the help. I am getting a real education on how this works. Much appreciated. I was checking everything out and I do have a BlueSea ACR unit. I guess what I got confused on was how you get things going again if you run the battery too low. I thought there was some sort of manual reset but I guess what they meant was I had to "manually" hook up a charger and get it back up before the unit will allow the truck to charge it again. Thanks.

 

[esimmers]

I agree that battery charge management is a PITA and the last thing that we want to be hassled with when all we want to do is enjoy the outdoors in our FWC. So to keep things as straightforward as possible, here are some things to keep in mind.

It is important to monitor your camper battery's state of charge but there is no simple "gas gauge" way to know how full your battery is like there is for your truck's gas tank. You can, however, come close to a "gas gauge" for your battery with an inexpensive digital voltmeter that you touch to your battery's terminals for a voltage reading. BUT, and this is a big BUT, to make an accurate one-time state-of-charge voltage reading you have to make sure that the battery is not being charged nor is a load connected to it. AND, for maximum accuracy, the battery should have been disconnected from a charging source or a load for an least a couple of hours! (And who can afford to do that when camping?)

Nevertheless, I strongly urge everyone to regularly monitor their camper battery's voltage even though it may be being charged or discharged. You will learn over time to pretty accurately estimate the state of charge of your battery by watching the voltage. Sure, if you want to get fancy you can install a Trimetric or other device that calculates state of charge by measuring amperage in and amperage out, but these devices are expensive and require careful installation and calibration.

I am attaching a battery state of charge chart for use with AGM batteries (the type of deep cycle lead acid batteries most commonly used in RVs). A new AGM battery when fully charged will measure close to 13 volts. And, again, remember that this is for a battery that is not being charged (because the voltage will appear to be higher) and not under load (a battery supplying electricity to an appliance will test at a lower voltage than it will test after the load is removed).

Nevertheless, it is good to make friends with your battery by regularly checking the voltage. You will learn over time how long you can run your regular appliances without depleting your battery too far. To avoid unduly shortening the life of your battery you should not let the battery discharge more than 50%. Referring to the chart, this means to not let the battery voltage drop below about 12 volts. But remember, this voltage measurement accurate only when nothing is charging or loading the battery because either will give false state-of-charge readings.

Solar panels, shore power and power from a running truck's alternator are all ways to charge the battery. Each have their disadvantages and advantages. Shore power may not be available; the solar panel may not be in direct sunlight; the length and small size of the wire from the engine compartment to your camper battery may prevent a high enough voltage to get to your battery to fully charge it. But we do the best we can, keep an eye on the voltage, and have fun outdoors!

Ed

 

[Longbeard87]

Thanks so much Ed for that. I am printing and laminating that chart to put next to my voltage meter.

 

[rando]

I would suggest that the simplest solution to understanding (and not worrying about) your batteries would be a SOC monitor (Victron BMV-700, Xantrex etc). It gives you the one number you really care about (% battery capacity remaining) and you can even set an alarm to beep when your battery needs to be recharged (30% SOC or so). They are a little more expensive, but no thinking required once it is installed. If you do want to get down and dirty with your system, they also give you everything you need to know - voltage, current in, current out, battery history etc etc.

 

[SeatoSea]

AGM state of charge.pngI agree that battery charge management is a PITA and the last thing that we want to be hassled with when all we want to do is enjoy the outdoors in our FWC. So to keep things as straightforward as possible, here are some things to keep in mind.

It is important to monitor your camper battery's state of charge but there is no simple "gas gauge" way to know how full your battery is like there is for your truck's gas tank. You can, however, come close to a "gas gauge" for your battery with an inexpensive digital voltmeter that you touch to your battery's terminals for a voltage reading. BUT, and this is a big BUT, to make an accurate one-time state-of-charge voltage reading you have to make sure that the battery is not being charged nor is a load connected to it. AND, for maximum accuracy, the battery should have been disconnected from a charging source or a load for an least a couple of hours! (And who can afford to do that when camping?)

Nevertheless, I strongly urge everyone to regularly monitor their camper battery's voltage even though it may be being charged or discharged. You will learn over time to pretty accurately estimate the state of charge of your battery by watching the voltage. Sure, if you want to get fancy you can install a Trimetric or other device that calculates state of charge by measuring amperage in and amperage out, but these devices are expensive and require careful installation and calibration.

I am attaching a battery state of charge chart for use with AGM batteries (the type of deep cycle lead acid batteries most commonly used in RVs). A new AGM battery when fully charged will measure close to 13 volts. And, again, remember that this is for a battery that is not being charged (because the voltage will appear to be higher) and not under load (a battery supplying electricity to an appliance will test at a lower voltage than it will test after the load is removed).

Nevertheless, it is good to make friends with your battery by regularly checking the voltage. You will learn over time how long you can run your regular appliances without depleting your battery too far. To avoid unduly shortening the life of your battery you should not let the battery discharge more than 50%. Referring to the chart, this means to not let the battery voltage drop below about 12 volts. But remember, this voltage measurement accurate only when nothing is charging or loading the battery because either will give false state-of-charge readings.

Solar panels, shore power and power from a running truck's alternator are all ways to charge the battery. Each have their disadvantages and advantages. Shore power may not be available; the solar panel may not be in direct sunlight; the length and small size of the wire from the engine compartment to your camper battery may prevent a high enough voltage to get to your battery to fully charge it. But we do the best we can, keep an eye on the voltage, and have fun outdoors!

Ed

thankyou for taking the time to lay this out. I will have my spouse read it as well!

 

[ntsqd]

We use solar and the alternator. I have on-board a dedicated shore power battery charger, but I can't tell you the last time I plugged it in. Must have been shortly before I got the solar working. Our 100W panel lays almost flat (I tilted it slightly, 0.25"/ 24", and drilled large holes in the high end of the frame so that hot air under it can vent) and here on the lower Left Coast that hasn't been a serious detriment. I'm sure that we could get more out of movable panel, but then I'd have to stop whatever else I'm doing (or not doing) to mess with that.

Our VSR is a BEP Marine unit bought ~6 months before they offered a dual sense version and about a year before Blue Seas bought them. So it only alt charges the camper, it can't solar charge the truck too. Unfortunately.

Batteries will self-discharge over time if left untended. I see solar as an investment in keeping the batteries healthy while the camper sits, and it happens to be a bonus other times too.

 

[Advmoto18]

This is one of those questions I think the compelling answer is..."IT DEPENDS."

IT depends on the type of batteries you have installed in the camper. If AGM, do they incorporate a digital controller?

It is nearly impossible to use solar or vehicle alternator to achieve Float Mode. You have to use shore power to achieve Float in most circumstances. Float will attain the highest possible charge for the batteries and greatly enhance battery useful life.

Last summer, after 3.5 days camped in a heavy forest, my Sure Power separator kicked in and I was unable to recharge the camper batteries using the truck's electrical system. Solar might have brought them back to life but it would have taken a LONG time and still would never have achieved float mode. One should seek out shore power if you have deeply discharged the camper batteries.

After the trip I installed the Blue Sea ACR 7623. The remote switch has LED lights allowing you to quickly ascertain the current operating mode and any faults. If camper batteries get into a deep state of discharge and the separator has activated, I can manually depress a switch on the 7623 and latch the truck's electrical system, via the 7623, to charge the camper batteries once the truck engine is running. You can select override without the truck running, but, you WILL discharge the vehicle batteries this way. Not a good option IMO.

Regularly or whenever possible, using shore power will attain the highest possible charge and promote healthy battery life.

 

[craig333]

Not sure why you claim that. My solar setup has no problem achieving float voltage. Using solar alone I've seen my SOC climb well past 100.

 

[JaSAn]

It is nearly impossible to use solar or vehicle alternator to achieve Float Mode. You have to use shore power to achieve Float in most circumstances. Float will attain the highest possible charge for the batteries and greatly enhance battery useful life . . .

Regularly or whenever possible, using shore power will attain the highest possible charge and promote healthy battery life.

??? I agree with Craig333. I am almost always at float voltage by 1 PM, reported by Trimetric (13.6 volts, 100%). Trimetric is calibrated by and reset by specific gravity checks (S.G= ~1.285) twice a year (spring and fall).

I do have alternator charging but don't use it much. The regulator in my alternator drops into float too fast, but it will get my batteries to 80% and if I have sun the charge controller will hold absorption voltage until the batteries are full.

Only time batteries are on shore power is when I pull them, store them in the garage on a battery maintainer (13.4 V).

jim

 

[Chadx]

Great info esimmers, but I'll point out that your AGM chart looks more like a regular flooded lead acid rather than AGM. Most AGM charts show about 12.5v for 50% state of charge on an AGM.

For everyone, I recommend getting the info directly from the manufacturer of your specific battery. In the case of the Exide FP-AGM24DP that FWC currently installs, Exide shows 50% SOC as 12.5v and 60% SOC as 12.6v and recommends charging when you get to 60%.

 

[Lobster]

I installed a xantrex inverter with a 40 amp charger in my shell. While building in the garage, I'd plug in except when working on the electrical system. After some time unplugged the charger would charge at 'bulk' rate, then move to 'absorption' followed by 'full'. This might take an hour or two between stages. I have an ARB fridge that runs off my 2 AGM golf cart batteries all the time. I also use the water pump to wash the dogs and myself at the beach. My camper has been on the truck for a month or so. I have 160 watt solar on the roof but this is my first experience with solar so I wondered how balanced my system is regarding supply vs usage. I plugged in my charger for the first time in a month and the cycle from bulk-absorbtion-full took about 3 minutes. Without all the fancy monitoring systems I'd say I'm pretty impressed with Solars ability to maintain my system. True I live in So.Cal and it's summertime.
Jim

 

[Captm]

It is nearly impossible to use solar or vehicle alternator to achieve Float Mode. You have to use shore power to achieve Float in most circumstances. Float will attain the highest possible charge for the batteries and greatly enhance battery useful life.

I have to chime in here as well, I've seen this stated several times before and must thoroughly disagree. I have never plug into shore power, in fact have no way to do so and yet see my battery fully charged daily via solar and/or alternator.
My system consists of a 125 amp/hr Lifeline battery, Trimetric controller and display panel, (2) 145 watt fixed panels, (1) 100 watt portable panel, Blue Sea Arc, 0/2 battery cables, 8 awg wiring for solar, and an alternator that will charge at high enough voltage and amperage for an AGM battery.

Cheers