Installing BEP714-100A Battery SW/Sensing VSR and Charging

petemos

I’m thinking of installing a BEP 714-100A 701 Battery Selector Switch With 100A Dual Sensing VSR and was wondering if I have to worry about how this unit will work with my shore power Guest charging system. In looking at any of the BEP diagrams I can find, they only show the charging system connect to one of the batteries and let the VSR determine which battery to charge. I could go this route by disconnecting the charger feed line to the second battery, but that seems to defeat some of the advantages of the charging unit in that it can charge both batteries concurrently and I would think more efficiently than the VSR switching between the batteries.

My question is, if I leave the two battery feeds from the charger intact, will the VSR mess up the charging unit or cause issues with the batteries, by trying to cross feed charging voltage across the VSR?
I would think I will be OK if I remember to leave the switch selector to off, but if I forgot, have the selector on the # 1 or # 2 battery and hook up to shore power for charging, am I going to mess up anything?

Thanks Jim

Sea Angel · Posted: Tue Jul 26, 2011 9:01 pm Post subject:

Jim;
The simple answer ... NO problem.
http://www.c-brats.com/modules.php?set_albumName=album1366&op=modload&name=gallery&file=index&include=view_album.php

This link is to Sea Angel's documentation of this system along with a copy of the diagrams and manual.

Simply, I have 3 batteries; 2 start, 1 house. The charger is for only 2 batteries.

I have the starboard and house batteries hooked directly to the charger as shown in the diagram. The port battery is charged via the "parallel" switch. The VSR will not energized/cut in till the set level is obtained. I usually don't switch to the parallel function till the strb relay is energized. This places the full charging current on both these batteries. When the paralle switch is turned the full charge current, less that needed by the 2 originally charged batteries is available to charge the port battery. This does work because when analyzed, all batteries are in parallel, via the relays and 'parallel' switch, thus the full current out of the 2 , 10A battery charger services all 3 batteries. Therefore, I have not had to buy a 3 battery charger. IT WORKS.

Hope this answers your question and will lend itself to the solution you are looking for.

Art

petemos

Hi Art. Thanks for the reply.
My setup is a little different as I only have one engine, two batteries and don’t plan to add a third right now. The switch and VSR is this model with only one switch and VSR.

This is the switch and VSR: www.bepmarine.com/home-mainmenu-8/product-273/714-100a-single-engine-two-battery-banks

It’s somewhat hard for me to see the full wiring and what is going on with your triple switch and two engines. My guest charger has two 10amp legs that go to each battery directly. So are you saying it is not material what position the selector switch is in when charging with shore power? That the VSR will not bridge the two 10amp to one battery depending on the charge level of the other and if it does it won’t mess up the charger and or batteries? I would think I would have the same issues today if I had my selector switch on both and charging with shore power.

My Guest charger just failed two weeks ago, maybe I messed it up by shore charging the batteries and leaving the selector in both, but I don’t recall.

Sorry for being somewhat dense on this switch/VSR thing, I really understand how the VRS and switch work normally with the engines, it’s with the charger that I’m concerned about and how it reacts to the VSR.

Jim

Aurelia · Posted: Tue Sep 20, 2011 11:44 pm Post subject:

We have one of these units and I have a question about how it works. We have a Guest charger wired directly to the starting batteries and another house bank charger wired to those batteries. Recently, the house charger started making an odd noise so I lost trust in it and disconnected it. Now
I notice that the VSR will allow the charge to flow to the house bank through the VSR unit once the starting batteries are topped off. This is nice but I am concerned that the banks are not switching cleanly from one to the other but rather balance charging across the banks which would not really work with very different starting vs. house batteries sizes. Any thoughts on what really occurs with these units? This is all with the motors off at the dock on shore power. I have not had time yet to prode around and fully test the charging behavior.

petemos · Posted: Wed Sep 21, 2011 2:17 pm Post subject:

I just installed the unit and then put the boat away for the season, so I can’t really tell you what I’m seeing. You are asking the same question I had when I went with this product. I contacted Guest who makes both the Switch, VSR and Charger I have. They told me there would not be a problem. I have only two batteries and the charger connects directly to both. The VRS I have looks at both batteries and once the one is fully charged it tries to charge the other battery no matter the battery switch selection. The switch only controls which battery I draw my house and engine power/charge from. In theory the non-selected switch battery should always be fully charged assuming the selected switched battery is charged.
With my charger, and I’m assuming this is why there is not a problem, both batteries are getting direct current from charger, so if the VRS looks to see what battery needs to be charged he either does not bother moving current to the other battery, as it’s already got the charge it needs or it doubles up and moves the charger current to the needed battery. So if you have a charger that puts out two 5 Amp legs, the VSR may reroute the not needed other 5 Amps to the low battery, so you now get 10 amps charging that battery. If that is how it really works, I can’t see there would be a problem. Also if this is how it works, going with a higher Amp Charger with only one leg and letting the VSR manage which battery gets charged would also be neat and maybe save some money.
That’s my take. Hopefully it makes sense and it actually works this way.
Jim

Aurelia · Posted: Wed Sep 21, 2011 4:58 pm Post subject:

I think if the "switching" is realy switching and not bridging or sharing, I am fine but I know what can happen if you basically try to parallel charge a mix of battery sizes and chemistries and that is what I am worried about. It it really relaying the flow of current to simple auto connecting the two banks? I will try to find out through some actual testing tonight or later in the week.

petemos · Posted: Wed Sep 21, 2011 6:17 pm Post subject:

Got me. Past my pay grade on this one, unless you can see the switching take place via a ohm/volt meter. Let me know what you find out? I'm using the same two battery types, so I don't see me having the same concerns that you may have.

Jim

Aurelia · Posted: Tue Oct 04, 2011 11:30 pm Post subject:

Update,

After testing in various sequences and charging from three sources in two directions, I have it in one " semi-final" configuration.

A guest ChargePro 5/5 two bank 10amp charger is wired to the starting (group 24 85AH deep cycle lead acid) batteries at 5amps per battery. Those charge to 13.7 volts then the relay clicks over a bridge (parallel connection) to our two group 31 105AH AGM batteries wired in parallel as a house battery. So the 10amp smart charger pushes power through the smaller starting batteries to the larger house batteries until the voltage comes up enough to allow the starting batteries to rise again and kick the charger into finishing mode then float mode. The smaller (but not small) starting batteries are taking some power for a couple of hours (typical) to as much as 12 hours if greatly discharged then the charger drops to reduced maintenance output. The two hour timeframe would be most typical.

This is not a perfect situation but the relatively low current passing though the starting set to the house set only lasts a matter of hours before current is at a nominal level. I is generally not advisable to mix batteries when charging but this situation with the VSR is a bit unique and I will be monitoring it's behavior.

risks--

-Overworking the starting set by artificially extending the charge time while the house banks tops off.

-Under charging the house bank because the charger volt ratings in it's three modes are about a tenth of a volt lower than optimum for the house set chemistry.

I know 10amps of charger seems like a small amount for such a significant set of batteries but these are the reasons why I find it acceptable.

The starting set supports only the motors so they really don't get discharged beyond starting duties.

The house set gets used and discharged significantly (normally down to 70-80%) when we anchor out but we use solar to help out and always motor our way somewhere pushing typically around 20-25amps from the motors which has proven to recover the charge on the house set pretty easily. If we did have a situation of deep discharge without sufficient motoring to recharge such as a short hop to a dock with shore power, or more than 4 nights of heavy anchoring use followed by further anchoring and use of the generator for charging. This situation has only occured twice so far in over 50 nights aboard and we had a solution.

I wired AC power into the house battery compartment where I also have two charging leads from the house bank sitting next to a portable 30amp charger for rare fast charging needs. I have to manually attach the leads, plug it in, and turn it on, but it really addresses this rare situation for us and acts as a backup charging method if we had a charger failure.

Thoughts? Should I get a better charger for the pool or separate the sets using switches while charging separately with independent chargers?

I really want to keep the boat as user friendly as possible and not have to throw switches and reset equipment settings all the time which was part of the original motivation to put in the VSR cluster.

Greg

Aurelia · Posted: Wed Oct 05, 2011 10:33 am Post subject:

And I measured 13.19 volts on the starting batteries and 13.23 on the house set while in float mode at that moment.

There are some static loads on the boat at rest (radios,nav, 12v accessories), but they seem to be small enough that the charger can keep up without trouble.

I left the boat without chargers hooked up for five days and the house set was down a tenth of a volt.

Les Lampman · Posted: Wed Oct 05, 2011 1:08 pm Post subject:

I'll see if I can simplify this (for once) and not complicate things! Laughing

The VSRs are just electronic switches. There are two varieties available: single sensing and dual sensing. BEP uses the single sensing VSRs in their switch clusters (but do make dual sensing VSRs).

What that means in that the VSR in the switch cluster senses the voltage of the starting battery (if wired in accordance with their directions). It doesn't "see" the house battery at all.

It also doesn't care where the power to charge the starting battery comes from, it's only sensing voltage. That means if you have an onboard AC-powered charger for the starting batteries the VSR will "close" if the starting battery voltage remains above "cut-in" voltage and will also charge the house battery. When the VSR closes the charger just still sees a battery "bank" and will react to it based on the voltage it sees and the algorithm in the battery charger.

If you have an onboard charger connected to the house battery the VSR will not react to a rising voltage and close to send current to the start battery since it's a single sense VSR and only senses the starting battery voltage.

If you have an onboard charger with two outputs (one to the house battery and one to the start battery) it won't hurt the VSR. Once the starting battery voltage comes up to cut-in voltage the VSR will still close and connect the batteries. A "smart" battery charge will sense the overall system voltage and adjust itself accordingly.

If you're routinely charging very depleted house batteries this way you're not doing your starting battery any favors. Once the starting battery is up at cut-in voltage and the VSR parallels the house and starting battery there will be a surge of current to the very low house battery, which may in fact take the system voltage below the cut-out voltage for the VSR, which in turn means it will sever the connection until the voltage comes back up on the starting battery...and then it's rinse and repeat until the house battery is at a higher voltage. That's a fair amount of stress on everything.

If you're just maintaining (floating) the batteries while the boat is in storage then you're not likely to see any issues. The system voltage is always maintained above VSR cut-in voltage and the charger just deals with all batteries as a single bank. At float charge levels the current is really low so the starting battery will not be damaged, and the house battery is never "down" so it doesn't ask for a lot of charge.

The best situation (in my opinion) is to have a load-sensing charger that can deal with different kinds of batteries (cranking and deep-cycle) and to put an on/off switch in the ground lead of the VSR. That way when the boat is plugged in and the charger is doing its thing you can flip the switch on the VSR ground lead to "off" and let the charger do its magic on the two separate and distinct batteries (or banks). Mind you, this isn't a "necessary" solution, just what I would recommend for long term use but if you're happy with how things are working for you now (and with battery life) I wouldn't change things.

Aurelia · Posted: Wed Oct 05, 2011 4:12 pm Post subject:

Perfect response Les and we are on the same page entirely.

Ours is the single sense and that is really the root of the situation. We did have a second charger in place and were doing exactly as you ideally suggest before that charger started making a noise I was uncomfortable with. I took it out and started down this latest path of experimentation. We do not use the current config to recover from deep discharges on the house bank so I am inclined to leave it just as you suggest. I have monitored the back and forth switching potential and it only does an initial switch over and stays there so no chattering to worry about at least with the current sets of batteries.

But, I also feel like it probably wouldn't kill me or anyone else to throw a switch when entering/exiting the boat and letting two smart chargers do the job rather than one. The ease of the current setup vs. the switching required by a perfect setup will be something to stew on. What would the next owner want.....

Thanks for a second sane opinion on this stuff and I officially qualify you to install charging systems on any future boat of mine.

thataway · Posted: Wed Oct 05, 2011 6:01 pm Post subject:

Agree 100% with Les. We went to larger charger for the house batteries when on shore power. The original charger for engine start batteries.

You do use the VSR when running on the engines, but this is s small part of the time. Another option with many engines--including Suzuki--is that there are dual battery charging outputs on the alternator output and when wired with two charging circuits, you don't need the VSR.

Sea Angel · Posted: Wed Oct 05, 2011 8:56 pm Post subject:

I agree with Les;
On Sea Angel I found that with only the two start batteries wired to the charger I would occassionally have the situation where the VSR would cycle on and off when the house battery was too low.

My fix seems to be working very effectively.

The starboard and house battery are wired directly to the GUEST 2610A Charger. I use the Emergency Parallel switch to charge the port start battery along with the starboard. This allows the full 5 amps to go to the house battery from one charger outlet and the second charger output goes to both start batteries. When the start battery swithes are OFF, the VSRs will NOT energize if your array is wired according to the BEP design and what I have on my documentation.

When the Battery switches are turned ON, the VSR can energize and all batteries can receive the full10amp source current. Once either, or both, VSR is energized everyone get the juice, by keeping the 'Emergency SW ON. If you did not leave this switch on , there is a possibility that the port battery could drop off line.

This method has worked without a single problem and never with the VSRs cycling. I spend a lot of time on a work rack at our marina during winter months and this method also allows more immediate power available to my house system to use the WALLAS and my electronics.

I did this also because I did not want to buy a replacement 3 bank charger to cover the 3 battery setup I have; let alone trying to run the wires under the aft deck from the water heater area.

Thanks for the input to all, on this subject.

Art