Electrical Gurus...Voltage sensitive Relay and Kinetik battery question

My Mastercraft X-45 has the Dual sensing Voltage sensitive relay shown here:



I recently swapped out the 4 year old lead acid batteries for a pair of KM-27 Kinetiks. I noticed that the relay light stays on even when the boat is turned off and even if the battery switch is in the off position. I found some terrific stuff on the manufacturers website that states that the light will sometimes stay on indicating that the batteries are being combined until the voltage of one of the batteries drops below 12.7. The problem being that Kinetik batteries are designed to have a slightly higher voltage and currently they maintain a voltage of 12.94 V. So my relay is always in the position to combine the batteries. I noticed the red light is always on and it is moderately warm to touch, just short of being hot.

Website detailing FAQ on the relay: http://bepmarine.com/home-mainmenu-8...ensitive-relay

kInetik Website where it states that their batteries rest at 13V compared to 12.6 or so for most lead acid batteries: http://www.kinetikaudio.com/2009/faq.asp

I think that this presents a bad situation because the relay is always going to draw both batteries down to 12.7 V and then cut out and isolate the batteries. It also might be bad for the relay to always be in the on position for weeks at a time. Am I right to think this? and should I consider a different isolator/relay system if I am going to continue with the Kinetiks?

Thanks in advance for all of you experience and thoughts here.

bump.

Sounds like it could be your charger and not your setup. If your charger will only put out 12.9v that would be the problem. You should have a 3 stage charger that deleivers a Bulk, Absorbtion, and float charge. Even the float charge of a 3 stage charger will be above 12.9v. Sounds like your BEP VSR is doing it's job.

TTG, I think you bring up a valid concern. If the VSR is keeping the batteries combined until it draws them down to 12.7 or so then your batteries will be .24 volts short of what they would like to stay at. .24v is a huge difference and may negatively affect the life of the batteries. Either that or your battery charger is going to constantly be charging and the VSR is going to stay on.

I know David from Earmark and myself have had luck having people use the Sure Power 1314 in conjunction with a perko style switch. Wire correctly you can then leave the switch in a position where the 1314 will work like it is designed to do. If you change to the off position on the switch then it takes the 1314 out of the equation and keeps the batteries as 2 separate banks for charging/resting.

If that switch has a 1, 2, 1 & 2 and off position you should be able to wire it with the 1314 pretty easily. All you would be looking at investing in is the 1314($65 or so) and probably some new cables.

The only problem I see with this setup would be that when you stop to jam the stereo the batteries won't disconnect until the 12.6/12.7v. I don't think it is as bad of a problem though as the starting battery would stay at 12.6 or higher. Once you start the boat it will jump back up to the high 13's or low 14's.

NU,

The problem here is that my VSR thinks my boat is running and combines the batteries even when the boat is shut down. That is because the kinetik voltage is higher than the cut out threshold of the VSR. The kinetiks run at 13V when resting, whereas most batteries are below that and don't create that problem. So my VSR is working overtime is the problem.

I don't even have the onboard charger hooked up yet...and that is my next step, but I don't want the charger to simply be fighting the loss of power because of the VSR being engaged all the time. I have an email out to BEP to find out if they think it is bad to have the VSR engaged continuously. And also to see what the charge draw is when it is engaged. The website says it pulls just 10 mA when not engaged.

So you have two batteries (both new Kinetics) and each is on one side of the VSR? Or are both kinetics on one bank and something else is on the other side of the vsr?

Could you just one simple on/off switch inline between one of the batteries and the vsr? Kinda a cludgy fix but wouldn't it work to manually turn that battery off, and then the vsr would shut itself down?

I don't know if I'm describing that right, but I think it would work.... kludgy to have a second switch for sure, but not as expensive as replacing the vsr. Would basically be the same as manually disconnecting one of the batteries.

Its usually no picnic getting worthwhile technical support from BEP. Regardless of which batteries you have its really important for them to be isolated during shore AC charging. You need a dual bank charger even with identical batteries since they are used and discharged very differently. Most ACR/VSR manufacturers do not have a plan for this and simply recommend that you place a single bank charger on the side of the most depleted battery because they assume that the ACR/VSR will keep the two banks combined during AC charging since the charger will raise the voltage.....which IMO is really awful advice. So to solve your particular issue, place a single on/off battery switch on the cranking battery side to open the circuit and provide isolation while AC charging. If you have an ACR/VSR that senses voltage from both sides it may draw only milliamps which should not be a major issue while on the AC charger.
You have the option of using an on/off cutoff switch on both sides of the relay or cutting the ground to the relay thereby disabling it during shore charging. It seems to me that several of the ACR/VSR manufactuers designed their stuff for fishing boats with no more than low current instrumentation on line while at rest and they do not serve the needs of towboats with large stereos very well. Its nice when you have the option of going from scratch so that we can design the system to precisely fit your system's needs ( which differ with each system) and without all the peripheral nonsense.

David
Earmark Marine

Thanks for the excellent advice as usual, David. I always am eager to hear what you have to say, and hoped that you would be one of the folks to chime in.

The Sure power 1314 might work better for what I am looking for. Looks like it does not combine the batteries unless it gets above 13.2 Volts. Which is part of my problem. My batteries get combined at too low of a voltage. I may just junk the stock VSR and put in the sure power. Thanks for the advice. But I still would run into the same problem if I hook up my onboard charger because the float charge is at 13.5 or so, IIRC. then the battery banks would be continuously combined while charging, but at least they would be separated when not charging, which is better than what I have now. And I guess I could fix that with a switch as discussed above. I just would like it to be automatic to take out the human error part of it.

There's a few things you can do. You can automatically govern every function other than an emergency override. But this is more complex from an initial wiring standpoint than most people are willing to accept. A single manual dual battery switch can be wired in an unconventional manner to serve multiple purposes including emergency override, auto operation and fixed open for charging. A simple on/off battery switch can give you the isolation for shore charging. Keep in mind that if you add a supplemental manual switch that the only time you will use it is when you put your boat on the trailer or unload it.

David
Earmark Marine

So I go to the boat tonight and the VSR is no longer engaged. The batteries are now down to 12.7 Volts. I do think that over time, the VSR draws them down when it is engaged. I had these batteries on my shelf for over a month.

I will just manually disconnect them for now until I get a decision made on what to do.

Originally Posted by david_e_m

Regardless of which batteries you have its really important for them to be isolated during shore AC charging. You need a dual bank charger even with identical batteries since they are used and discharged very differently. Most ACR/VSR manufacturers do not have a plan for this and simply recommend that you place a single bank charger on the side of the most depleted battery because they assume that the ACR/VSR will keep the two banks combined during AC charging since the charger will raise the voltage.....which IMO is really awful advice.
David
Earmark Marine

This is how mine is wired. Can you explain what the proplem is with this?

AJ,
From your post I assume that you have a single bank charger that is expected to charge dual batteries? If so its less than optimum but at least you are using a charger.
A multiphase charger profiles the battery and restores it according to a sequence that is designed to condition and protect the battery. The state of the battery determines which phase and for how long that phase is implemented by the charger. A dual bank charger has two independent circuits that reads and reacts according to each battery's profile. A stereo battery and a starting battery are used very differently, will have different characteristics as they age (even if they started out identical) and are put into storage with different levels of charge. A single bank charger can only see two separate batteries as one so any degree of precision is nullified. You risk a constant overcharge/undercharge scenerio between the two batteries. And even with a dual bank charger which is recommended, an ACR/VSR can serve to circumvent the isolation, so a switch is used to create the isolation during storage.

David
Earmark Marine

The easiest solution is to do what David and shawndoggy recommended: install an on/off switch for one of the batteries to isolate it from the isolator.

I'm not familiar with the BEP ACR, but another option is to install a Blue Sea ACR and connect the ACR to the load side of the switch (as opposed to the battery or source side of the switch.

http://bluesea.com/files/resources/i.../990310020.pdf

In the diagram on page 4, you can connect the ACR to the top posts of the switch instead of to the batteries. Then, when charging on the trailer, you can turn the battery switch to the "off" position and thereby isolate each bank of batteries from the ACR (and from each other). I talked with tech support at Blue Sea and this configuration came up as a good solution for using multiple bank battery chargers.

The disadvantage: voltage drop between the ACR and the batteries may impact the ACR's determination of when to close / open. If you connect the ACR directly to the batteries, you might come up with a shorter cable run and less voltage drop. But the cable runs in wakeboard boats are generally short and the cable sizes large enough that voltage drop shouldn't be an issue in this regard. You might be able to wire similarly with the BEP set up.

Another advantage of this configuration is it allows complete removal of the ACR from the batteries, eliminating the small constant draw that voltage-sensing relays impose on the batteries even when the battery switch if set to "off."

Using the configuration shown in the Blue Sea pdf means the ACR will close and connect the batteries in parallel any time you put a charger on either battery...so the only way to charge is to use a single-bank charger and let it charge both batteries. And, as David pointed out, that's less than ideal.

You can also wire a switch between the Blue Sea ACR's ground terminal, and ground.
Open/break the ground connection, and the ACR relay is deactivated (opened).

I use the Yandina C150 combiner on my electrical system. Starting battery is a small Optima redtop, stereo batteries are 2 Kinetik 2400's, the Optima gets the primary charge and the Kinetiks get the combined charge. Since the combiner does not close until 13.3 volts the system isolates the stereo batteries when the motor is not running. It works for me without any user input. If you could raise your combine voltage to 13.3 or 13.4 volts then it would work just fine, 12.9 is probably just a tad too low.

Mikeski, that is the one I want. I knew someone would be able to point out the right setup. But what happens when you have an onboard charger? The float charge on the Xantrex is 13.5 V IIRC, so in that case, the Yandina would keep all batteries connected. Can the Yandina be disconnected so the starting and house batteries are isolated regardless of the charge incoming?

I am sure that when charging overnight, you don't want the Kinetiks and Optima all together, right? Do you leave a charger on yours?

Update on this one more time. I disconnected one of the batteries and charged them both...both stay at 13.0 Volts or so. However, the little red light on the VSR comes on letting me know that it has opened the switch to combine to another battery (which doesn't exist since I disconnected it). Then I go to Maui for 6 days (tough life, I know). Now I get back and guess what? The connected battery is drained to 12.75 Volts and the disconnected battery is at 13.0 still. So my VSR sucks enough juice to drain my battery, until it gets to 12.75, which I think my Kinetik is not going to like over the long haul.

seems like the level @ which the acr combines / disconnects is a bit of a compromise. Downside of higher combined voltage is that batteries don't both get charged till boat is under load (i.e. not merely started and idling). At least my boat won't read 13.3 on the dash till I've got the RPMs up a bit.

Since you are manually turning the switch to "off" when you're done for the day anyway, why not just install a second switch on the ground for the acr as frosty suggests? That ground wire is really really small, so it would be a cheap way to fix it (just a cheap ignition protected switch). Even a full blown battery rated on off switch is $30 or less.

Only downside then is that when both switches are "on" the acr would be forcing your starting battery to back up your stereo battery till one of 'em drops below 12.75. How low do the kinetics go before getting damaged and does starting from the lower voltage put additional strain on the battery? So long as the kinetics can reliably start at 12.75 without damaging the battery, seems like the cheapest solution. When you get off the water, just switch both switches to off and you can be sure your batteries are separated.

I just throw the charger at any point in the system and let the combiner do it's job. I don't see any harm in charging the starting battery too, it's load is minimal compared to the Kinetiks. I will leave the charger on it for a week at a time, sometimes longer. All of my batteries are AGMs now but I did the same thing when I had golf cart batteries too. I sometimes charge them in the lead acid program so they get a higher voltage but it's not recommended and will likely shorten the life or just kill them. The red top was a costco battery so I was not too worried about overcharging it. The redtop is now 4 years old and has never let me down, the kinetiks are now 3 years old and seem to be going pretty good. They don't run as long as they did when new but my stereo is pulling more power now so it's tough to say if new Kinetiks would be any better? I will likely go with Golf Carts again when the Kinetiks go south.

Last night I disconnected the ground on my VSR and discovered that the Perko portion of the switch works perfectly when the ACR is disconnected. So I do think that the easiest solution is a switch on the VSR ground wire. If I leave the switch off, then I can use the batteries like a conventional Perko switch only.

Originally Posted by talltigeguy

Last night I disconnected the ground on my VSR and discovered that the Perko portion of the switch works perfectly when the ACR is disconnected. So I do think that the easiest solution is a switch on the VSR ground wire. If I leave the switch off, then I can use the batteries like a conventional Perko switch only.

LOL, what made you think of that?

Open/break the ground connection, and the ACR relay is deactivated (opened).

You have the option of using an on/off cutoff switch on both sides of the relay or cutting the ground to the relay thereby disabling it during shore charging.

Originally Posted by shawndoggy

LOL, what made you think of that?

I don't think I made it sound like it was my idea. And I appreciate the input from everyone above, especially shawndoggy.

The parts I was uncertain about is whether disconnecting the VSR would leave it in the open or closed position....and then since I am sort of stupid, I didn't know how the Perko switch would work with the VSR disconnected, since the perko switch is overridden by the VSR when it is connected. Regardless of the setting on the Perko switch, the VSR combines the batteries if it senses voltage greater than 12.7. Even if the Perko switch is only set to 1 battery.

Thanks again for walking me through this, everyone.

don't thank me.... Frosty and David were the ones smart enough to suggest the switch on the ground. I too was a little surprised when I figured out how "dumb" my "smart" acr was. Great advice on this forum. Dunno how anything got done before the internet.

dredging up this thread to point out that there is a $5 "automatic" workaround to this problem. The ground wire on the voltage sensing relay needs to be switched with a relay. When the relay is energized, the ground circuit will close and the voltage sensing relay will work. When the relay is not energized, the ground circuit will open and the voltage sensing relay will be disengaged with no possibility of combining the batteries. If you use ignition power to close the relay, then you'll automatically set the system up so that the voltage sensing relay will only work when the boat key is turned on.

Pin 30: to ACR ground
Pin 86: to IGN power (power comes on when keyed up)
Pin 85: to BATTERY ground
Pin 87: to BATTERY ground

I am not sure how that particular VSR works but Sure Power does not recommend doing this on there ground circuit. David may have more details but there becomes a problem with the circuitry resetting or something if you break the negative circuit. I have no personal knowledge of why it wouldn't work but they don't recommend doing it whether it be through an on off switch or a automatically with an ice cube relay.

Originally Posted by polarbill

I am not sure how that particular VSR works but Sure Power does not recommend doing this on there ground circuit. David may have more details but there becomes a problem with the circuitry resetting or something if you break the negative circuit. I have no personal knowledge of why it wouldn't work but they don't recommend doing it whether it be through an on off switch or a automatically with an ice cube relay.

That's interesting... I wonder why? I've got the blue sea add a battery (PN 7650) and blue sea customer support confirmed that breaking the ground is a safe way to set that system up.

Originally Posted by shawndoggy

That's interesting... I wonder why? I've got the blue sea add a battery (PN 7650) and blue sea customer support confirmed that breaking the ground is a safe way to set that system up.

Honestly, I don't understand it enough to guess why. I think it sounds like a good idea for the most part and would make it so you don't need a battery selector switch to run your dual bank charger.

I can understand why SurePower discourages breaking the ground on the solenoid while the positive remains since microprocessors typically get confused under those conditions (the microprocessor might pertain to the sensing circuitry). However, we have done the above prior to getting the word from SurePower. I am not aware of it causing a specific problem.
We have moved on from that anyway since in many of the larger systems we are having to supplement the solenoid with a manual switching scheme that addresses this issue as well as many others.
As you increase your stereo draw and increase the stereo battery bank amp/hours past a certain point and you have significantly discharged the bank while at rest, the ACR/VSR may not close. If it tries to close the immediate voltage sag may bounce it open again. Keep in mind how high the combining voltage and more importantly the latching voltage is on many of the ACR/VSRs. So many larger systems have exceeded the functional limitations of a standard ACR/VSR. That may be okay if you can run purely on the battery system until you get back to shore. But that may not be acceptable for someone taking a long weekend trip where AC power may not be available for several days. In that case you are more dependent on your alternator to service the stereo bank.
Also, with some of the new boat electronics where the stereo source cannot be separated from the touch control scheme you may have to combine the house bank and stereo bank into one and isolate the starting battery. This means that as the stereo pulls the voltage down the boat electronics are operating with a lower voltage too. Not good.
And that is just the tip of the iceberg. So these ACR/VSR systems can get involved. There should not be one scheme that is applied to every system. As the system increases in size and depending on your particular usage, the scheme must be altered. One size does not fit all. We design a custom
solution to match the total stereo and charging system.

David
Earmark Marine

Shawndoggy...

Thanks for coming up with a better solution, now that I have sold the boat. I think the idea is brilliant, and would work perfectly for that particular setup.

I will forward this thread to the new owner, and let him know that I think this modification would make it just a little more idiot proof. Especially with a new boat, I am sure he is going to forget, and draw down the amp batteries and overwork the alternator trying to get them back, or not be able to figure it out at all and kill the batteries by leaving them dead for too long.

I appreciate David's comments as usual, but hope it is not contrued to mean that it won't work for this X45's system, as I think it would work great in this particular situation.

no prob... I just installed the relay on my boat and wanted to share a way to do it (and it totally works for my blue sea add a battery, btw). Relays can be kindof daunting when you don't know how they work.

I think I am fighting a similar situation on my X-45 with Kinetic batteries.

I really need to get it figured out. I know Dave provides a ton of useful information here, I would like to pay him back with some business. Would it be too much to get in touch and work out a wiring / charging scheme for my setup? I am on a business trip to Korea right now but when I get back it would be nice to have ordered the parts and get right on it before I do more damage to these stupidly expensive batteries.

Wish I still lived in Texas.

CobraRob,
I'll send a PM.

David
Earmark Marine

Got it thanks! I am swamped at work right now but I will send you a detailed email when I get a chance.