Chinook RV

I read somewhere that the Low Voltage Disconnect kicks off the batteries at 11.8 volts left. Anyone able to confirm that? I'm usually still half asleep when this nice alarm clock would go off. Since I upgraded my battery bank, this didn't happen (thankfully!) this morning. I see 12.6 on the meter right now after a night of fan, fridge, LED TV on standby mode, small inverter in standby mode. Some day I may get real disconnect switches for those standby devices... But for now.. It's just nice to wake up on my own.

My 2004's build sheet (in closet) says it has the Sure Power model 135001. The attached PDF on page 2 above the schematic diagram states that model has a factory disconnect voltage of 11.8 volts.

I think you may be talking about two different things.

The stock Surepower (1315 model in my case) is a device that either connects or disconnects the start and house battery banks from each other. The idea is that when the device sees adequate voltage, it will connect the two banks (so you can charge the house bank via the alternator). When it sees inadequate voltage it opens and separates the banks (so that you cannot draw down your start bank with house usage).

The LVD (low voltage disconnect) is purely a coach (house) thing, and makes it so that the house bank is off limits (to house loads) when the voltage gets too low. I think this is what Manitou is referring to.

The LVD is a slightly crude way to do this, because by the time it disconnects the batteries are already way to low for good ongoing battery health. The modern/better (IMO) way to do this is to use a battery monitor such as a Victron BMV700 or a Smartgauge (these are different types). To compare the two with a crude analogy, the LVD shuts off your gas tank when you are down to 1/4 cup of gas, so you don't run out (but, ahem, too late to really be useful); the monitors are like a gas gauge that you can keep an eye on, so you can fill up when you get down to half a tank if you would like to - or not - but you know where you stand at all times.

In my rig the stock setup had the Surepower 1315 on the driver's fenderwell (under the hood), and the LVD in a small triangular upholstered box at the forward/outboard end of the couch (against the small pillar there).

So to add to what Blue~Go noted because both devices are made by Sure Power and the model numbers have some similarity so its confusing ........

The Sure Power 1315 is under the van hood (far right side facing the truck) and is referred to as a "Battery Separator".

The Sure Power 135001 is on the coach floor between the drivers seatback and the couch and is referred to as the "Low Voltage Disconnect". (PIC attached)

So.. 11.8 then yes? Almost afraid to ask, but how would someone upgrade this device? I didn't even know 11.8 was already into the damaging zone for the batteries. I'm starting to get the feeling the only good battery is a fully charged and therefor unused battery! (Ha!)

Manitou wrote:So.. 11.8 then yes? Almost afraid to ask, but how would someone upgrade this device? I didn't even know 11.8 was already into the damaging zone for the batteries. I'm starting to get the feeling the only good battery is a fully charged and therefor unused battery! (Ha!)

From the PDF I posted above:

SET POINT VERIFICATION OR ADJUSTMENT
Setting the LOW VOLTAGE DISCONNECT SET POINT: DO NOT ADJUST SET POINT UNLESS
ABSOLUTELY NECESSARY. The LVD is factory set to disconnect at 12.3V (Model 135000) or 11.8V
(Model 135001) or 12.1V (Model 135002) and reconnect at 13.0V. The reset point is not adjustable,
however the disconnect set point is adjustable from 11.0 to 12.5V DC. Due to a delay of approximately
one-minute, it is difficult to adjust the set point by monitoring the V OUT terminal. Therefore a SET POINT
INDICATOR LIGHT has been made available.

Manitou wrote:So.. 11.8 then yes? Almost afraid to ask, but how would someone upgrade this device?

I'm guessing this is something you aren't going to be into, but anyway, here is how I would upgrade it.

1) I wouldn't have an LVD. As I mentioned above, to me they are like a gas gauge that beeps at you after you are already at the side of the road, out of gas. "Thanks, buddy." I guess you could say it is better than nothing, and to be fair, I think Chinook accurately assessed how their target market would use the rigs (drive a lot, and/or hook up to electrical at parks). Also, these things were more expensive back then, and we didn't have the same typical usage of solar, etc. Just a different time and "place." Also, the RV-ing world is somewhat different than, say, the boating world (I'd say systems have been better for longer in teh boating world, and a larger percentage of boaters expect to spend more setting up their systems; also, in many places it's not possible to replace batteries or other gear - whereas in an RV you can head over to Wal-mart).

1a) Although for a very basic system, with maybe one house battery, I could potentially see the LVD (I'd still prefer gauges, but I realize they use LVD's in things like squad cars and very small boats). I mean, one battery is not a big investment if it dies a bit early due to being drawn down.

2) With a bigger system, I would (did) set up a good, sound charging/electrical system (just like anchoring, a weak link can be an issue), and then I would monitor it with a coulomb counter type meter (Victron, etc.), and a Smart Gauge type meter (if I had to choose just one, as interesting as the former data is, I'd take the Smart Gauge for a solid reading of SOC percentage). Hence I wouldn't need an LVD, as I would be managing the system myself (voluntarily shutting things down, or re-charging, before 11.x volts was reached). (If system is designed for usage, that shouldn't happen too often.) It's not a hard and fast rule, but generally it's good to keep batteries from going much below 50% (actually more important I think is to get them to 100% as often as possible, so there is some balancing to be done between bank size and re-charging capabilities). So with the gauges it's more like watching your gas gauge and voluntarily stopping to get gas before its needed - you just learn to keep an eye on it, and develop a feel for its usual behavior.

Note: Actually, I don't totally understand how the LVD decides the voltage, since generally you need a resting voltage to know where the batteries stand. Seems the LVD would be going off a non-resting voltage much of the time (?)

******

Thing is, a good system costs money and takes some effort to plan and install, and not everyone is "into it." Another way is to run an LVD and possibly just replace the batteries more often. This can make sense with fewer/cheaper batteries, and or people who find it more convenient and less painful to replace batteries.

Ha.. Blue~Go you do make me chuckle sometimes. It's not so much about if I'm "in to it" or just cant follow. I'd say this is a bit of both. I'll stick with the 11.8 standard setting but don't mean that to discount your view/knowledge. I simply have to pick my battles and this one isn't currently putting up much a fight. Believe me, I'll be back if these new batteries die in 2 years rather than at least 3-4 (or more if I'm lucky!)
In the mean time.. Thanks for your's and Concourse's input. Now I know there is a variable setting and/or possibly a whole other approach.

Manitou,

I'm sorry if it sounded like I didn't think you could follow along. That's not what I meant at all! The only reason I said I didn't think you'd be "into" it is because earlier when we were talking about batteries, you indicated that you didn't feel like spending more money/effort on your charging system at this point in time. I wanted to reply to your question though, and the two were sort of at cross purposes, which I was trying (and apparently not doing so well) to acknowledge.