how can I bypass or remove the LVD ??

[Concourse St Tropez]

I hate this LVD
I can monitor the voltage myself. How can I remove it ?

[Blue~Go]

I hate this LVD
I can monitor the voltage myself. How can I remove it ?

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After writing the following two replies, I looked up the manual for the LVD (presuming yours is also a Sure Power 135001; if not then it may be different), and I see two options that may work without disconnecting it. One is "manual override" which looks like it can be set to "permanent on." The other is adjusting the setpoint (if it could be adjusted down to something meaninglessly small). Since I don't have the LVD anymore, I only skimmed and highlighted the possible options in red boxes. Here is that manual. I will leave the following posts as well since why not have that information here too.

Sure Power 135001 manual.pdf

(80.51 KiB) Downloaded 265 times

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I removed mine as part of an overall electrical system upgrade. Like you, I monitor my voltage (and if it ever gets down to the level of the LVD cut-off, I'm doing something very wrong and my batteries will make me pay!)

So, in case you don't know already, it's in that little "triangle" of fabric covered wood at the forward/outboard/floor end of the couch. It is mounted to the pillar there. Blue with fins.

To simply bypass it and let the power through, well there is (on my '99) a red 8AWG wire that comes from the house batteries, to a 50 amp breaker (under the rig), and then through a hole in the floor under the LVD up to the LVD. Then another red 8AWG wire goes from the LVD up the pillar, over the big window, and (eventually!) down to the brown box with the loads and charger. Lots of voltage drop in that long run. But anyway, you could simply tie those two red 8AWG wires together on a power post or the like, which would bypass the LVD.

However, the LVD is a "roundhouse" of sorts and serves a few purposes. I took care of these in other ways, but just so you know.

1) Small wire(s) come from the LVD to the switch panel over the driver and to the "Off/On/Store" switch (I put in a "real" battery cutoff switch right by the batteries, so this is no longer necessary).

2) Small wire(s) to to a buzzer that tells you if you are charging while coach is in "Store" position (because the charge won't get through while it is in that position the way Chinook wired it, so the buzzer tells you to change that). (I wired not only main battery cutoff switch but also switch to loads so that I can charge while loads are off if I want to. I also don't have the same wire going TO the loads and FROM the charger as Chinook did - I have each wired on its own.)

3) I think the LVD also powers the "jump start" switch over the driver (I use a "real" battery switch for this now, but a modern separator will also do this function - such as Blue Sea 7622).

You can see the LVD functions in this diagram from the 2000 manual:

Here is a photograph of the diagram that is on the LVD itself (from my '99):

More in next post....

[Blue~Go]

Here are more photos showing the one (formerly) in my '99:

I don't know how much re-wiring you plan to do, so I won't go into more detail (yet?), but the way I set my rig up was in a style more like what I'm used to on boats. I also wanted to eliminate the major voltage drop of that long run to the "brown box" (charger and loads, charger particularly as pertains to the voltage drop).

[Concourse St Tropez]

Very interesting and informative thanks.
So I might connect the 2 red posts on the lvd and if I understood right it won't cut all power at 11.8
My agm battery can go down to 10.5 with no harm done..but 11 will be ok for me.
Could you explain the easy way to still have the boost start ?

[Blue~Go]

Very interesting and informative thanks.
So I might connect the 2 red posts on the lvd and if I understood right it won't cut all power at 11.8
My agm battery can go down to 10.5 with no harm done..but 11 will be ok for me.

Just curious: I don't know of any "12-volt" AGM batteries that can be taken down to 10.5 with no harm done. I would just about have a heart attack if mine ever got even close to that. For Lifeline AGM's (what I have), open circuit voltage at rest of 11.6 volts is considered 0% charge (Zero). I don't even want to think about 10.5. I tend to stay up above 12.2 volts (50% SOC) because that's a good target for long battery life. Not that I couldn't go below from time-to-time - say down to 12 volts - as long as I get them back up to 100% (12.8 volts) as often as possible. Here are two charts from their manual. The first shows at-rest voltage corresponding to state of charge in percent. The second shows anticipated life cycles for various regular rates of discharge. You can see how they would go way down if you discharged to even 11.6 volts.

Given the above, I'm actually the opposite: I didn't want or need the LVD because there is no way I'm ever letting my batteries get low enough for it to alarm. If I'm around the rig, I'm keeping an eye on voltage; and if I'm not, the batteries are disconnected from loads (AGM's stay "up" well in storage as long as it is not super hot.) My main goal was to re-wire for low voltage drop and with heavy enough wire to properly fuse it; the LVD just went because it wasn't needed in the re-wire.

Anyway, just wondering what type of batteries you have that are fine at 10.5 volts? I always like to learn more about these things, but I just don't know of any that would be. I could get by with a much smaller battery bank if I could draw them down that low between charges. Like maybe one 125 amp hour battery. That would be nice.

Could you explain the easy way to still have the boost start ?

I didn't read all the way through the LVD manual I linked to above to see if either the permanent manual mode or the adjustment to the low voltage alarm level would still allow that. My guess is that if you just bypass it entirely (by using it as a power post with both reds on same terminal) that it won't be powered at all, but I never tried that before removing mine and only skimmed the manual the other day before posting it.

There are ways to have boost start without the LVD at all. One way is to use a "modern" separator like a Blue Sea 7622, which has a remote switch you can use to combine the banks. It has other advantages over the SurePower 1315 (which was the original one in my rig), such as less voltage drop, ability to lock out for service work, etc. Or you can do what I did and just put in a manual switch. I rarely need to combine my banks for charging, so I prefer not to have the alternator charging by default when driving (which was the original setup). The alternator is the "least smart" charger I have, so my last choice. Hence I have a manual switch, which I can switch "on" to combine the banks when I do want to charge (rarely), or for "jump starting."

I also ran a heavier cable (1/0) for less voltage drop for both those tasks, as the #4 was a shade light, and not able to be easily fused (it wasn't fused at all). 2AWG would have been large enough to fuse, but as running the cable was the actual work, and running a 1/0 no more work than a 2AWG, I ran the 1/0. Much less voltage drop and no problem fusing to the high amps of the starter draw.

[Concourse St Tropez]

http://www.narbonneaccessoires.fr/energ ... vtech.html it is in French but you can see that they can go down to 10.6 v
I had this fact confirmed by the technicians.

[Blue~Go]

http://www.narbonneaccessoires.fr/energ ... vtech.html it is in French but you can see that they can go down to 10.6 v
I had this fact confirmed by the technicians.

Very interesting! I took a look. I think I may see "why" this is possible, but since my French is a bit rusty, maybe you can confirm I'm not making a mistake. So, I see this:

Décharge jusque 100% de sa capacité. 250 cycles.

What I'm getting from this is that you can discharge to 100% and have an expected lifetime of 250 cycles. This seems plausible, as comparing to the Lifeline, if I were to discharge to 0% (11.6) I'd have maybe just around 350 cycles. Roughly comparable. On the other hand, if Lifelines are discharged to 50%, they get 1,000 life cycles, and if cycled to stay at 75% charged, then they get around 2,300 life cycles.

But then there are other considerations. I'm thinking of three scenarios. I'll call them "1 (you)" and "2 (hypothetical)" and "3 (me)." I'm no mathematician, so correct me if I have something wrong here.

#1: If each 100% discharge is 100 amp hours, then with 250 life cycles you are getting 25,000 amp hours over the life of the battery. You only have to carry one battery around which is good for space and weight. OTOH you have to buy a new one six times as often as #2 and ten times as often as #3 (although it is less expense each time).

#2: This rig has two batteries at 125 amp hours each (these are the same physical size as most 100 amp hour batteries; they just have extra plates). So 250 amp hours total. If this person uses the same 100 amp hours as #1, that brings the bank down to around 60% charged (as opposed to 0% for #1). This gives a projected 1,500 life cycles. That's 150,000 life amp hours, but still the same amount of amps used per "day." So they last around six times as long, but this rig has to carry two batteries (weight/space). On the other hand, this can get through cloudy days or days without charger power and just give up a few life cycles (because drawing them down further on those days). It does cost #2 twice as much to replace them, but then they last six times as long.

#3 (my set up) has three batteries, for 375 amp hours. This is not necessary for the typical usage pattern, but I boondock most of the time, and wanted the reserve for cloudy stretches. If I use the same 100 amp hours, that puts the batteries at around 75% charged. Then they get 2,500 life cycles. or 250,000 lifetime amp hours. But I have to carry three batteries around. It costs more to replace them, although I only have to do it 1/10 as often. I also have more "insurance amp hours" on a stretch of cloudy days.

This would be different if you were not using 100 amp hours per day (or between chargings). I just used that as an example because that would be your battery going down to 0% charged. There would be different scenarios for using 50 amp hours per day, etc. One more thing is that 10 or even 11 volts won't make many RV appliances happy. So that may also be a factor.

Let me know if you see something wrong with my math!

BG

PS: Of course the other side of the equation is putting the amp hours back, but for the sake of discussion I "assumed" that all the example rigs could put the 100 amp hours back.

[Concourse St Tropez]

Your reasoning seems logical, but I had to re-read 3 times slowly to stay on track.
I wish the manufacturer would also say how many cycles at 10.6 v .....that could be scary !

[Blue~Go]

Your reasoning seems logical, but I had to re-read 3 times slowly to stay on track.
I wish the manufacturer would also say how many cycles at 10.6 v .....that could be scary !

I wish my French were up to the task! Then it would have been easier. Clearly I must take trip to St. Tropez to brush up on my language skills

I thought they were saying that discharging to 0% (which I guess they define as 10.6 v?) would yield 250 cycles. That seems somewhat inline with Lifeline's specs. I can't imagine anyone's AGM chemistry is THAT different, so I would expect them all to be similar (although a poor quality battery could do worse; I don't see how any of them can "cheat chemistry"). So my guess is that actually taking it down to 10.6 volts would likely not end well, in terms of battery life, and appliance life. I get a little twitchy if mine get down to 75%, but then that's just me. I'm sure I'll see lower on a cloudy stretch, but just not make a habit of it.

[Concourse St Tropez]

You can use the yahoo translator for to read the whole catalog of Narbonne accessories which I am sure you will find most interesting
Wouldn't it be cool to have a Chinook meeting on the beach of St Tropez ? lol
On a other subject..the light under the awning and the rear outside are not functioning, is it only the switches near the exit or are there some other hidden switches ?