specific dual battery controller/manager question

[theksmith]

dual battery management has been talked to death here, but i have a very specific question that i'm hoping someone can answer. when talking about automated dual battery controllers, what is the actual difference between so-called "intelligent" controllers and others? from what i'm reading, it seems like if you combine a timer in with a voltage sensor, you get "intelligent", but that's it... can anyone shed more light or correct any of the information below:


The "intelligent" systems i'm considering are:

National Luna Intelligent Solenoid ~$375
(not sure how senses the engine running, probably voltage, but allows main battery to remain on it's on for 5 minutes after start, then combines batteries, and keeps them combined till "their floating charge has dropped to 12.7V")
http://www.nationalluna.com/intelsol.htm

IBS-DBS Dual Battery System with Microprocessor ~$380
(not sure how senses the engine running, probably voltage, combine batteries immediately when engine running, then "If the engine is stopped, the two batteries will be disconnected automatically with some delay")
http://ibs-dual-battery.ch/en/produc...ry-system.html

The other automated systems i'm considering are:

Hellroaring ~$237 (BIC-95300B and remote module)
(no idea how this one decides when to combine/isolate)
http://www.hellroaring.com/battery1.php

ABR Sidewinder ~$290 (shipped, complete system with monitor)
(seems to just combine batteries whenever primary side is at 13.2v or higher, i.e. when alternator is on and working correctly)
http://www.sidewinder.com.au/page79.html
http://www.sidewinder.com.au/page161.html

i realize there are different constant/peak current ratings within these systems, and that one of them is a solid state system with it's own pros/cons, but i think they will all meet my basic needs... i'm just trying to figure out what the real difference are between how they automate battery connection and isolation.

thanks for any help!

[esh]

I think it is mostly marketing speak. Pick the behavior you want and go with it.

Here's another-
BEP Marine Voltage Sensitive Relay ~$175-225
5s timer, @13.7V combines, @12.8V disconnects batteries
300A continuous duty (and on/off/auto switch on housing), 125A version for ~$80
http://shop.sailboatowners.com/googl....htm?vp=168753 or ebay/froogle.google.com

[theksmith]

edited original post with details that i could decipher on each system, and i think i've answered my own questions. the National Luna and IBS are also temporary about linking, making it hard to forget you left the batteries linked. the IBS even has a warning beep every so often.

[alexrex20]

i've seen some setups that use an oil pressure sensor to close the solenoid and enable charging of the second battery. that's about as "hidden" and "hands-free" you can get, i think. but it all depends on what you want to do with your second battery.

in my research, i found the best compromise with the Painless kit. It uses a 3-way switch that:

1) Isolates both batteries indefinitely.
2) Combines the batteries only when the Ignition is turned to ON.
3) Combines both batteries indefinitely, regardless of Ignition switch position (i.e. Engine OFF).

Your "auto" mode would be #2.

[theksmith]

so here's my final thoughts on the subject, hopefully will help someone else make up their mind too

between "smart" automatic systems:

National Luna and IBS are similarly priced and the IBS seems to have maybe a couple more bells and whistles. The National Luna Kit does come very complete though as far as pieces parts you need. However, the National Luna's continuous amp rating just isn't competitive with the rest of these systems. If I had the money, I'd get the IBS system no questions asked - I just couldn't justify spending that much money for bells and whistles.

between "less-smart", but still automatic systems:

Hellroaring's BIC, Marinco's VSR, Blue Sea's ACR, Painless', and Redarc's system all work pretty much the same from my reading. The exception being that Hellroaring's system is completely digital, but may be loosing some voltage in the form of heat. I couldn't find any reason specifically that the Hellroaring setup was better than a quality constant-duty solenoid based setup. The Redarc is heavily uses in AU, but I couldn't even find a place selling it direct in the US. The Marinco 710-300A and Blue Sea PN 7622 are almost identical in features, with the Blue Sea having higher current ratings and coming with the remote switch.

The only other consideration for me was the Power-Gate perfect switch. It's amazing from an engineering standpoint, as it's solid state with none of the downsides and all of the upsides usually associated with solid state devices. Their marketing sucks, their prices are kinda high - meaning it's priced in the same place as the "smart" bells & whistles systems, but without any of the bells.

So in the end I'm going to order the Blue Sea ACR, because it's the cheapest yet hast the best ratings within it's class, and Blue Sea is known for other quality products. They also seem to be US-based, not sure where their stuff is manufactured.

Blue Sea PN 7622 - ML-Series Heavy Duty Automatic Charging Relay
500 Amp continuous rating
Dual voltage sensing
Silver alloy contacts
LED indicator
Manual switch as well as included remote switch
more technical info...

I found it for $150 to $175. I intend to add two battery monitoring LED's (one for each battery) at a cost of $29. So I'm looking at ~$180 for a nice relatively-simple system, with manual and remote control as well as some monitoring capability. The 500A continuous rating is overkill by far, but better to over-engineer than push the limits of a system. I'm lacking the intelligence to turn off "linking" of the 2 batteries automatically after a pre-set time, and lacking any sort of beeper or buzzer reminder that they are linked. For a $200 savings over the IBS system, I can live with that.

I'll also need some new battery terminals, some other lugs, a bit of small gauge wire, (still have the large gauge stuff left from re-locating my main battery), and so the cost will creep up. However, I'd rather continue to use pro-car-audio stuff that I source myself than what comes in any kit.

[Rando]

I have spent quite a lot of time building various 'smart' battery management systems, and have come to the conclusion that unless you are going to go the whole hog a get a system that measures currents not voltages, just buy yourself a heavy duty solenoid, and wire the control line to a switched source. That way the batteries are commoned when the car is running, and isolated when it it not. If you want to get super fancy, attach a single pole double throw three position switch to the solenoid coil, so you can connect the the control to the ignition switched line for normal operation (ie on when engine is running), leave it in the middle position (always isolated) or connect it to an always on for continuously connected mode.

Secondly, unless you have a winch and plan on winching off both batteries, a 85A solenoid is fine - and will only cost you about $25.

[theksmith]

I have spent quite a lot of time building various 'smart' battery management systems, and have come to the conclusion that unless you are going to go the whole hog a get a system that measures currents not voltages, just buy yourself a heavy duty solenoid, and wire the control line to a switched source. That way the batteries are commoned when the car is running, and isolated when it it not. If you want to get super fancy, attach a single pole double throw three position switch to the solenoid coil, so you can connect the the control to the ignition switched line for normal operation (ie on when engine is running), leave it in the middle position (always isolated) or connect it to an always on for continuously connected mode.

Secondly, unless you have a winch and plan on winching off both batteries, a 85A solenoid is fine - and will only cost you about $25.

i do plan to one day have a winch and expect to be able to combine batteries when winching if desired.

for me, going half-hog was the right answer. the automation of what i referred to as the "less-smart" systems (voltage sensing systems) is the right bang-for-buck that i'm looking for. they will disconnect the second battery in the event of alternator overcharge condition and more importantly, they will isolate the batteries if one is dying and starting to draw off too much charge from the "good" one. and of course they combine the batteries when the vehicle is running under normal conditions (just as your system would).

again, this was the right answer for me, but for some the $380 IBS system will be right and for some, your $25 solenoid will be right.

[alexrex20]

I intend to add two battery monitoring LED's (one for each battery) at a cost of $29. So I'm looking at ~$180 for a nice relatively-simple system, with manual and remote control as well as some monitoring capability.

i would recommend a single voltmeter gauge in the interior, controlled by a DPDT momentary switch. that way, you can monitor either battery on a single gauge, without having a 24/7 draw on the battery.

I'll also need some new battery terminals, some other lugs, a bit of small gauge wire, (still have the large gauge stuff left from re-locating my main battery), and so the cost will creep up. However, I'd rather continue to use pro-car-audio stuff that I source myself than what comes in any kit.

the little things add up fast. i've found the best prices at the eBay store GenuineDealz. they're based out of Georgia, don't charge for shipping, and you can even order cable by the foot. they sell the good stuff too - tinned solid copper terminals and lugs, fine-strand rubberized cable, etc. they're by far the cheapest prices i've seen online, and even cheaper than your local welding shop.

[theksmith]

thanks for the link to the parts, will check that out.

i would recommend a single voltmeter gauge in the interior, controlled by a DPDT momentary switch. that way, you can monitor either battery on a single gauge, without having a 24/7 draw on the battery.

i thought about a true digital readout, they are in fact cheaper than the actual tri-color indicators i want to use, but i prefer the feedback of a quick glance at color. i plan to wire 2 of these tri-color detectors (one for each battery) and put them on a relay controlled by the ignition switch (so that like you said, they won't draw current continuously).

this way, when i first turn on the vehicle, but it's not running, i should see 2 yellow dots, then when i crank up the vehicle, within a few moments, i should see 2 green dots. if i ever see anything but those combinations, something has gone wrong.

i will probably also add a momentary switch next to them that activates the relay as well, so that i can quickly check the batteries with the vehicle off without having get the key. i.e. just before bed i can press a button to double check that I still have 2 yellow dots (or by example, if one was red because i left something on at camp all day, i'd know right then).

these tri-color indicators have an accuracy of at least 0.05v and work off the following voltage table by default:

>15.20 Green/Red alternating (over-voltage)
>13.20 Green (charging)
>12.45 Amber (50% to 100%)
>12.25 Red (25% to 50%)
>12.00 Red 2 flashes, repeat
>11.80 Red 3 flashes, repeat
<11.80 Red 4 flashes, repeat

the seller will also custom program a voltage table in, so if i decide i want it red below 12.6 volts even, it could be that way.


there's also a dual readout digital monitor on ebay if someone wanted a nicely pre-packed advanced display: http://cgi.ebay.com/ebaymotors/Dual-...ht_1531wt_1060

[alexrex20]

oooh, i like that dual digital readout! i like the setup you described with the multi-color LEDs, but i also like simple and plug-and-play.

thanks for the links.