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Smart Battery Isolator/combiner [message #328312] Tue, 16 January 2018 15:53 Go to next message
Tomtom   United States
Messages: 20
Registered: June 2017
Location: Huntington Beach, CA
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Junior Member
I've read a bit on this forum and other places about these, but thought I'd summarize what I've done and learned and see if anyone had any thoughts to add.

I've seen these things called smart/automatic isolators, combiners, relays, etc, but basically they are a relay with some brains built in. You connect the relay between your house and chassis batteries and it senses when you are charging and closes the relay to charge both battery systems. When you are not charging, it senses this and opens the relay. Well, that's what I expected anyway, and it does do this, but with a catch that I will get to.

I added a solar panel to the coach 6 months ago or so, and I thought a relay like this would be really neat since the solar panel would keep both the house and chassis batteries charged while in storage. It would also charge both with the engine running or when connected to shore power. Also, a fringe benefit was not having the voltage drop of the stock diode battery isolator when charging from the engine alternator.

This is the one I bought
http://www.littelfuse.com/products/battery-management/battery-isolators/smart-battery-isolators/48525.aspx

I bought the 85 amp flavor and decided to install it in place of the diode style isolator and keep the stock boost relays as is. I also installed a indicator on the dash and a momentary switch for this relay (independent of the stock boost switch). I can't think of any use for the momentary remote switch, but I had a spot for it and put it in anyways. I've had it installed for a few weeks and so far works great and as advertised. When the voltage of either side is above 13.2 volts, it senses charging and closes the relay. But, when the charging is finished, (i.e. the sun goes down and/or the engine is turned off) it still stays closed! This is because it's setpoint for not charging is 12.7 volts. Turns out when fully charged the voltages are a little higher than 12.7 volts, and since there is essentially no draw on the battery in storage (except ironically the draw of this relays coil), it stays closed. Eventually, a few hours later the voltage goes below 12.7 and the relay will open. So, in my storage scenario, this will be a daily occurrence. Solar will top off the batteries, sun goes down, smart isolator relay drains batteries a bit, relay opens, repeat tomorrow. I can't find a published current draw for the relay, but my guess is that it is about an amp. On a 75deg or so day, the relay is hot to the touch, so probably about 130 F. If it wasn't for the high temps, I might have not given any of this a second thought. Even as a potential fire hazard, I'm not too concerned. It wasn't until a thought about some critter looking for a warm spot to hang out and maybe munch on some wires while he's there that I got to thinking that maybe this isn't a good idea.

I did notice some other similar products. A friend of mine uses this one on his SOB

https://www.bluesea.com/products/7601/m-Series__Automatic_Charging_Relay_-_12_24V_DC_65A

It only draws 90 mA when closed so likely doesn't get hot. It's only rated at 65 amps though, but when you consider the 60 amp breaker to the house batteries, it would probably work. I didn't mention this above, but the alternator is connected directly to the chassis battery in this installation, and my solar only can make about 5 amps.

Here is another bluesea type. This one has a momentary coil for moving the relay either direction so it doesn't have a continuous electrical load in either state. Seems like the best solution to me. Costs a bunch though.

https://www.bluesea.com/products/7620/ML-ACR_Automatic_Charging_Relay_-_12V_DC_500A


What do you guys think?

Thanks,

Tom C
77 Kingsley
Huntington Beach, CA


Tom 77 Kingsley. Mostly Stock, 455, Quad bag, tachometer, 16"wheels, Macerator. Southern California, huntington beach
Re: Smart Battery Isolator/combiner [message #328316 is a reply to message #328312] Tue, 16 January 2018 17:22 Go to previous messageGo to next message
Tom Lins is currently offline  Tom Lins   United States
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Registered: February 2004
Location: St Augustine, FL
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Senior Member
Not sure I would want the "hot" for the same reason you are concerned about it. In my first GMC I removed the isolater and installed a Yandina combiner (that JimK now sells) which is a solidstate device that does basically the same thing as the smart relay does. I do not remember it ever being hot. It connects both sides whenever there is charging voltage on one side and not the other as I remember it. On my SOB I had a Xantrex Echo Charge which works the same way the Yandina does. I plan to install a Yandina in the new GMC also. JWID



Tom Lins
St Augustine, FL
77 GM Rear Twin, Dry Bath, 455, Aluminum Radiator Quad-Bag Suspension Solar Panel
Manuals on DVD
YOUTUBE Channel: GMC Dealer Training Tapes
http://www.bdub.net/tomlins/
Re: Smart Battery Isolator/combiner [message #328317 is a reply to message #328316] Tue, 16 January 2018 19:48 Go to previous messageGo to next message
Justin Brady is currently offline  Justin Brady   United States
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Registered: April 2015
Location: Bell Buckle, TN
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Senior Member
I've had very good luck with these:
http://shop.pkys.com/Victron-Energy-Cyrix-ct-1224V-120A-Intelligent-Battery-Combiner_p_6769.html?gclid=EAIaIQobChMI4oG15-_d2AIVwpd-Ch395QDaEAQYASABEgK jevD_BwE


Justin Brady http://www.thegmcrv.com/ 1976 Palm Beach 455
Re: Smart Battery Isolator/combiner [message #328320 is a reply to message #328317] Tue, 16 January 2018 21:33 Go to previous messageGo to next message
Tomtom   United States
Messages: 20
Registered: June 2017
Location: Huntington Beach, CA
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Junior Member
SONICJK wrote on Tue, 16 January 2018 17:48
I've had very good luck with these:
http://shop.pkys.com/Victron-Energy-Cyrix-ct-1224V-120A-Intelligent-Battery-Combiner_p_6769.html?gclid=EAIaIQobChMI4oG15-_d2AIVwpd-Ch395QDaEAQYASABEgK jevD_BwE



Thanks! I hadn't seen these.

Tom


Tom 77 Kingsley. Mostly Stock, 455, Quad bag, tachometer, 16"wheels, Macerator. Southern California, huntington beach
Re: [GMCnet] Smart Battery Isolator/combiner [message #328322 is a reply to message #328317] Tue, 16 January 2018 23:32 Go to previous messageGo to next message
Olly Schmidt is currently offline  Olly Schmidt   United States
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Registered: February 2014
Location: Germany and Scottsville, ...
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Senior Member
Justin Brady schrieb/wrote
> I've had very good luck with these:
> http://shop.pkys.com/Victron-Energy-Cyrix-ct-1224V-120A-Intelligent-Battery-Combiner_p_6769.html?gclid=EAIaIQobChMI4oG15-_d2AIVwpd-Ch395QDaEAQYASABEgK jevD_BwE

hehe, have the same installed in my 23' - haven't seen any ill-effect yet.

--
Best regards

Peer Oliver Schmidt
PGP Key ID: 0x83E1C2EA

'76a Eleganza II 26', VA
'73 Sequoia 23', Germany, SH


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Best regards

Olly Schmidt
PGP Key ID: 0x18a9 3a1f 4196 bf22
'76a Eleganza II, VA
'73 Sequoia, SH, Germany
Re: [GMCnet] Smart Battery Isolator/combiner [message #328326 is a reply to message #328322] Wed, 17 January 2018 07:40 Go to previous messageGo to next message
Justin Brady is currently offline  Justin Brady   United States
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Registered: April 2015
Location: Bell Buckle, TN
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Senior Member
I've sold 100+ of them without any reports of issues. I love victron stuff.

Justin Brady http://www.thegmcrv.com/ 1976 Palm Beach 455
Re: Smart Battery Isolator/combiner [message #328330 is a reply to message #328312] Wed, 17 January 2018 08:45 Go to previous messageGo to next message
Matt Colie is currently offline  Matt Colie   United States
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Registered: March 2007
Location: S.E. Michigan
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Senior Member
Please be cautious with "Smart Combiners".

As many of you know, I was part of a boat electrics service group for many years. (This is where the coach was most used for 6 years.) While I like and have installed and replaced combiners as well as isolators, the combiners that are not rated at starting current (~400A for a 455) are easily damaged if left engaged when cranking. This can happen any time the demand combine capability is used even if the main engine battery is at a capable state of charge.

When a combiner fails, they often indicate that they are functioning properly, but in actual fact are not. The indicators are that it has engaged and there is any differential across the two main posts, it is toast. Repair is somewhere between impractical and impossible. Carry the KenB 1$ combiner in your kit just in case.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
Re: Smart Battery Isolator/combiner [message #328338 is a reply to message #328330] Wed, 17 January 2018 10:24 Go to previous messageGo to next message
Tomtom   United States
Messages: 20
Registered: June 2017
Location: Huntington Beach, CA
Karma: 0
Junior Member
Matt Colie wrote on Wed, 17 January 2018 06:45
Please be cautious with "Smart Combiners".

As many of you know, I was part of a boat electrics service group for many years. (This is where the coach was most used for 6 years.) While I like and have installed and replaced combiners as well as isolators, the combiners that are not rated at starting current (~400A for a 455) are easily damaged if left engaged when cranking. This can happen any time the demand combine capability is used even if the main engine battery is at a capable state of charge.

When a combiner fails, they often indicate that they are functioning properly, but in actual fact are not. The indicators are that it has engaged and there is any differential across the two main posts, it is toast. Repair is somewhere between impractical and impossible. Carry the KenB 1$ combiner in your kit just in case.

Matt


Interesting. Some units like this one have "start isolation", they say to protect sensitive circuits from voltage sags, but it seems it would protect against the failure mode you've observed too.

https://www.bluesea.com/products/7610/SI-ACR_Automatic_Charging_Relay_-_12_24V_DC_120A

Tom


Tom 77 Kingsley. Mostly Stock, 455, Quad bag, tachometer, 16"wheels, Macerator. Southern California, huntington beach
Re: [GMCnet] Smart Battery Isolator/combiner [message #328357 is a reply to message #328330] Wed, 17 January 2018 15:38 Go to previous messageGo to next message
Richard Denney is currently offline  Richard Denney   United States
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Matt, the Yandina 160 includes overload, but is rated for 400 amps closing
current. Even if you attempt to start a 455 solely through the combiner, it
will withstand 400 amps for the 2 seconds or so that it takes to go into
overload and shut down. It is overload-protected, and includes an LED
indication to show when it is in overload.

The trigger voltage is specified at 13.1 volts, so I think it will play
better with the PD converters than their 100-amp combiner. When I install
this one, I'll keep an eye on it for that. My first combiner, that I
killed, always stayed combined at the 13.2 sustain voltage. The one I
bought to replace it (I couldn't bear to use the warranty) combines at
13.2, and sometimes won't combine, but I think the problem is with my
converter. That will be a spring project.. But it will combine when the
converter senses high charging current and steps up the voltage to a higher
charging level.

The Yandina combiner is also warranted for life, even against lightning
damage.

And it is current-limited using its lead-in wires. If the engine battery is
capable, starting the 455 will not overload a Yandina combiner even if it
is combined.

Of course, there is nothing to prevent putting a 200-amp fuse or breaker in
line with the combiner, though I suspect the Combiner 160 already has that
internally.

Nothing is perfect and they do sometimes fail. I think KenH has lost one or
two over the years, and I blew one up when in a fit of stupidity I wired a
battery backwards. That stunt took out the alternator, too, though it
didn't fail completely until a couple of days later. The same could be said
for isolators. People say that isolators never fail, but I've been reading
GMCnet for many years and I've certainly heard of many failed isolators,
plus the one I had that failed. These big batteries can supply a lot of
current.

Rick "who likes not having to worry about a failed isolator causing a loss
of field sensing and runaway voltage" Denney

On Wed, Jan 17, 2018 at 9:45 AM, Matt Colie wrote:

> Please be cautious with "Smart Combiners".
>
> As many of you know, I was part of a boat electrics service group for many
> years. (This is where the coach was most used for 6 years.) While I like
> and have installed and replaced combiners as well as isolators, the
> combiners that are not rated at starting current (~400A for a 455) are
> easily
> damaged if left engaged when cranking. This can happen any time the
> demand combine capability is used even if the main engine battery is at a
> capable
> state of charge.
>
> When a combiner fails, they often indicate that they are functioning
> properly, but in actual fact are not. The indicators are that it has
> engaged and
> there is any differential across the two main posts, it is toast. Repair
> is somewhere between impractical and impossible. Carry the KenB 1$ combiner
> in your kit just in case.
>
>
--
'73 X-Glacier 230 "Jaws"
Northern Virginia
Offlist email: rick at rickdenney dot com
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Re: [GMCnet] Smart Battery Isolator/combiner [message #328374 is a reply to message #328357] Thu, 18 January 2018 08:20 Go to previous message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
Senior Member
Richard Denney wrote on Wed, 17 January 2018 16:38
Matt, the Yandina 160 includes overload, but is rated for 400 amps closing current. Even if you attempt to start a 455 solely through the combiner, it will withstand 400 amps for the 2 seconds or so that it takes to go into overload and shut down. It is overload-protected, and includes an LED indication to show when it is in overload.

The trigger voltage is specified at 13.1 volts, so I think it will play better with the PD converters than their 100-amp combiner. When I install
this one, I'll keep an eye on it for that. My first combiner, that I killed, always stayed combined at the 13.2 sustain voltage. The one I
bought to replace it (I couldn't bear to use the warranty) combines at 13.2, and sometimes won't combine, but I think the problem is with my
converter. That will be a spring project.. But it will combine when the converter senses high charging current and steps up the voltage to a higher charging level.

The Yandina combiner is also warranted for life, even against lightning damage.

And it is current-limited using its lead-in wires. If the engine battery is capable, starting the 455 will not overload a Yandina combiner even if it is combined.

Of course, there is nothing to prevent putting a 200-amp fuse or breaker in line with the combiner, though I suspect the Combiner 160 already has that internally.

Nothing is perfect and they do sometimes fail. I think KenH has lost one or two over the years, and I blew one up when in a fit of stupidity I wired a battery backwards. That stunt took out the alternator, too, though it didn't fail completely until a couple of days later. The same could be said for isolators. People say that isolators never fail, but I've been reading GMCnet for many years and I've certainly heard of many failed isolators, plus the one I had that failed. These big batteries can supply a lot of current.

Rick "who likes not having to worry about a failed isolator causing a loss of field sensing and runaway voltage" Denney

Rick,

I kind of hate to say this, but you are talking about your capability and understanding and sort of thinking this is universal. We all do this until we have to go out in the world and get our face smashed into the truth. Most people assume (we may get back to that word) that they are in the middle of that huge bell curve that represents humanity....
Well, I got news for you. Just being a successful GMC owner puts you way out on the right hand end of that curve. Most GMC owners are. If you have any doubt of this go read the other RV boards. And if that doesn't do it, try FaceBook. I have given up there. I spent way too much time telling writers to not do what they just read. It didn't always work, so now I know of two coaches lost to bad advice.

It is all a crap-shoot. Every time I think I have made something idiot proof, I get introduced to a better idiot.

My work has largely been little diesels, they are cold blooded and always take a lot of cranking - even the glowplug versions. The peak currents are also very high. That happens at a 18~20 CR even with a heavy flywheel.

Yes, isolators do fail, but a yellow canary level wrench using the Hazard Fright meter we provided can diagnose the failure with instructions over VHF. Combiners fail too, but the good diagnostic is above that level.

In the documentation we always provided, there was a complete limp-home procedure with how and what to move where to get things to work so the vessel could get where repairs could be effected. This is difficult to provide with the wire-lead Yandina, so we had to package a kit (included in the quote and not optional) with a set of pre-made cables and maybe even the wrenches to install same. This is not usually an issue with a coach. Yes, Yandina may have a lifetime warranty, but there needs to always be a work-round to get you underway when in a remote location.

Do I dislike combiners? No, but they have more components and more modes of failure than does a diode isolator. I can tell you that I have replaced many more combiners than I have isolators. Fortunately, the marine applications of the level vessel I work had not reduced to the simple isolation contactor that is now the common item in the motorhomes I see.

Matt


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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