Guest Battery Isolator

[dehler25]

After replacing all my 12v electronics and batts I found that I am charging my house batteries with my Gen but not the engine alternator. I have a Balmar 80-100 alt so that should be plenty to push what might be needed. There is a Guest 2430 battery isolator. I found a Sure power install doc which indicates that it was replaced at some point, but alsa nothing to document the Guest unit. It appears a straight forward layout except the unit has three terminals which would seem to be alt in center and two batts out. It is installed however with the alt feed stacked on one batt lead, second batt term vacant and the other batt lead separate. Would this have been done to eliminate the .7 volt drop for the diode bias? If the alt regulator has the sense on the start batt how would the house batts charge once the start batt is fully charged? Anyone know where I can find documentation on the Guest unit, I have seriously searched.

 

[Ron20324]

of course the first question is... did you try google?

 

[dehler25]

In every phrase concoction I could think of, I can find others for two alts and three batt configuration but not for the2430.

 

[Maine Sail]

Rx....

#1 Get rid of the isolator. They are a problematic device at best and not used today by competent installers. Today we have better options for charge management.

#2 Run the alt B+/pos & B-/neg direct to the house bank as well as regulator voltage sensing.

#3 Insert an ACR or Echo Charger or Duo Charger between the house and start banks..

#4 Route all other charge sources direct the house bank as well.

 

[capta]

#4 Route all other charge sources direct the house bank as well.

Are you saying that solar and wind charging should all go to the house bank and let the ACR or Echo Charger or Duo Charger maintain the eng bank? Even if the solar and wind chargers have multiple taps (2 or more batteries) and charging % choices?

 

[Bill Roosa]

the owners manual
one search took like 10 seconds using google and"Guest 2430 battery isolator"
http://cruisermarine.com/files/manuals/2532.pdf

 

[dehler25]

Saw that one early on, but it is a different unit 2532 vs 2430. The unit seems obvious, but I wanted to verify because it is relatively easy to blow out the rectifier.

 

[dehler25]

The isolator troubled me, one thing is that there is only a single sense circuit for the alternator and very different charging requirements between the deep cycle house bank and the starter batt. Previous owner tied the sense to the start batt and directly coupled the alt feed and house lead together. Engine starts in a quarter revolution so the start batt gives up little and the alt had nothing to do all while the house bank was dropping. PO's are fun to follow! I am going to investigate isolating the isolator to the ashes of time and replace as suggested. Thanks!

 

[Maine Sail]

The isolator troubled me, one thing is that there is only a single sense circuit for the alternator and very different charging requirements between the deep cycle house bank and the starter batt. Previous owner tied the sense to the start batt and directly coupled the alt feed and house lead together. Engine starts in a quarter revolution so the start batt gives up little and the alt had nothing to do all while the house bank was dropping. PO's are fun to follow! I am going to investigate isolating the isolator to the ashes of time and replace as suggested. Thanks!

The reg MUST sense the bank it is charging. If it is sensing the start battery, but feeding the house battery, you can cook your house batteries.

Regulators & Voltage Sensing (LINK)

Diode isolators can drop quite a bit of voltage when passing current, upwards of 1.1V - 1.2V and this does not include system wiring and terminal voltage drop..

They were never really intended for the long charging duration's with which we use them on boats when charging massive banks resulting in long times spent in bulk charging. This isolator got so hot the epoxy potting was physically melting. It was charging a massive 900Ah AGM bank and the alt was sized below the isolators specs.

 

[dehler25]

Have been looking at the Echo vs ACR, do you have a preference of one over the other, prices are close. The bias voltage drop really concerned me on the isolator once I discovered it existed and how it functioned. The pics make me think it had a nasty odor as well.