Yet another battery isolator question

[r39o]

So ya, another battery related thread. The SEARCH just is not strong for me.

I have questions relating to Isolators.

I have decided I do NOT want to use the standard Vanagon relay type of battery isolation. While this may work OK with two batteries of the same size and age and abuse, mixing two different batteries can cause issues (mostly overcharging.)

My setup up being a normal automotive lead acid starting battery and a pair of deep cycle golf cart batteries.

The main problem is actually 2 fold.
- One if the deep cycle pair is low (likely) and starting battery OK, the relay setup keeps pumping charge into the starting battery.
- Two is alternator load. A good isolator will charge the starting battery and then the next battery. Further I understand deep cycles really like a slower charge than a starting battery.

My current setup charges the deep cycle via solar or a on-grid smart battery charger (has a setting for deep cycle.) Start battery has a VW solar trickle and the alternator to keep it happy. This works OK, but not optimal.

I see others have a similar setups with high current deep cycle batteries, but the charging configuration seems mostly vague.

So what are others doing for this sort of setup?
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"Use the SEARCH, Luke" But first visit the Vanagon FAQ!

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[MidwestDrifter]

I am using a blue seas ACR with my setup. I have 2 GC2 batteries under the bench. No solar, I have a charger I connect manually if 120v is available.

No issues to report yet. The AUX batteries never get to 100% charge, but at about 90% from the alternator seems to be acceptable. I occasionally use a good smart charger to top them off.

The ACRs logic is pretty simple. There is no way to compensate for different battery chemistry (ie different max charging voltages). Since Both of my batteries are of the flooded type, I don't foresee any issues.
http://bluesea.com/productline/overview/387
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[crazyvwvanman]

To avoid the pumping problem simply use a SurePower 1314A as that is one of its features. I don't think Yandina or BlueSeas offer such a model.

AFAIK, the isolator relays do not charge one battery first and then move on the the next battery. They are not designed for that, no matter how misleading the manufacturers wording about the product may be in regards to this.


Mark

[r39o]

[crazyvwvanman]

You have misread the documentation. The start assist feature is disabled by default. You have to run a start signal wire to a pin on the logic module to enable it. I never want it so I never wire it up that way.

The same pin can be wired to a switched power pin and used to manually combine the batteries for start assist when the switch is on. A push button switch would normally be used for that in cases where someone wanted the aux battery to be able to help the starting battery, assuming the wiring was done in a suitable way to support that capability. Again I don't generally wire them that way either.

Just the basic function of the unit is all we need for VW Van auxiliary battery use.

Mark

[j_dirge]

[Phishman068]

The original poster mentions having a solar system in place.
We have nearly identical setups, deep cycle batteries seperated by an ARC with solar attached to the deep cycle.

One of the ingenious features of the blue seas ARC is that when it senses charge voltage on either side of the circuit for a certain interval, it combines the batteries. This however, means that if the deep cycle is getting power from the solar (Which it should, almost always), the ARC will engage and combine the batteries. It does this to try to feed power to the starting battery as well (wonderful), however this ends up allowing cranking amps from the deep cycle to flow through the ARC into the starting battery.
As mentioned, I see no reason why this would be a problem, especially if you use thick enough wires. I have 6 gauge and i'm confident in it, though I wouldn't "want" to use that wire to support the starting load alone (As in no starting battery in place).

I work on marine electronics every day, and they wire exactly this way. They do however, use giant sized cables, but generally they are extranious and can be accounted for only by the accountants.
B.O.A.T- "Bring Out Another Thousand"

-Craig

[westyventures]

Craig, the Surepower 1315 series does this bi-directional combining as well.

[thatvwbusguy]

Either type of ACR (automatic charging relay) will work for simple setups like we use in our vans. A dual sensing relay will separate the banks when the voltage drops beneath the low voltage threshold in either battery.

If you have two 6V batteries in series (or two 12V batteries in parallel) and they are properly connected, there is no reason to think that one of them should be lower than the other unless you have a failing cell in one.

Most people connect solar directly to the deep cycle auxiliary batteries and rely on the charge controller to manage the charging rate. While they are being charged from the alternator, you can limit the charging rate to some degree by choosing a wire with a lighter gauge (I like 8AWG for my system).

If your main concern is dumping large amounts of current out of your deep cycle batteries into your starting battery when cranking, Mark's suggestion of the Uni-Directional (single voltage sensing) SurePower 1314A is the simplest answer.

The 1314A only senses the state of charge in the starting battery. When the voltage in the starting battery is over 13.2V (usually whenever the vehicle is running) it connects to the auxiliary bank to charge. When the voltage in the starting battery drops below 12.7V (shortly after the engine is turned off), it separates the batteries and no juice is drawn back out of the auxiliary bank.

The 1314A does offer start assist as an option, but it is by no means necessary to use it if you don't want. They are also cheaper than the Blue Seas 7610 ACR or the Yandina.
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[r39o]

So where is an inexpensive (less expensive) place to buy one of these Sure Power isolators?
_________________
"Use the SEARCH, Luke" But first visit the Vanagon FAQ!

1990 Multivan EJ 22, Rancho trans 0.82 4th, Small Car front AC, CLKs w/ 215/65-16, homemade big brakes 303mm, Konis, Recaros, etc....

Click to see my ads for Cup holders, Subaru clutch fix and CLK wheels (no wheels currently)

[thatvwbusguy]

There is a 100A model (100A continuous, 400A inrush) listed on eBay right now for $35.75 with free shipping. That is probably as cheap as you will find one.
_________________
Jay Brown
'85 Zetec Westfalia
Newmarket, NH


If you want others to be happy, practice compassion.
If you want to be happy, practice compassion.

[crazyvwvanman]

Here is a place I have used several times. I order in multiples.

http://www.ase-supply.com/Sure_Power_1314_Battery_Separator_p/sp-1314a-b.htm

The $36 ones on Ebay right now are old used units. I wouldn't do it that way.

Mark

[dcaver01]

Glad I stumbled across this thread - I just upgraded to a battery bank and have a Blue Sea si-ARC. I'm running into a problem where the new battery bank has about 13.2+ V and the starter is about 12.5V - which means the Blue Sea device stays closed, charging the starter from the deep cycle bank. Not what I want, but it's how the si-ARC is designed.

I'm going to order the Sure Power 1314A - which sounds ideal - only connect the two batteries when the alternator has charged the starter battery up to 13.2V. Perfect. I want that voltage going one way only, never pulling power off the house bank.

Are there any other isolators I should look at or is this the best option?

[Jamos]

I wanted to bump this thread up, to ask what the current opinion of these Surepower units is, and to see if people thought they were still a good solution.

I recently did an engine conversion, and now have a 120amp alternator. I used to use a Yandina Combiner 100, and am now thinking about installing a Surepower 1314-200 instead.

Starting the engine is the only thing my primary battery does at this point, so I think a one-way charge from the alternator > both batteries, but NOT the other direction from my solar or shore power, that the 1314 provides would be perfect.

Any opinions or input would be great, thanks
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2020 Audi Q5

[puchfinnland]

current thinking is a DC DC charge regulator between the start and the house,

Also nothing wrong with a "continuous duty" relay between the 2 banks if the chemistry is the same.
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[Jamos]

Thanks for the input! I'm seeing the Victron DC-DC charger controller as an option, which looks like a very modern, "smart" device.
https://www.amazon.com/Victron-Orion-TR-Isolated-Charger-Supply/dp/B0851TPKV7/

Perhaps it's money better spent on something like that, which should also be more future-proof as battery technology evolves, as opposed to relay device.