OJ's dual battery system review

[goodtimes]

If you are going to be pulling high currents through the combiner (charging doesn't count) then you'll be better with a solenoid type device.

That is a limitation of the Hellroaring system. They are only rated for ~150 amps (and then only for a few seconds).

If anyone is using a Hellroaring BIC, and wants to be able to use the house battery to start the engine (or otherwise pull big loads from the house battery to the main battery), a suitably sized relay should be run in parallel to the isolator/combiner.

 

[Josh]

That is a limitation of the Hellroaring system. They are only rated for ~150 amps (and then only for a few seconds).

If anyone is using a Hellroaring BIC, and wants to be able to use the house battery to start the engine (or otherwise pull big loads from the house battery to the main battery), a suitably sized relay should be run in parallel to the isolator/combiner.

Correction: Your HR BIC is only rated for ~150a/20secs. Their more popular 95300 (the one I think should have been reviewed) is good for--

170a continuous
300a 20secs
500a 50mS

And that is just the back-up's share of the load (what passes through the BIC)! So for a heavy load (like winching) you've got that 170a continuous, your primary battery putting out it's equal share, and your alternator putting out another 50a or so. And by the time you've reached that 300-400a demand your winch motor is stalling anyway so who cares.

HR does suggest that in a case where the primary is completely discharged that one wait a minute or two after joining the two so that they can balance some and the draw is not completely through the BIC. Not an unreasonable price to pay for killing your primary.

And that's what I'm saying about the review. OJ tested the lesser spec'd 95150 because one of them had one. Not because it was the best comparative to the field.

Kind regards, Josh

 

[ntsqd]

How does it measure the voltage while it is charging? When I put a voltmeter on battery terminals when the engine is running, it shows the charging voltage.Even after I remove the charger, it takes many seconds for the voltage in the battery to drop before leveling off.

I do not know. However, I have run into other systems that apparently can do this. The first such was a very trick but not inexpensive marine battery bank manager/alternator regulator that is linked around here, somewhere.......

That needing to start with which ever battery isn't flat is my primary reason for employing the marine combiner switch. As pointed out, the marine switches are simple, robust, and a well proven solution. About the only downside is the surface area required to mount them.

Starting currents can easily exceed 200 amps for short time periods. A 4 HP (2.98kW) starter motor will draw 248 amps at 12 VDC; 271 amps at 11 VDC, and 284 amps at 10.5 VDC; and that assumes 100% efficiency.
Batteries effectively have no current limits. If the system asks for 1000 amps the battery will do it's best to deliver 1000 amps. It may not be able to sustain 1000 amps for very long, but it will try to deliver.

 

[goodtimes]

Correction: Your HR BIC is only rated for ~150a/20secs. Their more popular 95300 (the one I think should have been reviewed) is good for--

170a continuous
300a 20secs
500a 50mS

And that is just the back-up's share of the load (what passes through the BIC)! So for a heavy load (like winching) you've got that 170a continuous, your primary battery putting out it's equal share, and your alternator putting out another 50a or so. And by the time you've reached that 300-400a demand your winch motor is stalling anyway so who cares. That 500a rating at 50ms.

HR does suggest that in a case where the primary is completely discharged that one wait a minute or two after joining the two so that they can balance some and the draw is not completely through the BIC. Not an unreasonable price to pay for killing your primary.

And that's what I'm saying about the review. OJ tested the lesser spec'd 95150 because one of them had one. Not because it was the best comparative to the field.

Kind regards, Josh

With regards to the house battery supplementing the main battery when the engine is running...yes, the load rating (of the BIC) is quite suitable for most applications (like winching). You still need to be careful that you don't exceed the rating...but, for the reasons you mention, it isn't as big of a concern as trying to start the engine, from the aux battery through the BIC, when the main battery is dead.

Yes, you could combine the two batteries, let the dead main battery charge for a few minutes, then *hope* that you don't exceed the units capacity when you roll the key over. But that is what you are doing...hoping. Obviously, this is a decision that each owner will have to make based on the circumstances surrounding their particular situation.

Yes, the Hellroaring unit in the review was purchased and installed with no knowledge of the upcoming OJ article. I selected that model because Hellroaring felt that it was the best product for the application. Why would I second guess them on that?

To my knowledge, Hellroaring had no idea that one of their products would be used in the review. If they did, would they have offered to send a different model? Maybe, maybe not. But if this is the model that they are recommending to the average person who calls them, then I believe that it is a good model to include.

 

[grahamfitter]

That is a limitation of the Hellroaring system. They are only rated for ~150 amps (and then only for a few seconds).

If anyone is using a Hellroaring BIC, and wants to be able to use the house battery to start the engine (or otherwise pull big loads from the house battery to the main battery), a suitably sized relay should be run in parallel to the isolator/combiner.

I had an older Hellroaring BIC which worked fine to isolate the main battery from the traumatized house battery that was trying in vain to power a brutally inefficient thermoelectric cooler. The one time I needed to start the engine from the house battery I just used a jumper cable across the BIC terminals.

If one is worried about current draw through any electrical device maybe an inline fuse or circuit breaker would be of value?

Cheers,
Graham

 

[Josh]

I think this has pretty well wound down but I might conclude (in my mind. I don't presume to say my observations are "conclusive"):

-At 0.001ohms(on their biggest selling model), the voltage drop that OJ ominously eluded to is insignificant for what it matters.

-It sounds like, even given the numbers ntsqd cited on starting draw, Hellroaring Technologies' flagship unit (which isn't more expensive than the tested model, if anyone wondered) could easily handle anything other than gross mismanagement (.. cranking, and cranking, and cranking....) and it probably would handle even that.

-I stand by my assertion that OJ didn't give HRT the fairest of shakes. A couple of buddies get together and decide to what to compare in a authorative gear review based on what each of those buddies happen have under their hoods? Whether they're apples or oranges?

-And Brian "goodtimes" DeArmon: Your title of Contributing Editor and Implied Expert comes with some heavy responsibilities. Be educated before making repeated assertions about the "limitations of the[empasis mine] Hellroaring system" or what one musn't try to do with a [any] HRT BIC. The model you chose has these limitations... but you're speaking broadly and apparently across their product line. This isn't true and your title bears the responsibility of truth. I guess it also makes you subject to second guessing criticism from idiots like me

Kind regards, Josh

 

[Josh]

...

If one is worried about current draw through any electrical device maybe an inline fuse or circuit breaker would be of value?

Cheers,
Graham

HRT strongly recommends that you place a fuse between the back-up battery and the BIC. They stock them and will ship them out with your BIC. Now you're not just *hoping* to keep the smoke in when you roll the key over.

Kind regards, Josh

 

[goodtimes]

-And Brian "goodtimes" DeArmon: Your title of Contributing Editor and Implied Expert comes with some heavy responsibilities. Be educated before making repeated assertions about the "limitations of the[empasis mine] Hellroaring system" or what one musn't try to do with a [any] HRT BIC. The model you chose has these limitations... but you're speaking broadly and apparently across their product line. This isn't true and your title bears the responsibility of truth. I guess it also makes you subject to second guessing criticism from idiots like me

Kind regards, Josh

In case there is any confusion, "the" BIC that I am referring to, in all of my posts in this thread so far, is the unit that was reviewed. Since the review is the topic of this thread, I assumed that everyone would understand that. It wouldn't make much sense for me to start comparing the specs of some other model when we are talking about the one that I have installed in my jeep. So, no, I am not speaking about their entire product line...only of the model that was included in the review.

As for my comment about not pulling a load through the BIC bigger than it is rated for....I stand by that 100%. It is a safety issue. A fuse or breaker was mentioned. Yes, good idea to have one (I do), but it is sold as an accessory to a product. IMO, it should be included as part of it...but that is a decision for Hellroaring to make. The BIC, as sold, lacks that protection. Or, more specifically, it lacked that protection when I bought mine. I don't know if they have subsequently started including short circuit protection or not. So, if you were to buy and install one "as-is", without buying any accessories, you could quite easily 'let the smoke out' by trying to start the engine from the house battery.

We try to make things as fair and objective as possible, but no test will ever be perfect. There will always be something that could have been done differently, there will always be some special circumstance that could alter someones viewpoint on a piece of gear or a manufacturer, and there will always be someone who has an opinion that is different than that of the team reviewing a product. There is absolutely nothing wrong with that. How boring would the world be if we all thought exactly the same way?

Every person has to make the choice as to the strengths and weaknesses of each product they buy. The Hellroaring BIC that was included in the reveiw had some limitations. It also had some strengths, to quote one:

at the end of the day, the friggin' thing's $200 dollars cheaper than The Choice!

That is a factor that plays in the purchasing decision. Is living with the limitations of the BIC worth the difference in price, for *you* (referring to anyone)? Each individual has to make that decision for themself. If someone reads the review, considers the voltage drop, the amp load limitations, the fact that they (for safetys sake) should add in the cost of a fuse or breaker, etc., and still decides that the Hellroaring BIC is the best choice for them...great! They made an educated decision. It may not be the same decision as someone else...but so what? It is their vehicle, their wallet, and their decision. Just because it doesn't agree with what a magazine printed, doesn't mean it wasn't the right choice.

Case in point: Look at the isolator/combiner that is mounted under the hood of my TJ. I feel, even after participating in the review, that the product I selected is the right choice, for *me*. Others think there are better solutions out there. They may be right...but the product that I am using meets all of my needs, and I am completely satisfied with it, even if it wasn't selected as "Editors Choice".

 

[kjp1969]

Kevin, did you miss our new project vehicle? A $3,000 used DR650.

To address your main question: Absolutely nothing wrong with a manual switch, as we said. However, it's an alternative to an automatic system, and difficult to compare directly using the same parameters. Like a kinetic rope is an alternative to a winch, but difficult to compare directly.

As to that high-end gear, trust me that each one of us is frugal in the extreme. We have simply found, time and time again, that the best equipment is the cheapest in the long run, and worth saving for. Yes, sometimes we step beyond pure function into style (i.e. the J.W. Hulme in the duffel review), but we'd never compromise function for style.

Also, we will never knowingly feature a product that was copied from the original designer/manufacturer and reverse-engineered to be produced at a lower cost. Thus no $200 oriental clones of Warn winches in that review.

Action Packers versus Zarges? Fair one.

Ice chest versus Engel? Fair too, but ice costs money, and ties you to sources.

$100 Walmart tent? Not likely. Too much personal experience with cheap tents when I was guiding.

Back to DBS discussion -

Fair enough, and my mind just skipped over the KLR.

Let me be clear, one of the things I like best about OJ is the uncompromising search for quality and long term value. Its refreshing to be sure that never will I open the magazine only to read about something mediocre but cheap. But still, as in the case of a $40 manual switch versus a $400 automatic system, the case can be made that simpler and cheaper may be more reliable, and therefore a viable alternative.

 

[Antichrist]

One thing I can't find in the OJ review, nor on Hellroaring's web site, is whether or not their isolator uses schottky diodes or not, which would give a lower voltdrop.
I'm assuming they do, since it would be silly to spend all the developement time and not use them, but it would be nice to know for sure.

 

[tdesanto]

If we're going to seek out the best equipment, then I do wish the HR BIC95300B had been part of the review. At least I think that would have been a more “fair” comparison with the other systems. I understand that it wasn’t included and that it was clear which model was tested, but it is not their best product. I would have liked to see a statement that the higher capacity 95300B was not available for us to review, or something to that effect. It seemed like it was an apples to oranges comparison.

As for including what Hellroaring recommended, I had the opposite experience. I wasn’t sure which model to choose when I first got into dual battery setups; so, when I called up Hellroaring, over two years ago, and explained that I wanted to run a fridge, lights, and a winch, they immediately pointed me to their top choice, the 95300B. They also recommended that I install my system such that I would always have a fully charged and disconnected (when the engine isn’t running) backup battery; this way my house battery is my starting battery.

After installing it, I wanted to test the system to make sure that it would work. I unplugged my main battery and started my vehicle from the backup battery several times without any trouble.

The specs of the 9515B:

Max Current: 95 Amps Continuous
150 Amps 20 seconds
250 Amps 50ms

The Specs of the 95300B:

Max Current: 170 Amps Continuous
300 Amps 20 seconds
500 Amps 50ms

From their FAQ regarding high load use and/or winching (They mention here the 75300, wich the newer 95300 replaces):

Q: I want extra power for my winch but it is rated up to 400 amps. These operate longer than starting motors. Won't this burn up the isolator?
A: You will likely burn up your winch before you hurt the BIC-75300. If you use the Basic Backup Battery setup, you will be able to winch as long as your winch and batteries can handle. When you operate your winch, you will likely have a near fully charged main battery. In addition, the BIC-75300 can handle up to 150 amps continuously. Your backup battery can supply boost current to reduce the voltage drop at your main battery terminals. There are several points to keep in mind:
1) The only current through the Hellroaring BIC-75300 will be from just the backup battery. For batteries of equal charge, you can supply up to 300 amps continuously without alternator (for as long as the battery charge lasts and the winch doesn't overheat).
2) Your winch will quickly burn up if it is operated at full load continuously. A winch MFG. recommends less than 20 seconds at full load. Therefore, you likely will not operate at full load for very long.
3) Most winch ratings are at 12 volts. Full load (stall) current will be less due to battery terminal voltage drop. You can expect no more than about 88% of the rated current at full load (with a single battery). For the 400 amp rating, this is about 350 amps. With the Hellroaring BIC-75300 and another battery, this may be about 375 amps.
4) Your alternator can supply a portion of the current. This will be your alternator rating less about 10 to 15 amps for engine operation. Subtract more if you have other loads like headlights. With a 100 amp alternator, this should still leave about 75 amps for the winch. Even more is available with higher output alternators.
5) When wired for the Backup Battery setup, the Hellroaring BIC-75300 and backup battery will initially deliver close to 1/2 of the main battery current to the winch. For the example above, the batteries together will supply about 300 amps (375 amps less the 75 amp alternator output). Of this 300 amps, the main battery will supply about 160 amps and the auxiliary will supply about 140 amps. The backup will supply slightly less due to the typical unequal lengths of wire to the winch and some slight BIC resistance. This combination will increase the operating capacity to about 300% compared to a single battery alone. This is an excellent increase in performance. If the alternator output is not available, the BIC-75300 can handle initial currents up to 300 amps short term.
6) But, since a winch will quickly burn up if operated at full load for more than 20 seconds, a more realistic example will be the winch operating in the range of 125 to 200 amps. At the 200 amp load, the batteries together must supply 125 amps. Under this condition, the main battery would be expected to deliver 65 amps and the backup battery would be expected to supply about 60 amps. If the main battery charge is low, the backup battery and BIC-75300 will supply the majority of the 125 amps or more if needed.
7) With a BIC-75300 configured for the Backup Battery setup, you can also leave it in Auto mode and winch with your main battery only, thereby reserving your backup battery as a starting backup. In this case a battery such as an Optima yellow top (deep cycle) would be ideal as your main battery and any standard starting battery as your backup. If you winch often, and if you plan to use both batteries during winching, then both should be deep cycle rated batteries.

 

[Robthebrit]

One thing I can't find in the OJ review, nor on Hellroaring's web site, is whether or not their isolator uses schottky diodes or not, which would give a lower voltdrop.
I'm assuming they do, since it would be silly to spend all the developement time and not use them, but it would be nice to know for sure.

I do not believe it does use schottky diodes, I think solid state relays are simply fully saturated Field effect transistors (maybe with optical isolation to prevent weird grounding issues and allow compatibility with mechanical relays). This is just a guess because there is no junction volt drop on the BIC, the measured drop in voltage is basic ohm's law based on current and internal resistance. The volt drop over a semi-conductor junction is pretty much constant regardless of current or voltage.

Rob

 

[goodtimes]

As for including what Hellroaring recommended, I had the opposite experience. I wasn’t sure which model to choose when I first got into dual battery setups; so, when I called up Hellroaring, over two years ago, and explained that I wanted to run a fridge, lights, and a winch, they immediately pointed me to their top choice, the 95300B. They also recommended that I install my system such that I would always have a fully charged and disconnected (when the engine isn’t running) backup battery; this way my house battery is my starting battery.

That is interesting. I wonder why they had a change of heart...or if there was simply two different people (one that you talked to, and one that I talked to) with two different opinions about their product.

 

[tdesanto]

That is interesting. I wonder why they had a change of heart...or if there was simply two different people (one that you talked to, and one that I talked to) with two different opinions about their product.

Not sure. I believe I spoke with Mike Hines. I'm not sure if he is the owner or simply in charge of technical support. I can say this: I had him on the phone for at least 20-30 minutes discussing my options and making sure that I fully understood what I was getting into with the installation. He even helped me make sure I acquired all of the appropriate supplies (proper gauge wire, terminals, etc.) before the unit arrived so that I could begin installation right away.

Regardless, Brian, I was really glad to see that this company was represented in the article. I was very happy with my experience with their customer service and their product and I believe they deserve the credit.

 

[goodtimes]

I don't recall who I talked with....but whomever it was, they were friendly and didn't push the sale. Like you, I talked with them for quite awhile about what I wanted to accomplish, and different ways to do it. In the end, I followed their recommendation regarding isolating the aux (house) battery, and running all of my "camp junk" (fridge, radios, accy sockets, etc) from that, leaving my starting battery alone.

Yet another example of there being more than one way to skin a cat.