Dual Battery questions

[bulldog-yota]

I have seen the surepower units for sale online at RV parts/suppliers for around $80-90.

Kewl!! Was that for the isolator/interconnect devices or just for the isolators? I'm sure one can find them at a better price than Wrangler, I just got tired of looking for the specific unit I wanted to use, so I got it Wrangler. RV shops seem like a good bet though.

 

[firetruck41]

Both I believe, they were only a few dollars apart IIRC, the one I had bookmarked is no longer there, but I know I saw other places that had them for similar prices.

 

[bulldog-yota]

great!! if you find the links post them up, can help other guys save some $$$ in the future.

 

[firetruck41]

Here is a link, it has the 100 amp version of the one (200A) on the wrangler NW site. Both unidirectional and bidirectional for less than $70.

http://www.rvpartscenter.com/prodselect.asp?SID=20&DID=131&CID=395

 

[Rich]

...I think you'll find that if you run those specs past a design engineer who specializes in power managment, his response will be something like......bull****!...

I posted the link to the spec sheet for the Tyco Kilovac solenoid, from which I have previously summarized.

Mobi, since you are claiming bull****, I am interested in seeing what verifiable facts you have to back that up. What information do you have specific to the Tyco Kilovac soleniod that refutes the accuracy of their published specifications?

 

[mobi-arc]

Guys, it would take me half the night to respond to each issue individually, but I'll give it quick once-over. Rich, I've taken a lot of solenoids apart and we frequently test devices at 500 amps (+/-) in the shop. So I base my "bull****" claim on my personal observations. Have I switched that solenoid at 2000 amps 10,000 times? No. I am confident in my own observations to be incredibly skeptical of that rating. Ask Stan at Wrangler if, in his opinion, solenoids live up to their "specs." With respect to bullydogyota's comments on MOSFETS, with a PWM current limitation circuit, P-GATE enjoys protection from over-current and short circuit situations, so although your comment is valid with respect to earlier designs, it's no longer an issue. It's probably the reason why we install five devices per Army communications Hummer; three 400a relays and two 400a isolators. Why, because solenoids can't do it reliably, and you can't turn a solenoid on/off with a one milliamp trigger.

I don't even remember what the topic was....oh yea dual batteries. Guys, suggest you evaluate your options, decide what level of performance you can live with, check the pocket book, and roll the dice. There are lots of options at all different price-points. Take product specs with some skepticism. I mean who's actually going to turn a solenoid on and off 10,000 times at 2000 amps to test the veracity of the claim? They might as well have said 100,000 times at 20,000 amps. It's like saying a product can handle 300 amps for 2 milli-seconds.....who cares? It has no practical value. And, for the record, I don't think solenoids are the worst idea for dual battery isolation. I used a $10 on an overland Africa tour for 7 months with no complaints. It's just not the best choice for high-current switching and dual battery isolation easily falls into that category.

And lastly...would I steer a fellow Land Cruiser owner wrong?

 

[Rich]

So, no verifiable data to back up your claim that Tyco's specs are bogus? What are your personal observations specific to the Tyco solenoid for which I posted the link to the spec sheet?

 

[mobi-arc]

Bogus is an ugly word....reaching, gratuitous, or incredibly optimistic is how I would charactize that spec. I've taken it apart. Viewed the size of the contactors, know what a 500 amp arc does to contact surfaces, and exercised common sense. 2,000 amps...not a fricking prayer. Take it apart and see for yourself. I've seen ten dollar, 100 amp solenoids that are better engineered and will last dramatically longer that "premium" nationally recognized brands; brands that are typically associated with heavy duty industrial products. It's a little disconcerting.

So, no verifiable data to back up your claim that Tyco's specs are bogus? What are your personal observations specific to the Tyco solenoid for which I posted the link to the spec sheet?

 

[Beowulf]

So making claims that one will work better than the other is really more dependant on how well each has been designed.

The Bluesea (aka Tyco) ACR (aka solenoid) has a lifetime warranty.

The Mobi-Arc Powergate device has a 1 year warranty.

Draw your own conclusion.



..... and Mobi-Arc will post back some sob story about being a small company and they can't afford to offer lifetime warranties even though he claims dramatically longer life (and dramatically higher price) for his product vs the competitors (Surepower, Solenoids, Bluesea, Tyco, Hellroaring, etc.)

-B-

 

[bulldog-yota]

Mobi seems power MOSFET technology has dramatically evolved since I last worked with it like 15 years ago. Just so you know we used PWM for current limitation in one of the applications I worked on. And unless there are now MOSFETS with dramatically improved switching capabilities, your packaging still tels me you will be in world of hurt carrying 300A plus continious and disappaiting 19W. Remember these things are not used in a clean lab with cool temps. I would like to see the test data of the P-Gates tested at 300A in ambient temps of 80C or more. Gut feel tells me your juntion temps will be well over 150C, given the packaging, which is a serious dangour zone for these devices.

I worked in a lab where we have blown up many a MOSFET, solenoid and other solid state devices at ranges of 150-2000A. AT that time we were not able to get any MOSFET device that could reliably handle more than 250A at 60V, no matter what heatsink and cooling we used. I'm sure the technology has advanced, but I would like to see the verified test results of what I described above.

So I also assume you guys have overvoltage protection. Since you guys don't make the semiconductors yourselves are you at liberty to say which devices you actually use for the switching with the specs of these devices?

Back to topic, I believe solenoids have been proven to be more than reliable for the dual batt type application. It really depends if you get a quality product or not. These devices have a far easier life than starter solenoids who perform a dual function and always carry a very high load on contact. How many amps do you seriously think a dual batt isolator needs to switch on average application?

Just FYI this is from your own website

 

[bulldog-yota]

Here is a link, it has the 100 amp version of the one (200A) on the wrangler NW site. Both unidirectional and bidirectional for less than $70.

http://www.rvpartscenter.com/prodselect.asp?SID=20&DID=131&CID=395

Good find, wonder how much they would sell the 200A for.

 

[mobi-arc]

Need to update that. No longer applicable with the current limitation circuit. Not comfortable disclosing our components and methods as of yet, but RDS-on has diminished to the point where high current applications are not only possible, but reliable. Again, back to manufacturer's spec, most MOSFET manufacturers provide component specs and efficiencies based on impracticle cooling methods. That's where most designers make mistakes by trying to use far too few FETs to handle the amount of current their dealing with. Our junction temps are dramatically lower that 150C, we dissipate less that 19 watts at 500 amps, and running that kind of current continuously, the cables get hot, P-GATE is cool as a cucumber. World of hurt at 300 amps....not exactly, we're loafing at 300 amps...it's an impressive package and I enjoy the fact that you understand power. Most people think the divice looks pretty and don't understand how tremendous it is to carry a 20 kw switch in your pocket.

Scott

Mobi seems power MOSFET technology has dramatically evolved since I last worked with it like 15 years ago. Just so you know we used PWM for current limitation in one of the applications I worked on. And unless there are now MOSFETS with dramatically improved switching capabilities, your packaging still tels me you will be in world of hurt carrying 300A plus continious and disappaiting 19W. Remember these things are not used in a clean lab with cool temps. I would like to see the test data of the P-Gates tested at 300A in ambient temps of 80C or more. Gut feel tells me your juntion temps will be well over 150C, given the packaging, which is a serious dangour zone for these devices.

I worked in a lab where we have blown up many a MOSFET, solenoid and other solid state devices at ranges of 150-2000A. AT that time we were not able to get any MOSFET device that could reliably handle more than 250A at 60V, no matter what heatsink and cooling we used. I'm sure the technology has advanced, but I would like to see the verified test results of what I described above.

So I also assume you guys have overvoltage protection. Since you guys don't make the semiconductors yourselves are you at liberty to say which devices you actually use for the switching with the specs of these devices?

Back to topic, I believe solenoids have been proven to be more than reliable for the dual batt type application. It really depends if you get a quality product or not. These devices have a far easier life than starter solenoids who perform a dual function and always carry a very high load on contact. How many amps do you seriously think a dual batt isolator needs to switch on average application?

Just FYI this is from your own website

 

[mobi-arc]

My Totota is waranteed for 36,000 miles, my BFG's have no warranty......draw your own conclusions......jack-ass.

The Bluesea (aka Tyco) ACR (aka solenoid) has a lifetime warranty.

The Mobi-Arc Powergate device has a 1 year warranty.

Draw your own conclusion.



..... and Mobi-Arc will post back some sob story about being a small company and they can't afford to offer lifetime warranties even though he claims dramatically longer life (and dramatically higher price) for his product vs the competitors (Surepower, Solenoids, Bluesea, Tyco, Hellroaring, etc.)

-B-

 

[firetruck41]

My Totota is waranteed for 36,000 miles, my BFG's have no warranty......draw your own conclusions......jack-ass.

Your BFGs have a 6 year and/or "life of useable tread" warranty, what's your point .

 

[Beowulf]

My Totota is waranteed for 36,000 miles, my BFG's have no warranty......draw your own conclusions......jack-ass.

I understand everything now. Thanks for the clarification.

-B-

 

[bulldog-yota]

Need to update that. No longer applicable with the current limitation circuit. Not comfortable disclosing our components and methods as of yet, but RDS-on has diminished to the point where high current applications are not only possible, but reliable. Again, back to manufacturer's spec, most MOSFET manufacturers provide component specs and efficiencies based on impracticle cooling methods. That's where most designers make mistakes by trying to use far too few FETs to handle the amount of current their dealing with. Our junction temps are dramatically lower that 150C, we dissipate less that 19 watts at 500 amps, and running that kind of current continuously, the cables get hot, P-GATE is cool as a cucumber. World of hurt at 300 amps....not exactly, we're loafing at 300 amps...it's an impressive package and I enjoy the fact that you understand power. Most people think the divice looks pretty and don't understand how tremendous it is to carry a 20 kw switch in your pocket.

Scott

Interesting, will keep a lookout for your updates. You guys should definitely update your specs then as it doesn't jive with what you are saying here.

I understand the use of multiple FETs for high loads, but that doesn't change power losses/heat until you get to the outer ranges of operation.

So what is the temp diff of junction to ambient at full load? And tested for how long at what ambient temp?

Reason why I'm asking is that we had to drop FETs to about a 1/8 of the rated current and double the cooling capacity, to make them work reliably with technicians in the field. They were used in devices that had to dissipate up to 1500A at 52V, not just switch. Most of the power were switched through solenoids, which we never had an issue with in the field, and less than 20% of the power was switched with FETs with PWM to emulate a constant current draw overall. Lets just say the FETs were not as reliable as we would have liked, but then again that was some time ago. The systems tested perfect in many lab test, but somehow the technicians found a way of killing them.

 

[mobi-arc]

My point is thay my old buddy Beowulf suggests that's there's a direct correlation between a product's warranty and it's quality/performance/reliability, ect... My BFG's don't have any warranty associated with them, and it's good product. My Land Cruiser is only warranted for 3 year/ 36k miles, does that mean it's crap? Warranty is simply a marketing tool.

Your BFGs have a 6 year and/or "life of useable tread" warranty, what's your point .

 

[mobi-arc]

Junction temp is less than 40C below ambient at full current.

Interesting, will keep a lookout for your updates. You guys should definitely update your specs then as it doesn't jive with what you are saying here.

I understand the use of multiple FETs for high loads, but that doesn't change power losses/heat until you get to the outer ranges of operation.

So what is the temp diff of junction to ambient at full load? And tested for how long at what ambient temp?

Reason why I'm asking is that we had to drop FETs to about a 1/8 of the rated current and double the cooling capacity, to make them work reliably with technicians in the field. They were used in devices that had to dissipate up to 1500A at 52V, not just switch. Most of the power were switched through solenoids, which we never had an issue with in the field, and less than 20% of the power was switched with FETs with PWM to emulate a constant current draw overall. Lets just say the FETs were not as reliable as we would have liked, but then again that was some time ago. The systems tested perfect in many lab test, but somehow the technicians found a way of killing them.

 

[Hants]

MrMoMo, Rich, MikeS, bulldog-yota, firetruck41 -- thanks for the great info!

mobi-arc, while your product may be splendiferous, it is also VERY new in this market. You would probably get less push-back if you weren't so aggressive in your marketing/hyping/evangelizing/promoting on the forum. I've seen multiple threads degenerage into yada-yada-yada once the PowerGate is mentioned. (where's that dead-horse?)

I'll post-up my plans for review/comment once I get them off of the paper napkins and postits

 

[Beowulf]

My point is thay my old buddy Beowulf ...

I'm not your Buddy, I'm your antagonist.

You take every opportunity to run down the other manufacturers of dual battery electronic products calling them inefficient, failure prone, BS, old technology, etc. You continue to spread FUD about competing products; even those with lifetime warranties.

You don't supply us facts to back up your claims and you expect us to take your word because you've disassembled a similar solenoid.

Where are the 'Mud members supplying testimonials on your product? I've read 5 or 10 write-ups on the Hellroaring product. I've seen many positive reviews on the SurePower. I've read Raven's writeup on the BlueSea ACR. You've been telling us how great your product is for almost 3 years; 2 of those years it was vaporware. You are a vendor hawking your wares in the non-Vendor areas so I believe you should be prepared for some critique of your product and your claims of it's vast superiority to all of your competitors.

I'm not your Buddy, I'm a jack-ass skeptic and I apologize to the group if I come across too direct.

-B-