Great video showing how it works. I will give it run and let you all know how it works in my dual battery BR2.
1 Like
Thanks for the video, that appears to work nicely. I am building new LiFePo4 packs to replace my LiPo packs and I may integrate this. How much current is this designed to handle? Also, can you predict the failure mode? Would it combine the batteries or disconnect? Maybe the FM is unpredictable, just curious.
How can we contact you for ordering information?
Thanks!
I have now used this SeaView Systems board with my dual battery BR2 for several jobs. This works seamlessly as described by choosing highest voltage battery untill approaching equal voltage of other battery and then sharing the current.
I would recommend this to anyone considering running multiple batteries since I am pretty certain I ruined a battery prior to adding the SeaView Systems Dual Battery Controller.
2 Likes
Hi mate,
Are you still running with Duel battery set up with sea view configuration?
Iâd love to have mine set up in a similar way ruining with duel battery in separate enclosures and the the middle enclosure used for wiring up in parallel and all that good stuff. Will I need to upgrade my end cap currently only 4 hole (guess I will).
Are you still using your rear facing cam off the battery and utilising a twisted pair with fathom s board topside?
Iâm just drawing up plans as will be making some good mods once I return home from offshore. One being to run an âon & offâ switch at the surface on the fxti box but again with the expense of another twisted pair but itâs a good mod for our set up.
Cheers
Davie
Yes I am still running dual battery in traditional BR2 Heavy lift as well as in my new custom built 1000 meter rated ROV.
I like your idea about running switch from top side through tether. Works with copper tether but my systems are set up for fiber option.
You may want to put in a diode to suppress voltage spikes turning battery on and off through your contractor.
Cheers
Doug
@gcelec How are the mosfets in that design cooled? In a Heavy config one of these could be drawing ~100A through a single mosfet. That is a lot of heat to dissipate in a closed environment.
The mosfets arenât designed to handle a 100% duty cycle and can operate a heavy configuration without overheating.
Good to know. Thanks for the reply. In that case assume you are using high current power mosfets like IPT004N03L. I would still put two per channel.
Hey Chris. They arenât mosfets, they are ideal diodes.
Hello. May I know, what is the 16 pin IC that you used in the dual battery controller?
Before installing the MBM-150 (Multi-Battery Manager) I got a good look at it, anticipating that I would probably have to reverse engineer the part some day⌠Now I need a few more of these and unfortunately SeaView does not offer them any longer, and did not have any recommendation on an alternative part. Its a simple circuit, the IC your interested in is a LTC4353 Dual Ideal Diode Controller.
I got to looking into this and the LTC4359 looks like it can be an Ideal Diode Controller and it has a shutdown feature the can use a second MOSFET to act as a load switch. You could build a board that uses 2 of these circuits to safely combine 2 batteries in parallel and provide a power switch to manually disconnect the battery via the BR switch. New product idea for BR 
If they donât do it I may have tooâŚ
We did make a new version of the MBM-150 that you could connect a Blue Robotics switch to it to power the vehicle on or off as well as an output for a Blue Robotics LED. Unfortunately when we went to move from prototype to production, the components were on backorder and we couldnât get any indication of when they would be available.
1 Like
Thatâs a bummer, this would be a really useful product.
I donât have any experience designing these high current PCBâs so I am going to try to make the âparallel controller and main battery switchâ using 4 of the Thornwave TL-SSRâs. I figure using 2 of the unidirectional SSRâs for each battery (creating a bidirectional SSR that will not allow current to flow backward), and controlling them with a dedicated microcontroller that monitors the voltage of both batteries should give a good level of protection, and provide a main power switch. It could also allow a software controlled power cycle if needed. Hopefully the Thornwave parts work as good as they sound and the voltage drop across the SSRâs is not too much⌠I will have the parts this week and test it out.
Thanks for your help. We were also trying to get a few units of MBM-150. Weâve checked the market price of the IC and found out that the price is just ridiculous at the moment. Guess weâll have to wait for everything to settle down. 
That is a really good idea. It is such a hassle to take the battery out even after a short test.
Let us know how it goes.
Finally got some time to work on this. I did test the Thornwave SSRâs and they work good as a battery disconnect switch, but I decided to scrap my original idea of controlling bi-directional SSRâs based on each batteries voltage. That was too complex and I want a simple solution.
I bought some large MOSFETs and designed an Ideal Diode/Load Switch. So far they work great but I am still testing the limits and will do some more high current testing before I am ready to build more.
Forward voltage across each MOSFETs is only ~35mV @ 40A load, and they stay cool with no heat sink. They are rated for 600A, and I am hoping for them to work at about 80A continuous with little to no heat sink needed. Each battery can be turned on/off independently, or together depending on how you want to set it up. Each battery shares the load, without allowing the higher voltage battery to feed back into the lower voltage battery.
I also made boards for these MOSFETs that act as a simple Ideal Diode (with no load switch), as well as a simple load switch (battery disconnect).
5 Likes
That looks great. If you can make them to resell, Iâd be happy to forward inquiries I get to you.
1 Like
Thanks! I was planning to do that now that I have thoroughly tested these, but it looks like the MOSFET I was using is now difficult to find. I also see some others that were not available previously are becoming available, so maybe I will make a new design. I will update here if I do that.