Seeking Advice: The time Has Come -- Powering the New Van

renegadeoverland · 10-04-2019, 08:20 PM

Hey all, it is time to start powering the new van. I am starting fairly basic and want to do a quick sanity check on the plan I have in mind. Any thoughts/concerns/modifications are welcome

Main loads from the get go will be the inverter when turned on and my son's medical equipment (portable suction and Oxygen Concentrator) all at 12v loads (amperage/wattage can be provided if needed but I have the battery sizing setup for my needs and room to grow based on that data -- we also have tested this basic setup with our current van which has 300 AH of standard AGM batteries so 3 carbon foam should be more than enough -- and I am thinking of only doing 2 from the outset). The next power add will be a ARB 12v fridge but that is a bit deferred due to expense and needing to get the basic power system in place first.

due to cost, needs, and complexity, we are deferring adding solar right away but want this support designed in hence my use of the Kisae-DMT-1250 which has the ability to add solar support. I may look at adding an inverter Charger in the future in place of the small inverter but I dont see a need for that with our planned usage now so that will be a deferred expense.

I am particular interested in advice on sizing wire and fuses. I have a fairly ok understanding but additional thoughts seldom hurt.

Thanks

Scalf77 · 10-05-2019, 08:24 AM

I posted this thread a while back Reference: Rule of thumb for fusing and more This should help give you an understanding on determining loads and such for wiring and fusing. Of course the Blue Sea Circuit Wizard is a fantastic tool.
The other thing to reference is the manuals for the devices as they generally give a recommendation for wire size and fusing in their installation section. No matter what you need to make sure the fuse or breaker is sized for the wire. If you have a 70 amp fuse , the wire needs to be able to carry 70 amps. In almost all cases the size of the wire will be larger than what you expect to cover voltage drop.

You will have a lot of power in the three batteries, so you should think about fusing the output of the battery, I generally put a Class T fuse there, for their high AIC coverage. That fuse would go between battery and your bus bar

Wire's going out of the bus bar (source) needs to be fused close to the bus bar if the wire size goes down. In most cases the wire going to the bus bar will be larger than the individual wires going from the bus bar. In this case it means you need a fuse going to your ST Blade Fuse block.

A good fuse for the input of the KISAE DMT120 is a MRBF terminal fuse at the starting battery. Anything that can be dual sourced I fuse both ends. I also may fuse both ends of a wire that is long and unprotected.

I have installed about 4 KISAE units with the carbon foam batteries, and also installed one in my own rig with straight AGM. See this thread for installationhttp://www.sportsmobileforum.com/for...r-24264-2.html

I also highly recommend, a battery monitor. The Balmar SG-200 is the ticket, it will work well with the carbon foam batteries. While these batteries do well with Partial SOC, they still need to be occasionally fully charged,

Feel free to PM if you have any questions

-greg

renegadeoverland · 10-09-2019, 02:38 PM

Greg, thanks so much for the response, I will read through your links to get a feel for the fuse sizing.

A few follow up questions.

1) I was considering using the Kisae remote console (https://www.amazon.com/gp/product/B0...KIKX0DER&psc=1) that says it monitors the batteries as well, is that a sufficient monitor or would you still recommend the SG-200 as well?

2) I like terminal fuses a lot and planned on those for this application including replacing the bus bar in my drawing with a power bar able to work with terminal fuses like this to match your recommendation of a fuse per load off of that. Now to the question -- Do I need to fuse in between that bar and the output of the DMT-1250? Or is the terminal fuse (or fuse per load in general) sufficient? and in the event the answer is yes to that, the fuse there would need to be large enough to account for the summed currents of the loads branching off that bar, correct?

3) What do you mean by "Dual sourced"?

I am working on an updated drawing with these recommendations in place and a BOM for a final sanity check before I press order for anything.

Thanks for your time and for sharing your knowledge with us :-)

Neil

renegadeoverland · 10-09-2019, 04:28 PM

ok so I read through all that and the manuals for the items I intend to use, this is what I came up with. The fuse sizing rule of thumb post is impressive ... dense, and I cant promise I grok'd all of it ... but it is impressive. So here is my updated drawing

I decided to drop one of the batteries for now and see how it goes with two. That gives me roughly the same useable AH as my other van's setup. I can always add more if needed.

fuse sizes are based on manufacturers documentation. One note, Kisae recommends a 70A fuse at the battery for the DMT-1250 but I can only find 70A and 75A terminal fuses so thoughts on alternate? T-fuse for this application?

Based on the reading and everything else (my van is a 2019 Ford Transit with the battery under the driver seat) no wire run will be over 5 ft so I intend on using AWG #4 everywhere as that seems to comply with the min for everything. The question I have there is, if someone recommends a smaller wire, say a #6 or #8 is there a limitation to using the #4. It should have a higher ampacity but fused correctly my understanding that would be ok and there is no risk to overheating the wire in that case because of its higher capacity than I will be putting through it. Its been awhile since I have dealt with this theory though so as always thoughts welcome.

With all of that my BOM is as follows:

1 x Kisae DMT-1250
1 x Kisae Technology ACRM 1201 Battery Charger Remote
1 x Blue Sea Systems MRBF surface mount fuse block
1 x Blue Sea Systems Common BusBar
1 x Blue Sea Systems ST Blade ATO/ATC Fuse Block
1 x ONLINE LED STORE 12V DC 120 Amp Relay
2 x Oasis Carbon Foam Batteries
1x Blue Sea Systems MRBF Terminal fuse block
2 x 125A Blue Sea System Terminal Fuse
2 x 60A Blue Sea System Terminal Fuse
2 x 40A Blue Sea System Terminal Fuse
2 x 70A fuse (to be determined as I could not find terminal fuses in 70A)
1 x Samlex PST-300-12 inverter

As always thanks for the help and any further tweaks you see please call them out.

EDIT: Also I am not finding many options to purchase the DMT-1250 if you have a recommended place to order it please do let me know. Amazon has the DMT 1230 but not the 1250

Scalf77 · 10-11-2019, 08:43 PM

I apologies for the delay in reply.

The KISAE DMT-1250 does not monitor the battery, other than voltage and current that is being supplied from the DMT1250. That leaves a lot of holes, while many use voltage readings to determine State of Charge it can be fraught with error. A battery monitor is really the way to go. My current monitor of choice is the BALMAR SG200. There are other threads on here why I think it is the best choice. It also works well with the carbon foam batteries.

A couple of things with your drawing, you show the KISAE DMT1240 output going to input of the MRBF fuse bar. two things wrong there, normally you would run that from the battery and have a separate fuse that covers the battery to MRBF fuse3 block, It could be a terminal fuse, I generally put a class T fuse between the battery and any distribution.

You could use the now open position of (MRBF) fuse block for the KISAE, but the fuse block needs to be close to the KISAE to make this work, I normally don't go over a foot when I do this.

Now you need to look at your distribution, the STC blade fuse panel can take a maximum 125 amp fuse, generally most of us will never max out the fuse block so it is OK if you downsize accordingly. The problem you have is you are using a 60 amp terminal fuse, but downstream of the battery you have the 125 amp fuse and 40 amp fuse of inverter. More reasonable would be 125 amp from battery 80 amp on fuse and 40 on inverter, 80 + 40 = 120 which is less than the 125 amp battery fuse. The way you had it, the 60 amp from the battery would have been the limiting factor.

There is generally no problem in using larger wire, in fact most of the decision in wire size comes from voltage loss calculations. I have installed pretty much the same system in 4 Transits this summer, depending on your Transit, you might already have a 65 amp auxiliary fuse in in the seat. I have generally been just using terminal fuse, to keep my builds consistent.

You also will need to control the relay for the KISAE DMT-1250 input. There is a vehicle interface under the seat (right corner) that has low active sink, when the vehicle is in the Run State, it is pin 2 of this 8 pin connector. It is page 188 of the 2016 BEMM, this provides enough sink current for the relay, you would provide a 12 volt source for the other side of the coil. The proper thing to do would be purchase the mating connector, I generally have just tapped into using a posi-tap connector

I will try to fix up your drawing when I have a some more time.

-greg
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renegadeoverland · 10-17-2019, 11:36 AM

No Need to apologize, I really appreciate teh time you take to help sort things like this out.

Your comments about fusing make total sense, something felt off about it as I was drawing it up but I couldnt put my finger on it.

Would it be better to run a line directly from the output of the 1250 to the battery with a 60A fuse and then run a line from the battery to the distribution MBRF 3 block with the 120A fuse and only use 2 legs off the distribution for the blade fuse block and the inverter? That seems to avoid the 1ft limit you mention (though with my intended actual layout for this, being within that 1ft should be doable).

I am not sure how comfortable I am messing with the electrical system on a brand new van (and ours is the passenger van ... not sure if that makes a difference or not as I was reading in the manual you referenced and it seems to talk about up-fitting et c and I dont know if they changed anything in the cargo vans for up-fitters or if passenger vans had the same setups) so I might forgo the solenoid for now and just put a manual cutoff switch in (something like this). I am going to order the solenoid and talk to my local shop and see if they are familiar with wiring it in without messing anything up but both options will be on hand.

I feel like I have a good handle on the items I will need and will likely get those ordered today and will continue to converse here to finalize the wiring itself to be sure I dont miss anything else.

Thanks again
Neil

EDIT:

Here is an updated picture to address a few of your comments and what I had in mind based on my question of running a line from the 1250 to the battery ... I will be addingin the SG200 as well but I didnt add it to the drawing

Scalf77 · 10-20-2019, 07:45 AM

Here are a couple of diagrams for your layout, one is where I would use the MRBF Block as a output fuse for the KISAE. The other one I added an additional MIDI fuse because the MRBF is located to far away.

I hope this helps explain it better.

-greg

Twoxentrix · 10-20-2019, 09:11 AM

i know it happens a lot on this forum, and my education continues to broaden as I read threads like this - Very encouraging to see members partner in a build as you two have. Commendable & inspiring Scalf77.

SierraHawk · 03-10-2020, 08:49 PM

Time to replace batteries. Just wandered into this discussion and saw renegade's entries. I would also like to thank Greg. He has helped a lot of us along the way.