Blue Sea 7610, 7620, or Victron Orion to replace Sure Power?

[BrianW]

The time has come to replace the original Sure Power 1315 separator on my 2011 E250 5.4 with something newer. House battery bank is three AGM Group 31 batteries for about 300ah. No solar.

I've read most, if not all, of the excellent threads about separators, etc. I was going to move to the Blue Sea 7610 to keep things simple (and cheaper), but now I'm wondering if I should spend a bit more and get a DC-DC charger like the Victron. Most of the threads related to the Victron seem to be related to lithium batteries, and don't pertain to my use case. I'm also considering the Blue Sea 7620 to get the start boost switch, but not sure the extra $100+ is worth it for that.

So, is the Victron worth the extra $$ for my simple setup? And does the Victron also work to isolate the house and van systems, too, like the Sure Power does? We do often rely on alternator charging rather than plugging in when on road trips, so that's what has me thinking of the Victron. But in 13+ years of owning SMBs I've never really had charging issues even with the archaic Sure Power, but maybe I don't know what I'm missing! :-)

From photos online, to use the Victron it looks like I'd need to cut off the eye lugs on my current cables and just insert them into the Victron's screw-terminals, but those terminals look awfully small to fit the thicker-gauge power cables. I'm surprised they made them so small...

[1der]

The Victron Orions or most any DC to DC unit will provide single direction isolation and single direction charging.

Bi-direction charging is when solar is charging the house and you also want the chassis battery to receive charge - a few do this but not robustly.

All DC to DC have current limiting thresholds. This will be the most surprising difference from what you have now. Imagine how long it will take to charge your AGM's at 30 amps or 50 amps per hour even though more is available from your alternator.

On the good side, the DC to DC chargers are nice in the ability to multi stage charge your house bank.

If all you need is an isolator then the Blue Sea units are solid.

[Scalf77]

So a couple of questions first? Do you have Starcool or do you drive with any high current loads while driving such as water heater . something off of the inverter?

How large is your alternator?


My first inclination if staying with AGM, is to just go with the 7620. While I like the 7610, it does have some limitations the continuous current rating is 120 amps, and that rating is when using 1/0 gauge wire. The larger wire will limit some heat transfer to the FET in the 7610, which is the limited factor. Take that and not having the features of the 7620, it is worth the extra money.

Now, about the Victron DC to DC. I like Victron equipment, I am not a big fan of their DC to DC charger. They have one size, it is passively cooled. To get real performance you generally have to add your own cooling solution, otherwise it will be in derated mode. So the size of the cable input is because it is a 30 amp unit. There will be no charging of starter batteries while charging house with shore or solar, with out some other modifications. Note: there are some Dc to DC's that address this , but not Victron. You can run an additional units in parallel to increase output.

While the DC to DC will turn your alternator into a 3 stage charger, which I would say is normally a good thing. It is possible that you will most likely see a decrease in charging performance (over ACR solution). The other issue, is with AGM batteries the absorption stage is usually longer than Lithium. If you have large loads running you will probably never get out of absorption because you won't reach the tail current setting (current to high). This is not the end of the world, but it takes a little juice out of being a 3 stage charger.

[BrianW]

Thanks for the thoughts! No high current loads on the house side while driving (Starcool, heater, etc.). Usually just the frig. Standard Ford alternator as far as I know. Sounds like a DC-DC unit isn’t really necessary for my use. I guess I’ll spring the extra $$ for the better Blue Sea unit.

[BrianW]

Also, one other question: should I install the Blue Sea inside the van or in the engine compartment? SMB installed my current Sure Power under the gaucho next to the batteries/inverter ("installed" is a generous term; it was laying on the floor and the power cables were unprotected where they attached to the isolator lugs). On my previous van the isolator was in the engine bay, which of course has its downsides too. Is there any benefit to having the unit closer to the main van battery or the house battery?

[boywonder]

Originally Posted by BrianW

On my previous van the isolator was in the engine bay, which of course has its downsides too. Is there any benefit to having the unit closer to the main van battery or the house battery?

No real difference, although I like them inside to stay clean and shiny.

The Orion max cable size is 6 AWG.

.....What's been said above pretty much covers it. Two downsides of the Orion are:

Limited to 30A per unit......although with lithiums your alternator will thank you. That's why it's happy with 6 AWG.

It's not bi-directional.....so if your solar is connected to the house batteries than you won't be charging the starter battery without some creative wiring.

well...as mentioned maybe a third downside......they get hotter than a pistol when running.....

If you are married to AGMs get a Blue Sea separator.......if you are moving to a Lithium some time in the future the Orion is a good choice, or some other DC-DC converter. The AGMs don't mind the dumb 14V charging of the alternator; Lithiums not so much....and as you mentioned smart charging an AGM isn't a bad thing.

One other thing that the Blue Sea 762X gives you is simple and easy combining of the batteries. I have a big red battery combiner switch that shorts across the Orion for combining batteries in the event the starter battery is dead, and it works but I have to use my phone/bluetooth to disable/turn off the victron before combining.

[BrianW]

THANKS! @boywonder @Scalff77 @1der -- Blue Sea 7622 ordered (it was actually cheaper than the 7620 on Amazon). Should be installing it on Wednesday, hopefully.

[Scalf77]

you can get a good price on the 7622 on amazon of all places That is better than what I can do with my business discount at some other places.

[BrianW]

Originally Posted by Scalf77

you can get a good price on the 7622 on amazon of all places That is better than what I can do with my business discount at some other places.

That’s where I got it. $190 with Prime next day delivery [emoji106]

[BrianW]

I got the Blue Sea 7622 and installed it today in replacement of my SurePower unit. I have a few follow-up questions if anyone can help (paging @Scalf77). For anyone else contemplating this, there are several very good threads here on the forum with related info, in particular this thread. And Scalf77 has posted a useful PDF guide, too.

I haven't found answers to these few questions, though (see green circles I added to Greg's schematic, attached):

1. Both Greg's PDF schematics and the Blue Sea directions show fuses on positive battery cables from the van battery to the separator and from the separator to the house battery. My SMB does not currently have fuses on either of these cables, and I guess I should add them for safety. The Question: can they be a resettable circuit breaker and not a fuse? If a circuit breaker, how many amps should they be? Guess I need a few more cables, too. Sigh. Gotta love SMB wiring...

2. When adding the remote switch, does the power wire going to pins 8 and 3 on the switch have to come from the house battery, or can I use any hot 12v feed (most likely from the starting battery)? The house batteries are back under my gaucho over the passenger rear wheel, as is the isolator, and I plan to put the switch somewhere on the dash. I'd rather not run that hot wire all the way from the back of the van if I don't have to.

Thanks!