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Discussion Starter · #1 ·
My Metris 135 WB Cargo van with the auxiliary battery under the driver's seat will start its build in five days. While waiting, I have read a lot of the forum entries on electrics and builds. Thank you to everyone who has contributed their experiences and knowledge.

I wanted a plug & play solution so I could use it for emergencies at home when not on vacation. I looked at Bluetti, Goal Zero, EcoFlow, and Jackery in detail. I chose the brand new Jackery Explorer 1000 Pro with two 80-watt portable solar panels. Today the 1000 Pro arrived. It does recharge very quickly and very quietly. What I want to do is use the auxiliary battery to charge the 1000 Pro and/or power the DC 12-volt cooler while parked as a Plan B if the 1000 Pro ever has a problem.

The 1000 Pro can be charged via solar panels, AC 110-volt outlet, DC 12-volt plug, solar & AC, Solar & DC, or two DC 12-volt plugs. I think I need a simple battery management system to know how much auxiliary battery power is available. I also want two 12-volt ports with in-line fuses connected to the auxiliary battery. I plan on installing the plugs on the back of the driver's seat base. The 1000 Pro will be located directly behind the driver's seat. Electricity is not my strong point so I'm asking the Metris community to critique what ought to be a very simple interface between the auxiliary battery and the 1000 Pro. Am I missing anything? Any recommendations for a BMS? Share your thoughts now so I can avoid stupid mistakes.
 

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A DC/DC charger would probably be smart. I would reconsider charging from the Aux battery.

Your Jackery has a BMS built in.

You can pick if you want a DC/DC charger at 12v or somewhere higher according to the specs. People are using a Victron Orion to charge these portable generators using the solar port with a DC/DC charger with voltage set high, but within a safe range of their max spec for the port.

If you read some of the other battery threads much of them will apply to you if you decide to charge this with the alternator power. If you pick a DC/DC charge you can easily switch your AGM to a Lifepo4 under the seat some day.

If you are set on using the aux battery this way.. you don't need a "BMS". You need a low voltage cutoff like this Victron https://www.victronenergy.com/battery_protect/smart-battery-protect

I'd personally use Anderson connectors for your plugs and cords.
 

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I want to echo @pounce's comment:. People are using a Victron Orion to charge these portable generators using the solar port with a DC/DC charger with voltage set high, but within a safe range of their max spec for the port.

I don't know the spec on your Jackery, but it will charge very slowly from a 12v port so as to make solar essential in almost all conditions.
 
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Discussion Starter · #4 ·
In reply to Pounce, I know the Jackery has a BMS, but I should know the status of my auxiliary battery too. I want to know if I need to drive and recharge my auxiliary battery or if I have enough power to recharge the Jackery after several days of rain. I agree that Anderson connectors are better than what Jackery offers but I still have to use the DC8020 barrel connectors that they offer. If I change to a different battery technology in the future, won't the DC ports on the new auxiliary battery still work?

In replay to focus805, the DC 12V port is slow (10 hours) recharging but it has two DC8020 input ports so solar and auxiliary battery or two DC ports from the auxiliary battery can recharge the Jackery. I have Jackery technical support confirming the use of both DC8020 inputs can recharge the Jackery in under six hours from my auxiliary battery.

Electricity is harder for me than other aspects of my van build so again I thank you for your opinions and the education they provide. I will give everyone an update when I get my van and transition from ideas in my head to implementation.
 

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You don't need a "bms" for the agm battery. You can use that Victron item I mentioned. You must cut the current when the AGM goes low so this is the simple way.

Sure, you have to use the correct connector type at the Jackery, but you can put an Anderson jack at the seat base and an Anderson connector opposite the 8020 on the cable. Snip/splice, done.

MB doesn't want you doing this Btw.
 

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Hi again. I think I get your question now. You're going to need to have at least a fuse on your positive battery lead before the Jackery connector, be it Anderson (what I used for my solar panel to van connect). If you want to measure the current use, you could install a shunt and battery monitor on the negative side. Problem is, that won't tell you what's going on on the factory relay that charges the auxiliary battery, if that matters

I'd just install a 1 1/8 USB with voltmeter, or a real volt meter, and rely on the voltage to estimate state of charge (after some kind of fuse). As I recall, voltage and charge are pretty linear in the factory AGM battery, unlike your Jackery LiFePO4.

If this is way too basic, please take no offense.
 

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Discussion Starter · #9 ·
I have been looking at the Victron battery monitors like the BMV-702 for my auxiliary battery. I now know that I want to MONITOR my battery, not MANAGE my battery. I also think paying a professional to review my design ideas may be money well spent. The one thing that has to work is the electrical system for keeping my food cold.

The type of connectors used are determined by the cooler and the Jackery Explorer 1000 Pro. I am considering the Engel MT45 fridge/freezer which has several different optional wiring choices. The Jackery only gives me the barrel connectors.

I have to secure the Jackery while the van is traveling so any input and/or output cables won't get damaged if I slam on the brakes. The Jackery also needs ventilation to prevent overheating. It may end up directly behind the driver's seat on the floor in some sort of shallow 2 inch tall "box" with the shape of the Jackery cut into the top and a nylon strap going up over the Jackery to hold it in place.
 

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One of my battery projects is being installed as part of an official upfitter offering. Maybe that doesn't make me a professional, but I have spent a great deal of time on battery solutions for this van.

  • MB states do not have more than two batteries attached. The jackery is a 3rd.
  • You have more capacity in your jackery than the AGM battery so charging from that has the potential to destroy your AGM battery.
  • The BMV is a good product if you want a physical Guage, but the disconnect product is designed for your situation. You might consider the BMV712 and a relay.
  • You must include a cutoff circuit if you intend to charge from the aux battery. There are a number of ways to get there.
  • The AGM aux battery really doesn't charge very fast.
Wires are wires. Except for the plug at the device side everything else can change. Cut and splice without worry.

I like the Engle fridges. Good choice. If you get one consider the slide. Makes filling and accessing easy as well as securing it.

I know you won't want to hear this, but with all the gear needed to make charging from the aux battery correct it's probably easier to just get a lifefo4 battery for the drivers seat.

If you intend to leave the jackery plugged into the aux battery while driving and parked while having a fridge and whatever plugged in you have to also realize that it can drain your starter battery. That jackery has pass though charging. It won't just take its capacity if it has something attached.

At the end of the day I really do recommend an Orion and since you want a gauge and an app isn't enough add a BMV712. Charge only when the van is running or with solar.
 
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