Victron Energy: Alternator/Solar Charging - LFP Battery System

[shade]

After more fruitless research for specifics about the BMS 12/200, I decided I'm going to go ahead and use one so I can move forward with my project. If/when Victron releases a more desirable DC-DC charger, I can integrate it into the system, and still rely on the 12/200 for its charge splitting function.

 

[Alloy]

Yeah I am working on labels, there are 3 circuit breakers with disconnect switches built in....
Ford batteries to Buck Boost DC-DC charger 60A
Solar controler to pos bus 30A
BatteryProtect (after pos bus bar) to Aux Fuse box 30A

Chassis ground from Shunt/neg bus bar gotta add that one, thanks

I was thinking if a disconnect for the Lithium battery and protecting the feed to the Bluesea distribution panel

 

[luthj]

As far as heating goes, you can do some rough math based on the box surface area, mass/specific heat, insulation (if any), and ambient temps. That will let you determine heating needs. I prefer a well distributed heating system of at least 25W per 100AH of batteries. This lets you warm the pack up quickly after a heat soak, so that you can start charging it. Spread over 1 square foot, 90W is pretty low heat wise. You can bond that directly to the side of the pack. Ideally you would have one 45W pad on each of the larger sides. You need a good thermostat. Ideally one with a backup, such as a thermostatic disc switch (like in microwaves etc). Have that one kick off at say 110F, just as an emergency backup in case the heaters get stuck on.

 

[Alloy]

As far as heating goes, you can do some rough math based on the box surface area, mass/specific heat, insulation (if any), and ambient temps. That will let you determine heating needs. I prefer a well distributed heating system of at least 25W per 100AH of batteries. This lets you warm the pack up quickly after a heat soak, so that you can start charging it. Spread over 1 square foot, 90W is pretty low heat wise. You can bond that directly to the side of the pack. Ideally you would have one 45W pad on each of the larger sides. You need a good thermostat. Ideally one with a backup, such as a thermostatic disc switch (like in microwaves etc). Have that one kick off at say 110F, just as an emergency backup in case the heaters get stuck on.

I went back and forth with one of the silicon heating manufactures. The location of the thermostat (inside /outside air temp and/or battery temp) was an issue as was the wattage needed at 34F vs 10F.

 

[luthj]

My suggestion would be to use an external thermostat like this one.

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That gives you control over where the temp is sensed.

There really isn't much concern of overheating if your wattage per square foot is reasonable. For reference the sun at peak intensity is about 130W per square foot.

 

[SBDuller]

After more fruitless research for specifics about the BMS 12/200, I decided I'm going to go ahead and use one so I can move forward with my project. If/when Victron releases a more desirable DC-DC charger, I can integrate it into the system, and still rely on the 12/200 for its charge splitting function.

View attachment 541522

..cool! why does the BP220A fit?

 

[shade]

..cool! why does the BP220A fit?

I'm not sure what you're asking. I decided to use BP220s since it's possible for the total charge & loads to exceed a BP100, but not a BP220. I doubt it'll be over 100A either way, but it's possible, so spending a little more money for the higher capacity parts makes sense.

 

[SBDuller]

I'm not sure what you're asking. I decided to use BP220s since it's possible for the total charge & loads to exceed a BP100, but not a BP220. I doubt it'll be over 100A either way, but it's possible, so spending a little more money for the higher capacity parts makes sense.

OK, thats what I wanted to know.

 

[dreadlocks]

sorry guys I was out adventuring last weekend and getting ready for a big trip coming up soon, guess I'll rework my diagram.. that diagram is not 100% as I sit today, its what I've been working towards slowly.. all this crap is expensive heh, am about 90% there.. today I have just one BP for loads only, charge sources are hooked up to battery side so I never ran any current backwards through it.. tho I didnt know I couldn't, was just treating it like a normal relay.. oops.

no big deal to flip em around and change a bit of wiring.

 

[Alloy]

I'm not sure what you're asking. I decided to use BP220s since it's possible for the total charge & loads to exceed a BP100, but not a BP220. I doubt it'll be over 100A either way, but it's possible, so spending a little more money for the higher capacity parts makes sense.

I found out....if a 200amp (or 130A) alternator is connected to Port AB on a BMS12/200 it will limit the current to 80 amps.

 

[shade]

sorry guys I was out adventuring last weekend and getting ready for a big trip coming up soon, guess I'll rework my diagram.. that diagram is not 100% as I sit today, its what I've been working towards slowly.. all this crap is expensive heh, am about 90% there.. today I have just one BP for loads only, charge sources are hooked up to battery side so I never ran any current backwards through it.. tho I didnt know I couldn't, was just treating it like a normal relay.. oops.

no big deal to flip em around and change a bit of wiring.

For the most part, your system relies on solar charging, and you can control that pretty well through the Victron programming anyway. If I had that level of control of alternator charging, I'd be less concerned about automating the charge disconnect side, but I don't see a Balmar alternator in my future.

 

[shade]

I found out....if a 200amp (or 130A) alternator is connected to Port AB on a BMS12/200 it will limit the current to 80 amps.

Yep, with a 100A fuse in place, that's what can be delivered through a BMS 12/200 on that side. With a larger battery capacity and higher real world alternator output to utilize, I might skip the 12/200, but I think it's a good fit for what I want to do.

With my system, it's possible I could have 80A plus whatever solar charging is pumping into the battery, and that would be close enough to the limit of a 100A BatteryProtect that I'll step up to the 220A model.

 

[shade]

Good news, I think. The order status on the 160Ah Victron LFP battery kept showing as "processing", so I contacted Northern Arizona Wind & Sun to see if there was a delay, or if the battery was no longer available. Looks like it arrived at a friend's shop on Monday, so I may have one of the last of that capacity that's available. I should be able to pick it up tomorrow.

I haven't had a day off in a few weeks, so I haven't made any progress on a detailed schematic. With a trip planned in a month and I plan to pick up a 330W panel then, meaning I won't have it available for use. With the battery on hand, I'm going to do a partial installation with a 100W panel and a Victron charge controller, which should provide enough power to get the battery through a four day backpacking trip while I'm away from the truck at the Grand Canyon. I'll probably wait to install the alternator charging side until I have time to do it right, and test everything before hitting the road.

 

[shade]

Any suggestions for a 120V mains charger?

I'd like something flexible enough to take care of LA and LFP chemistries so I can also use it for maintenance charging LA start batteries. I'm not concerned about high amp output or "starting" modes. Victron has a 15A model that would work, but it has limited controls, and I'm open to other options.

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[dreadlocks]

The biggest that comes is 15A, which is not enough IMO.. I'm going for a ProNautic 1240p if Victron dont release something w/more umph before then.. you could go for the 1260p if you want to flex that LFP more.

I'm looking forward to charging from an EV spot in the PNW when they wont give me any sunshine..