Of grid camper. small solar/large battery?

Hi, I have a VW T3 (vanagon) 4x4 with a high top. I fitted 150w of solar on top and can’t fit more. I want to build a lithium battery possibly 280ah on a solar split charge system. I have the Renogy 50A DC-DC with MPPT. I want to know what BMS to go for? Also I would like to monitor my AH capacity. Mainly I only use 12v but may add an inverter later. Just further to add how fragile is lithium with my van being 4x4 should I go for AGM.

Thanks for any advise

I have 280Ah in my RV trailer that sees a lot of rough dirt roads (BLM and Forest Service). No problems. Compression of the cells is necessary!

I'm using the Overkill Solar 4s 120 amp BMS. You can get Ah remaining from the BMS app. But it's not something you can quickly see from a real battery monitoring system, like the Victron BMV-712 that has a wall mount display.

I'm not a fan of the Renogy DC-DC/MPPT product, but if you're looking for something to save space with, that may be a good solution instead of separate devices, one for DC-DC and one for MPPT.

Hi thanks for your reply. How much solar do you have with the 280ah battery? and will it last a few days? I don’t use much power 12v fridge and TV on a night. I don’t want to buy a battery that is too small or one that is to big for my needs

Your loads are going to be different from my loads. I have a toy hauler and it's "optimized" for long term outings. My refrigerator is propane/120v AC, and it runs on propane almost all the time. I have no TV in the trailer. I pulled it out not long after I bought the trailer. I have an inverter but it's only 1000 watts. Just enough to run the coffee maker and recharge laptops and phones. To run the microwave or air conditioning I have to fire up the on-board generator.

I have 560Ah of LiFePO4 battery capacity. Two 4s 280Ah batteries. With the 640 watts of solar on the roof, I can go for at least 10 days in decent weather. I say 10 days only because that's the longest I've been out. The black/gray tanks get a little full about that time. My limitation is the amount of vacation time I have available and the holding tanks. Once I retire and get a portable holding tank I could stay in one spot for a very long time.

Once the temperatures drop below 32° F, I put out my 640 watts of portable panels to supplement the roof panels. I use battery power like there is no end. I leave the lights on, make coffee, warm up water, leave the stereo on, etc.

Your setup is on a far bigger scale than mine. You would not be able to fit all that equipment in my van not if you wanted to get in it

Masher_T said:

Your setup is on a far bigger scale than mine. You would not be able to fit all that equipment in my van not if you wanted to get in it

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LOL! I have it crammed into a space that was not in use. You have to design for the space you have. Sometimes a good amount of creativity can get you more space than you think you had available.

Masher_T said:

Hi, I have a VW T3 (vanagon) 4x4 with a high top. I fitted 150w of solar on top and can’t fit more. I want to build a lithium battery possibly 280ah on a solar split charge system. I have the Renogy 50A DC-DC with MPPT. I want to know what BMS to go for? Also I would like to monitor my AH capacity. Mainly I only use 12v but may add an inverter later. Just further to add how fragile is lithium with my van being 4x4 should I go for AGM.

Thanks for any advise

Click to expand...

You may have to augment your charging abilities with a small gas generator, or get used to idling your engine alot.

Your power use and setup are not dissimilar to what Im doing.
Honda odyssey.
National luna 60l fridge freezer.
Fans, lg projector tv, etc..
Redarc 50a dc dc charger.
2 golf cart 6v batteries 205ah
Soon mounting 2 100w hqst panels.
Soon ditching the lead acid for lifepo 272 min. More likely 2x 272 @12v.
I use a harbor freight predator 2000 genny with a 25a charger now. Great genny for the price.
I want the huge battery capacity because come summer I want to run a portable AC in the van, its 6.5a 120AC continuous. Gonna convert it to dual hose operation so it actually cools the space.
I would expect with 2 272 ah banks it could run up to 6 hours. Its a very small portable, the predator 2000 handles its surge current easily and its one of those where you can shut it off in fan only mode and restart same, so you dont get compressor AND fan motor surge current at the same time.

HRTKD said:

I have 280Ah in my RV trailer that sees a lot of rough dirt roads (BLM and Forest Service). No problems. Compression of the cells is necessary!

I'm using the Overkill Solar 4s 120 amp BMS. You can get Ah remaining from the BMS app. But it's not something you can quickly see from a real battery monitoring system, like the Victron BMV-712 that has a wall mount display.

I'm not a fan of the Renogy DC-DC/MPPT product, but if you're looking for something to save space with, that may be a good solution instead of separate devices, one for DC-DC and one for MPPT.

Click to expand...

So youre using the overkill 12v 120a everyone is recommending...on a 12v 8 cell system? Or two of them? If the prior, doesnt that leave it only monitoring half the cells?
Does the 120a capacity have additional headroom for surge? Pretty sure my AC thru an inverter will exceed that on compressor startup.
Ive been thinking Id have to divide my 8 cells into 2 parallel banks with 2 BMS, 2 boxes, etc.

Batvette said:

So youre using the overkill 12v 120a everyone is recommending...on a 12v 8 cell system? Or two of them? If the prior, doesnt that leave it only monitoring half the cells?
Does the 120a capacity have additional headroom for surge? Pretty sure my AC thru an inverter will exceed that on compressor startup.
Ive been thinking Id have to divide my 8 cells into 2 parallel banks with 2 BMS, 2 boxes, etc.

Click to expand...

I have two 4s batteries, each with their own BMS. That gives me 240 amps of throughput. I haven't tried running air conditioning off my batteries. My 1000 watt inverter isn't large enough. I did try a 1500 watt space heater, just for giggles. The inverter went into overload mode after about 10 seconds.

Lol, i have a pretty old, compact 1500w ceramic heater. My $40 walmart 700w inverter will run it on low. Im in san diego coastal area where we consider 42 degrees a very chilly night so can live without it.