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My camper-truck mounted system (for off grid living and running MTB events)

Stupid Monkey

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Dec 14, 2019
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So I thought I'd do a thread to document everything.

I live in the camper Feb/March to Oct/November while I'm working on site, well usually, not this year with CV19 lockdown and no events / mass gatherings.

The camper/RV/truck is a 1995 Mercedes 814, 8m/26ft long and for last year I had 2 x 315w JA solar panels on there into a 12v 30A MPPT/Battery to Battery charger combined and that was awesome. However i needed the generator for my oven/microwave and also wanted to get a dishwasher and washing machine installed.

After much research Wills vids, along with this forum gave me the confidence to buy some cells from China (AliExpress / BLS)at Christmas and hoped to get it all up and running much earlier than now (and it still isnt)

The BLS cells arrived in a timely manner, 6 weeks, and were well packaged and looked "new" and were all the same voltage. With a mind to "do it right" i set the 24 x 150AH into 1 parallel bank and began charging / top balancing them with a 10A charger ....

There is a thread here https://diysolarforum.com/threads/top-balancing-dilemma.4613/ about that, but the long and short is it was going to take too long and then to speed up the process I configured them into a 12v setup but then blew up the charger ........
 

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After the 2 weeks of trickle charging everything went quiet for a bit, then I rushed to get them installed into the camper before setting off middle of feb for work, with the intention of carrying on with the install/commissioning of the new system.

That didnt happen, was too busy building MTB trails by day and doing event admin by night.

However I had got them installed and secured ready to wire up, as well as adding another 250L water tank under the seating area (now 700L / 185 US Gallon in total) and another MPPT and a Giandel PSW inverter to replace my Sterling modified sine wave one.
 

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However this setup with them stacked upright was not good for adding my huge bus-bars, so last week I re-did the battery box for them to sit in a normal orientation (terminals up) and also added some VHB tape to secure them to each other. Now the bus bars fit well.

All boxed in over the 6P4S setup (12v) ... BMS temporarily in place, connected and now I'm sat here while it charges at 30A from a mains charger (running off my old batteries), could still be a while!

However despite not doing a bench top-balance, what I have done and given that they were supposed to be new matched cells anyway the BMS is giving the same voltage for all 4 portions of the battery, well +/- 0.001v and I'm at 3.378v per bank while charging, did take them off charge for 30mins and check the voltage and that was 3.351v for all 4 sections.

I haven't decided if to just use it once charged/top balanced, or if to keep on the FLA for a little longer while i do a capacity test. with only a 100A BMS for now I cant do a 0.2C capacity test in 5 hours, that would require 180A load I do have a "capacity tester" with a 200w load, so thats like 60 hours. I may do that which will also then serve to compare the BMS shunt/capacity meter with my external shunt/display and the capacity tester which all should match - and if not hopefully at least 2 will agree.
 

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Once up and running I'll move the inverter to take power without going through the BMS so i can run all my loads, and in this good weather and with such a large capacity bank I should be able to manually make sure cells don't go under voltage.

I don't know if I'll be able to run events this year, but if I do then the timing/PA and the fridges for the bar and coffee machine will all hopefully run on the setup.

Next weekend should have been the first test 2/3rd May for my first of 3 big MTB events, have a look at last years video to see what I do if your intereested.


Maybe I'll need a second inverter (for surge loads of multiple fridges), or more panels, or even more cells to run the events, but with 3 big events (7 in total) planned for 2020 the aim was to try and see, and if not revert to the generator, and then upgrade before the next event so by the end of the year the system would be sorted.

I plan to get a @Chargery BMS so I can do more than 100A loads, although I've been running 2kw loads off the lead acids when the sun has been out and giving me 70A from the 3 panels .... and I've 3 more to fit too as part of the upgrade :)
 
Wow .... That's a LOT of capacity for an RV. Hope your solar can keep them charged.
 
Wow .... That's a LOT of capacity for an RV. Hope your solar can keep them charged.
I want to run a weekend mountain bike event off it even if its a dull day.
And the cost of cells = 2 x battle born's so I kinda look at the extra 450% of capacity as free ;)

And when i'm living it electric oven/kettle etc - I'll have over 6 kwhrs a day of harvest with 6 panels, I been getting 4.6/4.7 with 3 panels in this last week.
 
24 hours into the capacity test ..... all cell banks are still well matched in voltages. Looking good for these BLS cells.
 

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Awesome! Thanks for documenting. I’ll be following this to see progress, and to check out your adventures!
 
to update my experience .....

This battery setup has made a massive difference to my (full time) van life. Struggling for solar this time of year but the cells have been great, delivering the expected capacity all year.
Ran a MTB event off the system in September.

Got a Victron inverter/charger on the way as my 30A charger on a 900Ah pack take too long to charge from a generator, will now have 80A + the 30A charger for the genny to charge faster when I'm back in a forest in a week or so.
 
Not having everything through the BMS has been fine - low volt disconnect on the inverter works well enough - DC power and charging via the BMS not been a problem.
The new inverter/charger wont use the BMS either, even for charging, I'll just set voltage to 13.5v, but still leave the 30A charger through the BMS and at 13.8 or something.
I may even move the MPPT's to bypass the BMS ran most of summer charging to 13.6 as there was no need to go higher.

BMS just there to balance and cut off the DC power when needed. Battery bank temps fine in summer or winter - can manage without low temp disconnect.
 
Well my inverter cut off is 12v and bottom balance is good, however the new inverter can also take a feed from BMS - so in first year with brand new cells the risk I took as minimal. Always planned to upgrade the BMS, but for now its not needed and I cant pick the right one without it being a daft budget. Although i have looked at getting 6x100A cheap chinese ones and making the pack into 6 batteries rather than 1.
 
The LVD on the inverter wont protect the cells if you have one cell go low though will it?
....... or if 1 cell goes high when charging as we have seen happen several times on other threads.
 
....... or if 1 cell goes high when charging as we have seen happen several times on other threads.
charging is via BMS

And no, it wont, but checked it all summer when it was hardly under 50% - and gave it a bottom balance test in late September before there was that risk. No doubt over time, but the system isnt "finished"

Finances been especially rough this year - what upgrades i did was a big investment, and then as an event organiser - been massively hit by Covid. Not like I'm not around to monitor it as its my life really.

Its only now with mains power I have properly been able to investigate what I suspected in the summer on the lack of balancing with an extended period plugged into a smart charger and spending most of the day at whatever voltage i set
 
charging is via BMS

And no, it wont, but checked it all summer when it was hardly under 50% - and gave it a bottom balance test in late September before there was that risk. No doubt over time, but the system isnt "finished"

Finances been especially rough this year - what upgrades i did was a big investment, and then as an event organiser - been massively hit by Covid. Not like I'm not around to monitor it as its my life really.

Its only now with mains power I have properly been able to investigate what I suspected in the summer on the lack of balancing with an extended period plugged into a smart charger and spending most of the day at whatever voltage i set
Ahhh ..... missed that part. I would have been more worried about the charge cycle than the load, but you probably have DC loads in addition to the inverter, and those won't shut off on their own,
 
There are some pretty inexpensive low voltage cutoff devices that would probably handle your DC loads ..... Something like this one ..... even cheaper ones are available.

 
Yeah, DC side through 100A BMS, and charging.
Just the inverter is not through BMS - as 100A BMS and inverter pulls almost 200A loads
 
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