OBI Dweller Review and Discussion

[irishgrey]

I can't tell from your pictures, but it doesn't look like series wiring, from what I can tell. Series would mean the cabling was connected plus to minus and plus to minus at the batteries. It would also mean that instead of a 12 volt output at the inverter, with three batteries, you would have a 36 volt output as the voltages would add up.

To assure a more even power draw over a group of batteries in parallel, you would connect all the negative posts together and all the positive posts together. Then connect the feed wires with one at one end of the group on a negative post, and another at the other end of the group on a positive post. This would hold all batteries at the same level of charge and the voltage delivered would be 12 volts. Of course, the voltage is not exactly 12, but 12 is the category. The real measured voltage would be somewhere between 14.4 and about 12.5, depending on the load and charge rate, etc.

Series wiring adds the voltages. Three 12 volt batteries would deliver 36 volts (actually more like 42, as again, "12 volts" is a category, not an absolute number). Parallel wiring adds the amperages together. Three 100 Amp Hour batteries would deliver 300 AH at 12 volts.

Adjust your charging voltage with lithium batteries to not exceed 14.4 volts

copy ... thanks for clarifying raspy...

 

[irishgrey]

D13 Team... I just did the lithium battery upgrade... took out the big lead acid and replaced with 3 Li-Time 100ah.

• did the inverter settings
• installed the batteries using same wiring etc
• hooked to power, all 3 batteries fully charged everything working.

The original wiring has all 3 batteries wired separately all joining at the inverter ... I assume this is called a "Series" set up ?

I have turned everything on that could be turned on and only 1 battery ( batt no 2 ) is showing as being used... the other two batteries ( no 1 & no 3 ) are not showing any drain...

Is this because it's in Series so Batt no 2 will drain then batt 1 or 3 will kick in next ?

I've attached images of the Li Time app showing the 3 batteries , I numbered them 1 , 2, 3... bat no two is the first one on the set up to show drain...

Is my thinking correct ? If the system has charged all 3 batteries and only 1 is showing drain on the app then its a Series setup and the others kick in once the first battery ( no.2 ) is drained ?

Update on this, I've had everything turned on for 24 hours, battery number 2 ( the first to show a draw ) drained to 25% then battery no 3 kicked in, battery 2 & 3 are now showing a draw... battery no 1 still hasnt kicked in and still showing no draw... maybe it will start drawing when battery no 3 gets to 25% also...

All 3 batteries where 99% charged and awake when I installed them... everything I can turn on including a starlink has been running since 3pm PT yesterday as you can see by the li time BMS screen shots battery 1 still on standby..

 

[landy66]

Is there any chance your batteries are getting down to about 35* F and shutting down?

No - the batteries are not 'shut down' so to speak .. (and it's not that cold where I am currently) ... as the bluetooth/bms is active on all three and I can switch the app to see what's going on in each one ... also I have victron smart shunts on each battery and can see that only one out of the three is under load.... and when that one depletes .. load moves to the next one ... and so on... it's either fancy BMS stuff or.. more likely the way the three batteries are wired up ... pulling + and - from the battery nearest the inverter... as opposed to spanning the entire bank (as you mentioned above) ....

 

[irishgrey]

No - the batteries are not 'shut down' so to speak .. (and it's not that cold where I am currently) ... as the bluetooth/bms is active on all three and I can switch the app to see what's going on in each one ... also I have victron smart shunts on each battery and can see that only one out of the three is under load.... and when that one depletes .. load moves to the next one ... and so on... it's either fancy BMS stuff or.. more likely the way the three batteries are wired up ... pulling + and - from the battery nearest the inverter... as opposed to spanning the entire bank (as you mentioned above) ....

same same here Andy.. I've did a 24 hour test, turned everything on, only one battery ( of 3 ) is showing a draw, when it discharges to 25% it moves to the next battery I've emailed Litime will let you know what their reply is.

 

[Raspy]

No - the batteries are not 'shut down' so to speak .. (and it's not that cold where I am currently) ... as the bluetooth/bms is active on all three and I can switch the app to see what's going on in each one ... also I have victron smart shunts on each battery and can see that only one out of the three is under load.... and when that one depletes .. load moves to the next one ... and so on... it's either fancy BMS stuff or.. more likely the way the three batteries are wired up ... pulling + and - from the battery nearest the inverter... as opposed to spanning the entire bank (as you mentioned above) ....

I'm curious about this. And the parallel wiring should be as I described with the plus cable at one end of the group and the minus cable on the other end of the group. This assures even charging and discharging. There may be some other issue, so please keep us updated.

 

[Josh00333]

That's interesting they charge and batteries all seem to be working together.

Any reason we cant add one larger lith battery in the space? I've not looked or measured, but would we be able to get a 400 amp hr in there?

 

[irishgrey]

Team, I contacted Li-Time support to get answers on why the batteries ( all four of them ) were not drawing power equally.

Copy and pasted their answers below FYI.



Jan 19th reply from Li-Time…
Thanks for reaching out LiTime. If you connect the batteries in parallel, it is possible that the APP shows one battery discharged and the other 100% standby. This is a parallel bias current phenomenon, which is normal. Did you create a 4P1S system in the APP?


Jan 20th reply.
Thanks for your reply. When designing the LiTime Bluetooth battery, we focused on enhancing its ability to handle system surges by improving and balancing the BMS current collection accuracy and sampling range.

And finally, this allows our battery to accurately collect high currents of 500A or more, as well as currents as low as 1A.
When multiple batteries are connected to one battery system, the discharge current for each battery will be distributed according to the internal resistance of each battery. If the system is discharged at a lower current, it may affect the accuracy of the State of Charge (SOC) display for batteries discharged below 1A. And this does not impact the actual capacity or functioning of the system.


Two tips for improving the accuracy:

① Add loads to the system to increase the system discharge current;
Or ② Fully charge and discharge the battery system for one cycle to refresh and recalculate the State of Charge (SOC).

Thanks for your understanding and support. Have a nice day.

 

[Spencurai]

That's interesting they charge and batteries all seem to be working together.

Any reason we cant add one larger lith battery in the space? I've not looked or measured, but would we be able to get a 400 amp hr in there?

I replaced my lead with one 300AH Lifepo. It works GREAT. I did have to run all three cables to the terminals as using just one 16mm cable is not enough amp rating. I will come up with a cleaner solution later but having just one battery is way better.

 

[landy66]

it's actually possible to run them down so low that they start beeping and there's not even enough volts for the renogy inverter/charger to come on, so for these situations, I have the litime 14.6v 20a charger permanently attached to the first battery, so i can quickly plug that into my propane generator and breathe life back into the system ... otherwise jump-starting them can be a bit tricky.

 

[landy66]

I replaced my lead with one 300AH Lifepo. It works GREAT. I did have to run all three cables to the terminals as using just one 16mm cable is not enough amp rating. I will come up with a cleaner solution later but having just one battery is way better.

Are you using different size batteries in parallel? eg 300,100,100 ? I was wondering if that's ok to do ....

 

[BruderMaximus]

On mine, the caulking separates from the shower wall and not the Thetford toilet. I did replace the caulking with tape but it is separating from the walls too, even after first prepping the site with alcohol. I suppose to get tape or caulking to stick, the shower wall will need to be lightly sanded for adherence.

Try using home construction ZIP SYSTEMS tape. Not sure if you can find it in white. There are also window dealing tape builders use for installing windows.. watch some Matt Risingers Build Show youtube videos.. there's a solution in there. I've had to caulk my D15 string the toilet base to floor.

 

[BruderMaximus]

what the heck is 'fingernail polish'? What aisle at Home Depot?

Fingernail Polish... come on.. @ Home depot, it's in the paint section... you want the fingernail polish in the Rustoleum Can... the only rust proof fingernail polish to use.

 

[BruderMaximus]

Question: has anyone pulled the outside speakers? Is there a trick or are they just crazy glue - siliconed in there?

I took the ones inside out. There are 4 screws under the plastic bezel (that is siliconed down) so after you peel off the silicone, expect 4 screws as well.

 

[BruderMaximus]

I guess I'm confused. I set the wall panel AC/Heat switch to heat. Put heat at 60, fan was on 3, temp in trailer was in the 40's. Nothing came on. I tried this several times over a few days. Is there a switch under the bed? My propane was on the whole time as we cooked regularly outside. If you can't get heat without shore power then this is not much of an offroad/offgrid camper.

were you using the Truma Combib on propane (always have the water pump on when running the Truma propane) to make sure there is always water in the unit. For the electric AC / Heater. That only works on shore power as the plug it's plugged into is shore power fed only. You could try extension cording it to one of the inverter/battery fed outlets but, unless you've got 600ah LiPO batteries, you'll get an hour out of the 3 AGMs that come with it.

 

[BruderMaximus]

Yes, it was a bit of a mess. My Triangle branded tire blew out on the way to a camping trip in Big Sur California. I had to make temporary repairs at the campsite.

Interesting, never heard of Triangle tires. Mine came with Kendas which are supposed to be good.