58 replies to this topic

[Vic Harder]

Your explanation helped. I think my system is doing what it can but 4 days rain and canoes on has just squeezed the rocks dry. My battery did come back a bit on the drive with the camper main knob off. The alternator though good 140 amp is controlled by the truck computer and does not seem to put the juice through the separator .... maybe it is throttled.
The series option is out. I like to keep it as simple as possible. Weather and canoes on top did me in. Sun this afternoon should help.
Vic having s second battery would solve the lack of energy over time. We use mostly the isotherm small fridge and led lights, charge iPhone and iPad. I did revive that LiFePo4 DIY battery and will consider finding a place for it. Just 30 lbs more. Put the two in parallel.
Sounds nuts I know (the truck hood is hot ) but having the flex mounted on the hood would be a great solution to canoe on roof. Maybe a curved mount on canoes hull!!
Light canoes stay on roof when popping up.
IMG_0785.jpg

adding the 2nd battery will sure help when the sun doesn't co-operate.  Takes a long time to recharge two big batteries though!

[Vic Harder]

Great detail I need to know. Thanks Lars. To expand my capacity for four days of rain I am thinking of adding my newly reborn DIY LiFePo4 battery in parallel. I have a good BMS but need to know if it is okay to do this with a Battleborn (in parallel)... does the BMS of the dyi need to match the specs in the Battleborn? Any possible snafus?

Agreed, great detail! I'm curious about this question too.... two different BMS's.... I would guess no issue, but.... would love to here rando's input!

[rando]

There shouldn't be an issue with DIY battery in parallel, even with a different BMS.   

 

In an ideal world, the BMS never has to do anything because the charge parameters are all within the BMS limits and the cells are balanced. 

[buckland]

A footnote and question. I did find a few loose solder on a few cells on my dyi. Since then it sits at 13.3 or 13.4 daily so I have decided to add it to the camper. I have been making a new battery box for it and have the Renogy 1000 W inverter (to charge the ebike battery) in a cubby beneath the battery box (with vent holes).
As I will be putting these two batteries (Battleborn) in parallel I thought I would dedicate the Dyi battery as the charging one. So I believe I need a switch to keep both in parallel to solar charge but a switch that separates them for use of the inverter. Does anyone suggest a switch that would be a simple mechanical “both or one’?

[Wandering Sagebrush]

Rob,  marine battery switches may be an option for you.  Our boat switch has Off, Battery 1, Battery 2, and Both positions.

[buckland]

Thanks I’ll try poking around marine online shops. Much obliged.

[Wandering Sagebrush]

https://www.westmari...d-disc--3831393

[craig333]

I have a slightly different version in my camper and my Jeep.

[buckland]

That switch looks robust and will fit in the battery box. This is probably a simple question (dumb)....
I have two batteries in parallel which most the time will remain as one. 200 amp unit. I want to run the inverter only off one when needed to charge ebike. For this purpose I’d run extra positive leads to the switch IN posts from each battery and a positive lead from the inverter to the OUT.
Does the inverter negative then go to the battery I dedicated for inverter?

[Vic Harder]

the ground (-ve) of the system remains common to all batteries/systems.

 

Still wondering why you want to do this... are you wanting to ensure you don't drain the "reserve" battery?  I can't see an e-bike charger doing that.