33 replies to this topic

[rando]

I don't think that would be an issue, as long as your charge sources will switch on without seeing the battery voltage on their output. 

[Jack]

rando, how are you limiting charge current to 0.1C? Is this a capability of your BMS or some other device?

[rando]

I have a 160W solar panel and a 150Ah battery.      I would be very happy if I were to get my charge rate up to 0.1C, particularly in the winter  .     

 

That aside, you do have the ability to set the maximum charge current using the Victron MPPT chargers, so you could set a limit there.

[Jack]

Thanks rando. The reasons to get a Victron MPPT just keep adding up. I've got the 100/30. Really cold temperatures are not very common in the PNW, but they can get get down to -20' C / 0' F or so, especially east of the Cascades. If the battery goes below 1'C I can disable the DC-DC and run only solar down to -10' C. Charging/discharging should also warm the battery, and once we are on the road, the propane heater can keep the camper warm and the battery above 1'C. I really want to avoid the complexity of a battery heater. I've just swapped the stock 160 W Zamp with 3 x HQST 100 W flexible. Mounted with velcro and with tape on the leading edge - simple, quick and no holes. And now my wife can lift the roof

[rando]

Which battery do you have?  Battle born shuts off charge if the battery goes below 0C anyway, so there is nothing that needs to be done on the users end. 

[rando]

Also, on this topic, it is pretty disappointing to see Battleborn post this 'study' that is complete biased from the outset to make AGM batteries look bad:

https://battlebornba...te-paper-study/

 

Read the comments below the article to see how they had a large thumb on the scale for these tests.

 

While I am very satisfied with my LiFePO4 batteries, and strongly believe this chemistry will rapidly replace lead acid in most situations, seeing a bunch of marketing bollocks dressed up as some sort of scientific study from the market leader is disappointing.

[Jack]

rando, I have a DIY 280 Ah (thanks to you) with the Xiaoxiang BMS, so I can control pretty much everything.

[makalutoo]

That is quite the white paper. The comments were enlightening and while i’m no expert my BS alarm went on right away.
11amp hour out of a 210ah battery at room temperature?!? I think that is what they got until the battery dropped to 12.2 volts, but what did the resting voltage of the battery come back up to when they stopped pulling 80 amps off of it?

Their claims that gam batteries are basically worthless have been disproven in the field by millions. Sure, lithium is a superior battery in a ton of different ways but AGM’s still work.

Thanks for posting this rando. It was definitely an interesting read.

[rando]

rando, I have a DIY 280 Ah (thanks to you) with the Xiaoxiang BMS, so I can control pretty much everything.

 

My memory is clearly failing me!  

 

In which case, I would start with setting your charging low temperature limit to something very conservative like 3C and see how things go.  If you have troubles keeping the batteries charged, you can lower the limit, but you will likely be fine.  

[makalutoo]

Battleborne batteries have released their internally heated batteries. Look like they have a slightly different setup then some of the other options.

https://battlebornba...ed-battery-kit/