Battleborn? and or advice

[mcfarty]

Have a swift shell model that came with the Blue Sea 7611 and has a deep cycle battery in there.... Looking to upgrade the battery without having to get too involved in all new parts.

Hoping to run the stock furnace and a 12v 28l Dometic fridge off of this with little to no issues for overnight/multi day use during fall/winters. May get a battery blanket.

Will just keeping the Blue Sea ACR 7611 work fine with the 100ah Battleborn battery? Likely to add solar in the future as well.

Any experience in upgrading the battery to Lithium but keeping with the stock ACR?

Thanks!

 

[DiploStrat]

Have a swift shell model that came with the Blue Sea 7611 and has a deep cycle battery in there.... Looking to upgrade the battery without having to get too involved in all new parts.

Hoping to run the stock furnace and a 12v 28l Dometic fridge off of this with little to no issues for overnight/multi day use during fall/winters. May get a battery blanket.

Will just keeping the Blue Sea ACR 7611 work fine with the 100ah Battleborn battery? Likely to add solar in the future as well.

Any experience in upgrading the battery to Lithium but keeping with the stock ACR?

Thanks!

Short answer on the Blue Sea ACR is "probably not." The ACR connect voltage is something like 13.6v and that is very close to the rest/float voltage of lithium iron batteries. LiFEp04 batteries tend to hold at their rest voltage rather than dropping back the to "full" voltage of lead acid battery, 12.7v. The ACR opens at 12.7v. The result is that the ACR probably won't ever disconnect the batteries until it is
too late.

Also, lithium iron batteries tend to be near black holes for amps when deeply discharged, possibly posing a threat to your alternator. (At the exotic end, there is some viewing-with-alarm that if the BMS disconnects the battery it may damage the alternator/regulator. A battery to battery obviates this danger.)

Better "plug 'n play" option would be to replace the ACR with your choice of battery to battery chargers - l like the toys from Sterling Power and REDARC. (Each has its own plusses and minuses.)

 

[john61ct]

Vote here for Sterling, BB series.

How many Ah was the old one and was that enough for you?

 

[Rando]

First, I would look further than the Battle Born for the lithium battery, they are overpriced for what they are (and they do some seriously dodgy marketing). The most Ah/$ would be the DIY route, but it takes some work. The second cheapest would be most of the other drop in LiFePO4 packs, there are some out there that are approaching $500 /100Ah.

As for the isolator, DiploStrat is right the 'standard' isolators are designed for lead acid voltages and will be less effective with lithium. Your cheapest option would be an ignition triggered relay under the hood, beyond that you can look at lithium specific isolators (Victron Cyrix-Li) or a DC-DC charger. Victron makes a good DC-DC charger, particularly if you also think you may want a battery monitor or solar in the future as they will integrate well.

That being said, if you have solar, and park outside, you can just use the stock 7611 isolator, that is what I do most of the time. Don't believe the hype that you *need* a DC-DC charger. You may end up wanting one either to boost or to limit the charge current, but you don't necessarily need one. Try just swapping in a lithium battery first and see what happens.

 

[john61ct]

OP needs to clarify what energy sources are used.

An IGN solenoid works if the alternator is the only source, but then "see what happens" could mean having to replace both the solenoid and the alternator or at least getting it rebuilt, new diodes etc.

For that source, a DC-DC really is the only way to go.

If mains charger & solar only, then so long as they are close to the bank and setpoint-adjustable,

then yes, no DC-DC needed.

But if you have one, then you can save a lot on the other two, any old "close enough" profile will do, let the DC-DC handle it.

 

[Rando]

"see what happens" actually means seeing what is happening. If his battery draws 100A (it is not going to) and the alternator starts to overheat, then the OP needs to stop and consider another approach.

However, if the setup is like the 'standard' FWC install, then there is about 25' of 10AWG wire and two 30A breakers in the loop, there is no danger of burning up a solenoid or alternator. In this case you may want a DC-DC charger to increase the charge current.

 

[john61ct]

Well of course a depleted LFP battery over 100Ah will draw far more than 100A if that is available.

Putting dangerously sub par thin wiring in between it and a source is no way to regulate current, and while CP will prevent fires / melting of course they also put a stop to charging.

40A would be plenty for a little bank like that, but I have no idea which stock vehicles' alts are designed to output that continuously.

The point of the DCDC is not only to reduce the amps pulled by the bank, but to ensure a correct and steady voltage is maintained at the desired setpoint, whether the current fluctuates or not.