fusing both batt w charging relay what issues to expect?

[blueh20]

I am running3-100w renolgy solar panels on top of my 2014 ford E250 van which go to a 40 amp renolgy commander controller then to a 255 ah lifeline batt.

Also have a Blue Sea systems charging relay ml-acr connected between house batt and starter batt with 2/0 wire pos and neg, 15' each way.
The house batt is the main batt and starter batt is aux.

Running a blue sea 100amp fuse panel(fused with 30amp breaker) for led lights, arb fridge and a flojet that pulls 7.5 amps max. All wiring is complete loops back to panel.

Theoretically my Blue sea charging relay is suppose to let the "house" battery start the vehicle in case the "starter" battery goes dead. Havnt tried it yet.

I just put a 150 amp marine type fuse on each positive battery post in case my 2/0 positive wire"between batteries" ever grounds out on the frame, my alternator puts out about 80-100 amps.
I am just about ready to start the vehicle up with the new fuses in place, what to expect?

I assume though if the house battery ever did try to start the vehicle with those fuses in place that the cranking amps would blow both fuses immedietally, is this correct????

if so is their anyway to have the house battery start the vehicle while still having some kind of " frame shorting" protection ?


thanks for your input.

[MEXICOWANDERER]

I have seen failures of parallel charge relays that PREVENTS FOREVER amperes from flowing by switch from priority HOUSE BATTERIES to chassis batteries. The engine start battery is drained and unless you take the time to manually connect cables together you is screwed. Jumping is rather a pain in the A$S on a crowded two lane highway, the middle of an intersection or straddling railroad tracks. The cure is to replace the relay. Then make the engine starting battery (chassis) the priority battery. Nothing in the way between the alternator and engine starting battery.

Wire a commercial fishing trawler where the main engines are isolated from the battery and before you know it you'll have a stout Danforth anchor chained to your ankles.

[landyacht318]

You said you ran 2awg cables, plural, under the van. That makes me think instead of attaching the lifeline - terminal to nearby frame as many would do, you ran a black cable all the way to engine battery, physically in parallel wth the red cable?

If so, I approve as frame grounds seem to become problematic all too soon.

Your blue seas relay is a fine unit, my only issue with it is that when either battery sees charging current, from any source, it will combine the battery banks. Sounds fine and dandy, but if the solar is holding the lifeline above the voltage setpoint of the Blue seas ACR. then the engine battery will be sucking up some of the solar wattage, rather than all of it feeding the depleted lifeline house battery. The engine battery might not require being held at these higher voltages and could be overcharged. it depends on whether you also slightly cycle the engine starting battery, which do not really like being cycled.

Your stated loads are quite small. Your system is quite overbuilt if your loads are not going to increase rather dramatically, or if you go days on end with no solar input.

As far as the 51 amps minimum, that is when the battery is regularly depleted to the 50% or below range. Lifeline batteries basically have no upper amperage limit, they can handle whatever, as long as the voltage does not get too high( 14.4v at 77F). A 8d lifeline at 50% state of charge can likely accept well over 200 amps for at least 20 minutes before the voltage at the battery terminals rises to 14.4v, so do not fear overamping this battery. Overvolting might be a brief possibility with the alternator's voltage regulator but really i do not know what fords do in this regard.


IF you were trying to max out the alternator contribution to depleted lifeline, you could either move the 2awg cable from engine battery to + alternator output stud, and the - to an alternator mounting bracket. This has the advantage of being able to eliminate one of the fuses. Fuses are supposed to be close to the battery terminal, and the original alternator charge cable to engine battery is likely already fused, so you do not need one in between alternator and ACR, but you do need one between ACR and Lifeline if you choose to move the cables.

If you choose to NOT run the 2awg cables to alternator, then the original alternator to engine battery charging circuit now will have to pass the charging current for the lifeline, and it was not intended to do this. It is likely much tinner than 2awg. So you can add another cable between alternator (+) output stud and the engine battery to remove this bottle neck.

If you have grounded the lifeline to the engine battery, the original engine to engine battery ground is going to also carry the lifeline carging current, and it too is likely undersized for the extra 50 amp load, and will cause a resistive electrical bottle neck, slowing down charging. You can do the same, either add another parallel cable, or replace the original cable with a thicker one, or both if you really want to go crazy.

But with the loads you have stated I think the extra maximizing of charge current steps are not needed. With the ACR being bidirectional, the solar will be recharging the engine battery, so self jumpstarting is extremely unlikely to ever be required. If it is, do as recommended previously. Press the manual connect, wait a minute or longer for the lifeline to feed/charge the depleted engine battery, and it is very unlikely the 140 amp fuse would blow when starting the engine.

Lifeline has a very good manual on what their batteries would like to maximize their performance and longevity.

http://lifelinebatteries.com/wp-content/uploads/2015/12/6-0101-Rev-E-Lifeline-Technical-Manual.pdf

Rolls surrette also have a very well written manual that can help a Newb to lead acid battery living understand what batteries require to perform well and last a long time.

http://rollsbattery.com/public/docs/user_manual/Rolls_Battery_Manual.pdf

If you were to say, add a microwave and a 2KW inverter to power it and nuke 3 meals a day, then you would want to maximize alternator contribution and perhaps even run engine and microwave at same time, but the ARB fridge, and some USB ports are not going to put much of a dent in the 8d lifeline.

Read the Lifeline and rolls manuals more than once, slowly.

[red31]

MEXICOWANDERER wrote:
The priority battery should be direct and the aux battery charged by the relay.

sorry blue I thought there was a main and aux, there is not. If either is being charged above 13v then the batteries combine.

NOTES: Stud terminals A and B are interchangeable. Either battery bank can be connected to A or B.
If the ACR is to be used for cross connect, fuses between ACR terminals A and B and each battery
positive are not required according to ABYC guidelines. If the ACR is not used for cross connect,
install fuses to prevent a hazard if there is damage to the wires connecting the batteries to the ACR.
The fuses should be placed as close as possible to the batteries so that most of the wire is protected.

[LittleBill]

blueh20 wrote:
mexicowanderer, this acr has a 10sec. rating of 2000 amps, cranking 1 minute of 750amps.
I think the priority battery that the original owner set this up to be is the house battery, to keep the arb fridge going on cloudy days.

"NEVER put any component in the way of having the prime starter battery getting charged."

I am not sure whats in the way of the prime battery getting charged, the house battery doesnt draw off the start batt if the house batt drops under 13v.

blue you need to ignore his comment, they are based on isolator's, this is not an isolator, there is no main/aux on these like i told you, whatever side hits 13v first connects the relay, similar to what mex is saying with the ford relay.

[blueh20]

seems as though I am making a mountain out of a mole hill, have to take some (lots)time and re read all this info, thanks folks for sharing. I really appreciate it.

[blueh20]

mexicowanderer, this acr has a 10sec. rating of 2000 amps, cranking 1 minute of 750amps.
I think the priority battery that the original owner set this up to be is the house battery, to keep the arb fridge going on cloudy days.

"NEVER put any component in the way of having the prime starter battery getting charged."

I am not sure whats in the way of the prime battery getting charged, the house battery doesnt draw off the start batt if the house batt drops under 13v.

[LittleBill]

read what i wrote, it only benefits you, your relay is rated 500A continuous.

your loads are practically nothing, there is no concern for your alternator, again, most rv's have this same design built in, people have you concerned over an alternator for no reason

[blueh20]

Not only can I turn the relay off I also put a disconnect switch right at my house battery which is 10" from the relay and two feet from the battery..
So maybe I ought to just leave the two systems separated all the time so as to not stress out my alternator/regulator and that way I can figure out if the solar is up to the task of keeping house appliances going on its own, I only have:

led lights=1amp draw
dual usb charger= says "fast charge 4.8amp"
arb fridge=says 1.5 amps per hour(which is average rating)
adding flojet water pump=says 7.5 amps at full pressure, which will have very slight intermittent use.

and then only use the ACR if I ever get a dead starter battery? if this is the case it doesnt seem worth it to have those 2/0 battery cables all stretched through the frame and worrying about it shorting out or destroying the alt..thoughts

[MEXICOWANDERER]

The priority battery should be direct and the aux battery charged by the relay.

Relays have ratings. The 200 amp models can see 300 amps for cranking purposes.

But a parallel Ford starter relay is max rated for eight hundred amperes and they take the strain off the charge relay.

NEVER put any component in the way of having the prime starter battery getting charged.

[LittleBill]

like i said it bi direction, either side can charge either side

if the car is running, the alternator is charging, when the starter battery gets over 13v it connects the house battery, then the alternator charges the house battery

if the car is off, the solar/generator/shore power charges the house battery, when it gets to 13v to connects the starter battery and charges that battery


your making a big deal out of the relay for no reason, you should be in auto mode 99% of the time.

let it do its job and forget about it, there is a led on the relay itself that shows what mode it is in, if you care

leave it alone in my opinion it only benefits you.

this is no different then a isolator which is standard in rv's, with the added benefit this unit will charge the starter battery, isolator's don't

your alternator will be fine, if you still don't want it, i'll be more then happy to pay for shipping to my house for it 🙂

[blueh20]

thanks littlebill for getting back to me and for the link. Electronic manuals are very hard for my brain to understand, wiring diagrams no problem, but I am trying.

So when does alternator charging come into play with this relay?

Is the "main purpose" of this relay to allow the alternator to help charge the house battery on cloudy days while driving?

This relay is getting to be a big deal in my head, i am almost thinking I should get rid of it and let the solar system be a free standing system on its own, get rid of the battery cables connecting batteries together etc.?

especially if the house battery will only give a "try or two" to help the starter battery, doesnt seem like all these mental issues I have with battery cables connected, to much pressure for my altenator/regulator to handle, thoughts of fuses blowing is worth it? thoughts?

I have not set the van up for shore power yet and dont know if I should/would.
thanks

[LittleBill]

blueh20 wrote:
littlebill,

"when the voltage drops under 13v the banks disconnect, in this case using the override switch will allow the relay to connect the banks and start the motor",

I think I am starting to get the picture,
So if the starter battery is under 13v,(lets say I left the lights on), the charging relay will disconnect the house/starter battery from each other so as to not drain the house battery ?correct?

Then, unbeknownst to me when I try to start the van the battery is dead" but also disconnected from the house battery by the relay" because the start batt went under 13v? correct?

Then i go into the back of my van and do the override switch, let the batteries co mingle for 15 minutes or so, then turn the overide switch back OFF and start the van OR leave the override switch ON?

thanks

most of this is correct if you don't factor another charge source like solar, most people leave solar connected 24/7 so if the loads are low enough on the house battery to get it over 13v then it will connect the starter battery, if the solar is powerful enough it may even be able to keep up with the headlights and still charge the starter battery.

this all needs to be tested,

the override technique is correct, 15 minutes should get you enough power, if it doesn't , wait another 15 minutes after overriding and keep the switch in place, if you blow the fuses, you blow the fuses, i don't expect it to happen, but if this is something that commonly becomes a issue, you can replace the fuses with a circuit breaker.

to be honest that kind of load is only going to give you a couple attempts before the house battery is depleted as well..

[LittleBill]

blueh20 wrote:
littlebill, thanks for chiming in, I just learned ALOT about my charging relay in your post. And hope you can teach me some more.

"realistically you should never have a dead starter battery, that said if you do, i would recommend waiting a minute or so in override before attempting the start"

But how would I know I had a dead starter battery before I turned the key on and tried to start the engine.
Does the relay automatically/instantly send power from the house battery to the start battery if needed, or does it require a manual switching?

"in this case using the override switch will allow the relay to connect the banks and start the motor".

What position would I turn the over ride switch too? Does that "override" switching include pushing the button "down"?

In using the over ride switch, would I just let the batteries coexist for 15 minutes or so, then turn the switch off so to disconnect the two batteries before starting so I dont blow my 150 amp fuses? OR try and start the vehicle while they are both bonded together?
thanks

its pretty straight forward your manual is below

Clicky

long story short if the voltage is above 13v, either from the alternator or solar or generator or shore power they are connected.

in your first question of dead starter you have to ask yourself a couple questions, is the solar working are you on shore power? are you above 13v,if so the starter battery is connected to the solar/ shore power,

if your not doing solar/shore power etc and the voltage is below 13v, then the banks are not connected, thus it would just be the starter battery trying to start the engine.

even if the voltage was over 13v at the time you tried to start, the second you tried to start the voltage would easily drop under the 13v and disconnect the house battery, fuses can take a bit to blow depending on if they are slow blow etc.

i don't personally own this relay, but looking at the red switch that comes with it, "on" connects the battery's for as long as its in on position regardless of voltage, off is a permanent disconnect regardless of voltage, and auto works off voltage per side, (according to the manual after selecting off or on, auto takes 10 minutes to renable itself)

hope that helps

[blueh20]

littlebill,

"when the voltage drops under 13v the banks disconnect, in this case using the override switch will allow the relay to connect the banks and start the motor",

I think I am starting to get the picture,
So if the starter battery is under 13v,(lets say I left the lights on), the charging relay will disconnect the house/starter battery from each other so as to not drain the house battery ?correct?

Then, unbeknownst to me when I try to start the van the battery is dead" but also disconnected from the house battery by the relay" because the start batt went under 13v? correct?

Then i go into the back of my van and do the override switch, let the batteries co mingle for 15 minutes or so, then turn the overide switch back OFF and start the van OR leave the override switch ON?

thanks