E450 engine battery wet on top- overcharging?

miataroadster

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I am about to install a new alternator and solar charger for my portable power station when I noticed that the chassis battery is a little bit wet on top. I did some voltage checking....

14.19v........at rest, solar power connected
13.94v........after 30 mins solar power
disconnected

With solar off, the voltage has not changed when connected to shore power with converter off, still 13.94v.

With solar on or off, it went to up to 14.46v when connected to shorepower with converter on.

14.63v while engine on, solar on/off. This one is normal, yeah?

1. could it be that my solar charging system is overcharging the engine battery to get constant reading 14.19v during day time? The controller will only stop/trickle when the house batteries are charged.

Is there a way to disconnect the chassis battery from coach battery via breaker/s while solar charging is happening?(see attached pic of breaker nextvto chassis battery)

2. Maybe I'm just over thinking this. Since while driving, the car alternator will keep the voltage at 14.6 anyway. Or will it diminish after some driving time? I couldn't tell, it was only on idle for 15-20 mins.

3. Maybe the tiny spill was caused by me driving the mh up the curb to access my front yard parking space. Curb is about 7" high, and parking at an incline. Battery water looks OK, but I better check again when level.
 

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Splashed water is a possibility.

You might do a simple test to see if it's puddle water or electrolyte. Put some baking soda on the liquid and if it produces a foaming reaction it's electrolyte. Electrolyte will react vigorously. If only very minor reaction.

FWIW. It's not unusual to see 14v on a battery. My truck will charge at 14.2 for a while after starting. Later it drops to 13.8 or less as battery is fully charged.
 
I did not know about that trick, thank you, TitanMike! Good I have some baking soda in the fridge.

Good to know about voltage dropping after driving awhile.

What is weird is that my kids' car batteries have wet tops, too. Well, those batteries are 4-5 yo.

I will test and report.
 
Did the baking soda test- very little bubbling, but yes, electrolytes! Ugh!

I will clean it up and monitor it for any signs of wetting.

So is there a way to disable the solar charging the engine battery? I mean, could use my portable charger if needed.
 
Could your BIRD relay be stuck engaged? Depending on your RV, the BIRD should disconnect from charging the chassis battery once it is fully charged. I would guess you solar is coneected to your house battery and only connected to your chassis battery via the BIRD/Realy.
 
Did you check the house battery voltage while on shore power ?. That's what the converter is charging.

Have you tried another meter ? Voltages all seem high. A full charged battery will read 12.7 volts at rest, after the surface charge is gone.
 
It is not uncommon for the normal accumulation of acid salts on top of a battery to condensate moisture from the atmosphere. Just wash it off with a solution of baking soda and water, taking care to NOT get any inside the battery. While you are at it, remove the cables and clean the battery posts and wire terminals. Make sure they are installed fully down on the post and tight.

Bob
 
Could your BIRD relay be stuck engaged? Depending on your RV, the BIRD should disconnect from charging the chassis battery once it is fully charged. I would guess you solar is coneected to your house battery and only connected to your chassis battery via the BIRD/Realy.
I have no idea what BIRD is, but I'll Google it.
 
Did you check the house battery voltage while on shore power ?. That's what the converter is charging.

Have you tried another meter ? Voltages all seem high. A full charged battery will read 12.7 volts at rest, after the surface charge is gone.
No, I did not check house lithium batteries. I did notice like 40a then creeping down to lower amps at a quick glance after turning on converter. The FL chassis battery was charging too.

I haven't tried another volt meter. I will check again with a different one.
 
It is not uncommon for the normal accumulation of acid salts on top of a battery to condensate moisture from the atmosphere. Just wash it off with a solution of baking soda and water, taking care to NOT get any inside the battery. While you are at it, remove the cables and clean the battery posts and wire terminals. Make sure they are installed fully down on the post and tight.

Bob
Yes, top cleaned and sprayed red stuff on posts for corrosion prevention. I just need to recheck battery water level to see if I need to add more.
 
I have had wet battery tops before. Once from being overfilled and another time it was the post to case lost it's seal.
 
Did you install Lithium batteries and a lithium converter ?

If you did but didn't address the higher charging voltages of those peices, you will be overcharging your chassis battery. There is a system for the house battery to maintain the chassis battery that works fine if all batteries are the same but yours no longer are. I dont know what year your rig is but you need to look for a B.I.R.D or a BIM160 or BIM225. That will need to be replaced with a lithium compatable model.

Why are you replacing your alternator ?
 
Did you install Lithium batteries and a lithium converter ?

If you did but didn't address the higher charging voltages of those peices, you will be overcharging your chassis battery. There is a system for the house battery to maintain the chassis battery that works fine if all batteries are the same but yours no longer are. I dont know what year your rig is but you need to look for a B.I.R.D or a BIM160 or BIM225. That will need to be replaced with a lithium compatable model.

Why are you replacing your alternator ?
About 15 months ago I upgraded to lithium batteries. My converter does FL/Li. I selected lithium charging in my converter.

Rig is 2023.

Ok. I'll be checking BIRD. I'm hoping for easy replacing.

Sorry, it was confusing when I said alternator charger. I am installing a DC to DC Mppt battery charger(eTaker2000), similar to Bluetti Charger1. I will connect it to engine battery.
 
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If installing the DC to DC charger, you will be disconnecting the BIM anyway, it won't work with it together.
That leaves your chassis battery with no sorce of charging but that can be fixed with a 120 volt battery maintainer . Connect it to the chassis batteries and a non-inverter powered outlet.
 
Solar and shore power connected- both lithium house batteries and chassis battery charging at almost the same rate 14.5v according to my battery monitor(house) and voltmeter(chassis).

All batteries getting charged when engine is running.

I have BIM160. So if I just want to disable connection between the batteries, how do I do that? Yeah, I don't mind putting the chassis battery on trickle charger.

Another option- could I just put the converter charging type back to FL? Slow charging the LIPO4 is fine with me. My updated solar array I think will do a fine job when not connected to shore power.


Attached are my BIM pictures.
 

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Pretty simple, remover the small ground wire and tape it up. It can't work with a ground. Be sure it's open when you disable it, it's a latching relay.
Shore power off, engine off, no solar and it should be un-latched.
 
double check the BIM is deactivated after you remove the wire

use a multi meter on OHMS setting
to see if the battery A and Battery B terminals on the BIM are connected

If they are still connected ... remove the 2 small signal wires repeat test
or remove one of the battery cables
in any of the above ...tape OFF the ends of the signal and battery wires as they can short out if they touch something they shouldn't
 
Aussieguy,
It looks like I can pick up the rv from shop later today.

Checking for ohms- do I stick one probe to Battery A and then one probe to Battery B? What reading should I get? Sorry, I usually only use volt or amp with my meter.

IF still connected, "Remove 2 small signal wires"- are those the red(IGN) and brown(SIG) wires next to white(gnd)? So basically remove all 3 wires?
 
Battery A and then one probe to Battery B?
set meter to OHMs (looks like a horseshoe)
on a digital meter you want to see UL <----- GOOD

if the meter reads 0.000 (no resistance) <------ Bad that indicates the batteries are still connected

--------------------------------------------
meter with needle and scale
needle should not move... <---good

------------------------------------------------
if you disconnect the smaller wires you stop the BIM getting signal

if you disconnect the A or B battery removes the possibility of a fault in the BIM accidentally turning on
 

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