Dead house batteries

[Cmftblynumb]

I have searched the forum for this issue but have been unable to solve my problem to this point so I am going to once again ask for advice. I had the dreaded DEF head failure with the derate to 5mph and had to be towed to Freightliner in Orlando. They did not have enough pedestals to plug our coach in while it was there for 3 weeks being repaired. When I picked it up the house batteries were dead so I incorrectly thought running the generator while driving back to the campground then plugging into the 50amp would eventually start the recharge process. Left it plugged in overnight and no change all still dead. I put a battery charger on the house batteries but to this point (3 hours in) very little difference started at 2.7v now at 3.4v. My question is are the batteries more than likely never going to come back and have to be replaced or would they likely eventually charge back up? It is 8 - 6 volt batteries that are 14 months old. Thanks

[TheRod]

Hi Steve,
I'm certainly no expert on batteries, but I have had good success in reviving batteries over the years using the repair function of my charger. If your charger does not have a repair function, find a good one that repairs deep cycle batteries, it will be a good investment either way, whether successful or not. NOCO is the brand I use. You may try repairing one battery at a time.

[Tizbad]

Your on board charger will not charge the house batteries when they are that low. The easiest way to get them up high enough for the charger to take over would be to use the Battery Boost switch. This is like jumping the house batteries from your car or truck. Instead of just holding the switch for a while, depress it and then wedge a toothpick on the side of the switch to hold it down. This joins (bridges) your chassis batteries to the house batteries. You can see the voltage on both the house and chassis batteries on your SilverLeaf panel.

[Jon_C]

Being 6v and only 14 months old are working in your favor. Golf carts run them down on regular basis.

I would charge each individually for up to 24 hrs and check specific gravity, they may still be ok. Check water levels first.

[RVStitchy]

Can't really give you a solution other than some hope. I have had a couple instances where I ran good batteries completely dead (not in an RV). I took the batteries to my local battery sales/service company and they put them on a different type of charger. Took 3 days but they brought them back to life.

[Cmftblynumb]

The Silver Leaf is dead as well, my understanding is that on the 2016 the booster switch does not impact the house batteries, could be wrong but that was my interpretation from the dealer this morning. I guess I am down to trying to charge them independently one at a time. I am sure I could have done something else while it was at Freightliner but this is a real kick in the teeth after just dealing with the pain in the neck DEF head issue. It still blows my mind that Freightliner has no way to keep coaches plugged in at their lot, I understand motor homes are not their primary business but dang.

[Persistent]

Lead acid batteries left in a fully discharged state for 3 months are likely dead.
Lead acid batteries fully recharged after a week of discharge are likely still serviceable by normal recharging processes. Being discharged for 3 weeks is in between. The bank probably has a heavy layer of hardened sulfate crystals.

It may be recovered using special equipment. See this link for a field test of two devices.
https://www.motortrend.com/how-to/im...-fact-fiction/

Recovery may take longer than you have patients for.

[pasdad1]

How many amps is the separate battery charger you are trying? If it’s a 6-10 amp unit, this will take a very long time. See if you can get your hands on something at least 25 amps or higher.

Once you can get the voltage to something in the 10v range, the coach charger should recognize them, and begin charging.

Your coach charger can probably charge at 100-120 amps like mine does, and then the process will go faster.

Are these flooded wet cell batteries or AGM ?

[twinboat]

Your boost switch is nothing more then a jumper between the house and chassis battery.

If it don't work, borrow some heavy jumper cables. You need to get your house bank up to 12 volts so that the inverter/charger will sense that batteries are installed.

Plug it in, so the inverter/charger is ready and start the engine. If no charge to the house bank, connect the jumper cables.
Your isolation/bridging solenoid is probable bad, very common.

[Jon_C]

Originally Posted by Cmftblynumb

The Silver Leaf is dead as well, my understanding is that on the 2016 the booster switch does not impact the house batteries, could be wrong but that was my interpretation from the dealer this morning. I guess I am down to trying to charge them independently one at a time. I am sure I could have done something else while it was at Freightliner but this is a real kick in the teeth after just dealing with the pain in the neck DEF head issue. It still blows my mind that Freightliner has no way to keep coaches plugged in at their lot, I understand motor homes are not their primary business but dang.

Hopefully they held some charge and weren’t dead for the entire 3 weeks.

JMHO but if normal charging for 24 hrs doesn’t bring them back ( need to test under load to be sure) I would replace. But you’ve got nothing to lose by trying.

[Tizbad]

Originally Posted by Cmftblynumb

The Silver Leaf is dead as well, my understanding is that on the 2016 the booster switch does not impact the house batteries, could be wrong but that was my interpretation from the dealer this morning. I guess I am down to trying to charge them independently one at a time. I am sure I could have done something else while it was at Freightliner but this is a real kick in the teeth after just dealing with the pain in the neck DEF head issue. It still blows my mind that Freightliner has no way to keep coaches plugged in at their lot, I understand motor homes are not their primary business but dang.

SilverLeaf will remain dead until some life resumes with the house batteries via the boost switch, charging or jumping. Your boost switch does join the two banks together unless the bridge solenoid has died.

[Rev. Roy]

I hate to state the obvious but, since they are lead acid batteries, I hope you checked the water level. This is something we used to do back in my doing auto repair work years. I have a 12/24 v jump pack that I attached to a buddy's DP once and it worked to get his on board charging system started. I originally bought the jump pack for starting semis and farm equipment now I wouldn't travel without it. I am curious why it took 3 weeks.

[Cmftblynumb]

Attached is a picture of the charger and batteries. At this point I have tried charging in place hooked up as well as taken out one by one and I do not see any hope in them getting enough charge to kick in the coaches charging. As for why 3 weeks it was a DEF head sensor replacement, Freightliner was very uncommunicative during the repair process. It was towed to them on 1-03, I was given expected repair dates of 1-11, 1-13, 1-17, 1-19 and finally picked it up on 1-24. Just felt like I was at their mercy, I understand many owners have gone through the misery of the DEF head failure which is frustrating enough with the 5mph derate, but then to not have any way to keep a coach charged just seems like a brutal system. I am sure not everyone that goes through this ends up with an additional $5k in replacement batteries so interested to know what I could have done differently at Freightliner. The information that I have gathered from this forum has been very helpful to a motorhome owner learning on the go and it is much appreciated. The memories of our 5 month trip out west to Silverton, CO, Coulter Bay and West Glacier were priceless but it seems as though karma is now kicking us in the tail for having such a good time.

[twinboat]

Charger is hooked to one 6 volt battery, that won't work.

Move the black cable clamp out to the outer terminal, closer to the charger.

That gets you 12 volts and all batteries.