House batteries completely dead .. whats the best way to charge

97windsor · 10-14-2010, 07:52 AM

Hi My coach has sat at a dealer for 6 weeks waiting on parts and repairs (blowout, air bag, fenderwell and rear flap) and the house batteries are completely dead. I know running them completely dead is bad for them and want to recharge them the best way. The batteries were new early spring 2010. What is the best way to recharge them?
I am picking the coach up tomorrow and wonder, should I run the generator and rely on the invertor/charger to charge them, or just let the alternator from the engine recharge them on the way home? It will be driven about 1 1/2 hour home then I will plug in to shore power.
If I do let the alternator charge them will it tax the alternator and do any damage to it? I'm sure it would be charging at full output the entire drive home. Thanks in advance

Rex · 10-14-2010, 08:22 AM

You are correct about the alternator being over taxed in charging the batteries if they are flat. You need to measure the voltage on each and if they are below or near 5 volts, they are most likely toast and will need to be replaced.

I would start the generator before starting the engine, and run it at least an hour, then shut it down and check the battery voltage again. If they have not come up, as I said they are toast and should be replaced. If they do come up to 6 volts or near that or above they may be OK. At that voltage, you may be OK using the alternator. If you do, the batteries should be fully charged by the time you get home using the alternator.

Mike Canter · 10-14-2010, 01:14 PM

Make the guy that worked on it and forgot to disconnect the batteries plug it in and let it charge up slowly overnight. Once he has charged them overnight then the alternator can take over on the drive home. If the batteries are fairly new and the plates are not oxidized then they can survive going down to zero volts as long as they don't freeze.

gripper · 10-14-2010, 01:23 PM

OK, someone educate me here. I could have sworn that I was told, when I purchased my DP, that the house batteries are charged by the generator and/or the inverter only. That the alternator will only charge the chasis or engine batteries? Inquiring minds want to know.

Mike Canter · 10-14-2010, 01:28 PM

Can't tell you for sure that all MHs charge the batteries from the alternator while driving but my previous MH and my current MH do charge the house batteries while driving.

GaryKD · 10-14-2010, 01:53 PM

Hi gripper,
Not all coaches charge the house batteries from the alternator. If the coach has a B.I.R.D. (Bi-directional Isolator Relay) then that feature is installed on the coach. No BIRD (or similar device) no house battery charging from the engine alternator.

**RickO** · 10-14-2010, 02:34 PM

Quote:

Originally Posted by GaryKD

Hi gripper,
Not all coaches charge the house batteries from the alternator. If the coach has a B.I.R.D. (Bi-directional Isolator Relay) then that feature is installed on the coach. No BIRD (or similar device) no house battery charging from the engine alternator.

So, if I'm not mistaken, the BIRD is the same relay used for the "Battery Boost" feature which bridges the two battery banks together. Does having a Battery Boost switch necessarily mean that your coach batteries should charge from the alternator if things are working properly?

Rick

97windsor · 10-14-2010, 03:18 PM

Quote:

Originally Posted by gripper

OK, someone educate me here. I could have sworn that I was told, when I purchased my DP, that the house batteries are charged by the generator and/or the inverter only. That the alternator will only charge the chasis or engine batteries? Inquiring minds want to know.

Mine does charge the house batts from the engine, I think. I was there a few days ago and when I opened the door the step didn't work. I started the engine and the step went out as soon as the engine started. The inverter was off. I guess that means the engine sent power to the house batts.

gripper · 10-14-2010, 04:46 PM

97Windsor,

My apologies. I didn't intend to for kidnap your post. Just seemed like a good time to interject that question. I hope you got a satisfactory answer to your questions.

Gripper

AFChap · 10-14-2010, 05:06 PM

Quote:

the BIRD is the same relay used for the "Battery Boost" feature which bridges the two battery banks together.

WRONG ...the BIRD (Bi-directional Isolator Relay Device) is totally different/separate from the battery boost switch that momentarily bridges the two battery banks. The BIRD is more like a Trik-L-Start, etc. ...making sure that both battery banks are charged regardless of the power source, and that neither bank is unduly drained at any one time.

Drifter · 10-14-2010, 09:34 PM

The BIRD!

Monacoach · 10-22-2010, 08:04 PM

Quote:

Not all coaches charge the house batteries from the alternator. If the coach has a B.I.R.D. (Bi-directional Isolator Relay) then that feature is installed on the coach. No BIRD (or similar device) no house battery charging from the engine alternator.

Most Rvs have the I.R.D. some have the Bird. But you will be hard pressed to find a coach where the alternator does not charge the house batteries. The B in Bird is simply the Bi direction of shore power charging the Chassis batteries. If you have ever seen a Rv in modern times where the alternator does not charge the house batteries, it is because of a charging system malfunction not design. Sorry to doubt your statement but you have it backwards. Perhaps you meant to say that you need a bird to keep the chassis batteries charged from shore power. This statement would be correct.

Pat-13 · 10-26-2010, 01:10 AM

Since we're talking about charging the house batteries here, I have a new owner question. Should an '09 Dynasty be able to run the fridg and keep the house batteries charged if no other electrical demand is in use and the power source is 20amp 110? In my case I had a 100 ft heavy gage cord connected and the source CB kept tripping.