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cairnclub · 08-04-2019, 08:14 PM

Hey everyone! Just joined. I am a college student who just got his first motorhome - wanted one since I was a kid. Looking forward to many miles of fun.

Got a 2000 Fleetwood Bounder 39W Cummins 5.9 with all options!! 50k miles

Has a couple minor issues but the one I cannot figure out is this:

The house batteries are only ever charged when the main engine is running - they will not charge off of shore power. However all 110 VAC in the coach is working appliances and outlets when on shore power and when not. They are newer house batteries that pass the good/bad battery test.

DC accessories do work, just only if you have run a separate battery charger on the house batteries for a while or if the main engine has been run for a while. Had to use the AUX start switch to use power from the starting batteries to get the slide to come out.

The previous owner was very meticulous - could tell by the amount of literature, tools, and things I found in the RV. He had an AIMS 2k W pure sine wave inverter/charger installed probably to tackle this same problem. Unfortunately, he passed away before he could fix it. Even found a print out of a forum post he made years ago asking about this very same issue! No replies however

The voltage on the side of the inverter is the same as the house batteries even while on shore power when they should be charging the house batteries.

Replaced the rear GFCI outlet thinking it was breaking the 110 VAC connection to the inverter/converter - but realized that connection is likely OK because the 110 VAC outlets work when on shore power and when off so the inverter must be working.

So I am running out of ideas as to why they charge when the main engine is running but not on shore power. Also generator will only crank with engine running - just hear a pump like sound (not gen cranking) when trying to start it off house batteries (main engine not running). I think this is related to the first issue.

I can answer any questions about the issue and will try all suggestions!

Any help is appreciated, can't wait to start camping!!! Hopefully the picture loads.

Outbound · 08-04-2019, 08:41 PM

Welcome to the forum, sounds like your charger is not working, need to check battery volts with engine running and later when plugged into shore power, should show approx. 13.6 volts plugged in to shore power, also how old are your batteries, your gen set problem is probably due to low batteries.

cairnclub · 08-04-2019, 08:58 PM

Thanks for the reply - I will get the running battery voltage of the house batteries and after being on shore power for a while tomorrow. The starting batteries are brand new and the house batteries are only a few years old, they are Duracell 6v 4 of them. Cleaned all battery connections today and topped up water. I believe the previous owner replaced them at the same time as the inverter. Is the charger a separate unit from the inverter/converter?

Does anyone have any experience with that inverter/converter model?

Thanks!!!

justinpirie · 08-05-2019, 12:13 AM

Quote:

Originally Posted by cairnclub

Thanks for the reply - I will get the running battery voltage of the house batteries and after being on shore power for a while tomorrow. The starting batteries are brand new and the house batteries are only a few years old, they are Duracell 6v 4 of them. Cleaned all battery connections today and topped up water. I believe the previous owner replaced them at the same time as the inverter. Is the charger a separate unit from the inverter/converter?

Does anyone have any experience with that inverter/converter model?

Thanks!!!

Can you post the specs of the inverter/charger? It isn’t charging while plugged into 110v which is why you’re having issues. I wonder if it’s just an inverter and not a charger?

justinpirie · 08-05-2019, 12:17 AM

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Have you set the battery type and the charge percentage? It could be set to off.

l1v3fr33ord1 · 08-05-2019, 04:11 AM

cairnclub-

First off, welcome to iRV2!

Second, you should add a "signature" to your profile. It contains whatever info you want; most people put info about their coach there, so they don't have to type it into each message. Instructions for adding a signature are here.

Regarding the house batteries, the symptoms indicate the house batteries are not charged. The initial diagnosis is the inverter is not doing its charging job. Break out the owner's manual for the inverter and follow any troubleshooting steps in it. Here is a short list of common inverter problems:

1) turned off
2) circuit breakers open
3) no AC input
4) fuse in battery lead open
5) disconnected from battery bank (includes poor ground)
6) battery charge is not high enough to initiate inverter circuitry (If battery voltage is not above some base level the inverter won't start up. Need to use an external charger to get above that level.)

The positive news is that the cross-charging system that allows the engine alternator to charge the house batteries appears to work correctly- at least, by your description of the symptoms.

cairnclub · 08-05-2019, 06:03 AM

Almost positive the AIMS unit has a charging function because it says on the box "inverter charger"

Where could I find the fuse in battery lead?

Justin, I will check if it is set to the correct battery type/charge type. Thanks!

What might that base level voltage be for the inverter to charge? That seems odd that the batteries would have to be charged some before the inverter/charger will charge them fully.

l1v3fr33ord1 · 08-05-2019, 07:26 AM

cairnclub-

If you do not have a paper manual, read the model number off the inverter and look up the model at the AIMS Web site:

https://www.aimscorp.net/
or
https://www.aimscorp.net/RV_Manufacturers_and_Dealers

One 12V, 2000W inverter manual at which I looked has a troubleshooting guide.

A high-power inverter should be near the battery bank (it reduces the losses in the DC feed). At the inverter, follow the large battery cables backwards to the batteries. Somewhere in the positive lead you should find a fuse. You can also work forwards from the batteries to the inverter. That fuse is usually very close to the battery bank.

It's common to call inverter/chargers "inverters," which they are, but it does confuse folks, as there are inverters without charging sections. For background on inverters, see this link:

The 12volt Side of Life Part 2

cairnclub · 08-05-2019, 07:44 AM

I tested for voltage at the inverter DC terminals and it matches the house battery voltage so that fuse must be good?

I downloaded the AIMS manual and under troubleshooting no charging condition it says to "make sure the unit is powered on" lol I tried that.

I checked and it is set to the correct type of battery to charge

justinpirie · 08-05-2019, 09:19 AM

Did you set the charge rate? It can be set to zero, i.e off. What is the voltage at the batteries?

cairnclub · 08-05-2019, 09:41 AM

The charge rate is set to 50% Is that too low? Batteries are at about 11 volts because nothing has been charging them. Only main engine running charged them or an external separate charger.

Hmmm

justinpirie · 08-05-2019, 10:06 AM

I wonder if that charger has a low voltage cut off? Try charging it with an external charger to 100% SoC then see if the inverter can maintain it.

Unplanned Tourist · 08-05-2019, 10:29 AM

Any chance the inverter/charger is defective?

That would explain a lot.
I am still a fan of separate inverters and chargers. Much easier to troubleshoot.

Happy Glamping.

cairnclub · 08-05-2019, 03:09 PM

I think the AIMS unit is good because all the 110 VAC outlets work when shore power is disconnected.

So overnight and 1 day of sitting not connected to shore power - my house batteries went from 11.2 v to 2.5v!! Does that mean the batteries are bad? Or is there a massive current draw somewhere?

Noticed some slight swelling on the house batteries - not good right? Topped up with water but I am now leaning towards replacing them.

Everything is turned off.