# Purpose of Ambulance plug in charger



## dbatk

A newb question here, does the plug in charger for a Type III ambulance actually charge the batteries?  I have a PSD with two batteries in series that experience drainage.  This drainage occurs when plugged in or not.

Not engine heater, this is TX!

Any assistance is appreciated.  I am a new EMT who also volunteers for our local VFD.  I acquired an ambulance and don't have many local knowledgeable mechanics.

Thanks,


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## WhiskeySix5

Your "shore line" is to provide AC power to the inverter on your truck, which in turn supplies power to critical components onboard your box (heater for drugs, etc). If you batteries are dying down, it could be that you simply need to have the batteries replaced, because there is a bad cell somewhere, or, there may be some type of short or "draw" not connected to the vehicles inverter. If it is a box that has been in service awhile, our summers are notorious for eating up batteries. Your amp / volt meters should tell you something, or at least give you a starting direction.

I am by no means a mechanic, so I am just offering what little bit of info I know on the subject.

W


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## dbatk

Thanks for the quick response.  I had suspected it was for the inverter, I don't have any current need for continuous power in the box, ambulance is not in service.  I had mistakenly thought that the "shore line" could provide power to all the box's needs.  I was wrong!

The batteries are allegedly new, although I do need to check them.  I am going to try a 5 volt solar charger for RVs as a stop gap and plug it in the accessory port.

Any recommendations on the brand/type/amperage for batteries?  I'm thinking the highest amp in the light truck division.


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## JPINFV

If you're using the shore line, can you turn off the battery disconnect normally found between the driver's seat and the door?


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## medic417

It also probably still supplies power to the engine heater.  The diesels in Texas still have them as well.


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## dbatk

Yes I can turn off the disconnect.  If this is done does that bypass the batteries and use the shore line for box power?

Only a few days a year an engine heater would be necessary and this morning was one of them.  This unit is originally from S Carolina so I'm uncertain if its equipped.


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## medicdan

The shoreline is meant to keep equipment charged/charging while the engine is off. Apart from med heater/fridge, this may include monitor charger (batteries), vent, med pumps, portable suction, portable radios, etc. As others have said, I think the engine block heater is standard on all diesel chases-- even if in Texas.


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## WhiskeySix5

dbatk said:


> Yes I can turn off the disconnect.  If this is done does that bypass the batteries and use the shore line for box power?
> 
> Only a few days a year an engine heater would be necessary and this morning was one of them.  This unit is originally from S Carolina so I'm uncertain if its equipped.



You should always be switching the battery switch to off. If you are not doing that it probably explains why the batteries are drawing down. The shore line will not run "everything", but as Dan mentioned, critical "large draw" components.


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## dbatk

I do always switch to off when the engine is off.  I mostly ride with the disconnect off when driving as well.

Thanks for all the suggestions.  Next steps are to check the batteries CCA and look for a power drain.


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## socalmedic

we are not talking about the "module disconnect" that only kills the lights and other non-essentials in the back. there should be a master disconnect (a large switch that when off nothing works). my ambulances have a timer, 5 minutes after the key is removed the master disconnect kills everything except the MDT. also your batteries should be in "parallel", ie twice the amperage still 12v. its not un-common for type 3s to have 4 batteries. 

if you aren't using the truck often i would throw a maintenance charger on the rig, wired through the shore line when plugged in the batteries charge. many are wired with this from the factory. first place to start trouble shooting is to make sure when you plug it in the inverter should turn on. then check the GFI plug to make sure it isn't tripped. find the power panel and ensure all the breakers are on and check with a ammeter/volt meter (multi-meter) on the battery cables to see if you are getting a charging current.


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## dbatk

I have only two batteries, they are new off brand at 850 amps each.  They test good.  The spot for a battery under the hood is lacking a battery but has the connecting terminals routed there for jump starting.  I was wondering if it was possible to connect a third battery under the hood for more CCA.

The batteries are in a drawer on side of course, wired for only two.  I am going to pop the drawer open and see if a third could fit.

I will check the inverter on shore line power, keeping it plugged in to the SL has helped as the engine is warmer and cranks easier, although this is the rare time of year when its actually near freezing here.

Good stuff, thanks again to all


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## dbatk

Only room for two batteries in the drawer.

Two questions remain:

-  Can a third battery be placed under the hood in the normal battery position in parallel?

- With the shore line plugged in and the inverter switched on, it began a high pitched tone.  What does it mean?  

I switched it off and on again, same squeal.  I turned it off for now.  In the past I've seen inverters squeal like this when overloaded but the vehicle was off and the main disconnect under the driver seat switched to off.


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## socalmedic

1700 CCA (850 x2) is more than enough to turn over a diesel in even the coldest lower 48 climates. if you are getting a slow crank you need to have your electrical / starting system checked. could be an old started that needs new brushes. the squeal you hear could be just the invert, not necessarily a charger. like i said go get a $10 multi-meter and check the voltage at the battery lost with the rig un-plugged and then plug it in and check again. you should have a slight jump in voltage when plugged in if there is an on board charger, there are better ways of testing but I am not going to take the liability of telling you how to do that. also I would not recommend placing a third battery in any area other than the other two, you dont want resistance (wires) between the two sources. if there is room on the try go for it, if not it isnt needed. 

I have said in the past that I am an ASI certified diesel mechanic with experiance in HD detroit and cummins diesels.


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## WhiskeySix5

Electical issues on a box are no joke. These trucks have so much wiring, it could be anything. As SoCal mentioned a mutli meter is your go to for figuring out your draw and what not, but there could be so much more going on. 

Personally, all the responses given are great for helping you r/o issues, but I would get it to a shop to get checked out properly, at least if you ever plan on using it for patient care....


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## dbatk

Thanks for the suggestions.  It's off to the shop with it.  Hopefully in March!  My foster daughter just cost me two grand in repairs on her car after crashing our Camry 

I had the Ambulance sitting for 3 days, just went to check it and the batteries are so low the dash lights barely light up when switched to on...


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## socalmedic

i would pull the (-) battery cable so you dont destroy the new batteries. take it to an electrical shop to find what the drain is.


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## NewTex

I am also located in Texas (San Saba, Hill Country) and I have had to disconnect all of our ambulances block heaters. They were connected. Also 2 batteries have allways worked fine for us here, even when we get snow. Check to make sure that there is no corosion on the battery connections. Make sure the voltage on the post is the same as that on the clamp on the post. The high pitched squeel may indicate that the inverter is heading south or being overloaded or may mean nothing at all. Again check the voltage...should be between 13.4 and 14.4 VDC. Good luck


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## dieselman

dbatk said:


> A newb question here, does the plug in charger for a Type III ambulance actually charge the batteries?  I have a PSD with two batteries in series that experience drainage.  This drainage occurs when plugged in or not.
> 
> Not engine heater, this is TX!
> 
> Any assistance is appreciated.  I am a new EMT who also volunteers for our local VFD.  I acquired an ambulance and don't have many local knowledgeable mechanics.
> 
> Thanks,





dbatk said:


> A newb question here, does the plug in charger for a Type III ambulance actually charge the batteries?  I have a PSD with two batteries in series that experience drainage.  This drainage occurs when plugged in or not.
> 
> Not engine heater, this is TX!
> 
> Any assistance is appreciated.  I am a new EMT who also volunteers for our local VFD.  I acquired an ambulance and don't have many local knowledgeable mechanics.
> 
> Thanks,



I got the same problem, I shut down everything, including the mains shut-off/master disconnect (by the seat and door)/circuit breaker .  I ran a meter through all the fuses under the hood and under the dash while the vehicle was off and the main shut-off was off.  I shut off all the circuit breakers and still my batteries drain.  I guess it would make sense that the block heaters would be connected at all times as well.  That would explain why I never got a load from my fuses.  The block heaters are working off the inverter directly.  The 3000 watt inverter I have is behind the panel and the wiring runs behind the walls.  There is no way I can see to disconnect the inverter to the battery I can see at the moment.

Con't


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## dieselman

dbatk said:


> A newb question here, does the plug in charger for a Type III ambulance actually charge the batteries?  I have a PSD with two batteries in series that experience drainage.  This drainage occurs when plugged in or not.
> 
> Not engine heater, this is TX!
> 
> Any assistance is appreciated.  I am a new EMT who also volunteers for our local VFD.  I acquired an ambulance and don't have many local knowledgeable mechanics.
> 
> Thanks,


These things are a spaghetti of wires.  I am thinking of putting a relay in to connect and disconnect the battery poles if I cannot find a way to disconnect the batteries from the inverter.

Con't


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## dieselman

I am not using the battery as a medical service vehicle. I live in Canada, so the block heaters are a must.  If anyone has any idea how to disconnect the battery from the inverter or if there is a relay or wiring diagram, I would appreciate it. FYI I got two new batteries as well.   I have a 7.3 international diesel in a Ford F350.  The winter starts are horrid.  From doing massive research on why these things are so hard to start is:

Con't


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## dieselman

-0w-30 must be used during cold winter starts and preferably synthetic
-Ford's starter is most likely under-rated if your starter blows, but an aftermarket starter that is more powerful.
-Some people say that you should use 15w-40 at all times on a diesel but not true.  Check the viscosity for the diesels mine says I can go as low as 0w-30.
-The glow plugs burn very often on these vehicles and should be replaced
-There is also a fuel heater relay that always goes faulty.  I suggest bypass the relay and put a push button type on the wiring harness and control the glow plugs manually


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