Charge Voltage

[Firepower2]

I just had the Winnebago electrical looked at today. There is something wrong with the wiring for my 240volt charger to the battery as it only charges up to 13.2volts.

Anyway that is under control as I will run new heavy wires to fix that.

But I was told to get advice on the alternator charging voltage. With a lot of revs up it only charges at 13.6v and it was thought it should be higher like over 14v. That is 13.6v to the Hilux battery and the motor home battery. The charging amps were quite good but forget what they were.

Just wondered if the 13.6v is high enough as I think the AGM motor home battery should have more?

[bansheebuzz]

Your agm probably requires more to charge properly but 13.6 is actually good for a d4d hilux

[Firepower2]

Thanks - Mine is just a 2007 petrol Workmate 2.7

[Qwerty]

Get a dc to dc charger which will correctly charge your aux battery to 100% SOC. your alternator never will.

[Steveyb]

Problem is temperature compensated charging controlled by the ECU.

Listen to your qwerty, go toward the light... get the charger

[Firepower2]

It is never ending. To solve the 240v charger problem as I have a lot of resistance in the current wires, I am going to run heavy wires from the charger in the motor home to the AGM battery under the bonnet which is behind the Hilux battery.

So if I get a DC to DC charger does it do the Bulk, Float etc stages so as not to wreck the AGM battery.

I am only talking aloud but sounds like it would be simpler to put an inverter in line from the alternator and the 240v charger and charge that way. But unfortunately the I guess the inverter would need to be big and also cost a fortune.

So I am guessing at the moment if I charge from the 240v charger overnight and the battery is full then when the Hilux motor/alternator is turned on the voltage in the AGM will drop because being put out buy the alternator.

Then again is there really a problem say when charging an AGM battery from 12v. Float is probably 13.6v so if the alternator only charges at 13.6v it would just take longer than if it were charging over 14v. It is still charging quite a lot of amps - from memory it was about 6amps or more.

Am I on the right track? (No)

[Alby]

Problem is temperature compensated charging controlled by the ECU.

Listen to your qwerty, go toward the light... get the charger

This is the go!

[Qwerty]

Don't dwell on the voltages , what you posted seems fine

The problem is alternator (ecu controlled temp sensing and "eco smart") will only ever charge batteries to around 70% of capacity , and most of the useable part of your battery is in the 60-100% zone

A dc dc charger much like ac to dc charger , will correctly charge to 100% ,,,, with 3 or more stages (bulk , absorb , float). The dc gets its power from alternator like normal. (alternator sees it as load , like spotties or any other appliance)

Chuck all your batts on the ac charger too from time to time , for good measure

[Firepower2]

Thanks that explains it well.

Pity Winnebago does not put them on from new.

[Qwerty]

This is what I use.

Redarc Electronics have fielded many inquiries from customers over recent months relating to the problems experienced by them with the charging of dual or auxiliary batteries in late model vehicles. Simply the vehicle alternator was never designed to fully (100%) charge the main vehicle battery. It was however designed to maintain the charge of the main vehicle battery and run the electrical loads (i.e. lights, air-conditioner etc.) once the vehicle is running.

By introducing extra batteries into the vehicle charging system with the expectation that the alternator will recharge them from a partially or fully discharged state is not realistic. These problems have been exacerbated with the introduction of ECU controlled and temperature compensating alternators. These alternators can be found in late model vehicles such as the Toyota Prado with the D4D engine. They reduce the alternator output voltage to approximately 13.5 volts when the temperature under the bonnet reaches its predetermined level. So the charging of dual or auxiliary batteries regardless of where they are located has now become more difficult. New battery types (i.e. gel, AGM and calcium) also play their part in the ever-increasing challenge for the vehicle’s alternator to fully charge the dual or auxiliary batteries.

Redarc Electronics have successfully provided a solution to this problem with the release of the BCDC1220 - a Smart Start microprocessor controlled, in-vehicle, DC/DC 20 amp 12 volt, charging system. The BCDC1220, with its in-built smart battery isolator, will recharge and maintain the dual/auxiliary batteries to 100% by using one of its 3 charging algorithms (selectable on installation). The BCDC1220 includes special charging programs for Gel/AGM, standard (flooded) lead acid and popular Calcium type batteries and will step up the voltages to the required levels (from as little as a 9 volt DC input).

The BCDC1220 simply waits for the vehicle to start, sensing the charge from the alternator, and will then commence the charging of the dual/auxiliary battery. The first smart charging process is the ‘Boost’ stage. The BCDC1220 will then seamlessly switch to its second stage ‘Absorption’. Once the battery has reached a fully charged state the BCDC1220 will maintain the dual or auxiliary battery at 100% with its third stage ‘Float’.

The BCDC1220 was fully designed and manufactured in Australia by Redarc to overcome all the problems associated with the charging of dual or auxiliary battery systems, this includes:

• Alternator charging systemsBCDC1220

• Paralleled dissimilar battery types

• Voltage drop over long cable runs

• Over-current battery intake

• 24 volt DC vehicles charging 12 volt DC batteries

[bansheebuzz]

The hilux alternators are not ecu controlled and charging characteristics are set by the regulator which is temperature compensating, hence they always put out a higher voltage when cold. There is one wire that goes to the computer from the alternator thou this is just a monitor for the ecu so that it knows what the alternator is doing

[Qwerty]

Either way , alty wont charge an aux battery to anywhere near 100%

Use a dc charger you will get way more run time and longevity from your aux battery

[Firepower2]

Thanks qwerty6054 for all your information.

I have a 120watt solar panel to install soon. Someone just said that the solar panel could top up the AGM and maybe the need for a DC to DC charger is reduced.

[Qwerty]

For the price of a dc charger why wouldn't ya ... Basically taking advantage of that big fossil fuel burning generator that you're already running

As
To solar definately ,,, trickle charge through day

We've found in summer running only a 50l fridge , that a 120watt solar will almost take care of the fridges needs (keeps battery head above water Indefintely)

I'd spend on dc charger before solar

Both would be great combo (especially when parked up for a week)

[Alby]

If you get a Ctek 250 dual S DC to DC charger is has a built in solar panel regulator
I still think you are better off setting up the basics with the DC DC charger and treating the solar panel as a great addition to your power supply setup
They are pretty cheap now to what they used to be ( less than $300)

[Firepower2]

Thanks for the replies - much appreciated for the information and will look at the Ctek 250 dual S DC to DC charger.

First I'll get the 240v charger for the AGM battery going again which I'll have to do soon as we are going for a short trip next week. It turns out I have a big resistance between the charger in the motor home and the AGM under the bonnet and the charger only puts in a float charge. I'll run two new big heavy wires between the charger and the AGM so that should fix that.

[Qwerty]

Yeh that's an issue to fix period. (volt drop)

[Rebs]

Firepower2, do a topic search on this
7.5 Amp Fuse / Diode : Alternator Voltage Booster
and have a read. You might save yourself a quid!

[Qwerty]

Or ya might cook things over time.

[Firepower2]

I'll keep everything in mind but just want to get the charging system back to normal first.

I just replaced a solid state relay that was getting hot so I guess that will help and bought all the heavy wire to go from the AGM to the charger in the Winnebago, if I get keen soon.

I should know how it is going after I charge and discharge it for about a week.

Thanks